Water treatment method and composition

Abstract

To provide a novel treatment method for removing a specific polymer from water.SOLUTION: A water treatment method comprises a removal step of removing a polymer (I) containing a polymerization unit (I) based on a monomer represented by the following general formula (I) from water containing the polymer (I): CX1X3=CX2R(-CZ1Z2-A0)m (I), wherein X1 and X3 are each independently F, Cl, H, or CF3; X2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A0 is an anionic group; R is a linking group; Z1 and Z2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to methods and compositions for treating water. [Background technology]

[0002] Wastewater generated during industrial production may contain various chemical substances used in the production process, and methods for treating the wastewater have been proposed.

[0003] For example, Patent Document 1 describes a method for treating fluorine-containing wastewater, which comprises the steps of adding 15 to 70 mg of aluminum ions per 1 mg of fluoride ions to fluorine-containing wastewater, and adding a flocculant.

[0004] Patent Document 2 describes a wastewater treatment device for removing fluorine from sulfate-containing wastewater, which includes a mixing section that mixes the sulfate-containing wastewater with an aluminum-based inorganic flocculant, a solid-liquid separation section that separates the mixed liquid mixed in the mixing section into solid and liquid, and a supply means that supplies the solid content obtained by solid-liquid separation in the solid-liquid separation section to the mixing section.

[0005] Patent Document 3 describes a method for treating fluorine-containing wastewater by adding calcium to fluorine-containing wastewater and subjecting the fluorine in the wastewater to solid-liquid separation as an insoluble calcium fluoride, characterized in that calcium is added to the wastewater, a chemical agent containing a phosphate compound is added without separating the resulting insoluble precipitate, and then an aluminum salt having a basicity of 20 to 80% is added.

[0006] Non-Patent Document 1 describes a wastewater treatment device for removing fluorine from wastewater containing fluorine, in which an aluminum-based inorganic coagulant is mixed with the wastewater to generate flocs of aluminum hydroxide (Al2(OH)3), and the fluorine is adsorbed and coprecipitated by the flocs. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-241011 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-187779 [Patent Document 3] International Publication No. 2017-017833 [Non-patent literature]

[0008] [Non-Patent Document 1] Yuji Wada, "Advanced Treatment Method for Fluorine-Containing Wastewater," Science and Industry, 2002, Vol. 76, pp. 557-564 Summary of the Invention [Problem to be solved by the invention]

[0009] The present disclosure provides a novel treatment method for removing certain polymers from water. [Means for solving the problem]

[0010] The present disclosure provides a water treatment method (hereinafter also referred to as the "first treatment method of the present disclosure"), characterized by including a removal step of removing a polymer (I) from water containing the polymer (I), the polymer (I) comprising polymerization units (I) based on a monomer represented by the following general formula (I): CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0011] The polymer (I) is preferably a water-soluble polymer.

[0012] The removal step is preferably a step of subjecting water containing the polymer (I) to at least one of filtration, adsorption, and coagulation.

[0013] The removal step is preferably a step of carrying out coagulation in water containing the polymer (I).

[0014] The removing step is preferably a step of adding an inorganic flocculant to water containing the polymer (I).

[0015] The inorganic flocculant is preferably at least one metal salt selected from the group consisting of aluminum salts, iron salts, calcium salts, and silicate minerals containing divalent or higher metal elements and silicon.

[0016] The inorganic flocculant is preferably at least one aluminum salt selected from the group consisting of aluminum sulfate and polyaluminum chloride.

[0017] The removing step is preferably a step of adding a polymer flocculant to water containing the polymer (I).

[0018] The polymer flocculant is preferably an anionic polymer flocculant.

[0019] The removing step is preferably a step of adding an inorganic flocculant to water containing the polymer (I) and then adding a polymer flocculant.

[0020] The water containing the polymer (I) is preferably water that has been subjected to a fluoropolymer polymerization process.

[0021] The present disclosure also provides a composition comprising a polymer (I) containing polymerized units (I) based on a monomer represented by the following general formula (I), water, and a fluorinated polymer (excluding the polymer (I)), wherein the content of the polymer (I) is 250 ppm or less: CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0022] The polymer (I) may be a water-soluble polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more. The polymer (I) may be a polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less.

[0023] The present disclosure also provides a composition comprising a water-soluble polymer in which the ratio of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, water, and a fluorine-containing polymer (excluding the water-soluble polymer), wherein the content of the water-soluble polymer is 250 ppm or less.

[0024] The present disclosure also provides a composition comprising: a polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less; water; and a fluorine-containing polymer (excluding the polymer); and the content of the polymer is 250 ppm or less.

[0025] The fluorine-containing polymer preferably has an ion exchange rate of 53 or higher. The fluorine-containing polymer is preferably polytetrafluoroethylene. In the composition of the present disclosure, the content of the fluorine-containing polymer is preferably 1 to 5000 ppm. The composition of the present disclosure preferably further contains a divalent or higher valent metal ion. In the composition of the present disclosure, the content of divalent or higher valent metal ions is preferably 0.05 to 1000 mg / L or more.

[0026] The present disclosure further provides a composition comprising a polymer (I) including polymerized units (I) based on a monomer represented by the following general formula (I), water, and a divalent or higher metal ion, wherein the content of the polymer (I) is 250 ppm or less: CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0027] The present disclosure also provides a composition comprising a water-soluble polymer in which 50% or more of hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, water, and divalent or higher metal ions, wherein the content of the water-soluble polymer is 250 ppm or less.

[0028] The present disclosure also provides a composition comprising: a polymer in which 50% or more of hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less; water; and divalent or higher metal ions; wherein the polymer content is 250 ppm or less.

[0029] In the composition of the present disclosure, the content of divalent or higher valent metal ions is preferably 0.05 to 1000 mg / L or more.

[0030] The present disclosure also provides a water treatment method, comprising the step of removing a water-soluble polymer from water containing the polymer, in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms.

[0031] The present disclosure further provides a water treatment method, comprising the step of removing a polymer from water containing a polymer in which 50% or more of hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less. [Effects of the Invention]

[0032] The treatment method of the present disclosure is capable of removing specific polymers such as the above polymer (I) in a novel manner. DETAILED DESCRIPTION OF THE INVENTION

[0033] Before specifically describing the present disclosure, some terms used herein will be defined or explained.

[0034] In this specification, unless otherwise specified, the term "organic group" means a group containing one or more carbon atoms or a group formed by removing one hydrogen atom from an organic compound. Examples of the "organic group" are: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; a non-aromatic heterocyclic group optionally having one or more substituents, a heteroaryl group optionally having one or more substituents, cyano group, formyl group, RaO-, RaCO-, RaSO2-, RaCOO-, RaNRaCO-, RaCONRa-, RaOCO- RaOSO2- and, RaNRbSO2- (In these formulas, Ra independently represents: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; A non-aromatic heterocyclic group which may have one or more substituents a heteroaryl group optionally having one or more substituents; Rb is independently H or an alkyl group which may have one or more substituents. Includes. The organic group is preferably an alkyl group which may have one or more substituents. In this specification, unless otherwise specified, the term "substituent" refers to a substitutable group. Examples of the "substituent" include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonyl group, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, an aromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, a sulfamoyl group, an aliphatic sulfonamido group, an aromatic sulfonamido group, a heterocyclic sulfonamido group, an amino group, an aliphatic amino group, an These include an amino group, an aromatic amino group, a heterocyclic amino group, an aliphatic oxycarbonylamino group, an aromatic oxycarbonylamino group, a heterocyclic oxycarbonylamino group, an aliphatic sulfinyl group, an aromatic sulfinyl group, an aliphatic thio group, an aromatic thio group, a hydroxy group, a cyano group, a sulfo group, a carboxy group, an aliphatic oxyamino group, an aromatic oxyamino group, a carbamoylamino group, a sulfamoylamino group, a halogen atom, a sulfamoylcarbamoyl group, a carbamoylsulfamoyl group, a dialiphatic oxyphosphinyl group, and a diaromatic oxyphosphinyl group. The aliphatic group may be saturated or unsaturated and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic group include alkyl groups having a total of 1 to 8, preferably 1 to 4, carbon atoms, such as a methyl group, an ethyl group, a vinyl group, a cyclohexyl group, and a carbamoylmethyl group. The aromatic group may have, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic group include aryl groups having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms in total, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, and a 4-methanesulfonylphenyl group. The heterocyclic group may have a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the heterocyclic group include a 5- or 6-membered heterocycle having a total of 2 to 12, preferably 2 to 10, carbon atoms, such as a 2-tetrahydrofuryl group and a 2-pyrimidyl group. The acyl group may have an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the acyl group include acyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as an acetyl group, a propanoyl group, a benzoyl group, and a 3-pyridinecarbonyl group. The acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc., such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include acylamino groups having a total of 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and alkylcarbonylamino groups having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. The aliphatic oxycarbonyl group may be saturated or unsaturated and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic oxycarbonyl group include alkoxycarbonyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, and a (t)-butoxycarbonyl group. The carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 9 carbon atoms, preferably an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 5 carbon atoms, such as an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, and an N-phenylcarbamoyl group. The aliphatic sulfonyl group may be saturated or unsaturated and may have a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic sulfonyl group include alkylsulfonyl groups having a total of 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, such as methanesulfonyl. The aromatic sulfonyl group may have a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic sulfonyl group include arylsulfonyl groups having a total of 6 to 10 carbon atoms, such as a benzenesulfonyl group. The amino group may have an aliphatic group, an aromatic group, a heterocyclic group, or the like. The acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include an acylamino group having a total of 2 to 12 carbon atoms, preferably a total of 2 to 8 carbon atoms, and more preferably an alkylcarbonylamino group having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. The aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, or a 2-pyridinesulfonamide group. The sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having 1 to 9 carbon atoms in total, a dialkylsulfamoyl group having 2 to 10 carbon atoms in total, an arylsulfamoyl group having 7 to 13 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 12 carbon atoms in total, more preferably a sulfamoyl group, an alkylsulfamoyl group having 1 to 7 carbon atoms in total, a dialkylsulfamoyl group having 3 to 6 carbon atoms in total, an arylsulfamoyl group having 6 to 11 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 10 carbon atoms in total, such as a sulfamoyl group, a methylsulfamoyl group, an N,N-dimethylsulfamoyl group, a phenylsulfamoyl group, and a 4-pyridine sulfamoyl group. The aliphatic oxy group may be saturated or unsaturated and may have a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, etc. Examples of the aliphatic oxy group include alkoxy groups having a total of 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, such as a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, and a methoxyethoxy group. The aromatic amino group and heterocyclic amino group may have an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group fused with the aryl group, an aliphatic oxycarbonyl group, preferably an aliphatic group having 1 to 4 carbon atoms in total, an aliphatic oxy group having 1 to 4 carbon atoms in total, a halogen atom, a carbamoyl group having 1 to 4 carbon atoms in total, a nitro group, or an aliphatic oxycarbonyl group having 2 to 4 carbon atoms in total. The aliphatic thio group may be saturated or unsaturated and is an alkylthio group having a total of 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, such as a methylthio group, an ethylthio group, a carbamoylmethylthio group, or a t-butylthio group. The carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the carbamoylamino group include a carbamoylamino group, an alkylcarbamoylamino group having a total of 2 to 9 carbon atoms, a dialkylcarbamoylamino group having a total of 3 to 10 carbon atoms, an arylcarbamoylamino group having a total of 7 to 13 carbon atoms, and a heterocyclic carbamoylamino group having a total of 3 to 12 carbon atoms, preferably a carbamoylamino group, an alkylcarbamoylamino group having a total of 2 to 7 carbon atoms, a dialkylcarbamoylamino group having a total of 3 to 6 carbon atoms, an arylcarbamoylamino group having a total of 7 to 11 carbon atoms, and a heterocyclic carbamoylamino group having a total of 3 to 10 carbon atoms, such as a carbamoylamino group, a methylcarbamoylamino group, an N,N-dimethylcarbamoylamino group, a phenylcarbamoylamino group, and a 4-pyridinecarbamoylamino group. In this disclosure, ranges expressed by endpoints include all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.). In this disclosure, the term "at least 1" includes all numbers greater than or equal to 1 (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.). In this disclosure, ppm and ppb are values calculated on a mass basis unless otherwise specified. The processing method of the present disclosure will now be described in detail.

[0035] The first treatment method of the present disclosure is characterized by including a removal step of removing polymer (I) from water containing polymer (I) including polymerized units (I) based on a monomer represented by the following general formula (I): CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0036] The removal step is preferably a step of subjecting water containing the polymer (I) to at least one of filtration, adsorption, and coagulation. The filtration, adsorption, and coagulation steps may be performed in combination, or each of the filtration, adsorption, and coagulation steps may be repeated multiple times.

[0037] (filtration) The filtration method is not limited, and examples thereof include a method of contacting water containing the polymer (I) with a filter aid, a method of passing water containing the polymer (I) through a filtration membrane, etc. The filtration temperature is not particularly limited, and may be, for example, 0 to 50°C.

[0038] (Method of contacting water containing polymer (I) with a filter aid) For example, when water containing the polymer (I) is contacted with a filter aid and then filtered, or when the water is contacted with a filter aid holding member holding a filter aid, the polymer (I) captured by the filter aid and the filtrate are separated. Filter aids are generally used for the purpose of improving filtration characteristics, such as reducing filtration resistance and preventing clogging of filter media, and are usually particulate, powdery, or fibrous substances. The filter aid serves to trap the polymer (I) in the water.

[0039] The filter aid is not particularly limited, and is preferably at least one selected from the group consisting of diatomaceous earth, filter sand (manganese sand, manganese zeolite, activated carbon, anthracite, ceramic sand, etc.), perlite, and cellulose, with diatomaceous earth being more preferred.

[0040] The larger the particle size of the filter aid, the more the increase in filtration pressure is suppressed and the filtration rate is increased, so that the amount of water treated per unit time can be increased. On the other hand, the smaller the particle size of the filter aid, the more effective it is in capturing the polymer (I), so that the concentration of the polymer (I) in the filtrate can be further reduced. The average particle size of the filter aid is preferably 1 to 1000 μm, more preferably 1 to 500 μm, even more preferably 1 to 200 μm, still more preferably 10 to 100 μm, and particularly preferably 20 to 60 μm. When the average particle size of the filter aid is 20 μm or more, preferably 40 μm or more, more preferably 60 μm or more, and even more preferably 80 μm or more, the filtration rate can be increased, and the amount of water treated per unit time can be further increased. Furthermore, when the average particle size of the filter aid is 80 μm or less, preferably 60 μm or less, more preferably 40 μm or less, and even more preferably 20 μm or less, the effect of capturing polymer (I) is further enhanced, and the concentration of polymer (I) contained in the filtrate can be further reduced. The average particle size of the filter aid refers to the volume-based average particle size (volume average particle size) measured using a laser diffraction particle size distribution measuring device. As the filter aid, diatomaceous earth having an average particle size of 20 to 60 μm is particularly preferred.

[0041] The filter aid may be added to the water containing the polymer (I). This filtration process, in which the filter aid is directly added to the liquid to be filtered, is generally called "body feed." Body feed has the advantage of effectively suppressing an increase in filtration pressure, thereby increasing the amount of water processed per unit time and enabling long-term filtration while maintaining a high filtration rate.

[0042] The filter aid may be used by being held by a filter aid holding member. The filter aid holding member holds the filter aid, thereby separating water into the polymer (I) captured by the filter aid and the filtrate (solid-liquid separation). The filter aid holding member may be, for example, a cloth-like material such as filter cloth, filter paper, or metal mesh, a porous material such as sintered metal or sponge, or a filler such as gravel or sand. The type of filter aid holding member used can be appropriately selected depending on the conditions of the water to be treated, etc.

[0043] For example, a layer of filter aid may be formed on the surface of the filter aid holding member. Forming a layer of filter aid on the surface of the filter aid holding member before filtration is generally called "precoating". Precoating can effectively prevent clogging of the filter aid holding member, thereby suppressing an increase in filtration pressure, and as a result, increasing the amount of water treated per unit time.

[0044] The pore size of the filter aid retention member can be appropriately set depending on the particle size of the filter aid used. The pore size of the filter aid retention member may be, for example, 1 to 1000 μm. The smaller the pore size of the filter aid retention member, the more reliably the filter aid can be retained. On the other hand, the larger the pore size of the filter aid retention member, the more the pressure loss during filtration can be reduced. When diatomaceous earth is used as the filter aid, the pore size of the filter aid retention member is preferably smaller than the average particle size of the filter aid, for example, preferably 60% or less of the average particle size of the filter aid. The material constituting the filter aid retention member is not particularly limited, and may be, for example, synthetic fibers such as polypropylene, polyester, polyamide, polyimide, polyacrylonitrile, polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), vinylidene chloride, vinylon, glass fiber, cotton, etc.

[0045] In the first treatment method of the present disclosure, body feeding or precoating may be performed alone, or body feeding and precoating may be combined. By combining body feeding and precoating, polymer (I) in water can be captured more efficiently and an increase in filtration pressure can be further suppressed, allowing polymer (I) to be removed efficiently over a long period of time.

[0046] The amount of filter aid can be appropriately set depending on the water to be treated and the type of filter aid used, and is not limited to a specific amount. For example, the amount of filter aid added to water in body feed may be such that the concentration of the filter aid in the water containing polymer (I) is 1 to 10,000 ppm, preferably 10 to 1,000 ppm, more preferably 20 to 100 ppm. The amount of filter aid used in precoating may be such that the thickness of the layer of filter aid formed on the surface of the filter aid holding member is 0.5 to 10 mm, preferably 1 to 7 mm.

[0047] (Method of passing water containing polymer (I) through a filtration membrane) By passing water containing the polymer (I) through a filtration membrane, the polymer (I) contained in the water can be removed. The type of the filtration membrane is not particularly limited and may be appropriately selected depending on the water containing polymer (I), the filtration conditions, etc. As the filtration membrane, any one of reverse osmosis membrane, nanofiltration membrane, filter paper, microfiltration membrane, and ultrafiltration membrane may be used, or two or more types of filtration membranes may be used in combination. Specifically, a filtration membrane having a pore size of 0.05 nm to 25 μm can be used. Furthermore, as the reverse osmosis membrane, nanofiltration membrane, or ultrafiltration membrane, a filtration membrane having a pore size of 0.05 nm to 0.5 μm can be used. The filtration membrane may have, for example, a NaCl rejection rate of 10% or more. The NaCl rejection rate is a value calculated by filtering a NaCl solution (raw water) through the filtration membrane to obtain permeate, measuring the NaCl concentrations of the raw water and the permeate, and then using the following formula: NaCl rejection rate (%) = (1 - (NaCl concentration in permeate water) / (NaCl concentration in raw water)) x 100 The shape of the filtration membrane is not particularly limited, and may be, for example, a flat membrane, a spiral membrane, or a tubular membrane. When a plurality of filtration membranes are used in combination, single membranes may be arranged in series, or a so-called composite membrane in which a plurality of membranes are pre-laminated may be used. In membrane filtration, the filtration pressure may be appropriately set depending on the water to be treated, the type of filtration membrane to be used, etc.

[0048] The above-mentioned filtration is also preferably pressure filtration. By performing pressure filtration, the polymer (I) can be removed more efficiently. Known devices can be used as appropriate for pressure filtration. For example, pressure filtration may be performed using a pressure filter equipped with a candle-type filter. When a pressure filtration device is used, the cake layer formed on the surface of the filter aid holding member can be periodically peeled off by applying internal pressure, allowing water to be treated stably over a long period of time. Alternatively, water may be separated from the polymer (I) by vacuum filtration. When pressure filtration or vacuum filtration is performed, the filtration pressure can be appropriately set depending on the water to be treated, the filter aid and filter aid holding member used, and the type of filtration device.

[0049] (adsorption) The adsorption can be carried out by contacting water containing the polymer (I) with an adsorbent. A commonly used method can be used to contact water containing the polymer (I) with an adsorbent. For example, the adsorption can be carried out by adding an adsorbent to water containing the polymer (I) and stirring the mixture, or by a column method in which water containing the polymer (I) is passed through a column packed with an adsorbent. The packed column used in the column method may be a moving type, a fixed bed type, or a fluidized bed type. When using a method of adding an adsorbent to water containing the polymer (I) and stirring the mixture, it is preferable to separate the adsorbent that has adsorbed the polymer (I) from the water after adsorption after stirring. The method for separation is not limited, and for example, filtration or the like can be used. As a filtration method, the method described above for filtering water containing the polymer (I) can be used.

[0050] The adsorbent is not particularly limited, but is preferably at least one selected from the group consisting of ion exchange resins, chelating agents, synthetic adsorbents, activated carbon, silica gel, clay, and zeolites. Furthermore, alumina, carbon nanotubes, and the like can also be used as the adsorbent. The adsorbent is preferably at least one selected from the group consisting of an ion exchange resin, a chelating agent, a synthetic adsorbent, and activated carbon. The use of an ion exchange resin, a chelating agent, a synthetic adsorbent, or activated carbon as the adsorbent can improve the adsorption rate of the polymer (I). The adsorbent is more preferably an ion exchange resin. The use of an ion exchange resin can further increase the adsorption rate of the polymer (I). For the adsorption, one type of adsorbent may be used alone, or two or more types of adsorbents may be used in combination.

[0051] The ion exchange resin may be either a cation exchange resin or an anion exchange resin. Examples of the anion exchange resin include ion exchange resins having amino groups and / or quaternary ammonium groups as functional groups. The ion exchange resin is preferably a strongly basic anion exchange resin. The basicity of the anion exchange resin can be varied depending on the type of polymer backbone and / or functional group. Commercially available anion exchange resins include the Diaion (trademark) SA series manufactured by Mitsubishi Chemical Corporation, A200, A300, and PFA694E manufactured by Purolite Co., Ltd., and the Amberlite (trademark) series and IRA4002OH and other Amberjet (trademark) series manufactured by Organo Corporation. Examples of the cation exchange resin include ion exchange resins having carboxylic acid groups and / or sulfonic acid groups as functional groups. The acidity of the cation exchange resin can be varied depending on the type of polymer backbone and / or functional group. As the cation exchange resin, a commercially available product may be used, such as the Diaion (trademark) SK series manufactured by Mitsubishi Chemical Corporation, C100 manufactured by Purolite Co., Ltd., or the Amberlite (trademark) series manufactured by Organo Corporation. The ion exchange resin preferably has a pore diameter of 1 to 5000 Å. From the viewpoint of removal efficiency, the pore diameter is preferably 50 Å or more, more preferably 100 Å or more, and even more preferably 150 Å or more. Alternatively, the pore diameter may be 200 Å or more, or 250 Å or more. The pore diameter may also be 1000 .ANG.. The pore diameter can be calculated, for example, by measuring the specific surface area and the total pore volume by a gas adsorption method. From the viewpoint of removal efficiency, the ion exchange resin preferably has a total exchange capacity of 0.1 eq / L-resin or more, more preferably 0.5 eq / L-resin or more, and even more preferably 0.9 eq / L-resin or more. The larger the total exchange capacity, the better, but the upper limit may be, for example, 5.0 eq / L-resin. Moreover, ion exchange resins are usually spherical and have an average particle size of about 300 to 1300 μm.

[0052] The chelating agent is usually a compound having a multidentate ligand capable of coordinating with a metal ion to form a chelate compound. There are no limitations on the material or whether it is a gel type or an MR type, and examples thereof include resins in which functional groups have been introduced into styrene-divinylbenzene copolymers, phenol polymers, etc. Examples of the chelating agent include iminodiacetic acid type, iminopropionic acid type, aminophosphonic acid type such as aminomethylenephosphonic acid type, polyamine type, aminocarboxylic acid type, dithiocarbamic acid type, thiol type, amidoxime type, and pyridine type. The chelating agent is preferably spherical and may have an average particle size of about 300 to 1300 μm. Specific examples of chelating agents include the "Uniselect" (trade name) series (manufactured by Unitika Ltd.), the "Lewatit" (trade name) series (manufactured by Lanxess K.K.), and the "Eporus" (registered trademark) (trade name) series (manufactured by Miyoshi Oil & Fats Co., Ltd.) (Z-7, Z-100, SE-3, AS-4).

[0053] The synthetic adsorbent is a porous resin that does not have an ion exchange group, and known synthetic adsorbents can be used. Examples of ion exchange groups include amino groups, quaternary ammonium groups, carboxylic acid groups, and sulfonic acid groups. Specific examples of synthetic adsorbents include styrene-divinylbenzene copolymer and other styrene-based resins, (meth)acrylic acid ester-ethylene glycol dimethacrylate copolymer and other acrylic resins, methacrylic resins, polyvinyl resins, and dextran-based resins. Specific examples of commercially available synthetic adsorbents include styrene-based resins such as Diaion HP10, Diaion HP20, Diaion HP21, Diaion HP40, Diaion HP50, Sepapease SP207, Sepapease SP70, Sepapease SP825, Sepapease SP850, and Sepapease SP207 (all manufactured by Mitsubishi Chemical Corporation), Amberlite XAD1180N, Amberlite XAD2000, Amberlite XAD4, and Amberlite FPX66 (all manufactured by Organo Corporation); and acrylic resins such as Diaion HP2MG (manufactured by Mitsubishi Chemical Corporation) and Amberlite HXAD-7HP (manufactured by Organo Corporation). The synthetic adsorbent preferably has a pore diameter of 1 to 5000 Å. From the viewpoint of removal efficiency, the pore diameter is preferably 50 Å or more, more preferably 100 Å or more, and even more preferably 150 Å or more. It may also be 200 Å or more, or 250 Å or more. It may also be 1000 Å or less. The pore diameter can be calculated, for example, by measuring the specific surface area and total pore volume by gas adsorption method. The synthetic adsorbent has a specific surface area of 300m 2 / g or more. The specific surface area is preferably 400m 2 / g or more is more preferable, and 500m 2 / g or more is more preferable, and 600m 2 The upper limit of the specific surface area is not limited, but for example, 2000 m 2 / g or less, and 2 / g or less, and 2 / g or less. Furthermore, the synthetic adsorbent is usually spherical and has an average particle size of about 200 to 1300 μm.

[0054] The activated carbon can be produced from a carbonaceous material. Examples of carbonaceous materials include those that can be carbonized, activated, or otherwise processed to produce activated carbon, such as wood, sawdust, charcoal, coconut shells, walnut shells, and other fruit shells, and fruit seeds; coals such as peat, lignite, brown coal, bituminous coal, and anthracite; mineral materials such as petroleum pitch and coal pitch; tars such as coke, coal tar, and petroleum tar; and petroleum distillation residues. These materials may be in the form of powder, granules, or fibers, or may be molded from these materials.

[0055] The above activated carbon has a specific surface area of 500m 2 / g or more. The specific surface area is preferably 1000m 2 / g or more is more preferable, and 1500m 2 / g or more is more preferable, and 1800m 2 / g or more is particularly preferred, and 2000m 2 The upper limit of the specific surface area is not limited, but for example, 2500 m 2 / g. The shape of the activated carbon is not particularly limited, and may be, for example, pellets, granules, powder, or spherical particles. The activated carbon may be commercially available. Examples of commercially available activated carbon include Shirasagi (trademark) manufactured by Osaka Gas Chemicals Co., Ltd., Filtrasorb (trademark) CAL, Diahope (trademark), and Diasorb (trademark) manufactured by Calgon Carbon Japan Co., Ltd., and the Evadia (trademark) series manufactured by Suing Corporation.

[0056] When activated carbon is used as the adsorbent, it is preferable that the activated carbon be highly activated. By using highly activated carbon, the adsorption rate of polymer (I) can be increased compared to ordinary activated carbon. The activated carbon preferably has improved adsorption performance by undergoing steam activation treatment. In the steam activation treatment, it is preferable to expose the activated carbon to steam at a temperature of 120°C or higher, for example, 130 to 350°C, particularly 150 to 1000°C, and at a pressure of 0.2 MPa or higher, for example, 0.5 to 15 MPa, particularly 1 MPa to 15 MPa. The time for the steam activation treatment may generally be 10 seconds to 50 hours, for example, 10 minutes to 10 hours. During activation, heating may be performed in a furnace. Cations may be impregnated onto the surface of the activated carbon. Examples of cations include metal ions, metal oxide ions, and ammonium ions. Examples of metals include metal atoms in Groups 1 to 13 of the periodic table (e.g., alkali metals (e.g., Li, Na, K), alkaline earth metals (e.g., Mg, Ca), Ti, Zr, V, Cr, Fe, Ni, Cu, and Zn).

[0057] In the above adsorption, the amount of adsorbent relative to the water containing polymer (I) is not limited, but may be, for example, 0.01 to 1000 g per 1000 g of water containing polymer (I). The amount is preferably 0.1 g or more, more preferably 1 g or more, and even more preferably 5 g or more per 1000 g of water containing polymer (I). Also, the amount is preferably 500 g or less.

[0058] The temperature during the adsorption is not particularly limited, but may be, for example, 0 to 50°C.

[0059] The adsorption apparatus usable in the above adsorption is not particularly limited as long as it is an adsorption apparatus equipped with the above adsorbent, and various adsorption apparatuses may be appropriately used depending on the purpose. The adsorption apparatus may be, for example, a packed column packed with an adsorbent, specifically, an ion exchange column or an activated carbon column.

[0060] In the first treatment method of the present disclosure, it is preferable to adsorb the polymer (I) onto an adsorbent and then recover the adsorbent. The recovery method is not particularly limited and a conventionally known method may be used. For example, the adsorbent to which the polymer (I) is adsorbed may be separated by the above-mentioned filtration.

[0061] (agglomeration) Among the above-mentioned filtration, adsorption, and coagulation, coagulation is preferred because it can further improve the removal efficiency of polymer (I). The coagulation can be carried out, for example, by adding a coagulant to water containing polymer (I). The removal step is preferably a step of adding a coagulant to water containing polymer (I). In the removal step, it is preferable to add the coagulant to water containing polymer (I) and then stir the mixture. The stirring time is not limited and may be set appropriately depending on the amount of polymer (I) in water and the amount of coagulant added. The stirring time may be set appropriately, for example, within a range of 0 minutes to 100 hours.

[0062] Examples of the flocculant include inorganic flocculants, organic flocculants, and polymer flocculants. The amount of the flocculant to be added may be appropriately selected depending on the amount of polymer (I) contained in water, the type of flocculant, etc., and may be, for example, 300% by weight or less, 0.01% by weight or more, or 50% by weight or more, or 0.01% by weight or less, based on the amount of polymer (I).

[0063] The removal step is particularly preferably a step of adding an inorganic flocculant to water containing the polymer (I).The removal step is a step of flocculating the polymer (I), and one of the preferred embodiments is a step of adding an inorganic flocculant to water containing the polymer (I). Examples of the inorganic flocculant include metal salts, and commercially available products may be used. 2+ , Ca 2+ Seawater containing the above and low molecular weight cationic polymer flocculants can also be used. The amount of the inorganic flocculant added is preferably 0.01% by weight or more, more preferably 0.04% by weight or more, even more preferably 0.1% by weight or more, particularly preferably 1% by weight or more, particularly preferably 5% by weight or more, and most preferably 10% by weight or more, based on the polymer (I). The amount is preferably 300% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less, and even more preferably 20% by weight or less, based on the polymer (I). The amount of the inorganic flocculant added to the water containing the polymer (I) is preferably 1 ppm by weight or more, more preferably 10 ppm by weight or more, and even more preferably 20 ppm by weight or more, and is preferably 15,000 ppm by weight or less, more preferably 10,000 ppm by weight or less, and even more preferably 5,000 ppm by weight or less.

[0064] The inorganic flocculant is preferably a metal salt. The inorganic flocculant that is a metal salt is preferably a metal salt containing a divalent or higher metal element. The valence of the metal element constituting the metal salt is preferably divalent or higher, more preferably trivalent or higher, and may be trivalent. The upper limit of the valence of the metal element constituting the metal salt is not particularly limited, but may be, for example, hexavalent or lower. Here, the divalent or higher metal element constituting the metal salt is more preferably at least one metal element selected from the group consisting of Fe, Al, and Ca, even more preferably at least one metal element selected from the group consisting of Fe and Al, and particularly preferably Al. Furthermore, the counter ion of the metal element constituting the metal salt is more preferably at least one selected from the group consisting of sulfate ions, hydroxide ions, fluoride ions, nitrate ions, and chloride ions, even more preferably at least one selected from the group consisting of sulfate ions and chloride ions, and particularly preferably sulfate ions. As used herein, the term "metal salt" refers to a simple salt, a double salt, and / or a complex salt. Additionally, the term "salt containing a divalent or higher metal element" refers to a simple salt, a double salt, and / or a complex salt containing a divalent or higher metal element.

[0065] The metal salt is preferably at least one metal salt selected from the group consisting of aluminum salts (e.g., aluminum sulfate, polyaluminum chloride, etc.), iron salts (e.g., ferrous hydroxide, ferric hydroxide, ferrous sulfate, ferric sulfate, polyferric sulfate, etc.), calcium salts (e.g., calcium hydroxide, calcium chloride, calcium sulfate, calcium carbonate, calcium nitrate, calcium fluoride, etc.), and silicate minerals containing a divalent or higher metal element and silicon (e.g., kaolinite, montmorillonite, zeolite, etc.). Examples of the silicate mineral include commercially available silica-alumina flocculants, such as Flonite 723, Flonite 113, Flonite 101, Flonite S, and Flonite D manufactured by Japan Activated Clay Co., Ltd. The metal salt that can be used as the flocculant may be in a form that generates a metal salt or converts a counter ion of a metal element of a metal salt in the step of adding the flocculant. An example of such an embodiment is a case where a metal salt having a counter ion such as a metal hydroxide is added to water containing the polymer (I). In such an embodiment, the counter ion of the metal salt is converted. The conversion of the counter ion of the metal salt may result in a better impurity removal effect.

[0066] The inorganic flocculant is preferably at least one metal salt selected from the group consisting of iron salts and aluminum salts, more preferably at least one metal salt selected from the group consisting of ferric chloride, aluminum sulfate, and polyaluminum chloride, even more preferably at least one aluminum salt selected from the group consisting of aluminum sulfate and polyaluminum chloride, and particularly preferably aluminum sulfate.

[0067] Examples of the polymer flocculant include sodium alginate, chitin / chitosan flocculants, cationic polymer flocculants, anionic polymer flocculants, amphoteric polymer flocculants, and nonionic polymer flocculants, and it is preferable that the polymer flocculant be at least one selected from the group consisting of cationic polymer flocculants, anionic polymer flocculants, amphoteric polymer flocculants, and nonionic polymer flocculants.

[0068] The amount of the polymer flocculant added is preferably 0.001% by weight or more, more preferably 0.004% by weight or more, and particularly preferably 0.01% by weight or more, relative to the polymer (I). There is no upper limit to the amount of the polymer flocculant added, and it is preferably 50% by weight or less, more preferably 30% by weight or less, and particularly preferably 20% by weight or less, relative to the polymer (I). The amount of the polymer flocculant added is preferably 0.1 ppm by weight or more, more preferably 1 ppm by weight or more, and even more preferably 2 ppm by weight or more, relative to the water containing the polymer (I). Also, it is preferably 15,000 ppm by weight or less, more preferably 10,000 ppm by weight or less, and even more preferably 5,000 ppm by weight or less.

[0069] Examples of the cationic polymer flocculant include polyaminoalkyl methacrylates such as dimethylaminoethyl methacrylate, polyethyleneimine, halogenated polydiallylammonium, chitosan, and urea-formalin resin. Commercially available cationic polymer flocculants include Takifloc C-403, C-408, C-805, C-806, and C-809 manufactured by Taki Chemical Co., Ltd.; and Aronfloc EC-509L, C-508, CX-400, C-303, and CX-333 manufactured by MT Aquapolymer Co., Ltd.

[0070] Examples of the anionic polymer flocculant include polyacrylamide-based polymer flocculants such as sodium polyacrylate, partial hydrolyzed polyacrylamide, partially sulfomethylated polyacrylamide, and poly(2-acrylamide)-2-methylpropane sulfate. Commercially available anionic polymer flocculants include Floclan A1210 manufactured by Katayama Nalco Corporation; Takifloc A-102, A-103, A-177T, A-108T, A-142, and A-50 manufactured by Taki Chemical Co., Ltd.; Acofloc A-95, A-110, and A-150 manufactured by MT Aquapolymer Co., Ltd.; Sumifloc FA-40 and FA-50 manufactured by MT Aquapolymer Co., Ltd.; and Diafloc AP199, Ap120C, Ap784, and DF732B manufactured by Mitsubishi Chemical Corporation.

[0071] Examples of the nonionic polymer flocculant include polyacrylamide and polyethylene oxide. Commercially available nonionic polymer flocculants include Takifloc N-100T, N-131, and A-122T manufactured by Taki Chemical Co., Ltd.; Acofloc N-100 and N-210 manufactured by MT Aquapolymer Co., Ltd.; Sumifloc FN-10H and FN-20H manufactured by MT Aquapolymer Co., Ltd.; and Diafloc NP500, NP780, and DF500 manufactured by Mitsubishi Chemical Corporation.

[0072] Examples of the amphoteric polymer flocculant include a copolymer of acrylamide, aminoalkyl methacrylate, and sodium acrylate. Commercially available amphoteric polymer flocculants include Takifloc MC-601, MC-602, and MC-603 manufactured by Taki Chemical Co., Ltd.; Diafloc KA003 and KA606A manufactured by Mitsubishi Chemical Corporation; and the like.

[0073] Among the above polymer flocculants, anionic polymer flocculants are preferred.

[0074] The temperature for the aggregation is not particularly limited, but is, for example, preferably 0° C. or higher, more preferably 5° C. or higher, and even more preferably 10° C. or higher. The temperature is also preferably 50° C. or lower, more preferably 40° C. or lower, and even more preferably 30° C. or lower.

[0075] In the removal step, only an inorganic flocculant may be added as a flocculant, only a polymer flocculant may be added, or both an inorganic flocculant and a polymer flocculant may be added. Furthermore, the inorganic flocculant and the polymer flocculant may be added simultaneously, or the inorganic flocculant may be added first and then the polymer flocculant, or the polymer flocculant may be added first and then the inorganic flocculant. Furthermore, the polymer flocculant and the inorganic flocculant may be added in multiple batches, or the polymer flocculant and the inorganic flocculant may be added alternately.

[0076] The removal step is particularly preferably a step of adding an inorganic flocculant to water containing the polymer (I) and then adding a polymer flocculant. By adding the inorganic flocculant, the surface charge of the polymer (I) is neutralized by the opposite charge, causing flocculation and forming flocs. Thereafter, a polymer flocculant is added to coarsen the flocs, and the flocs flocculated with the inorganic flocculant are crosslinked to form coarse flocs, thereby enabling the polymer (I) to be removed more efficiently. In this case, the amount of inorganic flocculant added is preferably 0.01% by weight or more, more preferably 0.04% by weight or more, even more preferably 0.1% by weight or more, particularly preferably 1% by weight or more, particularly preferably 5% by weight or more, most preferably 10% by weight or more, and preferably 300% by weight or less, more preferably 50% by weight or less, even more preferably 30% by weight or less, and particularly preferably 20% by weight or less, based on the polymer (I). The amount of the inorganic flocculant added to the water containing the polymer (I) is preferably 1 ppm by weight or more, more preferably 10 ppm by weight or more, and even more preferably 20 ppm by weight or more, and is preferably 15,000 ppm by weight or less, more preferably 10,000 ppm by weight or less, and even more preferably 5,000 ppm by weight or less. The amount of the polymer flocculant added is preferably 0.001% by weight or more, more preferably 0.004% by weight or more, and particularly preferably 0.01% by weight or more, based on the weight of the polymer (I), and is preferably 50% by weight or less, more preferably 30% by weight or less, and even more preferably 20% by weight or less. The amount of the polymer flocculant added is preferably 0.1 ppm by weight or more, more preferably 1 ppm by weight or more, and even more preferably 2 ppm by weight or more, relative to the water containing the polymer (I). Also, it is preferably 15,000 ppm by weight or less, more preferably 10,000 ppm by weight or less, and even more preferably 5,000 ppm by weight or less.

[0077] In the removal step, it is also preferable to add a pH adjuster to the water containing the polymer (I) to adjust the pH after adding the inorganic flocculant to the water containing the polymer (I) and before adding the polymer flocculant. By adjusting the pH, the polymer (I) can be removed more efficiently. In the removal step, before adding the polymer flocculant, the pH is preferably set to 4.0 or higher, more preferably 5.0 or higher, and even more preferably 6.0 or higher, and the pH is preferably set to 11.0 or lower, more preferably 9.0 or lower, and even more preferably 8.0 or lower. The pH adjuster is not limited, and for example, an acid compound or an alkaline compound can be used. Examples of the acid compound include hydrochloric acid (HCl), nitric acid (HNO), sulfuric acid (HSO), phosphoric acid (HPO), etc., with hydrochloric acid (HCl) or nitric acid (HNO) being particularly preferred. Examples of the alkaline compound include alkali metal hydroxides such as NaOH and KOH; alkaline earth metal hydroxides such as Mg(OH) and Ca(OH); and salts with buffering properties such as disodium hydrogen phosphate. Examples of the organic compound include ammonia and amines. The pH can be measured using a pH meter (for example, Horiba pH meter D-20).

[0078] In the first treatment method of the present disclosure, it is preferable to perform coagulation in water containing the polymer (I), and after coagulating the polymer (I), remove the coagulated polymer (I) from the water containing the polymer (I). The method for removing the coagulated polymer (I) from the water containing the polymer (I) is not limited, but examples thereof include filtration. The filtration method is not limited, and the above-mentioned methods can be appropriately adopted. In the first treatment method of the present disclosure, it is preferable to aggregate the polymer (I) and then recover the aggregated polymer (I). The recovery method is not limited, but examples thereof include filtration. The filtration method is not limited, and the above-mentioned methods can be appropriately adopted.

[0079] The removal step is particularly preferably a step of adding an inorganic flocculant to water containing the polymer (I), then adding a polymer flocculant, and filtering the water containing the flocculated polymer (I). In this embodiment, after adding the inorganic flocculant to the water containing the polymer (I), a pH adjuster may be added to the water containing the polymer (I) to adjust the pH before adding the polymer flocculant. The pH can be within the above range, and it is also preferable to adjust the pH to, for example, 5.0 to 9.0 (preferably 6.0 to 8.0).

[0080] The removal step is preferably a step of reducing the concentration of polymer (I) in the water containing polymer (I) to 50% or less, more preferably 40% or less, even more preferably 30% or less, especially preferably 20% or less, and particularly preferably 10% or less, of the concentration before the removal step.

[0081] The removal step is also preferably a step of reducing the concentration of polymer (I) in the treated water to 250 ppm or less, more preferably 200 ppm or less, even more preferably 100 ppm or less, still more preferably 80 ppm or less, particularly preferably 60 ppm or less, and particularly preferably 50 ppm or less.

[0082] By the above-mentioned removal step, dimers and trimers of the monomers that form the structural units constituting the polymer (I) can also be removed from the water containing the polymer (I).

[0083] The dimer and trimer may be a dimer and trimer of a monomer represented by general formula (I) (hereinafter, sometimes referred to as monomer (I)). The dimer and trimer may be a polymer formed from one type of monomer (I) as the monomer (I) represented by general formula (I), or may be a copolymer formed from two or more types of monomer (I) having different structures. In addition, examples of the dimer and trimer include dimers and trimers of the monomers described below as monomers that form suitable structural units that constitute polymer (I).

[0084] The polymer (I) contains polymerized units (I) based on a monomer represented by the following general formula (I): The polymer (I) preferably contains two or more polymerized units (I). CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more. X 2 is preferably F, Cl, H or CF3. 1 and Z 2 is preferably F or CF3. In the present disclosure, the anionic group includes functional groups that provide anionic groups such as sulfate groups, carboxylate groups, acid groups such as -COOH, acid salt groups such as -COONH4, etc. The anionic group includes sulfate groups, carboxylate groups, phosphate groups, phosphonate groups, sulfonate groups, or -C(CF3)2OM (wherein M is -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.) is preferred, with a sulfate group, a carboxylate group, a phosphate group, a phosphonate group or a sulfonate group being more preferred. The polymer (I) may contain only polymerized units (I) based on one type of monomer represented by general formula (I), or may contain polymerized units (I) based on two or more types of monomers represented by general formula (I).

[0085] The above R is a linking group. In the present disclosure, a "linking group" is an (m+1)-valent linking group, and when m is 1, it refers to a divalent linking group. The linking group may be a single bond and preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. There is no upper limit, but it may be, for example, 100 or less, or 50 or less. The linking group may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain carbon atoms but may be a catenary heteroatom such as oxygen, sulfur, or nitrogen. m is an integer of 1 or more, preferably 1 or 2, and more preferably 1. When m is an integer of 2 or more, Z 1 , Z 2 and A0 may be the same or different. Next, a preferred structure when m is 1 in general formula (I) will be described.

[0086] The above R is preferably, for example, a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group. When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced with a halogen atom other than fluorine, such as chlorine, and may or may not contain a double bond. R may be either linear or branched, and may be cyclic or acyclic. R may also contain a functional group (e.g., ester, ether, ketone, amine, halide, etc.). R may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group. R may be, for example, a hydrocarbon group in which no fluorine atoms are bonded to the carbon atoms, a hydrocarbon group in which some of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, and these may contain an oxygen atom, a double bond, or a functional group.

[0087] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond, and in the hydrocarbon group, some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with fluorine. R is preferably -(CH2) a -, -(CF2) a -, -O-(CF2) a -, -(CF2) a -O-(CF2) b -, -O(CF2) a -O-(CF2) b -, -(CF2) a -[O-(CF2) b ] c -, -O(CF2) a -[O-(CF2) b ] c-, -[(CF2) a -O] b -[(CF2) c -O] d -, -O[(CF2) a -O] b -[(CF2) c -O] d -, -O-[CF2CF(CF3)O] a -(CF2) b -, -[CF2CF(CF3)O] a -, -[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -(CF2) b - and at least one selected from the combinations thereof. In the formula, a, b, c, and d are independently at least 1. a, b, c, and d may independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100.

[0088] R is represented by the following general formula (r1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g - (r1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the following general formula (r2): -CF2-O-(CX 7 2) e -(O) g - (r2) (In the formula, X 7 are each independently H, F or CF3, e is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the formula:

[0089] Specific examples of suitable R include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CH2-, and the like. Among these, the above R is preferably a perfluoroalkylene group which may contain an oxygen atom, specifically, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, or -CF2-O-CF(CF3)CF2-O-.

[0090] -R-CZ of the above general formula (I) 1 Z 2 - is the following formula (s1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (s1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group), and in formula (s1), Z 1 and Z 2 More preferably, they are F or CF3, and even more preferably, one is F and the other is CF3. In addition, in the above general formula (I), -R-CZ 1 Z 2 - is the following formula (s2): -CF2-O-(CX 7 2) e -(O) g -CZ 1Z 2 - (s2) (In the formula, X 7 are each independently H, F, or CF3, e is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (s2), Z 1 and Z 2 More preferably, one is F and the other is CF3.

[0091] -R-CZ of the above general formula (I) 1 Z 2 - as -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-OC(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-C F(CF3)-, -CF2-O-CF2-C(CF3)2-, -CF2-O-CF2CF2-CF2-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-C F2CF2-C(CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF 3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2- O-CF(CF3)CF2-CF2-, -CF2-O-CF(CF3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-C(CF3)2-, -CF2- O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, or -CF2-O-CF(CF3)CF2-OC(CF3)2 - is preferred, -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF 3) -CF(CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O-CF(CF3)- is more preferable.

[0092] The polymer (I) is also preferably highly fluorinated. For example, anionic groups (A) such as phosphate moieties (e.g., CH2OP(O)(OM)2) and sulfate moieties (e.g., CH2OS(O)2OM) are preferably present. 0 ), it is preferred that 80% or more, 90% or more, 95% or more, or 100% of the C—H bonds in the polymer (I) are substituted with C—F bonds.

[0093] The polymer (I) contains an anionic group (A 0 ) except for the C—F bond, it is also preferable that the compound has no C—H bond. 1 , X 2 , and X 3 are all F, and R is preferably a perfluoroalkylene group having one or more carbon atoms, and the perfluoroalkylene group may be either linear or branched, may be cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0094] The polymer (I) may be partially fluorinated. That is, the polymer (I) may contain an anionic group (A 0 ), it is also preferred that the alkyl group has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0095] The anionic group (A 0) may be -SO3M, -OSO3M, -COOM, -SONR'CH2COOM, -CH2OP(O)(OM)2, [-CHO]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CHO]2P(O)(OM), -CH2CH2OSO3M, -P(O)(OM)2, -SONR'CH2CH2OP(O)(OM)2, [-SONR'CH2CHO]2P(O)(OM), -CH2OSO3M, -SONR'CH2CH2OSO3M, or -C(CF3)2OM. Among these, -SO3M, -COOM, or -P(O)(OM)2 is preferred, -SO3M or -COOM is more preferred, and -COOM is even more preferred. The above M represents -H, a metal atom, or -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and is preferably Na, K or Li. The above M is —H, a metal atom, or —NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR 7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is especially preferred, and -NH4 is most preferred. In the polymer (I), each polymer unit (I) may have a different anionic group or may have the same anionic group.

[0096] The polymer (I) is also preferably a polymer containing polymerized units (Ia) based on a monomer represented by the following formula (Ia). CF2=CF-O-Rf 0 -A 0 (Ia) (In the formula, A 0 is an anionic group, and Rf 0is a perfluorinated divalent linking group which may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and which optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.

[0097] The polymer (I) is also preferably a polymer containing polymerized units (Ib) based on a monomer represented by the following formula (Ib). CH2=CH-O-Rf 0 -A 0 (Ib) (In the formula, A 0 is an anionic group, and Rf 0 is a perfluorinated divalent linking group defined by formula (Ia).

[0098] In general formula (I), A 0 is a sulfate group. 0 is, for example, -CH2OSO3M, -CH2CH2OSO3M, or -SO2NR'CH2CH2OSO3M, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above. A 0 is a sulfate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), and the like. In the above formula, M is the same as above.

[0099] In general formula (I), A 0In one preferred embodiment, A is a sulfonate group. 0 An example of such a group is -SO3M, where M is the same as above. A 0 is a sulfonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)3SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH(CF2CF2SO3M), CH2=CH((CF2)3SO3M), etc. In the above formulas, M is the same as above.

[0100] In formula (I), A 0 A is preferably a carboxylate group. 0 Examples of A include -COOM or -SO2NR'CH2COOM, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above. 0 is a carboxylate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(O(CF2)4COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) nCOOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH(CF2CF2COOM), CH2=CH((CF2)3COOM), CF2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM), CF2=CF(OCF2 CF(CF3)OCF2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM), etc. In the above formula, R' is H or C 1-4 is an alkyl group, and M is the same as above.

[0101] In formula (I), A 0 In one preferred embodiment, A is a phosphate group. 0 Examples of the alkyl group include -CH2OP(O)(OM)2, [-CH2O]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CH2O]2P(O)(OM), [-SON2NR'CH2CH2O]2P(O)(OM) and -SON2NR'CH2CH2OP(O)(OM), where R' is an alkyl group having 1 to 4 carbon atoms and M is the same as above. A 0is a phosphate, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(OCF2CF2SO2N(CH3 )CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0102] In formula (I), A 0 In one preferred embodiment, A is a phosphonate group. 0 is a phosphonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)3P(O)(OM)2), where M is the same as above.

[0103] The polymer (I) is preferably a polymer (1) containing polymerized units (1) based on a monomer represented by the following general formula (1). CX2=CY(-CZ2-O-Rf-A) (1) (In the formula, X's may be the same or different and are -H or -F; Y's are -H, -F, an alkyl group or a fluorine-containing alkyl group; Z's may be the same or different and are -H, -F, an alkyl group or a fluoroalkyl group; Rf's are fluorine-containing alkylene groups having 1 to 40 carbon atoms or fluorine-containing alkylene groups having 2 to 100 carbon atoms and an ether bond; A's are -COOM, -SO3M, -OSO3M or C(CF3)2OM (M's are -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group, provided that at least one of X, Y, and Z contains a fluorine atom. The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0104] In the above general formula (1), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0105] In the above general formula (1), Y is —H, —F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have a carbon number of at least 1. The alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. The fluorine-containing alkyl group is an alkyl group containing at least one fluorine atom, and may have a carbon number of at least 1. The fluorine-containing alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. The above Y is preferably -H, -F or -CF3, and more preferably -F.

[0106] In the above general formula (1), Z may be the same or different and is —H, —F, an alkyl group or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have a carbon number of at least 1. The alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. The fluorine-containing alkyl group is an alkyl group containing at least one fluorine atom, and may have a carbon number of at least 1. The fluorine-containing alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. The above Z is preferably -H, -F or -CF3, and more preferably -F.

[0107] In the general formula (1), at least one of X, Y, and Z contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0108] In the general formula (1), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms. The number of carbon atoms in the fluorine-containing alkylene group is preferably 2 or more. The number of carbon atoms in the fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0109] The carbon number of the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The carbon number of the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less. For example, the following formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5). Specific examples of the fluorine-containing alkylene group having an ether bond include -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples thereof include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2- and the like. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0110] In the above general formula (1), A is -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M is -H, a metal atom, or -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group). R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula: The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and is preferably Na, K or Li. The above M is —H, a metal atom, or —NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is especially preferred, and -NH4 is most preferred. The above A is preferably -COOM or -SO3M, and more preferably -COOM.

[0111] Examples of the monomer represented by general formula (1) include the following formula (1a): CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A (1a) (wherein each X is the same and represents F or H, n5 represents 0 or an integer of 1 to 10, and A is as defined above) is a suitable example of a fluoroallyl ether compound. In the formula (1a), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in that PTFE particles having a small primary particle size can be obtained. A is preferably —COOM, and M is preferably H or NH4. The polymer (1) may be a homopolymer of the fluoroallyl ether compound represented by the general formula (1a), or may be a copolymer with other monomers.

[0112] The polymerized units (1) are preferably polymerized units (1A) based on a monomer represented by the following general formula (1A). CH2=CF(-CF2-O-Rf-A) (1A) (wherein Rf and A are the same as above.) The polymer (1) may be a homopolymer of the monomer represented by the general formula (1A) or a copolymer with other monomers.

[0113] Specific examples of the monomer represented by formula (1A) include those represented by the following formula:

[0114] [ka]

[0115] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is H, F, or CF3; p1+q1+r1 are integers from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, except for Z 3 and Z 4 are both H, then p1+q1+r1+s1 is not 0). More specifically,

[0116] [ka]

[0117] Among them,

[0118] [ka]

[0119] It is preferable that:

[0120] As the monomer represented by the above general formula (1A), it is preferable that A in formula (1A) is -COOM, and in particular, at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above) is preferred, with CH2=CFCF2OCF(CF3)COOM being more preferred.

[0121] Further, examples of the monomer represented by the general formula (1) include the monomer represented by the following formula:

[0122] CF2=CFCF2-O-Rf-A (wherein Rf and A are the same as above)

[0123] More specifically, [ka] etc.

[0124] The polymer (I) is also preferably a polymer (2) containing polymerized units (2) based on a monomer represented by general formula (2). CX2=CY(-O-Rf-A) (2) (In the formula, X's are the same or different and represent -H or F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond; and A is the same as defined above.)

[0125] In general formula (2), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0126] In the general formula (2), Y is —H, —F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have a carbon number of at least 1. The alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. The fluorine-containing alkyl group is an alkyl group containing at least one fluorine atom, and may have a carbon number of at least 1. The fluorine-containing alkyl group preferably has 6 or less carbon atoms, more preferably 4 or less carbon atoms, and even more preferably 3 or less carbon atoms. Y is preferably -H, -F or -CF3, and more preferably -F.

[0127] In the general formula (2), it is preferable that at least one of X and Y contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0128] In the general formula (2), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms. The fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms. The number of carbon atoms in the fluorine-containing alkylene group is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0129] The monomer represented by general formula (2) is preferably at least one selected from the group consisting of monomers represented by general formulas (2a), (2b), (2c), (2d) and (2e). CF2=CF-O-(CF2) n1 -A (2a) (wherein n1 represents an integer of 1 to 10, and A is the same as defined above.) CF2=CF-O-(CF2C(CF3)F) n2 -A (2b) (wherein n2 represents an integer of 1 to 5, and A is as defined above.) CF2=CF-O-(CFX 1 ) n3 -A (2c) (In the formula, X 1 represents F or CF3, n3 represents an integer of 1 to 10, and A is as defined above. CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -A (2d) (wherein n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, and A and X 1 is the same as the definition above.) CF2=CF-O-(CF2CF2CFX1 O) n5 -CF2CF2CF2-A (2e) (wherein n5 represents an integer of 0 to 10, and A and X 1 is the same as the definition above.)

[0130] In the formula (2a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less.

[0131] Examples of the monomer represented by the above formula (2a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), and CF2=CF(O(CF2)3COOM) (wherein M is as defined above).

[0132] In the above formula (2b), n2 is preferably an integer of 3 or less, from the viewpoint of the dispersion stability of the resulting composition.

[0133] In the above formula (2c), n3 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0134] In the above formula (2d), X 1 is preferably -CF3 from the viewpoint of dispersion stability, n4 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0135] Examples of the monomer represented by the above formula (2d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, and CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM (wherein M represents H, NH4, or an alkali metal). In the above formula (2e), n5 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably —COOM, and M is preferably H or NH 4 . An example of the monomer represented by the above formula (2e) is CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0136] The polymer (I) is also preferably a polymer (3) containing polymerized units (3) based on a monomer represented by general formula (3). CX2=CY(-Rf-A) (3) (In the formula, X's are the same or different and represent -H or -F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond; and A is the same as defined above.) The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0137] In general formula (3), Rf is preferably a fluorine-containing alkylene group having a carbon number of 1 to 40. In general formula (3), at least one of X and Y preferably contains a fluorine atom.

[0138] The monomer represented by general formula (3) is represented by general formula (3a): CF2=CF-(CF2) n1 -A (3a) (wherein n1 represents an integer of 1 to 10, and A is as defined above), and a monomer represented by general formula (3b): CF2=CF-(CF2C(CF3)F) n2 -A (3b) (wherein n2 represents an integer of 1 to 5, and A is as defined above), is preferred. In the formula (3a) and the formula (3b), A is preferably -SO3M or -COOM, and M is H, a metal atom, or NR 74. It is preferably an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0139] In the above formula (3a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. A is preferably —COOM, and M is preferably H or NH 4 . An example of the monomer represented by the above formula (3a) is CF2=CFCF2COOM (wherein M is as defined above).

[0140] In the above formula (3b), n2 is preferably an integer of 3 or less from the viewpoint of dispersion stability of the resulting aqueous dispersion, A is preferably —COOM, and M is preferably H or NH 4 .

[0141] Next, a preferred configuration when m in general formula (I) is an integer of 2 or more will be described.

[0142] It is also preferable that the polymer (I) is a polymer (4) containing polymerization units (4) based on at least one monomer selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). CF2=CF-CF2-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(4a) (In the formula, Z 1 , Z 2 and A are the same as above, Q F1 and Q F2 are the same or different and are a single bond, a fluorine-containing alkylene group which may contain an ether bond between carbon atoms, or a fluorine-containing oxyalkylene group which may contain an ether bond between carbon atoms. CF2=CF-OQ F1 -CF(-Q F2 -CZ 1 Z 2-A)2(4b) (In the formula, Z 1 , Z 2 , A, Q F1 and Q F2 is the same as above)

[0143] The monomers represented by general formula (4a) and general formula (4b) include: [ka] etc.

[0144] The polymer (I) is preferably at least one selected from the group consisting of polymer (1), polymer (2) and polymer (3), and more preferably polymer (1).

[0145] The polymer (I) may be a homopolymer consisting of only the polymerized unit (I), or may be a copolymer containing the polymerized unit (I) and a polymerized unit based on another monomer copolymerizable with the monomer represented by general formula (I). From the viewpoint of solubility in the polymerization medium, a homopolymer consisting of only the polymerized unit (I) is preferred. The polymerized units (I) may be the same or different in each occurrence, and the polymer (I) may contain polymerized units (I) based on two or more different monomers represented by general formula (I).

[0146] The other monomer is preferably a fluorine-containing ethylenic monomer having 2 or 3 carbon atoms, such as CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-isomer), CHF=CHCF3 (Z-isomer), etc. Among these, at least one selected from the group consisting of tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CF2=CFCl) and vinylidene fluoride (CH2=CF2) is preferred, with tetrafluoroethylene being more preferred, due to its favorable copolymerizability. Therefore, the polymerized units based on the other monomer are preferably monomer units (polymerized units) based on tetrafluoroethylene. The polymerized units based on the other monomers may be the same or different in each occurrence, and the polymer (I) may contain polymerized units based on two or more different types of other monomers.

[0147] The other monomers include those represented by the following formula (n1-2):

[0148] [ka]

[0149] (In the formula, X 1 , X 2 are the same or different H or F;X 3 is H, F, Cl, CH3 or CF3; X 4 , X 5 are the same or different and are H or F; a and c are the same or different and are 0 or 1. Rf 3 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0150] Specifically, CH2=CFCF2-O-Rf 3 , CF2=CF-O-Rf 3 , CF2=CFCF2-O-Rf 3 , CF2=CF-Rf 3 , CH2=CH-Rf 3 , CH2=CH-O-Rf 3 (In the formula, Rf 3 is the same as the above formula (n1-2)).

[0151] Examples of the other monomers include those of formula (n2-1):

[0152] [ka]

[0153] (In the formula, X 9 is H, F or CH3; Rf 4 Also included are fluorine-containing acrylate monomers represented by Rf (a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and an ether bond). 4 The base is

[0154] [ka]

[0155] (wherein d3 is an integer of 1 to 4; e3 is an integer of 1 to 10).

[0156] Examples of the other monomers include those of formula (n2-2): CH2=CHO-Rf 5 (n2-2) (In the formula, Rf 5 Also included are fluorine-containing vinyl ethers represented by the formula (wherein the alkyl group is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0157] Specific examples of the monomer of formula (n2-2) include:

[0158] [ka]

[0159] (wherein e6 is an integer of 1 to 10) are preferred.

[0160] More specifically,

[0161] [ka]

[0162] Examples include:

[0163] Others, formula (n2-3): CH2=CHCH2O-Rf 6 (n2-3) (In the formula, Rf 6 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), a fluorine-containing allyl ether represented by the formula (n2-4): CH2=CH-Rf 7 (n2-4) (In the formula, Rf 7 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), and the like.

[0164] Specific examples of the monomers represented by the above formulas (n2-3) and (n2-4) include:

[0165] [ka]

[0166] Examples of such monomers include:

[0167] The polymer (I) generally has a terminal group. The terminal group is a terminal group generated during polymerization, and typical terminal groups are independently selected from hydrogen, iodine, bromine, linear or branched alkyl groups, and linear or branched fluoroalkyl groups, and may optionally contain at least one catenary heteroatom. The alkyl or fluoroalkyl group preferably has 1 to 20 carbon atoms. These end groups generally originate from the initiator or chain transfer agent used to form polymer (I) or are generated during the chain transfer reaction.

[0168] The polymer (I) preferably has a content of polymerized units (I) of 1.0 mol% or more, more preferably 3.0 mol% or more, even more preferably 5.0 mol% or more, even more preferably 10 mol% or more, particularly preferably 20 mol% or more, and particularly preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, particularly preferably 90 mol% or more, particularly preferably substantially 100 mol%, and most preferably consists solely of polymerized units (I). In the polymer (I), the content of polymerization units based on other monomers copolymerizable with the monomer represented by general formula (I) is preferably 99.0 mol% or less, more preferably 97.0 mol% or less, even more preferably 95.0 mol% or less, even more preferably 90 mol% or less, particularly preferably 80 mol% or less, and particularly preferably 70 mol% or less, more preferably 60 mol% or less, even more preferably 40 mol% or less, even more preferably 20 mol% or less, particularly preferably 10 mol% or less, particularly preferably substantially 0 mol%, and particularly preferably does not contain polymerization units based on other monomers.

[0169] The number average molecular weight of the polymer (I) is 0.1×10 4 More than 0.2 × 10 is preferable. 4 More preferably, 0.3 × 10 4 More preferably, 0.4×10 4 More than 0.5 × 10 is particularly preferable. 4 More than 1.0 × 10 4 More than 3.0 × 10 is particularly preferable. 4 The above is particularly preferable, and 3.1 × 10 4 More than 75.0×10 4 The following is preferable: 50.0 x 10 4 Less than 40.0 x 10 is more preferable. 4 More preferably, 30.0 x 10 4 The following is particularly preferred: 20.0 × 10 4The following are particularly preferred. The number average molecular weight and the weight average molecular weight described below are values calculated by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. When measurement by GPC is not possible, the number average molecular weight of polymer (I) can be determined from the correlation between the number average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0170] The weight average molecular weight of the polymer (I) is 0.2×10 4 More than 0.4 × 10 is preferable. 4 More preferably, 0.6 × 10 4 More preferably, 0.8×10 4 More than 1.0×10 is particularly preferable. 4 More than 5.0 × 10 is particularly preferable. 4 More particularly preferred is 10.0 x 10 4 More particularly, 15.0 × 10 4 More particularly, 20.0 × 10 4 The above is particularly preferable, and 25.0 × 10 4 More than 150.0×10 4 The following is preferable: 100.0 x 10 4 Less than 60.0 x 10 is preferable. 4 More preferably, 50.0 x 10 4 The following is particularly preferred: 40.0 x 10 4 The following are particularly preferred:

[0171] The polymer (I) is preferably water-soluble. Water-soluble means the property of being easily dissolved or dispersed in water. The particle size of the water-soluble polymer (I) cannot be measured by, for example, dynamic light scattering (DLS). On the other hand, the particle size of the water-insoluble polymer (I) can be measured by, for example, dynamic light scattering (DLS). From the viewpoint of water solubility, polymer (I) preferably has an ion exchange ratio (IXR) of 53 or less. The IXR is defined as the number of carbon atoms in the polymer backbone relative to the ionic group. Precursor groups that become ionic upon hydrolysis (e.g., -SOF) are not considered ionic groups for the purpose of determining IXR. IXR is preferably 0.5 or more, more preferably 1 or more, even more preferably 3 or more, even more preferably 4 or more, particularly preferably 5 or more, and particularly preferably 8 or more. IXR is more preferably 43 or less, more preferably 33 or less, and particularly preferably 23 or less. In polymer (I), the ionic (anionic) groups are typically distributed along the polymer backbone. The polymer (I) comprises a polymer backbone with recurring side chains attached to the backbone, which preferably carry ionic groups. Preferably, polymer (I) comprises ionic groups having a pKa of less than 10, more preferably less than 7. The ionic groups of polymer (I) are preferably selected from the group consisting of sulfonate, carboxylate, phosphonate, and phosphate. The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When salts are used, preferably the salts are alkali metal or ammonium salts. A preferred ionic group is a sulfonate group. The ion exchange capacity of the polymer (I) is, in order of preference, 0.80 meg / g or more, 1.50 meg / g or more, 1.75 meg / g or more, 2.00 meg / g or more, 2.50 meg / g or more, 2.60 meg / g or more, 3.00 meg / g or more, and 3.50 meg / g or more. The ion exchange capacity is the content of ionic groups (anionic groups) in the polymer (I) and is calculated from the composition of the polymer (I).

[0172] The polymer (I) can be produced by a conventional method except for using the above-mentioned monomers. The polymerization of the monomer (I) is preferably carried out substantially in the absence of a fluorine-containing surfactant (excluding the monomer (I) represented by general formula (I)) described below. "Substantially in the absence of a fluorine-containing surfactant" means that the amount of the fluorine-containing surfactant relative to the medium used for the polymerization of the monomer (I) is 10 ppm by mass or less. The amount of the fluorine-containing surfactant relative to the medium is preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and even more preferably 1 ppb by mass or less.

[0173] In the water containing the polymer (I), the content of the polymer (I) is not particularly limited, but is preferably 10% by mass or less, for example, from the viewpoint of increasing the removal efficiency. In the water containing the polymer (I), the content of the polymer (I) is more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less, and may be more than 0%, 0.005%, 0.006%, 0.008%, 0.010% by mass or more, 0.020% by mass or more, 0.025% by mass or more, or 0.1% by mass or more. The content of the polymer (I) can be measured by solid-state NMR. The content of the polymer (I) can be measured by methods described in WO 2014 / 099453, WO 2010 / 075497, WO 2010 / 075496, WO 2011 / 008381, WO 2009 / 055521, WO 1987 / 007619, JP 61-293476 A, WO 2010 / 075494, WO 2010 / 075359, WO 2012 / 082454, WO 2006 / 119224, WO 2013 / 085864, WO 2014 / 099453, WO 2014 / 099454, WO 2014 / 099455, WO 2014 / 099456, WO 2014 / 099457, WO 2014 / 099458, WO 2014 / 099459 ... Measurement methods for each polymer described in Publication No. 2012 / 082707, International Publication No. 2012 / 082703, International Publication No. 2012 / 082454, International Publication No. 2012 / 082451, International Publication No. 2006 / 135825, International Publication No. 2004 / 067588, International Publication No. 2009 / 068528, JP 2004-075978, JP 2001-226436, International Publication No. 1992 / 017635, International Publication No. 2014 / 069165, JP 11-181009, etc. are described. The water containing the polymer (I) may contain one single type of polymer (I), or may contain two or more different types of polymer (I).

[0174] The water containing the polymer (I) may contain substances other than the polymer (I) and water, and may be a dispersion, an aqueous solution, or the like. Examples of the substance other than the polymer (I) and water include a non-fluorine-containing polymer other than the polymer (I), a fluorine-containing polymer (fluoropolymer) other than the polymer (I), and an oligomer. It is also preferred that the fluorine-free polymer and fluorine-containing polymer other than the polymer (I) do not contain polymerized units (I) based on the monomer represented by the general formula (I). As the fluoropolymer other than polymer (I), a fluoropolymer having an ion exchange rate (IXR) higher than 53 is preferred. Fluoropolymers other than preferred polymer (I) have no ionic groups or have a limited number of ionic groups that result in an ion exchange rate higher than about 100. The ion exchange rate of fluoropolymers other than preferred polymer (I) is preferably 1000 or higher, more preferably 2000 or higher, and even more preferably 5000 or higher. Fluoropolymers other than the above polymer (I) include PTFE, copolymers of TFE and other monomers copolymerizable with TFE (fluorine-containing monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, isobutene, alkyl vinyl ether, etc.) (for example, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and and ethylene-tetrafluoroethylene copolymer (ETFE), etc.), fluororesins such as polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE), fluororubbers such as vinylidene fluoride-hexafluoropropylene copolymer (FKM), tetrafluoroethylene-propylene rubber (FEPM), and tetrafluoroethylene-perfluoromethylvinyl ether rubber (FFKM), and fluorine-containing elastomers. The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by weight or less of a modifying monomer. The fluoropolymer is preferably at least one selected from the group consisting of PTFE and melt-processable fluororesin containing 60.0 to 98.0 mass % of TFE units and 2.0 to 40.0 mass % of other monomers, and more preferably PTFE. The water containing the polymer (I) may contain the polymer (I) and a fluoropolymer other than the polymer (I), more preferably the water contains the polymer (I) and at least one selected from the group consisting of PTFE and melt-processable fluororesin containing 60.0 to 98.0 mass% of TFE units and 2.0 to 40.0 mass% of other monomers, and further preferably the water contains the polymer (I) and PTFE.

[0175] The water containing the polymer (I) preferably has a content of substances other than the polymer (I) and water of 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less. The lower limit of the content of substances other than the polymer (I) and water is not limited, but may be, for example, 0% by mass or 0.1% by mass.

[0176] The water content of the polymer (I)-containing water is preferably 99.0% by mass or more, more preferably 99.5% by mass or more, and even more preferably 99.8% by mass or more.

[0177] The pH of the water containing the polymer (I) to be subjected to the removal step (the water containing the polymer (I) before the removal step, for example, before the inorganic flocculant is added) may be, for example, 1.5 to 13.5, or may be 2 to 13. The pH of the water containing the polymer (I) can be adjusted with a pH adjuster, which is not limited, and examples of the pH adjuster that can be used include the acid compounds and alkali compounds mentioned above.

[0178] The water containing the polymer (I) is not particularly limited as long as it contains the polymer (I), and may be, for example, water (wastewater) generated in industrial production. A preferred embodiment of the present disclosure is that the water containing the polymer (I) is wastewater. The removal method of the present disclosure is effective, for example, for treating water generated in a polymer production process described below, and is particularly effective for treating water that has undergone a polymerization process. Therefore, a preferred embodiment of the present disclosure is that the water containing the polymer (I) is water generated in a polymer production process. The water containing the polymer (I) is preferably water that has undergone a polymerization process, more preferably water that has undergone a polymerization process for a fluoropolymer (fluoropolymer). The polymerization process may be, for example, a process of polymerizing a monomer (e.g., the fluoromonomer described below) in an aqueous medium in the presence of the polymer (I). The aqueous medium is a reaction medium for polymerization and refers to a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as an alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40° C. or lower.

[0179] The water generated in the polymer production process may include water that has undergone the polymerization process of polymerizing one or more monomers, as well as water that has been generated in a pretreatment process before the polymerization process (for example, a process for preparing an emulsifier at a predetermined concentration, etc.), and water that has been generated in a posttreatment process after the polymerization process (for example, a process for concentrating an aqueous dispersion, a solid-liquid separation process, a coagulation process, a washing process, a dehydration process, a drying process, a heat treatment process, etc.). The water that has undergone the polymerization process may include water that has been generated in the polymer production process, particularly in the fluoropolymer production process described below. As the water containing the polymer (I), for example, the water that has been generated in the polymer production process may be used as is, or the water that has been diluted or concentrated may be used. The water containing the polymer (I) includes an aqueous solution, a dispersion, and a liquid obtained by liquefying a gas (such as an exhaust gas generated in a drying step, which will be described later). Hereinafter, the explanation will be given taking the fluoropolymer production process as an example, but the water that has undergone the polymerization process is not limited to water produced in the fluoropolymer production process, but includes water produced in any polymer production process.

[0180] In this specification, the term "fluoropolymer production process" refers to any process for producing a fluoropolymer by polymerizing one or more monomers including a fluoromonomer, and is not limited to any particular production process. The fluoropolymer can also be produced by polymerizing a fluoromonomer in the presence of polymer (I). The water containing the polymer (I) preferably contains water obtained in the process for producing a fluoropolymer using the polymer (I).

[0181] In this specification, the "fluorine-containing monomer" is not particularly limited as long as it is a monomer having at least one fluorine or fluoroalkyl group, and may include, for example, trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, and fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E-isomer), CHF=CHCF3 (Z-isomer), and the like. The fluorine-containing monomer is preferably a monomer other than the monomer represented by general formula (I).

[0182] In this specification, the "fluoropolymer" (fluoropolymer) may be one obtained by polymerizing a monomer containing one or more of the above-mentioned fluoromonomers, and may be, for example, a fluoropolymer exemplified as a substance other than polymer (I) and water, but is not limited thereto. In the first treatment method of the present disclosure, the fluoropolymer may be PTFE. The PTFE may be a TFE homopolymer, a modified PTFE containing TFE units and modified monomer units based on a modified monomer copolymerizable with TFE, or a high-molecular-weight PTFE or a low-molecular-weight PTFE. High molecular weight PTFE is usually non-melt-processible and fibrillating, and has, for example, a standard specific gravity (SSG) of 2.130 to 2.280. The standard specific gravity is measured by the water displacement method in accordance with ASTM D-792 using a sample molded in accordance with ASTM D4895-89. In the present disclosure, "high molecular weight PTFE" means that the standard specific gravity is within the above range.

[0183] The first treatment method of the present disclosure may include the following fluoropolymer production process. In this specification, the "fluoropolymer production step" is not particularly limited as long as it is a step included in the production process of a fluoropolymer, and may include one or more steps constituting a known fluoropolymer production process. The "fluoropolymer production step" may include, in addition to a polymerization step of polymerizing one or more monomers including a fluoromonomer, a pretreatment step before the polymerization step (e.g., a step of preparing an emulsifier at a predetermined concentration) and a posttreatment step after the polymerization step (e.g., a step of concentrating an aqueous dispersion, a solid-liquid separation step, a coagulation step, a washing step, a dehydration step, a drying step, a heat treatment step, etc.). Specific examples of the "fluoropolymer production step" will be described below, but the method according to this embodiment is not limited to the following specific examples.

[0184] As described above, the fluoropolymer is produced by polymerizing one or more monomers including a fluoromonomer. In this polymerization step, the monomer is preferably polymerized in an aqueous medium, thereby obtaining an aqueous dispersion in which polymer particles are dispersed in the aqueous medium. The polymerization step is preferably carried out in the presence of polymer (I). The water containing the polymer (I) may be one obtained by polymerization using polymer (I). When used in the state of an aqueous dispersion, the obtained aqueous dispersion may be concentrated by a concentration step (e.g., phase separation concentration, electrical concentration, filtration using an ultrafiltration membrane, filtration using a reverse osmosis membrane (RO membrane), nanofiltration, etc.). In this case, the liquid containing polymer (I) remaining after recovering the concentrated aqueous dispersion may be included in the "water containing polymer (I)" in this specification. After the polymerization step, it is preferable to add a salt or an acid to the aqueous dispersion in a coagulation step to coagulate the fluoropolymer. Then, it is preferable to separate and recover the coagulated fluoropolymer in a solid-liquid separation step. The liquid containing polymer (I) remaining after separating and recovering the fluoropolymer can be included in the "water containing polymer (I)" in this specification.

[0185] The fluoropolymer separated and recovered in the solid-liquid separation step may be washed with a washing liquid such as an aqueous medium in the washing step. The wastewater containing the polymer (I) generated in the washing step may be included in the "water containing the polymer (I)" in this specification. The washing liquid containing the polymer (I) used in the washing step may be included in the "water containing the polymer (I)" in this specification. The fluoropolymer separated and recovered in the solid-liquid separation step may be mechanically dehydrated in the dehydration step. The liquid containing polymer (I) removed from the fluoropolymer in the dehydration step may be included in the "water containing polymer (I)" in this specification. The fluoropolymer after dehydration may be washed with a washing liquid, and wastewater containing the polymer (I) generated in this washing step may be included in the "water containing the polymer (I)" in this specification. The washing liquid containing the polymer (I) used in this washing step may also be included in the "water containing the polymer (I)" in this specification.

[0186] The fluoropolymer obtained after the above-mentioned washing step and / or dehydration step may be heated and dried in a drying step to remove the remaining water and organic solvent as an exhaust gas. A liquid containing polymer (I) obtained by liquefying the exhaust gas generated in the drying step may be included in the "water containing polymer (I)" in this specification. The exhaust gas generated in the drying step may contain, in addition to water vapor and an organic solvent, the polymer (I) entrained in the fluoropolymer. Therefore, it is preferable to wash this exhaust gas with a washing liquid such as water or an alkaline aqueous solution. The washing liquid containing the polymer (I) used for washing the exhaust gas may also be included in the "water containing the polymer (I)" in this specification.

[0187] The fluoropolymer obtained after the drying step may be formed into a desired shape such as pellets in a heat treatment step. The liquid containing the polymer (I) obtained by liquefying the exhaust gas generated in the heat treatment step may be included in the "water containing the polymer (I)" in this specification. The exhaust gas generated in the heat treatment step may contain polymer (I) entrained in the fluoropolymer. Therefore, it is preferable to wash this exhaust gas with a washing liquid such as water or an alkaline aqueous solution. The wastewater containing polymer (I) generated by washing this exhaust gas may be included in the "water containing polymer (I)" in this specification. The washing liquid containing polymer (I) used for washing the exhaust gas may also be included in the "water containing polymer (I)" in this specification.

[0188] A single washing liquid may be obtained by washing both the exhaust gas generated in the drying step and the exhaust gas generated in the heat treatment step together. The wastewater (water) containing the polymer (I) generated by washing both the exhaust gas generated in the drying step and the exhaust gas generated in the heat treatment step together may be included in the "water containing the polymer (I)" in this specification.

[0189] The water containing the polymer (I) may be water produced in the production process of one type of fluoropolymer, or may contain water produced in the production processes of multiple different types of fluoropolymers. For example, the water containing the polymer (I) may be a mixture containing water produced in the production process of fluororubber and water produced in the production process of PTFE (such as low-molecular-weight PTFE), and the water produced in the production processes of two types of fluoropolymers can be treated simultaneously by the first treatment method of the present disclosure. Furthermore, the water containing the polymer (I) may be water produced in one of the steps included in the production process of the fluoropolymer, or may contain water produced in multiple different steps. For example, the water containing the polymer (I) may be a mixture of water obtained in a process for producing a fluoropolymer using the polymer (I) and water obtained in a process for producing a fluoropolymer using a fluorinated surfactant. Alternatively, the mixture may be a mixture of water obtained in a fluoropolymer production process using polymer (I) and water obtained in a fluoropolymer production process using a hydrocarbon surfactant. The hydrocarbon surfactant is not particularly limited and may be a surfactant having a hydrophilic portion and a hydrophobic portion on the same molecule. These may be cationic, nonionic, or anionic. For example, anionic hydrocarbon surfactants include RLM (wherein R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when the alkyl group has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or may form a ring). L is -ArSO3 - , -SO3 - , -SO4-, -PO3 - or COO - and M is H, a metal atom, or NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group, -ArSO3 -is an aryl sulfonate. ) Specifically, CH3-(CH2) such as lauric acid and lauryl sulfate n -LM (wherein n is an integer of 6 to 17, and L and M are the same as above). Mixtures in which R is an alkyl group having 12 to 16 carbon atoms and LM is sulfate can also be used. Anionic hydrocarbon surfactants include R 6 (-LM)2(wherein, R 6 is a linear or branched alkylene group having one or more carbon atoms which may have a substituent, or a cyclic alkylene group having three or more carbon atoms which may have a substituent, and when the number of carbon atoms is three or more, it may contain a monovalent or divalent heterocycle or may form a ring. - , -SO3 - , -SO4-, -PO3 - or COO - and M is H, a metal atom, or NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group, -ArSO3 - is an aryl sulfonate. ) In addition, as anionic hydrocarbon surfactants, R 7 (-LM)3(wherein, R 7 is a linear or branched alkylidyne group having one or more carbon atoms which may have a substituent, or a cyclic alkylidyne group having three or more carbon atoms which may have a substituent, and when the number of carbon atoms is three or more, it may contain a monovalent or divalent heterocycle or may form a ring. - , -SO3 - , -SO4-, -PO3 - or COO - and M is H, a metal atom, or NR 54. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group. -ArSO3 - is an aryl sulfonate. ) Examples of anionic hydrocarbon surfactants include Versatic (registered trademark) 10 manufactured by Resolution Performance Products and Avanel S series (S-70, S-74, etc.) manufactured by BASF.

[0190] Anionic hydrocarbon surfactants also include siloxane hydrocarbon surfactants. Examples of siloxane hydrocarbon surfactants include those described in Silicone Surfactants, R.M. Hill, Marcel Dekker, Inc., ISBN: 0-8247-00104. The structure of siloxane hydrocarbon surfactants includes a distinct hydrophobic portion and a hydrophilic portion. The hydrophobic portion includes one or more dihydrocarbylsiloxane units, where the substituents on the silicone atoms are entirely hydrocarbon. These siloxane surfactants can also be considered hydrocarbon surfactants in the sense that the carbon atoms of the hydrocarbyl groups are entirely substituted with hydrogen atoms, even if they may be substituted with halogens such as fluorine, i.e., the monovalent substituents on the carbon atoms of the hydrocarbyl groups are hydrogen.

[0191] The hydrophilic portion of the siloxane hydrocarbon surfactant may contain one or more polar moieties containing ionic groups such as sulfates, sulfonates, phosphonates, phosphate esters, carboxylates, carbonates, sulfosuccinates, taurates (as free acids, salts, or esters), phosphine oxides, betaines, betaine copolyols, and quaternary ammonium salts. The ionic hydrophobic portion may also contain ionically functionalized siloxane grafts. Examples of such siloxane hydrocarbon surfactants include polydimethylsiloxane-grafted (meth)acrylates, polydimethylsiloxane-grafted polyacrylate salts, and polydimethylsiloxane-grafted quaternary amines. The polar portion of the hydrophilic portion of the siloxane hydrocarbon surfactant may contain nonionic groups formed by polyethers such as polyethylene oxide (PEO) and mixed polyethylene oxide / propylene oxide polyethers (PEO / PPO); monosaccharides and disaccharides; and water-soluble heterocycles such as pyrrolidinone. The ratio of ethylene oxide to propylene oxide (EO / PO) can be varied in mixed polyethylene oxide / propylene oxide polyethers.

[0192] The hydrophilic portion of the siloxane hydrocarbon surfactant may also contain a combination of ionic and nonionic moieties, such as ionically end-functionalized or randomly functionalized polyethers or polyols. Preferred are siloxanes with nonionic moieties, i.e., nonionic siloxane surfactants.

[0193] The arrangement of hydrophobic and hydrophilic moieties in the structure of the siloxane hydrocarbon surfactant may take the form of a diblock polymer (AB), a triblock polymer (ABA) (where "B" represents the siloxane portion of the molecule), or a multiblock polymer. Alternatively, the siloxane surfactant may comprise a graft polymer.

[0194] Siloxane hydrocarbon surfactants are also disclosed in US Pat. No. 6,841,616.

[0195] Siloxane-based anionic hydrocarbon surfactants include SilSense, available from Noveon® Consumer Specialties of Lubrizol Advanced Materials, Inc. TM PE-100 Silicone, SilSense TM CA-1 silicone and the like.

[0196] Examples of anionic hydrocarbon surfactants include Lankropol® K8300, a sulfosuccinate surfactant from Akzo Nobel Surface Chemistry LLC. Examples of sulfosuccinate surfactants include sodium diisodecyl sulfosuccinate (Emulsogen® SB10 from Clariant) and sodium diisotridecyl sulfosuccinate (Polirol® TR / LNA from Cesapinia Chemicals).

[0197] Anionic hydrocarbon surfactants include PolyFox (registered trademark) surfactants from Omnova Solutions, Inc. TM PF-156A, PolyFox TM PF-136A, etc.)

[0198] Examples of anionic hydrocarbon surfactants include those represented by the general formula (α): R 10 -COOM (α) (In the formula, R 10 is a monovalent organic group containing one or more carbon atoms. M is H, a metal atom, NR 11 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 11R is H or an organic group, and may be the same or different. 11 as H or C 1-10 is preferably an organic group represented by the formula: 1-4 From the viewpoint of surface activity, the organic group R 10 The number of carbon atoms in R is preferably 2 or more, and more preferably 3 or more. 10 The number of carbon atoms in is preferably 29 or less, more preferably 23 or less. The metal atom of M may be an alkali metal (Group 1) or an alkaline earth metal (Group 2), and preferably Na, K, or Li. M may be H, a metal atom, or NR 11 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 11 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, Na, K or NH4 is even more preferred, Na or NH4 is especially preferred, and NH4 is most preferred.

[0199] Compound (α) includes R 12 -COOM(in the formula, R 12 is a linear or branched alkyl group, alkenyl group, alkylene group or alkenylene group having 1 or more carbon atoms, which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group or alkenylene group having 3 or more carbon atoms, which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocycle, or may form a ring. M is the same as above. ) are also included. Specifically, CH3-(CH2) n -COOM (wherein n is an integer of 2 to 28, and M is the same as above).

[0200] From the viewpoint of emulsion stability, the compound (α) may be one that does not contain a carbonyl group (excluding the carbonyl group in a carboxyl group). Examples of the hydrocarbon-containing surfactant that does not contain a carbonyl group include those represented by the following formula (A): R-COO-M(A) (wherein R is an alkyl group, alkenyl group, alkylene group, or alkenylene group containing 6 to 17 carbon atoms, which may contain an ether bond. M is H, a metal atom, NR 11 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 11 are the same or different and are H or an organic group having 1 to 10 carbon atoms.) is a preferred example. In the above formula (A), R is preferably an alkyl group or an alkenyl group (which may contain an ether group). The alkyl group or alkenyl group in the above R may be linear or branched. The number of carbon atoms in the above R is not limited, but is, for example, 2 to 29.

[0201] In the above formula (A), when R is a linear alkyl group, R preferably has 3 to 29 carbon atoms, more preferably 5 to 23. When the above alkyl group is branched, R preferably has 5 to 35 carbon atoms, more preferably 11 to 23. When the above alkenyl group is linear, R preferably has 2 to 29 carbon atoms, more preferably 9 to 23. When the above alkenyl group is branched, R preferably has 2 to 29 carbon atoms, more preferably 9 to 23.

[0202] Examples of the alkyl group and alkenyl group include a methyl group, an ethyl group, an isobutyl group, a t-butyl group, and a vinyl group.

[0203] Further, examples of the anionic hydrocarbon surfactant include carboxylic acid hydrocarbon surfactants. Examples of the carboxylic acid hydrocarbon surfactants include butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)linolenic acid, eleostearic acid, arachidic acid, 8,11-eicosadienoic acid, mead acid, arachidonic acid, behenic acid, lignoceric acid, nervonic acid, cerotic acid, montanic acid, melissic acid, crotonic acid, myristic acid, hydroxypropyl methylcellulose ... Examples of suitable salts include oleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid, linoleic acid, eicosadienoic acid, docosadienoic acid, linolenic acid, pinolenic acid, α-eleostearic acid, β-eleostearic acid, mead acid, dihomo-γ-linolenic acid, eicosatrienoic acid, stearidonic acid, arachidonic acid, eicosatetraenoic acid, adrenic acid, bosseopentaenoic acid, eicosapentaenoic acid, osbondoic acid, sardine acid, tetracosapentaenoic acid, docosahexaenoic acid, herring acid, and salts thereof. Particularly preferred are at least one selected from the group consisting of lauric acid, capric acid, myristic acid, pentadecylic acid, palmitic acid, and salts thereof. The salts include those in which the hydrogen atom of the carboxyl group is bonded to a metal atom of the formula M, NR 11 4. Examples include, but are not limited to, imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent.

[0204] Furthermore, examples of anionic hydrocarbon surfactants that can be used include those described in International Publication Nos. 2013 / 146950 and 2013 / 146947. Examples include those having a saturated or unsaturated aliphatic chain with 6 to 40 carbon atoms, preferably 8 to 20 carbon atoms, and more preferably 9 to 13 carbon atoms. The saturated or unsaturated aliphatic chain may be either a straight chain or a branched chain, or may have a cyclic structure. The hydrocarbon may be aromatic or may have an aromatic group. The hydrocarbon may have a heteroatom such as oxygen, nitrogen, or sulfur.

[0205] Examples of anionic hydrocarbon surfactants include alkyl sulfonates, alkyl sulfates, alkylaryl sulfates, and salts thereof; aliphatic (carboxylic) acids and salts thereof; alkyl phosphates, alkylaryl phosphates, and salts thereof; and among these, alkyl sulfonates, alkyl sulfates, aliphatic carboxylic acids, and salts thereof are preferred.

[0206] As the alkyl sulfate or its salt, ammonium lauryl sulfate and sodium lauryl sulfate are preferred. The aliphatic carboxylic acid or a salt thereof is preferably succinic acid, decanoic acid, undecanoic acid, undecenoic acid, lauric acid, hydrododecanoic acid, or a salt thereof.

[0207] The fluorine-containing surfactant may, for example, be an anionic fluorine-containing surfactant. The anionic fluorine-containing surfactant may be, for example, a surfactant containing fluorine atoms and having a total carbon number of 20 or less excluding the anionic group.

[0208] The fluorine-containing surfactant may also be a surfactant containing fluorine in the anionic moiety having a molecular weight of 800 or less. The "anionic portion" refers to the portion of the fluorine-containing surfactant excluding the cation. For example, F(CF2) represented by the formula (IA) described below. n1 In the case of COOM, "F(CF2) n1 The "COO" part.

[0209] The above-mentioned fluorine-containing surfactant also includes a fluorine-containing surfactant having a LogPOW of not more than 3.5. The LogPOW is a partition coefficient between 1-octanol and water, and is expressed as LogP (where P represents the ratio of the fluorine-containing surfactant concentration in octanol to the fluorine-containing surfactant concentration in water when a 1:1 octanol / water mixture containing the fluorine-containing surfactant undergoes phase separation). The LogPOW is calculated from the HPLC elution time of the sample solution using standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) with known octanol / water partition coefficients under the following conditions: column: TOSOH ODS-120T column (φ4.6 mm×250 mm, manufactured by Tosoh Corporation), eluent: acetonitrile / 0.6% by mass HClO₄ / water=1 / 1 (vol / vol%), flow rate: 1.0 mL / min, sample amount: 300 μL, column temperature: 40°C, detection light: UV 210 nm. A calibration curve between each elution time and the known octanol / water partition coefficient is then prepared, and the LogPOW is calculated from the HPLC elution time of the sample solution based on this calibration curve.

[0210] Specific examples of the fluorine-containing surfactants include those described in U.S. Patent Application Publication Nos. 2007 / 0015864, 2007 / 0015865, 2007 / 0015866, 2007 / 0276103, 2007 / 0117914, 2007 / 142541, 2008 / 0015319, and U.S. Pat. No. 3,250,808. , U.S. Pat. No. 3,271,341, JP 2003-119204 A, WO 2005 / 042593, WO 2008 / 060461, WO 2007 / 046377, WO 2007 / 119526, WO 2007 / 046482, WO 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, WO 2013 / 189824, and WO 2013 / 189826.

[0211] The anionic fluorine-containing surfactant may be a compound represented by the following general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl or F. n0 is a linear, branched or cyclic alkylene group having 3 to 20 carbon atoms, in which some or all of the H's are substituted with F, and the alkylene group may contain one or more ether bonds, and some of the H's may be substituted with Cl. Y 0 is an anionic group. Y 0 The anionic group may be -COOM, -SO2M, -SO3M or -C(CF3)2OM, or may be -COOM or -SO3M. M is H, metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7is H or an organic group. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), such as Na, K, or Li. R 7 As for H or C 1-10 may be an organic group of H or C 1-4 may be an organic group of H or C 1-4 The alkyl group may be: M is H, a metal atom, or NR 7 4, and may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 7 4, which may be H, Na, K, Li, or NH4. Above Rf n0 may be one in which 50% or more of H is substituted with fluorine.

[0212] The general formula (N 0 ) as a compound represented by The following general formula (N 1 ): X n0 -(CF2) m1 -Y 0 (N 1 ) (In the formula, X n0 is H, Cl, or F, m1 is an integer of 3 to 15, and Y 0 is as defined above, a compound represented by the following general formula (N 2 ): Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 ) (In the formula, Rf n1 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, and X n1 is F or CF3, and Y 0 is as defined above, a compound represented by the following general formula (N 3 ): Rf n2 (CH2) m3 -(Rfn3 ) q -Y 0 (N 3 ) (In the formula, Rf n2 is a partially or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, m3 is an integer of 1 to 3, and Rf n3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, and Y 0 is as defined above, a compound represented by the following general formula (N 4 ): Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 ) (In the formula, Rf n4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond; Y n1 and Y n2 are the same or different and are H or F, p is 0 or 1, and Y 0 is as defined above.) and a compound represented by the general formula (N 5 ): [ka] (In the formula, X n2 , X n3 and X n4 Rf may be the same or different and are H, F, or a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond. n5 is a linear or branched partially or fully fluorinated alkylene group having 1 to 3 carbon atoms, which may contain an ether bond; L is a linking group; Y 0 is as defined above, where X n2 , X n3 , X n4 and Rf n5 The total number of carbon atoms is 18 or less.

[0213] The general formula (N 0 ) More specifically, the compounds represented by the formula (IA) include perfluorocarboxylic acids (IA) represented by the following general formula (IA), ω-H perfluorocarboxylic acids (II) represented by the following general formula (II), perfluoropolyether carboxylic acids (III) represented by the following general formula (III), perfluoroalkyl alkylene carboxylic acids (IV) represented by the following general formula (IV), perfluoroalkoxy fluorocarboxylic acids (V) represented by the following general formula (V), perfluoroalkyl sulfonic acids (VI) represented by the following general formula (VII), ω-H perfluoro sulfonic acids (VII) represented by the following general formula (VII), perfluoroalkyl alkylene sulfonic acids (VIII) represented by the following general formula (VIII), alkyl alkylene carboxylic acids (IX) represented by the following general formula (IX), fluorocarboxylic acids (X) represented by the following general formula (X), alkoxy fluoro sulfonic acids (XI) represented by the following general formula (XI), compounds (XII) represented by the following general formula (XII), and compounds (XIII) represented by the following general formula (XIII).

[0214] The perfluorocarboxylic acid (IA) is represented by the following general formula (IA): F(CF2) n1 COOM (IA) (wherein n1 is an integer of 3 to 14, and M is H, a metal atom, or NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0215] The ω-H perfluorocarboxylic acid (II) is represented by the following general formula (II): H(CF2) n2 COOM (II) (wherein n2 is an integer of 4 to 15, and M is as defined above).

[0216] The perfluoropolyether carboxylic acid (III) is represented by the following general formula (III): Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM (III) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above.

[0217] The perfluoroalkyl alkylene carboxylic acid (IV) is represented by the following general formula (IV): Rf 2 (CH2) n4 Rf 3 COOM (IV) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, and Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer of 1 to 3, and M is as defined above.

[0218] The alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V): Rf 4 -O-CY 1 Y 2 CF2-COOM (V) (In the formula, Rf 4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond; Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.

[0219] The perfluoroalkylsulfonic acid (VI) is represented by the following general formula (VI): F(CF2) n5 SO3M (VI) (wherein n5 is an integer of 3 to 14, and M is as defined above).

[0220] The ω-H perfluorosulfonic acid (VII) is represented by the following general formula (VII): H(CF2) n6 SO3M (VII) (wherein n6 is an integer of 4 to 14, and M is as defined above).

[0221] The perfluoroalkyl alkylene sulfonic acid (VIII) is represented by the following general formula (VIII): Rf 5 (CH2) n7 SO3M (VIII) (In the formula, Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is as defined above.

[0222] The alkyl alkylene carboxylic acid (IX) is represented by the following general formula (IX): Rf 6 (CH2) n8 COOM (IX) (In the formula, Rf 6 is a linear or branched partially or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, n8 is an integer of 1 to 3, and M is as defined above.

[0223] The fluorocarboxylic acid (X) is represented by the following general formula (X): Rf 7 -O-Rf 8 -O-CF2-COOM (X) (In the formula, Rf 7 is a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond; Rf 8 is a linear or branched, partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.

[0224] The alkoxyfluorosulfonic acid (XI) is represented by the following general formula (XI): Rf 9 -O-CY 1 Y 2 CF2-SO3M (XI) (In the formula, Rf 9 is a linear or branched alkyl group having 1 to 12 carbon atoms, which may contain an ether bond, and which may contain chlorine, and which is partially or completely fluorinated; Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.

[0225] The compound (XII) is represented by the following general formula (XII): [ka] In the formula, X 1 , X 2 and X 3 may be the same or different and are H, F and linear or branched partially or fully fluorinated alkyl groups having 1 to 6 carbon atoms which may contain ether bonds; Rf 10 is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y 0 is an anionic group. Y 0 may be -COOM, -SO2M, or -SO3M, and may be -SO3M or COOM (wherein M is as defined above). Examples of L include a single bond and a partially or fully fluorinated alkylene group having 1 to 10 carbon atoms which may contain an ether bond.

[0226] The compound (XIII) is represented by the following general formula (XIII): Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII) (In the formula, Rf 11is a fluoroalkyl group containing chlorine and having 1 to 5 carbon atoms, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above. Compound (XIII) is represented by the formula: CF2ClO(CF2CF(CF3)O) n9 (CF2O) n10 CF2COONH4 (a mixture having an average molecular weight of 750, wherein n9 and n10 are defined above).

[0227] As mentioned above, examples of the anionic fluorine-containing surfactant include carboxylic acid surfactants and sulfonic acid surfactants.

[0228] In the first treatment method of the present disclosure, when the water containing the polymer (I) contains solid components, it is also preferable to further include a pretreatment step of removing the solid components from the water containing the polymer (I) before the removal step. The solid components include uncoagulated polymer, flocculant, particulate polymer, etc. The solid components are, for example, components that may remain in the water after separating and recovering the polymer produced in the above-mentioned polymer production process. For example, in the solid-liquid separation step as the above-mentioned polymer production process, the liquid containing the polymer (I) remaining after separating and recovering the polymer, i.e., the water after separating and recovering the polymer, may contain uncoagulated polymer that was not completely recovered in the solid-liquid separation step. When removing the polymer (I) from the liquid containing the polymer (I) remaining after separating and recovering the polymer, such solid components may adversely affect the process of removing the polymer (I), so it is desirable to remove them from the water before the removal step. In this specification, the non-coagulated polymer refers to the polymer component that is dispersed in the remaining water after the polymer polymerization process, adding a flocculant, carrying out the solid-liquid separation process, and separating and recovering the polymer, and that becomes a gel-like substance and deposits on the surface of the filter material such as a filter.The particle size of the non-coagulated polymer may be about 0.01 μm to 5.0 μm. The particle size of the particulate polymer that can be contained in the water containing the polymer (I) is not limited, but may be, for example, a polymer with a particle size of about 0.1 μm to 0.2 μm. That is, the water containing the polymer (I) may contain solid components, and the solid components may include uncoagulated polymer and / or fine particle polymer. In the first treatment method of the present disclosure, the concentration of solid components in the water containing the polymer (I) is not particularly limited, and water with any solid component concentration can be treated. The concentration of solid components in the water containing the polymer (I) may vary depending on the polymer production process, but may be, for example, 0.1 ppm to 50,000 ppm. Furthermore, by the above pretreatment step, for example, the solid content in the water containing the polymer (I) is preferably 0.05 ppm to 500 ppm, more preferably 0.05 ppm to 50 ppm, and even more preferably 0.05 ppm to 10 ppm. The lower limit of the solid content may be 0.1 ppm. The method for removing solid components is not limited, and examples thereof include filtration, etc. Examples of filtration methods include a method of separating solid components using a UF membrane or an MF membrane, a method using a filter aid, and a method using a liquid cyclone. Examples of the MF membrane include a safety filter, a hollow fiber membrane, a flat membrane, and a spiral membrane. Examples of the filter aid include diatomaceous earth, filter sand (manganese sand, manganese zeolite, anthracite, ceramic sand, etc.), perlite, cellulose, etc.

[0229] The polymer (I) may also be a water-soluble polymer described below in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, or a polymer (polymer α) in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, which contains ionic groups, and which has an ion-exchange rate of 53 or less.

[0230] The present disclosure also provides a composition (hereinafter also referred to as "first composition of the present disclosure") comprising a polymer (I) containing polymerization units (I) based on a monomer represented by the following general formula (I), water, and a fluorinated polymer (excluding the polymer (I)), wherein the content of the polymer (I) is 250 ppm or less: CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater. The first composition of the present disclosure may be an aqueous solution of polymer (I) or a dispersion of polymer (I).

[0231] In the first composition of the present disclosure, the polymer (I) is the same as that described in the first treatment method of the present disclosure, and a suitable embodiment can be adopted as appropriate. Among them, the above-mentioned polymer (1) is preferred.

[0232] The first composition of the present disclosure has a polymer (I) content of 250 ppm or less relative to the mass of the composition. The polymer (I) content is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of polymer (I) in the first composition of the present disclosure can be measured by the same method as for water containing polymer (I), for example, by solid-state NMR measurement. The first composition of the present disclosure may contain one single type of polymer (I), or may contain two or more different types of polymers (I).

[0233] The first composition of the present disclosure contains a fluorine-containing polymer other than the polymer (I). As the fluoropolymer other than polymer (I), any fluoropolymer other than polymer (I) described in the first treatment method of the present disclosure can be appropriately employed, and a suitable embodiment can be appropriately adopted. As the fluoropolymer other than polymer (I), a fluoropolymer having an ion exchange ratio (IXR) higher than 53 is preferred. Furthermore, as the fluoropolymer other than polymer (I), PTFE is preferred. When the first composition of the present disclosure contains PTFE, the PTFE may be a TFE homopolymer, or a modified PTFE containing TFE units and modified monomer units based on a modified monomer copolymerizable with TFE, or may be a high-molecular-weight PTFE or a low-molecular-weight PTFE. As the PTFE in the composition of the present disclosure, the PTFE described in the first treatment method of the present disclosure can be appropriately adopted.

[0234] In the first composition of the present disclosure, the content of the fluorine-containing polymer other than the polymer (I) is preferably 5000 ppm or less based on the mass of the composition. More preferably, it is 2000 ppm or less, even more preferably, it is 1000 ppm or less, and particularly preferably, it is 500 ppm or less. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, may be more than 0 ppm, may be 1 ppm or more, or may be 100 ppm or more. The content of fluoropolymers other than polymer (I) can be determined by a method of separating solid components (fluoropolymers other than polymer (I)) using an MF membrane. When the first composition of the present disclosure contains PTFE, the PTFE content is preferably 5000 ppm or less by mass of the composition. More preferably, it is 2000 ppm or less, even more preferably, it is 1000 ppm or less, and particularly preferably, it is 500 ppm or less. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, may be more than 0 ppm, may be 1 ppm or more, or may be 100 ppm or more. The PTFE content can be determined by a method of separating the solid component (PTFE) using an MF membrane.

[0235] The first composition of the present disclosure may contain a substance other than the polymer (I), water, and the fluoropolymer. The first composition of the present disclosure may contain, for example, a flocculant or the like described in the first treatment method of the present disclosure. The first composition of the present disclosure may also contain metal ions or divalent or higher metal ions. As the divalent or higher metal ions, those contained in the third composition of the present disclosure described below may be appropriately contained. The content of divalent or higher metal ions in the composition is preferably 0.05 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. The content of divalent or higher metal ions is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less.

[0236] In the first composition of the present disclosure, the total amount of polymer (I), water, and fluoropolymer other than polymer (I) is preferably 95.0 mass% or more, more preferably 99.0 mass% or more, and even more preferably 99.9 mass% or more, and it is particularly preferable that the composition consists essentially of polymer (I), water, and fluoropolymer other than polymer (I).

[0237] The first composition of the present disclosure can be obtained by removing the polymer (I) from water produced in the above-mentioned fluoropolymer production process. The removal method can be appropriately adopted from the embodiments described in the above-mentioned first treatment method of the present disclosure. In particular, the removal step involves flocculating the polymer (I), and the first composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant to water containing the polymer (I).

[0238] The present disclosure also provides a composition (hereinafter also referred to as the "second composition of the present disclosure") comprising a polymer (I) including polymerized units (I) based on a monomer represented by the following general formula (I), water, and a divalent or higher metal ion, wherein the content of the polymer (I) is 250 ppm or less: CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater. The second composition of the present disclosure may be an aqueous solution of polymer (I) or a dispersion of polymer (I).

[0239] In the second composition of the present disclosure, the polymer (I) is the same as that described in the first treatment method of the present disclosure, and any suitable embodiment can be adopted as appropriate. Among them, the above-mentioned polymer (1) is preferred.

[0240] The second composition of the present disclosure has a polymer (I) content of 250 ppm or less relative to the mass of the composition. The polymer (I) content is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of polymer (I) in the second composition of the present disclosure can be measured by the same method as for water containing polymer (I), for example, by solid-state NMR measurement. The second composition of the present disclosure may contain one single polymer (I) or may contain two or more different polymers (I).

[0241] The second composition of the present disclosure contains divalent or higher metal ions. The divalent or higher metal ions are not particularly limited, but are preferably, for example, ions of metals constituting the metal salts described above as inorganic flocculants, and are preferably, for example, at least one selected from the group consisting of Fe, Al, and Ca. The second composition of the present disclosure preferably has a divalent or higher metal ion content of 0.05 mg / L or more relative to the composition. More preferably, it is 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. The divalent or higher metal ion content is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less. The content of the divalent or higher metal ions is measured by the Pack Test method (manufactured by Kyoritsu Chemical Research Institute).

[0242] The second composition of the present disclosure may contain a substance other than polymer (I), water, and divalent or higher metal ions. For example, it may contain a flocculant or the like described in the first treatment method of the present disclosure. The second composition of the present disclosure may also contain a fluoropolymer other than polymer (I). As the fluoropolymer other than polymer (I), those contained in the first composition of the present disclosure can be appropriately adopted. As the fluoropolymer other than polymer (I), a fluoropolymer having an ion exchange ratio (IXR) higher than 53 is preferred. The second composition of the present disclosure may also contain PTFE. The PTFE is the same as that which may be contained in the first composition of the present disclosure. In the second composition of the present disclosure, the content of the fluorine-containing polymer other than the polymer (I) is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The content of fluoropolymers other than polymer (I) can be determined by a method of separating solid components (fluoropolymers other than polymer (I)) using an MF membrane. When the second composition of the present disclosure contains PTFE, the PTFE content is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, based on the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The PTFE content can be determined by a method of separating the solid component (PTFE) using an MF membrane.

[0243] In the second composition of the present disclosure, the total amount of polymer (I), water, and divalent or higher metal ions is preferably 95.0% by mass or more, more preferably 99.0% by mass or more, and even more preferably 99.9% by mass or more, and it is particularly preferable that the composition consists essentially of polymer (I), water, and divalent or higher metal ions.

[0244] The second composition of the present disclosure can be obtained by removing the polymer (I) from water produced in the above-mentioned fluoropolymer production process. The removal method can be appropriately adopted from the embodiments described in the above-mentioned first treatment method of the present disclosure. In particular, the removal step involves flocculating the polymer (I), and the second composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant (preferably a metal salt) to water containing the polymer (I).

[0245] The present disclosure also provides a water treatment method (hereinafter also referred to as the "second treatment method of the present disclosure"), characterized by comprising a step of removing a water-soluble polymer from water containing the water-soluble polymer in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms. Water-soluble refers to the property of being easily dissolved or dispersed in water. The particle size of a water-soluble polymer cannot be measured by, for example, dynamic light scattering (DLS). On the other hand, the particle size of a water-insoluble polymer can be measured by, for example, dynamic light scattering (DLS). In the second treatment method of the present disclosure, the removal step can employ all the same methods as the first treatment method of the present disclosure, except that water containing a water-soluble polymer in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms is used. The "proportion of hydrogen atoms bonded to carbon atoms replaced with fluorine atoms" is calculated as the ratio of the number of fluorine atoms to the total number of hydrogen atoms bonded to carbon atoms and halogen atoms (including fluorine atoms) bonded to carbon atoms. The removal step is preferably a step of flocculating water containing a water-soluble polymer, more preferably a step of adding a flocculant to water containing a water-soluble polymer, even more preferably a step of adding an inorganic flocculant to water containing a water-soluble polymer, and particularly preferably a step of adding an inorganic flocculant to water containing a water-soluble polymer and then adding a polymer flocculant. As the flocculant, inorganic flocculant, and polymer flocculant, those described in the first treatment method of the present disclosure can be appropriately used.

[0246] In the second treatment method of the present disclosure, the removal step is preferably a step of reducing the concentration of the water-soluble polymer in the water containing the water-soluble polymer to 50% or less of the concentration before the removal step, more preferably 40% or less, even more preferably 30% or less, especially preferably 20% or less, and particularly preferably 10% or less. The removal step is also preferably a step of reducing the concentration of the water-soluble polymer in the treated water to 250 ppm or less, more preferably 200 ppm or less, even more preferably 100 ppm or less, still more preferably 80 ppm or less, particularly preferably 60 ppm or less, and particularly preferably 50 ppm or less.

[0247] The water-soluble polymer is not particularly limited, and any water-soluble polymer of the above-mentioned polymer (I) in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms can be used, or any water-soluble polymer other than the above-mentioned polymer (I) in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms can be used.

[0248] Examples of the water-soluble polymer include those represented by the following general formula (I): CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater. Examples of the polymer include a water-soluble polymer containing polymerized units (I) based on a monomer represented by the following formula: In the water-soluble polymer, the content of the polymerized unit (I) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 99% by mass or more.

[0249] The water-soluble polymer may contain polymerized units based on a fluorine-containing monomer such as trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, fluorovinyl ether (FVE), CH2=CFCF3, CHF=CHCF3 (E-isomer), or CHF=CHCF3 (Z-isomer).

[0250] The water-soluble polymer may also contain polymerized units based on a non-fluorine-containing monomer. The non-fluorine-containing monomer may be a monomer having a radically polymerizable ethylenically unsaturated bond, and examples thereof include acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, hydrolyzable silyl group-containing monomers, hydroxyl group-containing alkyl vinyl ethers, carboxylic acid vinyl esters, and α-olefins. Among these, the non-fluorine-containing monomer is preferably at least one selected from the group consisting of acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, and hydrolyzable silyl group-containing monomers. The non-fluorine-containing monomer is more preferably at least one monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters, unsaturated carboxylic acids, and at least one monomer selected from the group consisting of hydrolyzable silyl group-containing monomers. In addition, a monomer having a radically polymerizable ethylenically unsaturated bond may be used in combination.

[0251] The acrylic acid ester or methacrylic acid ester is preferably an acrylic acid alkyl ester in which the alkyl group has 1 to 10 carbon atoms, or a methacrylic acid alkyl ester in which the alkyl group has 1 to 10 carbon atoms. Examples of the acrylic acid alkyl ester and the methacrylic acid alkyl ester include (meth)acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, n-propyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. The alkyl acrylate or alkyl methacrylate may also be a hydroxyl group-containing acrylic monomer having a hydroxyl group and a (meth)acryloyl group in the molecule, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, or 4-hydroxybutyl methacrylate. These acrylic acid esters or methacrylic acid esters may be used alone or in combination of two or more kinds, and n-butyl acrylate and methyl methacrylate are preferred.

[0252] Among them, the non-fluorine-containing monomer is preferably at least one (meth)acrylic acid alkyl ester selected from the group consisting of methyl methacrylate, n-butyl acrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate, wherein the acrylic acid ester or methacrylic acid ester does not contain a hydrolyzable silyl group.

[0253] As the acrylic acid ester or methacrylic acid ester, a combination of n-butyl acrylate and methyl methacrylate or a combination of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl methacrylate is more preferred, and a combination of n-butyl acrylate, methyl methacrylate and 2-ethylhexyl methacrylate is particularly preferred. In addition, it is also preferred to combine a hydroxyl group-containing acrylic monomer having a hydroxyl group and a (meth)acryloyl group.

[0254] Specific examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, vinylacetic acid, crotonic acid, cinnamic acid, 3-allyloxypropionic acid, 3-(2-allyloxyethoxycarbonyl)propionic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, maleic anhydride, fumaric acid, fumaric acid monoester, vinyl phthalate, vinyl pyromellitic acid, undecylenic acid, etc. Among these, at least one selected from the group consisting of acrylic acid, methacrylic acid, vinylacetic acid, crotonic acid, itaconic acid, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, 3-allyloxypropionic acid, and undecylenic acid is preferred because of its low homopolymerizability, making it difficult to form a homopolymer, and because the introduction of a carboxyl group is easily controlled.

[0255] Examples of the hydrolyzable silyl group-containing monomer include: CH2=CHCOO(CH2)3Si(OCH3)3, CH2=CHCOO(CH2)3Si(CH3)(OCH3)2, CH2=CHCOO(CH2)3Si(OC2H5)3, CH2=CHCOO(CH2)3Si(CH3)(OC2H5)2, CH2=C(CH3)COO(CH2)3Si(OCH3)3, CH2=C(CH3)COO(CH2)3Si(CH3)(OCH3)2, CH2=C(CH3)COO(CH2)3Si(OC2H5)3, CH2=C(CH3)COO(CH2)3Si(CH3)(OC2H5)2, CH2=C(CH3)COO(CH2)2O(CH2)3Si(OCH3)3, CH2=C(CH3)COO(CH2)2(CH2)3Si(CH3)(OCH3)2, CH2=C(CH3)COO(CH2) 11 Si(OCH3)3, CH2=C(CH3)COO(CH2) 11 Si(CH3)(OCH3)2, These hydrolyzable silyl group-containing monomers may be used alone or in combination of two or more.

[0256] As the hydrolyzable silyl group-containing monomer, at least one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane is preferred, and γ-methacryloxypropyltriethoxysilane is more preferred.

[0257] Examples of the hydroxyl group-containing alkyl vinyl ethers include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, glycerol monoallyl ether, etc. In terms of excellent polymerization reactivity, at least one selected from the group consisting of 4-hydroxybutyl vinyl ether and 2-hydroxyethyl vinyl ether is preferred.

[0258] Examples of vinyl carboxylate esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl cyclohexylcarboxylate, vinyl benzoate, and vinyl para-t-butylbenzoate.

[0259] Examples of the α-olefins include ethylene, propylene, n-butene, isobutene, and styrene.

[0260] The number average molecular weight of the water-soluble polymer is 0.1×10 4 More than 0.2 × 10 is preferable. 4 More preferably, 0.3 × 10 4 More preferably, 0.4×10 4 More than 0.5 × 10 is particularly preferable. 4 More than 1.0 × 10 4 More than 3.0 × 10 is particularly preferable. 4 The above is particularly preferable, and 3.1 × 10 4 More than 75.0×10 4 The following is preferable: 50.0 x 10 4 Less than 40.0 x 10 is more preferable. 4 More preferably, 30.0 x 10 4More preferably, 20.0 x 10 4 The weight average molecular weight of the water-soluble polymer is particularly preferably 0.2×10 4 More than 0.4 × 10 is preferable. 4 More preferably, 0.6 × 10 4 More preferably, 0.8×10 4 More preferably, 1.0×10 4 More than 5.0 × 10 is particularly preferable. 4 More particularly preferred is 10.0 x 10 4 More particularly, 15.0 × 10 4 More particularly, 20.0 × 10 4 The above is particularly preferable, and 25.0 × 10 4 More than 150.0×10 4 The following is preferable: 100.0 x 10 4 Less than 60.0 x 10 is preferable. 4 More preferably, 50.0 x 10 4 The following is particularly preferred: 40.0 x 10 4 The following are particularly preferred: The number average molecular weight and weight average molecular weight are values calculated by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. When GPC measurement is not possible, the number average molecular weight of the water-soluble polymer can be determined from the correlation between the number average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0261] The water-soluble polymer preferably has an ion-exchange ratio (IXR) of 53 or less. The IXR is preferably 0.5 or more, more preferably 1 or more, even more preferably 3 or more, even more preferably 4 or more, especially preferably 5 or more, and particularly preferably 8 or more. The IXR is more preferably 43 or less, even more preferably 33 or less, and particularly preferably 23 or less. In the water-soluble polymer, the ionic (anionic) groups are typically distributed along the polymer backbone. The water-soluble polymer comprises a polymer backbone with recurring side chains attached to the backbone, which preferably carry the ionic groups. The water-soluble polymer preferably comprises ionic groups (anionic groups) having a pKa of less than 10, more preferably less than 7. The ionic groups of the water-soluble polymer are preferably selected from the group consisting of sulfonates, carboxylates, phosphonates, phosphates, and mixtures thereof. The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When salts are used, preferably the salts are alkali metal or ammonium salts. A preferred ionic group is a sulfonate group.

[0262] The water containing the water-soluble polymer is not particularly limited, and examples thereof include water generated in a polymer production process such as a production process of the water-soluble polymer, a polymer polymerization process using the water-soluble polymer, etc. The water containing the water-soluble polymer may be wastewater.

[0263] In the water containing the water-soluble polymer, the content of the water-soluble polymer is not particularly limited, but is preferably 10% by mass or less, for example, from the viewpoint of increasing the removal efficiency. In the water containing the water-soluble polymer, the content of the water-soluble polymer is more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less, and may be more than 0%, 0.005%, 0.006%, 0.008%, 0.010% by mass or more, 0.020% by mass or more, 0.025% by mass or more, or 0.1% by mass or more. The content of the water-soluble polymer can be measured, for example, by solid-state NMR. The water containing the water-soluble polymer may contain one single type of water-soluble polymer, or may contain two or more different types of water-soluble polymers.

[0264] The water containing the water-soluble polymer may contain substances other than the water-soluble polymer and water, and may be in the form of a dispersion, an aqueous solution, or the like. Examples of substances other than water-soluble polymers and water include non-fluorine-containing polymers other than water-soluble polymers, fluorine-containing polymers other than water-soluble polymers, and oligomers. The fluoropolymer other than the water-soluble polymer is a fluoropolymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is less than 50%, or a water-insoluble fluoropolymer. As the fluorine-containing polymer other than the water-soluble polymer, a fluorine-containing polymer having an ion exchange ratio (IXR) higher than 53 can be mentioned. Fluoropolymers other than the preferred water-soluble polymers have no ionic groups or a limited number of ionic groups that result in an ion exchange ratio greater than about 100. The ion exchange rate of the fluoropolymer other than the water-soluble polymer is preferably more than 53, more preferably 100 or more, even more preferably 1000 or more, particularly preferably 2000 or more, and particularly preferably 5000 or more. Examples of the fluoropolymer other than the water-soluble polymer include those described in the first treatment method of the present disclosure. Examples of the polymer include copolymers of PTFE, TFE, and another monomer copolymerizable with TFE (fluorine-containing monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)); fluororesins such as polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE); vinylidene fluoride rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymer, fluororubbers such as tetrafluoroethylene-propylene rubber (FEPM), and tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers. The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by weight or less of a modifying monomer. The fluoropolymer other than the water-soluble polymer is preferably at least one selected from the group consisting of PTFE and melt-processable fluororesin containing 60.0 to 98.0 mass% of TFE units and 2.0 to 40.0 mass% of other monomers, and more preferably PTFE.

[0265] The water containing the water-soluble polymer preferably has a content of substances other than the water-soluble polymer and water of 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less. The lower limit of the content of substances other than the water-soluble polymer and water is not limited, but may be, for example, 0% by mass or 0.1% by mass. The water containing the water-soluble polymer preferably has a water content of 99.0% by mass or more, more preferably 99.5% by mass or more, and even more preferably 99.8% by mass or more.

[0266] The present disclosure also provides a composition (hereinafter also referred to as the "third composition of the present disclosure") comprising a water-soluble polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, water, and a fluorine-containing polymer (excluding the water-soluble polymer), wherein the content of the water-soluble polymer is 250 ppm or less. The third composition of the present disclosure is preferably an aqueous solution of a water-soluble polymer.

[0267] In the third composition of the present disclosure, the water-soluble polymer is the same as that described in the second treatment method of the present disclosure, and any suitable embodiment can be adopted as appropriate.

[0268] The third composition of the present disclosure has a water-soluble polymer content of 250 ppm or less relative to the mass of the composition. The water-soluble polymer content is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of the water-soluble polymer in the third composition of the present disclosure can be measured by the same method as for water containing a water-soluble polymer, for example, by solid-state NMR measurement. The third composition of the present disclosure may contain one single water-soluble polymer, or may contain two or more different water-soluble polymers.

[0269] The third composition of the present disclosure contains a fluoropolymer other than the water-soluble polymer. As the fluoropolymer other than the water-soluble polymer, any fluoropolymer other than the water-soluble polymer described in the second treatment method of the present disclosure can be appropriately adopted, and a suitable embodiment can be appropriately adopted. The ion exchange rate of the fluoropolymer other than the water-soluble polymer is preferably more than 53, more preferably 100 or more, even more preferably 1000 or more, particularly preferably 2000 or more, and particularly preferably 5000 or more. As the fluorine-containing polymer other than the water-soluble polymer, PTFE is preferred.

[0270] In the third composition of the present disclosure, the content of the fluorine-containing polymer other than the water-soluble polymer is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The content of fluoropolymers other than water-soluble polymers can be determined by a method of separating solid components (fluoropolymers other than water-soluble polymers) using an MF membrane.

[0271] The third composition of the present disclosure may contain a substance other than the water-soluble polymer, water, and a fluoropolymer other than the water-soluble polymer. For example, it may contain a flocculant or the like described in the second treatment method of the present disclosure. The third composition of the present disclosure may also contain metal ions or divalent or higher metal ions. As the divalent or higher metal ions, those contained in the second composition of the present disclosure may be appropriately contained. The content of divalent or higher metal ions in the composition is preferably 0.05 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. The content of divalent or higher metal ions is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less.

[0272] In the third composition of the present disclosure, the total amount of the water-soluble polymer, water, and the fluoropolymer other than the water-soluble polymer is preferably 95.0% by mass or more, more preferably 99.0% by mass or more, and even more preferably 99.9% by mass or more, and it is particularly preferable that the composition consists essentially of the water-soluble polymer, water, and the fluoropolymer other than the water-soluble polymer.

[0273] The third composition of the present disclosure can be obtained by removing the water-soluble polymer from water containing the water-soluble polymer described in the second treatment method of the present disclosure. The removal method can be appropriately adopted from the embodiments described in the second treatment method of the present disclosure. In particular, the removal step involves flocculating the water-soluble polymer, and the third composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant to water containing the water-soluble polymer.

[0274] The present disclosure also provides a composition (hereinafter also referred to as the "fourth composition of the present disclosure") comprising a water-soluble polymer in which 50% or more of hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, water, and divalent or higher metal ions, the water-soluble polymer content being 250 ppm or less. The fourth composition of the present disclosure is preferably an aqueous solution of a water-soluble polymer.

[0275] In the fourth composition of the present disclosure, the water-soluble polymer is the same as the water-soluble polymer described in the second treatment method of the present disclosure, and any suitable embodiment can be adopted as appropriate.

[0276] The fourth composition of the present disclosure has a water-soluble polymer content of 250 ppm or less relative to the mass of the composition. The water-soluble polymer content is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of the water-soluble polymer in the fourth composition of the present disclosure can be measured by the same method as for water containing a water-soluble polymer, for example, by solid-state NMR measurement. The fourth composition of the present disclosure may contain one single water-soluble polymer, or may contain two or more different water-soluble polymers.

[0277] The fourth composition of the present disclosure contains divalent or higher metal ions. The divalent or higher metal ions are not particularly limited, but are preferably, for example, ions of metals constituting the metal salts described above as inorganic flocculants, and for example, at least one selected from the group consisting of Fe, Al, and Ca is preferred. In the fourth composition of the present disclosure, the content of the divalent or higher metal ions is preferably 0.05 mg / L or more relative to the composition. More preferably, it is 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. The content of the divalent or higher metal ions is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less. The content of the divalent or higher metal ions is measured by the Pack Test method (manufactured by Kyoritsu Chemical Research Institute).

[0278] The fourth composition of the present disclosure may contain a substance other than the water-soluble polymer, water, and divalent or higher metal ions. For example, it may contain a flocculant or the like described in the first treatment method of the present disclosure. The fourth composition of the present disclosure may also contain a fluoropolymer other than the water-soluble polymer. As the fluoropolymer other than the water-soluble polymer, those described in the second treatment method of the present disclosure can be appropriately adopted. As the fluoropolymer other than the water-soluble polymer, a fluoropolymer having an ion exchange ratio (IXR) higher than 53 is preferred. The fourth composition of the present disclosure may also contain PTFE. As the PTFE, those described in the second treatment method of the present disclosure can be appropriately adopted. In the fourth composition of the present disclosure, the content of the fluorine-containing polymer other than the water-soluble polymer is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The content of fluoropolymers other than water-soluble polymers can be determined by a method of separating solid components (fluoropolymers other than water-soluble polymers) using an MF membrane.

[0279] In the fourth composition of the present disclosure, the total amount of the water-soluble polymer, water, and divalent or higher metal ions is preferably 95.0% by mass or more, more preferably 99.0% by mass or more, and even more preferably 99.9% by mass or more, and it is particularly preferable that the composition consists essentially of the water-soluble polymer, water, and divalent or higher metal ions.

[0280] The fourth composition of the present disclosure can be obtained by removing the water-soluble polymer from water containing the water-soluble polymer described in the second treatment method of the present disclosure. The removal method can be appropriately adopted from the embodiments described in the second treatment method of the present disclosure. In particular, the removal step involves flocculating the water-soluble polymer, and the fourth composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant (preferably a metal salt) to water containing the water-soluble polymer.

[0281] The present disclosure also provides a water treatment method (hereinafter also referred to as the "third treatment method of the present disclosure"), characterized by comprising a step of removing a polymer from water containing a polymer in which 50% or more of hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, the polymer contains ionic groups, and the polymer has an ion exchange rate of 53 or less. In the third treatment method of the present disclosure, the removal step can employ all the same methods as the first treatment method of the present disclosure, except that water containing a polymer (hereinafter also referred to as "polymer α") in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, the polymer contains ionic groups, and the ion exchange rate is 53 or less. The removal step is preferably a step of flocculating the water containing the polymer α, more preferably a step of adding a flocculant to the water containing the polymer α, even more preferably a step of adding an inorganic flocculant to the water containing the polymer α, and particularly preferably a step of adding an inorganic flocculant to the water containing the polymer α and then adding a polymer flocculant. As the flocculant, inorganic flocculant, and polymer flocculant, those described in the first treatment method of the present disclosure can be appropriately used. The water containing the polymer α is not particularly limited, and examples thereof include water generated in a polymer production process such as a production process of the polymer α, a polymer polymerization process using the polymer α, etc. The water containing the polymer α may be wastewater.

[0282] In the third treatment method of the present disclosure, the removal step is preferably a step of reducing the concentration of polymer α in the water containing polymer α to 50% or less of the concentration before the removal step, more preferably 40% or less, even more preferably 30% or less, especially preferably 20% or less, and particularly preferably 10% or less. The removal step is also preferably a step of reducing the concentration of polymer α in the treated water to 250 ppm or less, more preferably 200 ppm or less, even more preferably 100 ppm or less, still more preferably 80 ppm or less, particularly preferably 60 ppm or less, and particularly preferably 50 ppm or less.

[0283] The polymer α is not particularly limited, and a water-soluble or water-insoluble polymer can be used from the above-mentioned polymer (I), which is a polymer in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, which contains an ionic group, and which has an ion-exchange rate of 53 or less; or a polymer other than the above-mentioned polymer (I), which is a polymer in which 50% or more of the hydrogen atoms bonded to carbon atoms have been substituted with fluorine atoms, which contains an ionic group, and which has an ion-exchange rate of 53 or less, can also be used.

[0284] The polymer α is, for example, a polymer represented by the following general formula (I): CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater. Examples of the polymer include a water-soluble or water-insoluble polymer containing polymerized units (I) based on a monomer represented by the following formula: In the polymer α, the content of the polymerized unit (I) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 99% by mass or more.

[0285] The polymer α may contain polymerization units based on a fluorine-containing monomer based on trifluoroethylene, tetrafluoroethylene (TFE), vinylidene fluoride (VdF), vinyl fluoride (VF), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), hexafluoroisobutylene, perfluoroalkylethylene, fluorovinyl ether (FVE), CH═CFCF, CHF═CHCF (E-isomer), CHF═CHCF (Z-isomer), or the like.

[0286] The polymer α may also contain polymerized units based on a fluorine-free monomer. The fluorine-free monomer may be a monomer having a radically polymerizable ethylenically unsaturated bond, and examples thereof include acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, hydrolyzable silyl group-containing monomers, hydroxyl group-containing alkyl vinyl ethers, carboxylic acid vinyl esters, and α-olefins. Among these, the fluorine-free monomer is preferably at least one selected from the group consisting of acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, and hydrolyzable silyl group-containing monomers. The non-fluorine-containing monomer is more preferably at least one monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters, unsaturated carboxylic acids, and at least one monomer selected from the group consisting of hydrolyzable silyl group-containing monomers. In addition, a monomer having a radically polymerizable ethylenically unsaturated bond may be used in combination. As the non-fluorine-containing monomer, those described above for the water-soluble polymer can be used.

[0287] The number average molecular weight of the polymer α is 0.1×10 4 More than 0.2 × 10 is preferable. 4 More preferably, 0.3 × 10 4 More preferably, 0.4×10 4 More than 0.5 × 10 is particularly preferable. 4 More than 1.0 × 10 4 More than 3.0 × 10 is particularly preferable. 4 The above is particularly preferable, and 3.1 × 10 4 More than 75.0×10 4 The following is preferable: 50.0 x 10 4 Less than 40.0 x 10 is more preferable. 4 More preferably, 30.0 x 10 4 More preferably, 20.0 x 10 4 The weight average molecular weight of the polymer α is particularly preferably 0.2×10 4 More than 0.4 × 10 is preferable. 4 More preferably, 0.6 × 10 4 More preferably, 0.8×10 4 More preferably, 1.0×10 4 More than 5.0 × 10 is particularly preferable. 4 More particularly preferred is 10.0 x 10 4 More particularly, 15.0 × 10 4 More particularly, 20.0 × 10 4 The above is particularly preferable, and 25.0 × 10 4 The above is most preferable. Also, 150.0×10 4 The following is preferable: 100.0 x 10 4 Less than 60.0 x 10 is preferable. 4 More preferably, 50.0 x 10 4 The following is particularly preferred: 40.0 x 10 4 The following are particularly preferred: The number average molecular weight and weight average molecular weight are values calculated by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. When GPC measurement is not possible, the number average molecular weight of the water-soluble polymer can be determined from the correlation between the number average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0288] The polymer α is preferably water-soluble. Water-soluble means the property of being easily dissolved or dispersed in water. The particle size of a water-soluble polymer α cannot be measured by, for example, dynamic light scattering (DLS). On the other hand, the particle size of a water-insoluble polymer α can be measured by, for example, dynamic light scattering (DLS). The polymer α has an ion exchange ratio (IXR) of 53 or less. The IXR is preferably 0.5 or more, more preferably 1 or more, even more preferably 3 or more, even more preferably 4 or more, particularly preferably 5 or more, and particularly preferably 8 or more. The IXR is more preferably 43 or less, more preferably 33 or less, and particularly preferably 23 or less. In the polymer α, the ionic groups are typically distributed along the polymer backbone. The polymer α comprises a polymer backbone with recurring side chains attached to the backbone, the side chains preferably having ionic groups. Preferably, polymer α comprises ionizable groups having a pKa of less than 10, more preferably less than 7. The ionizable groups of polymer α are preferably selected from the group consisting of sulfonates, carboxylates, phosphonates, phosphates, and mixtures thereof. The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When salts are used, preferably the salts are alkali metal or ammonium salts. A preferred ionic group is a sulfonate group.

[0289] In the water containing the polymer α, the content of the polymer α is not particularly limited, but is preferably 10% by mass or less, for example, from the viewpoint of improving removal efficiency. In the water containing the polymer α, the content of the polymer α is more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less. Furthermore, the content may be more than 0% by mass, more than 0.005% by mass, more than 0.006% by mass, more than 0.008% by mass, 0.010% by mass or more, more than 0.020% by mass, more than 0.025% by mass, or 0.1% by mass or more. The content of the polymer α can be measured, for example, by solid-state NMR. The water containing the polymer α may contain one single type of polymer α, or may contain two or more different types of polymer α.

[0290] The water containing the polymer α may contain substances other than the polymer α and water, and may be a dispersion, an aqueous solution, or the like. Examples of the substance other than the polymer α and water include a non-fluorine-containing polymer, a fluorine-containing polymer other than the polymer α, and an oligomer. A fluoropolymer other than polymer α is a fluoropolymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is less than 50%, which does not contain an ionic group, or which has an ion exchange rate of more than 53. As the fluoropolymer other than polymer α, a fluoropolymer having an ion exchange ratio (IXR) higher than 53 can be mentioned. The preferred fluoropolymers other than polymer α have no ionic groups or have a limited number of ionic groups that result in an ion-exchange rate higher than about 100. The ion-exchange rate of the fluoropolymers other than polymer α is preferably 1,000 or higher, more preferably 2,000 or higher, and even more preferably 5,000 or higher. Specific examples of the fluoropolymer other than the polymer α include the fluoropolymers described in the first treatment method of the present disclosure, which have a ratio of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms of less than 50%, which do not contain ionic groups, or which have an ion exchange ratio (IXR) higher than 53. Examples of the polymer include copolymers of PTFE, TFE, and another monomer copolymerizable with TFE (fluorine-containing monomers such as vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, and perfluoro(alkyl vinyl ether), hydrocarbon olefins such as ethylene, propylene, and isobutene, and alkyl vinyl ethers) (e.g., tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE)); fluororesins such as polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene (ECTFE); vinylidene fluoride rubbers (FKM) such as vinylidene fluoride-hexafluoropropylene copolymer, fluororubbers such as tetrafluoroethylene-propylene rubber (FEPM), and tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM), and fluorine-containing elastomers. The PTFE may be a homopolymer of TFE, or may be a modified PTFE containing 99.0% by mass or more of TFE and 1.0% by weight or less of a modifying monomer. The fluoropolymer other than the polymer α is preferably at least one selected from the group consisting of PTFE and melt-processable fluororesin containing 60.0 to 98.0 mass % of TFE units and 2.0 to 40.0 mass % of other monomers, and more preferably PTFE.

[0291] The water containing the polymer α preferably has a content of substances other than the polymer α and water of 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less. The lower limit of the content of substances other than the polymer α and water is not limited, but may be, for example, 0% by mass or 0.1% by mass. The water containing the polymer α preferably has a water content of 99.0% by mass or more. It is more preferably 99.5% by mass or more, and even more preferably 99.8% by mass or more.

[0292] The present disclosure also provides a composition (hereinafter also referred to as the "fifth composition of the present disclosure") comprising: a polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less; water; and a fluorine-containing polymer (excluding the polymer); the content of the polymer is 250 ppm or less.

[0293] In the fifth composition of the present disclosure, the polymer (polymer α) in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, which contains ionic groups, and which has an ion exchange rate of 53 or less is the same as that described in the third treatment method of the present disclosure, and any suitable embodiment can be adopted as appropriate. The fifth composition of the present disclosure may be an aqueous solution of the polymer α or a dispersion of the polymer α.

[0294] In the fifth composition of the present disclosure, the content of polymer α is 250 ppm or less relative to the mass of the composition. The content of polymer α is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of polymer α in the fifth composition of the present disclosure can be measured by the same method as that for water containing polymer α, for example, by solid-state NMR measurement. The fifth composition of the present disclosure may contain one single type of polymer α, or may contain two or more different types of polymer α.

[0295] The water containing the polymer α contains a fluoropolymer other than the polymer α. As the fluoropolymer other than the polymer α, those described in the third treatment method of the present disclosure can be appropriately adopted, and a suitable embodiment can be appropriately adopted. The ion exchange rate of the fluoropolymer other than polymer α is preferably more than 53, more preferably 100 or more, even more preferably 1000 or more, particularly preferably 2000 or more, and particularly preferably 5000 or more. As the fluoropolymer other than the polymer α, PTFE is preferred.

[0296] In the fifth composition of the present disclosure, the content of the fluoropolymer other than polymer α is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The content of fluoropolymers other than polymer α can be determined by a method of separating solid components (fluoropolymers other than polymer α) using an MF membrane.

[0297] The fifth composition of the present disclosure may contain a substance other than the polymer α, water, and a fluoropolymer other than the polymer α. For example, it may contain a flocculant or the like described in the third treatment method of the present disclosure. The fifth composition of the present disclosure may also contain metal ions, or may contain divalent or higher valent metal ions. As the divalent or higher valent metal ions, those contained in the second composition of the present disclosure may be appropriately contained. The content of divalent or higher metal ions in the composition is preferably 0.05 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. The content of divalent or higher metal ions is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less.

[0298] In the fifth composition of the present disclosure, the total amount of polymer α, water, and fluoropolymers other than polymer α is preferably 95.0 mass% or more, preferably 99.0 mass% or more, more preferably 99.9 mass% or more, and it is particularly preferable that the composition consists essentially of polymer α, water, and fluoropolymers other than polymer α.

[0299] The fifth composition of the present disclosure can be obtained by removing the polymer α from water containing the polymer α described in the third treatment method of the present disclosure. The removal method can be appropriately adopted from the embodiments described in the third treatment method of the present disclosure. In particular, the removal step involves flocculating the polymer α, and the fifth composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant to the water containing the polymer α.

[0300] The present disclosure also provides a composition (hereinafter also referred to as the "sixth composition of the present disclosure") comprising: a polymer in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, the polymer contains an ionic group, and the polymer has an ion exchange rate of 53 or less; water; and divalent or higher metal ions; and the polymer content is 250 ppm or less.

[0301] In the sixth composition of the present disclosure, the polymer (polymer α) in which the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is 50% or more, which contains ionic groups, and which has an ion exchange rate of 53 or less is the same as that described in the third treatment method of the present disclosure, and any suitable embodiment can be adopted as appropriate. The sixth composition of the present disclosure may be an aqueous solution of the polymer or a dispersion of the polymer.

[0302] In a sixth composition of the present disclosure, the content of polymer α is 250 ppm or less relative to the mass of the composition. The content of polymer α is preferably 200 ppm or less, more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, particularly preferably 25 ppm or less, and particularly preferably 10 ppm or less. The lower limit of the content is not particularly limited, but is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, even more preferably 1 ppm or more, even more preferably 2 ppm or more, and particularly preferably 5 ppm or more. The content of polymer α in the sixth composition of the present disclosure can be measured by the same method as that for water containing polymer α, for example, by solid-state NMR measurement. The sixth composition of the present disclosure may contain one single type of polymer α, or may contain two or more different types of polymer α.

[0303] The sixth composition of the present disclosure contains divalent or higher metal ions. The divalent or higher metal ions are not particularly limited, but are preferably, for example, ions of metals constituting the metal salts described above as inorganic flocculants, and for example, at least one selected from the group consisting of Fe, Al, and Ca is preferred. In the sixth composition of the present disclosure, the content of the divalent or higher metal ions is preferably 0.05 mg / L or more relative to the composition. More preferably, it is 0.1 mg / L or more, even more preferably 0.15 mg / L or more, and particularly preferably 0.2 mg / L or more. Furthermore, the content of the divalent or higher metal ions is preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 250 mg / L or less, even more preferably 100 mg / L or less, particularly preferably 50 mg / L or less, particularly preferably 10 mg / L or less, and most preferably 5 mg / L or less. The content of the divalent or higher metal ions is measured by the Pack Test method (manufactured by Kyoritsu Chemical Research Institute).

[0304] The sixth composition of the present disclosure may contain a substance other than polymer α, water, and divalent or higher metal ions. For example, it may contain a flocculant or the like described in the third treatment method of the present disclosure. The sixth composition of the present disclosure may also contain a fluoropolymer other than polymer α. As the fluoropolymer other than polymer α, those described in the third treatment method of the present disclosure can be appropriately adopted. As the fluoropolymer other than polymer α, a fluoropolymer having an ion exchange ratio (IXR) higher than 53 is preferred. The fourth composition of the present disclosure may also contain PTFE. As the PTFE, those described in the third treatment method of the present disclosure can be appropriately adopted. In the sixth composition of the present disclosure, the content of the fluoropolymer other than polymer α is preferably 5000 ppm or less, more preferably 2000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the mass of the composition. The lower limit of the content is not particularly limited, but may be substantially 0 ppm, more than 0 ppm, 1 ppm or more, or 100 ppm or more. The content of fluoropolymers other than polymer α can be determined by a method of separating solid components (fluoropolymers other than polymer α) using an MF membrane.

[0305] In the sixth composition of the present disclosure, the total amount of polymer α, water, and divalent or higher metal ions is preferably 95.0% by mass or more, more preferably 99.0% by mass or more, and even more preferably 99.9% by mass or more, and it is particularly preferable that the composition essentially consists of polymer α, water, and divalent or higher metal ions.

[0306] The sixth composition of the present disclosure can be obtained by removing the polymer α from water containing the polymer α described in the third treatment method of the present disclosure. The removal method can be appropriately adopted from the embodiments described in the third treatment method of the present disclosure. In particular, the removal step involves flocculating the polymer α, and the sixth composition of the present disclosure can be suitably obtained by a method that employs a step of adding an inorganic flocculant (preferably a metal salt) to the water containing the polymer α. [Example]

[0307] Next, the present disclosure will be explained using experimental examples, but the present disclosure is not limited to only such experimental examples.

[0308] In the experimental examples below, the following formula: CH2=CF(CF2OCFCF3COOH) A homopolymer of a monomer represented by the following formula (number average molecular weight: 90,000, weight average molecular weight: 190,000) (hereinafter referred to as "polymer A") was used. The number average molecular weight and weight average molecular weight were measured by gel permeation chromatography (GPC) using a GPC HLC-8020 manufactured by Tosoh Corporation and Shodex columns (one GPC KF-801, one GPC KF-802, and two GPC KF-806M columns connected in series) with tetrahydrofuran (THF) as a solvent at a flow rate of 1 ml / min, and the molecular weight was calculated using monodisperse polystyrene as a standard.

[0309] The values in the experimental examples were measured by the following methods.

[0310] Polymer A content in the treated aqueous solution The content of polymer A in the aqueous treatment solution was measured by the following method.

[0311] Preparation of a calibration curve for polymer A Five levels of aqueous solutions containing sodium trifluoroacetate and polymer A of known concentrations were prepared. 19 F NMR measurement was performed. Using a first-order approximation from the concentrations of sodium trifluoroacetate and polymer A in each sample and the peak area values of sodium trifluoroacetate and polymer A, a was calculated from the following relational expression (1). A=a×5×B×W×136.00 / (3×X×256.08) (1) A: Peak area value (δ) derived from CF2 and CF3 of polymer A F ppm:-78~-88(-CF-CF2-O-, >CF-CF3)) W: Concentration of polymer A (ppm) B: Peak area value of trifluoroacetic acid (δ F ppm:-76(CF3-)) X: Trifluoroacetic acid concentration (ppm) The chemical shift was determined by setting the peak derived from CF3 of sodium trifluoroacetate at -76.0 ppm.

[0312] The treated aqueous solution was concentrated using an evaporator. After concentration, sodium trifluoroacetate was added to the treated aqueous solution. 19 F NMR measurement was performed. The content of polymer A in the treated aqueous solution was calculated from the concentration of sodium trifluoroacetate in the measurement sample and the peak area values of sodium trifluoroacetate and polymer A according to the following relational formula (2). Y=3×C×Z×P×256.08 / (a×5×D×Q×136.00) (2) C: Peak area value of polymer A (δ F ppm:-78~-88(-CF-CF2-O-, >CF-CF3)) Y: Polymer A content in the treatment aqueous solution (ppm) D: Peak area value of trifluoroacetic acid (δ F ppm:-76(CF3-)) Z: Trifluoroacetic acid concentration (ppm) P: Mass of concentrated pretreatment aqueous solution (g) Q: Mass of concentrated post-treatment aqueous solution (g) The chemical shift was determined by setting the peak derived from CF3 of sodium trifluoroacetate at -76.0 ppm.

[0313] pH Measurement was performed using a Horiba pH meter D-20.

[0314] Dissolved aluminum concentration in the treated water solution Measurements were performed using Pack Test Aluminum (manufactured by Kyoritsu Chemical Research Institute, model WAK-AI, measurement limit 0.05 mg / L), a simple water quality analysis product.

[0315] Example 1 As a model aqueous solution, 0.37 g of a 26.8 mass % aluminum sulfate aqueous solution was added to 100 g of an aqueous solution (aqueous solution A) containing 500 ppm of polymer A. The polymer A-containing aqueous solution (aqueous solution A) was stirred in a container at a temperature of 25°C for 30 minutes. After stirring, the pH was 3.2. A 25% aqueous solution of NaOH was added as a pH adjuster to the polymer A-containing aqueous solution (aqueous solution A) to adjust the pH to 7.3. To the pH-adjusted aqueous solution, 0.34 g of a 0.07% by mass aqueous solution of polyacrylamide partial hydrolysate (product name: Floclan A1210, manufactured by Katayama Nalco Corporation) was added. After stirring at a temperature of 25°C for 30 minutes, an aluminum precipitate was deposited. The precipitated aluminum precipitate was filtered with filter paper to obtain a treated aqueous solution. The concentration of polymer A in the treated aqueous solution was 42 ppm. The concentration of dissolved aluminum in the treated aqueous solution was 1 mg / L.

[0316] Example 2 A treated aqueous solution was obtained in the same manner as in Experimental Example 1, except that the amount of aluminum sulfate aqueous solution added was 0.05 g, the pH before pH adjustment was 2.9, and the pH after pH adjustment was 6.8. The concentration of polymer A in the obtained treated aqueous solution was 90 ppm. The concentration of dissolved aluminum in the obtained treated aqueous solution was 0.5 mg / L.

Claims

1. The method includes a step of removing the polymer (I) from water containing the polymer (I) comprising polymerization units (I) based on a monomer represented by the following general formula (I), wherein the removal step is a step of flocculating the water containing the polymer (I) by adding an inorganic flocculant and a polymer flocculant to the water containing the polymer (I), and wherein the number average molecular weight of the polymer (I) is 1.0 × 10 ４ wherein the proportion of hydrogen atoms bonded to carbon atoms in the polymer (I) that have been substituted with fluorine atoms is 50% or more, and the ion exchange rate of the polymer (I) is 53 or less. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

2. 2. The treatment method according to claim 1, wherein the inorganic flocculant is at least one metal salt selected from the group consisting of aluminum salts, iron salts, calcium salts, and silicate minerals containing divalent or higher metal elements and silicon.

3. 3. The treatment method according to claim 1, wherein the inorganic flocculant is at least one aluminum salt selected from the group consisting of aluminum sulfate and polyaluminum chloride.

4. 4. The treatment method according to claim 1, wherein the polymer flocculant is an anionic polymer flocculant.

5. 5. The treatment method according to claim 1, wherein the removing step comprises adding an inorganic flocculant to water containing the polymer (I) and then adding a polymer flocculant.

6. 6. The treatment method according to claim 1, wherein the water containing the polymer (I) is water that has been subjected to a fluoropolymer polymerization process.

7. A ０ The anionic group is —SO ３ M (wherein M is —H, a metal atom, —NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ７ The treatment method according to any one of claims 1 to 6, wherein:

8. The composition comprises a polymer (I) containing polymerized units (I) based on a monomer represented by the following general formula (I), water, and a fluorine-containing polymer (excluding the polymer (I)) which has no ionic group or has an ion exchange rate higher than 53, wherein the content of the polymer (I) is 0.1 ppm or more and 250 ppm or less, and the number average molecular weight of the polymer (I) is 1.0 × 10 ４ or more, wherein the proportion of hydrogen atoms bonded to carbon atoms in the polymer (I) that have been substituted with fluorine atoms is 50% or more, and the ion exchange rate of the polymer (I) is 53 or less. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

9. A ０ The anionic group is —SO ３ M (wherein M is —H, a metal atom, —NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ７ The composition of claim 8, wherein:

10. 10. The composition according to claim 8, wherein the fluorine-containing polymer is polytetrafluoroethylene.

11. The composition according to any one of claims 8 to 10, wherein the content of the fluorine-containing polymer is 1 to 5000 ppm.

12. The composition according to any one of claims 8 to 11, further comprising a divalent or higher valent metal ion.

13. 13. The composition according to claim 12, wherein the content of divalent or higher valent metal ions is 0.05 to 1000 mg / L or more.

14. The polymer (I) contains polymer units (I) based on a monomer represented by the following general formula (I), water, and divalent or higher metal ions, the content of the polymer (I) being 250 ppm or less, the divalent or higher metal ions being ions of at least one metal selected from the group consisting of Fe, Al, and Ca, and the number average molecular weight of the polymer (I) being 1.0 × 10 ４ or more, wherein the proportion of hydrogen atoms bonded to carbon atoms in the polymer (I) that have been substituted with fluorine atoms is 50% or more, and the ion exchange rate of the polymer (I) is 53 or less. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

15. A ０ The anionic group is —SO ３ M (wherein M is —H, a metal atom, —NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ７ The composition of claim 14, wherein:

16. 16. The composition according to claim 14, wherein the content of divalent or higher valent metal ions is 0.05 to 1000 mg / L.

17. The composition according to any one of claims 8 to 16, further comprising a polymer flocculant.

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