Wastewater treatment agent and wastewater treatment method

Abstract

To provide a wastewater treatment agent and a wastewater treatment method which can efficiently remove an element of interest or a compound thereof, especially a complex, from wastewater.SOLUTION: A wastewater treatment agent for removal of a group 6 to 16 element or a compound of the element from wastewater containing the element or the compound comprises an organic ammonium compound having at least one structure of organic ammonium salts. Preferably, the organic ammonium compound having the structure of organic ammonium salts has a solubility to water of 1 mass% or more, and the wastewater treatment agent comprises a dithiocarbamate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a wastewater treatment agent and a wastewater treatment method, and more particularly to a treatment agent for an element of Groups 6 to 16 or a compound thereof and a method for treating water containing the same. [Background technology]

[0002] Various treatments have been performed to separate and recover elements or compounds of Groups 6 to 16, such as copper, zinc, and nickel, from industrial wastewater, business wastewater, and other sources for purposes such as water purification, detoxification, and reuse of these elements. In particular, wastewater containing complexes of these elements (compounds in which the elements or other compounds are complexed with ligands) is difficult to treat, and various methods have been investigated. For example, techniques for removing metals from wastewater containing metal complexes have been proposed, including coagulation and precipitation, which removes metal ions as sparingly soluble salts such as hydroxides or sulfides; coagulation and separation removal methods using inorganic or organic coagulants; adsorption methods using activated carbon, inorganic adsorbents, or ion exchange resins; and membrane separation methods such as reverse osmosis, electrodialysis, and ultrafiltration. However, these conventional techniques have the following problems. In the coagulation and precipitation methods, the pH of the wastewater must be adjusted to approximately 1 to 2 to fully dissociate the complexes. In particular, the pH must be adjusted to 1 or less to dissociate copper complexes. Other problems include the inability to sufficiently treat metal complexes, the generation of large amounts of sludge from coagulants, and the impractical application of the sulfide method, which is one of the coagulation and sedimentation methods, due to the toxicity, corrosiveness, and strong odor of harmful gases generated from sulfur-based compounds.The adsorption method also has the problem of generating large amounts of treated material after treatment.

[0003] In membrane separation methods such as reverse osmosis, electrodialysis, and ultrafiltration, it is difficult to remove metals if the wastewater contains organic matter, and prior separation and removal using a flocculant is necessary, which generates a large amount of sludge, resulting in high treatment costs. Furthermore, in all of the above methods, if the metals contained in the wastewater form complexes, the treatment effect is significantly reduced.

[0004] On the other hand, Patent Document 1 discloses a wastewater treatment agent used for treating wastewater containing heavy metal ions, such as water used to wash printed wiring boards and wastewater from plating, which contains at least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionous acid, salts thereof, mercaptocarboxylic acid esters, and dithionous acid esters, and at least one cationic polymer selected from the group consisting of dicyandiamide condensates, polyallylamine, polyvinylamine, and acid salts thereof.

[0005] However, when the wastewater treatment agent disclosed in Patent Document 1 was used, the sulfur-based compound used in the treatment had a strong, irritating odor and could potentially worsen the working environment, and sufficient performance could not be obtained.

[0006] Patent Document 2 also discloses a method of adding a metal collector and a water-soluble polymer to a solid substance to immobilize metals present in the solid substance. However, this method targets metals in fly ash, and metal complexes in wastewater have not been sufficiently investigated.

[0007] Furthermore, Patent Document 3 discloses a method in which a salt of dithiocarbamic acid, a polyamine having 3 to 8 nitrogen atoms, and an alkaline earth metal compound are added to an aqueous solution containing a compound capable of forming a complex with nickel and nickel, and then an inorganic flocculant is added in an amount equal to or greater than the content of the compound capable of forming a complex with nickel, and then solids are removed, and tests are conducted using simulated wastewater.

[0008] However, actual wastewater often contains not only compounds with complexing ability but also large amounts of salts, and the purification treatment effect of metals and other substances in actual wastewater is insufficient. Furthermore, the removal of salts and the addition of coagulants are necessary, making the operation complicated and requiring equipment space. Furthermore, the generation of large amounts of sludge increases treatment costs. Furthermore, the method is unable to adequately treat metals at high concentrations. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-18311 [Patent Document 2] Japanese Patent Application Publication No. 4-267982 [Patent Document 3] Japanese Patent Application Publication No. 2019-69434 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, an object of the present invention is to solve the above-mentioned problems in the conventional art and to provide a wastewater treatment agent and a wastewater treatment method that can efficiently remove Group 6 to 16 elements or compounds thereof, particularly complexes among the compounds, from wastewater. [Means for solving the problem]

[0011] As a result of extensive investigations to solve the above problems, the present inventors have found that metals and the like contained in wastewater can be efficiently removed by adding to the wastewater an organic ammonium compound having an organic ammonium salt structure, or an organic ammonium compound having an organic ammonium salt structure and a dithiocarbamate, and have arrived at the present invention.

[0012] That is, the wastewater treatment agent of the present invention is a wastewater treatment agent for removing Group 6 to 16 elements or compounds thereof from wastewater containing the elements or compounds thereof, and contains at least one organic ammonium compound having an organic ammonium salt structure.

[0013] The organic ammonium compound is represented by any one of the following formulas (I) to (III).

[0014] [ka]

[0015] (In formula (I), the numbers in parentheses l, m, and n represent repeating units of the polymer, and the order of bonding is arbitrary. l, m, and n represent the mole percentages of the repeating units in the polymer. The total of l, m, and n is 100 mole percent, l and m are 0 mole percent or more, and at least one of them is 0.1 mole percent or more, and n is 0 mole percent or more. In the repeating units in parentheses l, X represents the main skeleton of the repeating units derived from the raw material monomer, and two or more types of repeating units may be present, and R 1 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and R 2 ~R 4 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms; A - represents an anion. o is 0 or 1. In the repeating unit enclosed in parentheses of m, R 5 , R 7 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms, and R 6 , R 8 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and B - represents an anion. p and q are 0 or 1. In the repeating unit enclosed in parentheses of n, Y represents a repeating unit derived from the raw material monomer. Y may have two or more types of repeating units. R 2 ~R 4 , R 5 and R 7 When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0016] [ka]

[0017] (R in formula (II) 9 ~R 11 , R 13 ~R 15 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms, and R 12represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and C - , D - represents an anion. r and s represent integers, r is 1 or more, s is 0 or more, and the sum of r and s is 2 or more. The bonding order of r and s (repeating units) is arbitrary. t and u are 0 or 1, and the sum of t and u is 1 or more. When t and u are 0, N has no charge, and when they are 1, N is a nitrogen cation. R 9 ~R 11 and R 13 ~R 15 When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0018] [ka]

[0019] (R in formula (III) 16 ~R 19 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms; E - indicates an anion. 16 ~R 19 When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0020] The organic ammonium compound has a solubility in water at 20°C of less than 1% by mass.

[0021] The organic ammonium compound has a solubility in water at 20°C of 1% by mass or more.

[0022] Also included are dithiocarbamates.

[0023] Moreover, the target of treatment in the wastewater is a complex of the element.

[0024] The wastewater treatment method of the present invention includes a step of adding to wastewater a wastewater treatment agent for removing Group 6 to 16 elements or compounds thereof from wastewater containing the elements or compounds thereof, the wastewater treatment agent including at least one organic ammonium compound having an organic ammonium salt structure.

[0025] The organic ammonium compound is represented by any one of the above formulas (I) to (III).

[0026] The organic ammonium compound has a solubility in water at 20°C of less than 1% by mass.

[0027] The organic ammonium compound has a solubility in water at 20°C of 1% by mass or more.

[0028] The method also includes a step of adding at least one organic ammonium compound having an organic ammonium salt structure and a dithiocarbamate, either separately or in advance, to wastewater.

[0029] The method also includes a step of adjusting the pH to 3 to 7, and further includes a step of adjusting the pH after adding the organic ammonium compound and the dithiocarbamate.

[0030] The method further includes a step of adding an inorganic flocculant.

[0031] The step of adding the inorganic flocculant is performed before the step of adding the organic ammonium compound and the dithiocarbamate.

[0032] In addition, this is a process in which the wastewater is adjusted to a pH of 3 to 7, the inorganic flocculant is added, then the organic ammonium compound and dithiocarbamate are added, the pH is adjusted, and a polymer flocculant is added.

[0033] Moreover, the target of treatment in the wastewater is a complex of the element. [Effects of the Invention]

[0034] According to the wastewater treatment agent and wastewater treatment method of the present invention, elements of Groups 6 to 16 or compounds thereof, particularly complexes among the compounds, can be simply and efficiently removed from wastewater. DETAILED DESCRIPTION OF THE INVENTION

[0035] The wastewater treatment agent of the present invention is a wastewater treatment agent for removing Group 6 to 16 elements or compounds thereof from wastewater containing such elements or compounds, and contains at least one organic ammonium compound having an organic ammonium salt structure (sometimes referred to as an organic ammonium compound in this specification).

[0036] The organic ammonium compound having at least one or more organic ammonium salt structures includes, for example, a compound having an organic ammonium salt structure as part of a polymer, and a compound having multiple nitrogen atoms in which at least one or more nitrogen atoms have an organic ammonium salt structure.

[0037] The organic ammonium compound of the present invention may be represented by any one of the following formulas (I) to (III).

[0038] [ka]

[0039] (In formula (I), the numbers in parentheses l, m, and n represent the repeating units of the polymer, and the order of bonding may be arbitrary, and the polymer may be in the form of random copolymerization or block copolymerization. l, m, and n represent the mol % of the repeating units in the polymer. The total of l, m, and n is 100 mol %, l and m are 0 mol % or more, and at least one of them is 0.1 mol % or more, and n is 0 mol % or more. In the repeating units in parentheses l, X represents the main skeleton of the repeating units derived from the raw material monomer, and may have two or more types of repeating units, and R 1 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and R 2 ~R 4each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms; A - represents an anion. o is 0 or 1. In the repeating unit enclosed in parentheses of m, R 5 , R 7 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms, and R 6 , R 8 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and B - represents an anion. p and q are 0 or 1. In the repeating unit enclosed in parentheses of n, Y represents a repeating unit derived from the raw material monomer. Y may have two or more types of repeating units. R 2 ~R 4 , R 5 and R 7 When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0040] [ka]

[0041] (R in formula (II) 9 ~R 11 , R 13 ~R 15 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms, and R 12 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and C - , D - represents an anion. r and s represent integers, r is 1 or more, s is 0 or more, and the sum of r and s is 2 or more. The bonding order of r and s (repeating units) is arbitrary. t and u are 0 or 1, and the sum of t and u is 1 or more. When t and u are 0, N has no charge, and when they are 1, N is a nitrogen cation. R 9 ~R 11 and R 13 ~R 15When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0042] [ka]

[0043] (R in formula (III) 16 ~R 19 each independently represents a hydrogen atom or an optionally substituted monovalent hydrocarbon group having 1 to 22 carbon atoms; E - indicates an anion. 16 ~R 19 When is a hydrocarbon group, it may form a ring together with the adjacent group via a nitrogen atom.

[0044] R in formulas (I) to (III) 2 ~R 5 , R 7 , R 9 ~R 11 , R 13 ~R 19 R each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms. 1 , R 6 , R 8 , R 12 Each of A is independently a divalent hydrocarbon group having 1 to 22 carbon atoms. - , B - , C - , D - , E - are each independently an anion.

[0045] The hydrocarbon group may have a cyclic structure and may contain a substituent. Adjacent hydrocarbon groups may bond together via a nitrogen atom to form a cyclic structure.

[0046] The hydrocarbon group is not particularly limited, but examples thereof include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, etc. The monovalent aliphatic hydrocarbon group is not particularly limited, but examples thereof include an alkyl group, an alkenyl group, an alkynyl group, etc. The alkyl group may be straight-chain or branched. Examples of the alkyl group include, but are not limited to, a methyl group, an ethan-1-yl group, a propan-1-yl group, a 1-methylethan-1-yl group, a butan-1-yl group, a butan-2-yl group, a 2-methylpropan-1-yl group, a 2-methylpropan-2-yl group, a pentan-1-yl group, a pentan-2-yl group, a hexane-1-yl group, a heptan-1-yl group, an octan-1-yl group, a 1,1,3,3-tetramethylbutan-1-yl group, a nonan-1-yl group, a decan-1-yl group, an undecane-1-yl group, a dodecane-1-yl group, a tridecane-1-yl group, a tetradecane-1-yl group, a pentadecan-1-yl group, a hexadecan-1-yl group, a heptadecan-1-yl group, and an octadecan-1-yl group.The alkenyl group may be straight-chain or branched. Examples of the alkenyl group include, but are not limited to, a vinyl group, a prop-1-en-1-yl group, an allyl group, an isopropenyl group, a but-1-en-1-yl group, a but-2-en-1-yl group, a but-3-en-1-yl group, a 2-methylprop-2-en-1-yl group, a 1-methylprop-2-en-1-yl group, a pent-1-en-1-yl group, a pent-2-en-1-yl group, a penta-3-en-1-yl group, a pent-4-en-1-yl group, a pent-5-en-1-yl group, a pent-6-en-1-yl group, a pent-7-en-1-yl group, a pent-8-en-1-yl group, a pent-9-en-1-yl group, a pent-10-en-1-yl group, a pent-11-en-1-yl group, a pent-12-en-1-yl group, a pent-13-en-1-yl group, a pent-14-en-1-yl group, a pent-15-en-1-yl group, a pent-16-en-1-yl group, a pent-17-en-1-yl group, a pent-18-en-1-yl group, a pent-19-en-1-yl group, a pent-20-en-1-yl group, a pent-21-en-1-yl group, a pent-22-en-1-yl group, a pent-23-en-1-yl group, a pent-24-en-1-yl group, a pent-25-en-1-yl group, a pent-26-en-1-yl group, a pent-27-en-1-yl group, a pent-28-en-1-yl group, a En-1-yl group, pent-4-en-1-yl group, 3-methylbut-2-en-1-yl group, 3-methylbut-3-en-1-yl group, hex-1-en-1-yl group, hex-2-en-1-yl group, hex-3-en-1-yl group, hex-4-en-1-yl group, hex-5-en-1-yl group, 4-methylpent-3-en-1-yl group, 4-methylpent-3-en-1-yl group, hept-1-en-1-yl group, hept- 6-en-1-yl group, oct-1-en-1-yl group, oct-7-en-1-yl group, non-1-en-1-yl group, non-8-en-1-yl group, dec-1-en-1-yl group, dec-9-en-1-yl group, undec-1-en-1-yl group, undec-10-en-1-yl group, dodec-1-en-1-yl group, dodec-11-en-1-yl group, tridec-1-en-1-yl group, tridec-12-en-1-yl group, tet Examples thereof include a ladec-1-en-1-yl group, a tetradec-13-en-1-yl group, a pentadec-1-en-1-yl group, a pentadec-14-en-1-yl group, a hexadec-1-en-1-yl group, a hexadec-15-en-1-yl group, a heptadec-1-en-1-yl group, a heptadec-16-en-1-yl group, an octadec-1-en-1-yl group, an octadec-9-en-1-yl group, and an octadec-17-en-1-yl group.The alkynyl group may be straight-chain or branched. Examples of the alkynyl group include, but are not limited to, an ethynyl group, a prop-1-yn-1-yl group, a prop-2-yn-1-yl group, a but-1-yn-1-yl group, a but-3-yn-1-yl group, a 1-methylprop-2-yn-1-yl group, a penta-1-yn-1-yl group, a penta-4-yn-1-yl group, a hexa-1-yn-1-yl group, a hexa-5-yn-1-yl group, a hepta-1-yn-1-yl group, a hepta-6-yn-1-yl group, an oct-1-yn-1-yl group, an oct-7-yn-1-yl group, a nona-1-yn-1-yl group, a nona-8-yn-1-yl group, a dec-1-yn-1-yl group, a dec ... Examples thereof include a carboxyl-9-yn-1-yl group, an undec-1-yn-1-yl group, an undec-10-yn-1-yl group, a dodec-1-yn-1-yl group, a dodec-11-yn-1-yl group, a tridec-1-yn-1-yl group, a tridec-12-yn-1-yl group, a tetradec-1-yn-1-yl group, a tetradec-13-yn-1-yl group, a pentadec-1-yn-1-yl group, a pentadec-14-yn-1-yl group, a hexadeca-1-yn-1-yl group, a hexadeca-15-yn-1-yl group, a heptadec-1-yn-1-yl group, a heptadec-16-yn-1-yl group, an octadec-1-yn-1-yl group, and an octadec-17-yn-1-yl group.

[0047] The alicyclic hydrocarbon group is not particularly limited, but examples of monovalent groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

[0048] The aromatic hydrocarbon group is not particularly limited, but examples thereof include a phenyl group, a naphthalene group, an anthracene group, and groups containing aromatic ring residues such as residues thereof.

[0049] The monovalent aromatic hydrocarbon group is not particularly limited, and examples thereof include a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a 2,4,5-trimethylphenyl group, a 2,4,6-trimethylphenyl group, a 4-ethylphenyl group, a 4-propylphenyl group, a 4-isopropylphenyl group, a 4-butylphenyl group, a 4-tert-butylphenyl group, a 4-pentylphenyl group, a 4-tert-pentylphenyl group, a 2,4-bis(4-tert-pentyl)phenyl group, a 1,1,3,3-tetramethylbutylphenyl group, a 2-methyl-5-tert-butylphenyl group, a 4-pentylphenyl group, a 4-hexylphenyl group, a 4-heptylphenyl group, a 4-octylphenyl group, Examples of such alkyl groups include a 4-nonylphenyl group, a 4-decanylphenyl group, a 4-undecylphenyl group, a 4-dodecylphenyl group, a 4-tridecylphenyl group, a 4-tetradecylphenyl group, a 4-pentadecylphenyl group, a 4-hexadecylphenyl group, a 4-heptadecylphenyl group, a 4-octadecylphenyl group, a 4-biphenyl group, a 2-methoxyphenyl group, a 3-methoxyphenyl group, a 4-methoxyphenyl group, a 2-ethoxyphenyl group, a 3-ethoxyphenyl group, a 4-ethoxyphenyl group, a 2-chlorophenyl group, a 2-fluorophenyl group, a 4-fluorophenyl group, a 2-trifluoromethylphenyl group, a 4-trifluoromethylphenyl group, a 4-hydroxyphenyl group, a benzyl group, an α,α-dimethylbenzyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, and a 9-anthracenyl group.

[0050] Examples of the divalent hydrocarbon group include groups in which one hydrogen atom has been removed from the above groups.

[0051] The substituent is not particularly limited, and examples thereof include an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a phosphorus-containing group, a halogen, etc. The substituent may substitute for a hydrogen atom of the hydrocarbon group, may be included by interrupting the hydrocarbon group, or may be included at the base end of the hydrocarbon group.

[0052] The oxygen-containing group is not particularly limited, but examples thereof include a hydroxy group, an alkoxy group, an aldehyde group, a carboxy group, a urea group, a urethane group, an amide group, an imide group, an ether group, a carbonyl group, an ester group, a carbamate group, a carbamoyl group, a polyoxyethylene group, and a heterocyclic group containing an oxygen atom. Among these, a hydroxy group, a carboxy group, and an ester group having an alkyl moiety with 1 to 4 carbon atoms are preferred. Among the above-mentioned substituents, a carboxy group and an ester group having an alkyl moiety with 1 to 4 carbon atoms are more preferred.

[0053] The nitrogen-containing group is not particularly limited, but examples thereof include a cyano group, a cyanato group, an isocyanate group, a nitro group, a nitroalkyl group, an amide group, a urea group, a urethane group, an imide group, a carbodiimide group, an azo group, a heterocyclic group containing a nitrogen atom, a primary amino group, a secondary amino group, a tertiary amino group, and an aminoalkyl group.

[0054] The sulfur-containing group is not particularly limited, but examples thereof include a thioether group, a thiophene group, a thiazole group, a thiol group, a sulfo group, a sulfide group, a disulfide group, a thioester group, a thioamide group, a sulfonyl group, a thiocarbonyl group, a thiourea group, a thiocarbamate group, and a dithiocarbamate group.

[0055] The phosphorus-containing group is not particularly limited, but examples thereof include a phosphonic acid group, a phosphonous acid group, a phosphinic acid group, a phosphinous acid group, a phosphate group, a pyrophosphate group, and ester groups thereof.

[0056] Halogens include fluorine, chlorine, bromine and iodine.

[0057] Anion A of formula (I) to (III) - ~E -Examples of the ion include, but are not limited to, halide ions (fluoride ions, chloride ions, bromide ions, iodide ions), sulfate ions, sulfite ions, hydroxide ions, nitrate ions, carboxylate ions, carbonate ions, and phosphate ions. Among these, halide ions are preferred due to their high reactivity. Furthermore, among halide ions, bromide ions and chloride ions are preferred, with chloride ions being even more preferred, as they have high reactivity with the substance to be treated and further improve the treatment effect.

[0058] In terms of water solubility and reactivity with the above elements or their compounds, especially with complexes among the compounds (improvement of removal rate), R in formula (I) 1 ~R 8 , R in formula (II) 9 ~R 15 , R in formula (III) 16 ~R 19 In the above combination, when one or more hydrogen atoms are bonded to the nitrogen cation, the other group is a hydrocarbon group having 1 to 22 carbon atoms, preferably a hydrocarbon group having 1 to 18 carbon atoms. When no hydrogen atoms are bonded to the nitrogen cation, a hydrocarbon group having 1 to 8 carbon atoms is preferred.

[0059] Specific examples of the main skeleton of the repeating unit derived from the raw material monomer represented by X in formula (I) and the monomer serving as the raw material for the repeating unit represented by Y include, but are not limited to, (meth)acrylate-based monomers, styrene-based monomers, acrylamide-based monomers, olefin-based monomers, vinyl-based monomers, and glucose-based monomers. Among these, (meth)acrylate-based monomers, styrene-based monomers, and acrylamide-based monomers are preferred because they provide a high treatment effect, and (meth)acrylate-based monomers, acrylamide-based monomers, and glucose-based monomers are more preferred.

[0060] The (meth)acrylate monomer is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate.

[0061] The styrene-based monomer is not particularly limited, but examples thereof include alkyl styrenes such as styrene, α-methylstyrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, isopropylstyrene, butylstyrene, isobutylstyrene, t-butylstyrene, s-butylstyrene, pentylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrenes such as chlorostyrene, fluorostyrene, bromostyrene, dibromostyrene, and iodostyrene; alkoxystyrenes such as p-methoxystyrene; arylstyrenes such as p-phenylstyrene; styrenesulfonic acid or a salt thereof, nitrostyrene, aminostyrene, hydroxystyrene, 4-(trimethoxysilyl)styrene, and vinylstyrene.

[0062] The acrylamide monomer is not particularly limited, but examples thereof include (meth)acrylamide, N,N-dimethylacrylamide, (meth)N,N-diethylacrylamide, (meth)N,N-dipropylacrylamide, (meth)N,N-diisopropylacrylamide, (meth)acryloylmorpholine, diacetone (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N,N-bishydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N,N-bishydroxyethyl (meth)acrylamide, N-hydroxypropyl (meth)acrylamide, N,N-bishydroxypropyl (meth)acrylamide, N-hydroxybutyl (meth)acrylamide, and N,N-bishydroxybutyl (meth)acrylamide.

[0063] The olefin-based monomer is not particularly limited, but examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-phenyl-1-butene, 6-phenyl-1-hexene, 3-methyl-1-butene, 4-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 3-methyl-1-pentene, 4-methyl-1-hexene, 5-methyl-1-hexene, 3-methyl-1-butene, 4-methyl-1-pentene, 5-methyl-1-hex ... ,3-dimethyl-1-pentene, 3,4-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, vinylcyclohexane, hexafluoropropene, tetrafluoroethylene, 2-fluoropropene, fluoroethylene, 1,1-difluoroethylene, 3-fluoropropene, trifluoroethylene, 3,4-dichloro-1-butene, butadiene, hexadiene, isoprene, dicyclopentadiene, norbornene, acetylene, and the like.

[0064] The vinyl monomer is not particularly limited, but examples thereof include vinyl acetate, vinyl propionate, vinyl alcohol, allyl alcohol, (meth)acrylonitrile, methacrylonitrile, N-vinylpyrrolidone, vinyl chloride, vinyl bromide, vinyl iodide, vinylidene chloride, vinylidene bromide, vinylidene iodide, vinyl sulfonic acid and salts thereof, methacrylsulfonic acid and salts thereof, 2-acrylamido-2-methylsulfonic acid and salts thereof, N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, acrylic acid, (meth)acrylic acid, vinylacetic acid, crotonic acid, cinnamic acid, myristoleic acid, palmitoleic acid, oleic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, citraconic acid, citraconic acid monoester, and the like.

[0065] The glucose-based monomer is not particularly limited, but examples thereof include α-glucose, β-glucose, and hydroxyethyl glucose.

[0066] The organic ammonium compound represented by formula (I) is not particularly limited, but may be a homopolymer or copolymer of the above-mentioned raw material monomers, and examples of the copolymer include random, alternating, block, and graft copolymers. It may also be a compound in which the above-mentioned substituents, hydrocarbon groups, etc. are bonded to the terminal of a (co)polymer, or a compound having a repeating unit with a nitrogen cation only at the terminal of a (co)polymer.

[0067] As the organic ammonium compound represented by formula (I), in addition to (co)polymers obtained by chain reactions using the raw material monomers listed above, polymers obtained by successive reactions such as polycondensation reactions and polyaddition reactions can also be used. Examples of the organic ammonium compound include, but are not limited to, urea resins, melamine resins, urethane resins, polyanilines, polyvinylamidines, chitosan, etc.

[0068] The repeating units of the polymer in formula (I) may be one type or a combination of two or more types, and the order of bonding may also be arbitrary.

[0069] The organic ammonium compound represented by formula (I) is not particularly limited, but preferred examples include (co)polymers of amine salts or quaternary products of acylamino(meth)acrylic acid esters, (co)polymers of amine salts or quaternary products of Mannich-modified polyacrylamide, amine salts or quaternary products of polyvinylamidine, amine salts or quaternary products of vinylamidine copolymers, amine salts or quaternary products of polyvinylamine, amine salts or quaternary products of polyallylamine, amine salts of polyvinylimidazoline, ammonium group-containing styrene resins, epichlorohydrin dimethylamine condensates, (co)polymers of dialkyldimethylammonium salts, (co)polymers of dimethyldiallylammonium salts, amine salts or quaternary products of polyaniline, and amine salts or quaternary products of polypyrrole. Polyquaternium (a compound containing a quaternary ammonium center in a polymer; e.g., Polyquaternium-1, Polyquaternium-7, Polyquaternium-51, Polyquaternium-61), a name given to several polymer electrolytes based on the International Nomenclature of Cosmetic Ingredients, can also be used. Furthermore, the organic ammonium compound represented by formula (I) can be a cationized product (amine salt) of a natural or amino acid-based polymer compound, including, but not limited to, a cationized product (amine salt) of a polysaccharide or polyamino acid. Also usable are salts or quaternized products of chitosan, cationized cellulose (e.g., Polyquaternium-10), cationized starch, cationized guar gum, and amine salts of polyamino acids. Among these, (co)polymers of amine salts or quaternized products of acylamino(meth)acrylic acid esters, amine salts or quaternized products of vinyl amidine copolymers, ammonium group-containing styrene resins (e.g., polyvinylbenzyltrimethylammonium chloride), salts or quaternized products of chitosan, and O-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethyl cellulose chloride (polyquaternium-10) are preferred because they provide high treatment effects, and polymers of amine salts or quaternized products of acylamino(meth)acrylic acid esters, amine salts or quaternized products of vinyl amidine copolymers, and O-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethyl cellulose chloride are more preferred.The polymer of the amine salt or quaternary product of an acylamino(meth)acrylic acid ester is not particularly limited, but specific examples thereof include a polymer of 2-((meth)acryloyloxy)ethyldimethylamine salt or 2-((meth)acryloyloxy)ethyltrimethylammonium chloride. Of these, a polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride is preferred. The amine salt or quaternary product of a vinylamidine copolymer is not particularly limited, but specific examples thereof include a copolymer of acrylamide, acrylonitrile, N-vinylacrylamidine hydrochloride, N-vinylacrylamide, vinylamine hydrochloride, and N-vinylformamide.

[0070] In terms of reactivity with the above elements or compounds thereof, particularly complexes, the greater the content of nitrogen cations in the side chains of the compounds represented by formula (I), the greater the treatment effect, so l in formula (I) is preferably 0.1 mol % or more, m is 0, l is more preferably 10 mol % or more, still more preferably 50 mol % or more, particularly preferably 70 mol % or more, and most preferably 100 mol %. When o in formula (I) is 0 or 1, R 1 is preferably an aliphatic hydrocarbon group having an ester group, a phenyl group, an ether group, a polyoxyethylene group, or a hydroxyl group as a substituent. 1 is more preferably an aliphatic hydrocarbon group having an ester group, an ether group, a polyoxyethylene group or a hydroxyl group, and even more preferably an ester group having an alkyl moiety having 1 to 4 carbon atoms, a polyoxyethylene group or a hydroxyl group.

[0071] The organic ammonium compound represented by formula (II) is not particularly limited, but examples thereof include polyalkylene polyamines. Preferred examples include organic ammonium compounds obtained by reacting amine compounds such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tributylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, tetrabutylenepentamine, pentaethylenehexamine, and polyethyleneimine, or structural isomers thereof, with a quaternizing agent such as an acid or alkyl halide. Structural isomers include linear, branched, and cyclic structures. These may be used alone or in mixtures of two or more. The molar ratio of the amine compound to the quaternizing agent such as an acid or alkyl halide is not particularly limited, as long as the nitrogen atom contained in the amine compound has at least one nitrogen cation. When the amine compound has two or more nitrogen cations, the nitrogen cations may not be adjacent.

[0072] The compound represented by formula (III) includes a compound in which a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, which may have a substituent, is bonded to a nitrogen cation, and R 16 ~R 19The groups may be the same (symmetric ammonium salts) or different (asymmetric ammonium salts), and may form a cyclic structure in which adjacent groups are bonded. To obtain a high treatment effect, the group bonded to the nitrogen cation is preferably an aliphatic hydrocarbon group. Examples of compounds represented by formula (III) include (mono-, di-, tri-, and tetra-) alkylammoniums, and the groups other than the alkyl group may be hydrogen atoms, aromatic hydrocarbon groups, or alicyclic hydrocarbon groups, and the alkyl groups may be the same or different. Compounds represented by formula (III) other than (mono-, di-, tri-, tetra-)alkylammonium are not particularly limited. Preferred examples include organic ammonium compounds such as choline, DL-carnitine, and betaine (trimethylglycine), as well as ammonium compounds obtained by reacting cyclic amine compounds such as aziridine, pyrrolidine, pyrroline, pyrrole, pyrazolidine, piperidine, piperazine, homopiperazine, 2-methylpiperazine, pyrimidine, pyrazine, thiomorpholine, thiazine, 1-azaadamantane, and 2-azaadamantane with an acid or a quaternizing agent such as an alkyl halide. Compounds having two or more nitrogen atoms may have a structure containing one or more nitrogen cations. Among these, (mono-, di-, tri-, tetra-)alkylammonium is preferred, and tetraalkylammonium is preferred because it has a wide usable pH range and is highly effective in removing target elements or compounds thereof.

[0073] The organic ammonium compounds other than those represented by the above formulas (I) to (III) are not particularly limited, and examples thereof include dicyandiamide-ammonium chloride-formaldehyde polycondensation products, dicyandiamide-ammonia-formaldehyde polycondensation products, dicyandiamide-formaldehyde polycondensation products, dicyandiamide-polyalkylenepolyamine polycondensation products, amine salts of acylbiguanide condensation products, polyquaterniums, and the like.

[0074] In terms of the treatment effect, the organic ammonium compound of the present invention is preferably a compound represented by the above formulas (I) to (III). Among these, the compound represented by formula (I) is preferred over the compounds represented by formulas (II) and (III) because it has a larger molecular weight and is more likely to form an insoluble solid (floc) produced by the reaction of the organic ammonium compound with an element of Groups 6 to 16 or a compound thereof, particularly a complex thereof.

[0075] In terms of efficient treatment of the object to be treated, when the organic ammonium compound used in the present invention is used alone, it can be dissolved or dispersed in wastewater before use. When used as a dispersion, it is preferable that the solubility in water at 20°C is less than 1 mass %.

[0076] Alternatively, water-soluble organic ammonium compounds with a solubility of 1% by mass or more in water at 20°C can be used. This allows for uniform mixing with wastewater, resulting in increased reactivity with the target element or compound, improving the effectiveness of removing the target element or compound. From the perspective of high treatment efficiency and reduced dosage, organic ammonium compounds having multiple nitrogen cations per molecule are preferred over organic ammonium compounds having a single nitrogen cation per molecule, and organic ammonium compounds of formulas (I) and (II) having multiple nitrogen cations per molecule are preferred over compounds of formula (III) having a single nitrogen cation per molecule. Furthermore, as mentioned above, organic ammonium compounds of formula (I) are preferred over compounds of formulas (II) and (III) because they are more reactive and provide good effects with smaller dosages.

[0077] Among the compounds of formula (I), water-soluble organic ammonium compounds can be used as described above. Among them, when treating an anionic complex of the element, from the viewpoint of treatment effect, compounds consisting only of cationic units and repeating units are preferred over compounds having anionic units and repeating units. Compounds having no hydroxyl groups in the repeating units are more preferred because they are not solubilized after reaction with the object to be treated. Compounds having no cyclic structures in the repeating units are even more preferred because of the steric reactivity of the repeating units.

[0078] On the other hand, R in formula (I) 2 ~R 4 The number of hydrogen atoms in R is such that the usable pH range is wide and the effect of removing the target element or its compound is high. Therefore, when o in formula (I) is 0, 2 ~R 4 The number of hydrogen atoms in R is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. 2 ~R 4 The number of hydrogen atoms is preferably 2 or less, more preferably 1 or less, and even more preferably 0.

[0079] The molecular weight of the compound represented by formula (I) is preferably 17 million or less, more preferably 10 million or less, and even more preferably 5 million or less, in terms of improving the viscosity of the treatment water and workability when dissolving the treatment agent. Also, in terms of achieving the desired effect with a small amount, the molecular weight is preferably 10,000 or more, more preferably 100,000 or more, and even more preferably 1 million or more.

[0080] [Wastewater treatment agent containing organic ammonium compounds and dithiocarbamic acid salts] The wastewater treatment agent of the present invention may further contain a dithiocarbamate. The inclusion of a dithiocarbamate improves the effect of removing the target element or its compound, particularly its complex. Examples of dithiocarbamate salts include, but are not limited to, alkali metal salts, alkaline earth metal salts, or ammonium salts of dithiocarbamic acid obtained by reacting an amine compound with carbon disulfide and a base. These salts may be in the form of a solid or an aqueous solution. Examples of amine compounds include, but are not limited to, ethylamine, diethylamine, propylamine, dipropylamine, piperazine, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, heptaethyleneoctamine, morpholine, polyethyleneimine, and derivatives thereof. Examples of derivatives of amine compounds include, but are not limited to, reaction products with benzyl chloride. Among the above amine compounds, diethylamine, piperazine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and polyethyleneimine are preferred, with diethylamine, piperazine, tetraethylenepentamine, and polyethyleneimine being more preferred, and tetraethylenepentamine and piperazine being even more preferred. Tetraethylenepentamine includes linear, branched, and cyclic structures, and one or a mixture of two or more types can be used. Examples of alkali metals include lithium, sodium, and potassium. Examples of alkaline earth metals include magnesium and calcium. Among these, alkali metals are preferred, with sodium and potassium being more preferred. The molar reaction ratio of the amine compound to carbon disulfide is not particularly limited.

[0081] The dithiocarbamate does not have an irritating odor and can be suitably used in wastewater treatment.

[0082] The organic ammonium compound of the present invention has cationic properties and therefore reacts with, for example, an anionic complex or the like, and the charge-neutralized or cationic reactant reacts with an anionic dithiocarbamate, thereby improving the effect of removing the target element or compound thereof. Therefore, it is preferable to use an organic ammonium compound and a dithiocarbamate in combination.

[0083] The bond adjacent to the nitrogen cation of the organic ammonium compound of the present invention preferably consists of only single bonds, since this reduces the solubility of the treated product and improves the treatment capacity.

[0084] When treating using an organic ammonium compound and a dithiocarbamate in combination, among the compounds of formulas (I), (II), and (III), water-soluble organic ammonium compounds with a solubility in water of 1% by mass or more at 20°C are preferred because they can be uniformly mixed with wastewater, resulting in high reactivity with the target element or compound, and improved effectiveness in removing the target element or compound. Furthermore, they facilitate uniform mixing with the water-soluble dithiocarbamate, simplifying the treatment process. On the other hand, from the perspective of high treatment efficiency and reduced dosage, organic ammonium compounds having multiple nitrogen cations per molecule are preferred over organic ammonium compounds having a single nitrogen cation per molecule, and organic ammonium compounds of formulas (I) and (II) having multiple nitrogen cations per molecule are preferred over compounds of formula (III) having a single nitrogen cation per molecule. Furthermore, organic ammonium compounds of formula (I) are preferred over compounds of formulas (II) and (III) because they are more reactive and provide good effects with smaller dosages.

[0085] When treating using an organic ammonium compound and a dithiocarbamate in combination, among the compounds of formula (I), water-soluble organic ammonium compounds are preferred as described above. Among these, when treating an anionic complex of the element, from the viewpoint of treatment effect, compounds consisting only of cationic units and repeating units are more preferred than compounds having anionic units and repeating units. Compounds having no hydroxyl groups in the repeating units are even more preferred because they are not solubilized after reaction with the target to be treated. Compounds having no cyclic structures in the repeating units are particularly preferred because of the steric reactivity of the repeating units.

[0086] On the other hand, R in formula (I) 2 ~R 4 The number of hydrogen atoms in R is such that the usable pH range is wide and the effect of removing the target element or its compound is high. Therefore, when o in formula (I) is 0, 2 ~R 4 The number of hydrogen atoms in R is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. 2 ~R 4 The number of hydrogen atoms is preferably 2 or less, more preferably 1 or less, and even more preferably 0.

[0087] The molecular weight of the compound represented by formula (I) is preferably 17 million or less, more preferably 10 million or less, and even more preferably 5 million or less, in terms of improving the viscosity of the treatment water and workability when dissolving the treatment agent. Also, in terms of achieving the desired effect with a small amount, the molecular weight is preferably 10,000 or more, more preferably 100,000 or more, and even more preferably 1 million or more.

[0088] Furthermore, when the organic ammonium compound represented by formula (II) is used in combination with a dithiocarbamate, the organic ammonium compound of the present invention is preferably a compound in which all nitrogen atoms are cationic, from the viewpoint of the treatment effect when treating an anionic complex of the element.

[0089] When the organic ammonium compound represented by formula (III) is used in combination with a dithiocarbamate, it is preferable to use an organic ammonium compound having a hydroxyl group, a carboxyl group, or an ester group from the viewpoint of improving water solubility. However, from the viewpoint of insolubilizing the flocs produced by the reaction and enhancing the effect of removing the target element or its compound, it is preferable to use an organic ammonium compound having a carboxyl group or an ester group rather than a hydroxyl group.

[0090] When the organic ammonium compound of the present invention and a dithiocarbamate are used in combination, the water-soluble organic ammonium compound and the dithiocarbamate may be added separately, but it is preferable to add a mixture thereof in advance.

[0091] The wastewater treatment agent of the present invention is intended to treat elements or compounds of Groups 6 to 16 of the periodic table. Examples of Group 6 elements include chromium, molybdenum, tungsten, and seaborgium. Examples of Group 7 elements include manganese, technetium, rhenium, and bohrium. Examples of Group 8 elements include iron, ruthenium, osmium, and hassium. Examples of Group 9 elements include cobalt, rhodium, iridium, and meitnerium. Examples of Group 10 elements include nickel, palladium, platinum, and darmstadtium. Examples of Group 11 elements include copper, silver, gold, and roentgenium. Group 12 elements include zinc, cadmium, mercury, and copernicium; Group 13 elements include boron, aluminum, gallium, indium, thallium, and nihonium; Group 14 elements include carbon, silicon, germanium, tin, lead, and flerovium; Group 15 elements include nitrogen, phosphorus, arsenic, antimony, bismuth, and moscovium; and Group 16 elements include oxygen, sulfur, selenium, tellurium, polonium, and livermorium. Among the above elements, Group 6 elements include chromium, molybdenum, and tungsten; Group 7 elements include manganese; Group 8 elements include iron, ruthenium, and osmium; Group 9 elements include cobalt, rhodium, and iridium; Group 10 elements include nickel, palladium, and platinum; Group 11 elements include copper, silver, and gold; Group 12 elements include zinc, cadmium, and mercury; Group 13 elements include boron, gallium, indium, and thallium; Group 14 elements include germanium, tin, and lead; Group 15 elements include arsenic, antimony, and bismuth; and Group 16 elements include selenium and tellurium. Chromium, manganese, iron, cobalt, nickel, copper, zinc, boron, tin, arsenic, and selenium, or compounds thereof, can be suitably treated. For example, among these, metals contained in industrial wastewater as metal ions or metal compound ions, and harmful metals for which wastewater standards have been established, such as chromium, manganese, iron, nickel, copper, zinc, cadmium, mercury, and lead, can be more suitably treated.

[0092] In terms of the treatment amount per unit gram of the treatment agent of the present invention, elements in Groups 6 to 16 can be treated suitably. Among these, elements in Groups 10 to 14, which are classified as intermediate acids or soft acids according to the HSAB rule, can be treated more suitably, nickel, copper, zinc, cadmium, mercury, and lead, which are elements in Periods 4 to 6 of Groups 10 to 14, can be treated even more suitably, and nickel, copper, and zinc, which are elements in Period 4 of Groups 10 to 12, which are intermediate acids, can be treated particularly suitably, with copper being treated most suitably among these.

[0093] In the present invention, the term "treatment" refers to a treatment for separating the target Group 6 to 16 element or its compound, particularly a complex, from the water to be treated, and includes, but is not limited to, a treatment for separating the resulting adsorbate when the treatment agent of the present invention adsorbs the target element or its compound, and a treatment for separating the insoluble matter resulting from the reaction between the treatment agent of the present invention and the target element or its compound.

[0094] The compound of the element is not particularly limited, but examples thereof include substances bonded to the element via covalent bonds, ionic bonds, coordinate bonds, etc.

[0095] The substance that forms a coordinate bond is not particularly limited, but examples thereof include complexes.

[0096] Examples of the complex include complexes of the above elements and the following complex-forming agents.

[0097] The complex-forming agent is a monodentate or polydentate complex formed by an amino group, a carboxy group, a hydroxyl group, an ether group, a phosphate group, or the like, and is not particularly limited to such a complex-forming agent. Examples of the complex-forming agent include ammonia, amine compounds (e.g., ethylenediamine, diethylenetriamine, triethylenetetramine, pyridine, and aniline, but are not particularly limited to such a complex-forming agent), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetraminehexaacetic acid (TTHA), ethylenedioxybis(ethylamine)-N,N,N',N'-tetraacetic acid, nitrilotrimethylphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, citric acid, and salts thereof. The method for treating the complex of the element and the complex-forming agent is not particularly limited, but includes, for example, a treatment in which the treating agent of the present invention neutralizes the charge of the complex and aggregates it, and the resulting insoluble treated product is separated.

[0098] The organic ammonium compound of the present invention has a high treatment effect, and therefore can be used effectively even when the complexing agent is contained in an excess amount relative to the element. The excess amount can be, for example, a molar ratio of the element to the complexing agent (element:complexing agent) of 1:1 or more, more than 1:1, 1:1.5 or more, or 1:2.0 or more.

[0099] The organic ammonium compound of the present invention has a high treatment effect and can be used effectively even when the wastewater contains coexisting salts, such as sulfates, nitrates, carbonates, phosphates, and halide salts.

[0100] Next, the wastewater treatment method of the present invention will be described. The wastewater treatment method of the present invention comprises a step of adding the wastewater treatment agent of the present invention to wastewater. That is, the wastewater treatment agent is for removing Group 6 to 16 elements or compounds thereof, particularly complexes among the compounds, from wastewater containing the elements or compounds thereof, and comprises a step of adding to the wastewater a wastewater treatment agent containing at least one organic ammonium compound having an organic ammonium salt structure.

[0101] In the step of adding the wastewater treatment agent of the present invention to wastewater, preferably, the pH of the wastewater is adjusted to a predetermined value, for example, pH 3 to 7, and then an organic ammonium compound having an organic ammonium salt structure and, optionally, a dithiocarbamate are added to the wastewater. The organic ammonium compound of the present invention reacts with, for example, an anionic complex in wastewater containing a complex, eliminating the need to adjust the pH to 1 to 2 to dissociate the target element from the complex. Treatment can be performed suitably even at a pH of 3 or higher, thereby simplifying the wastewater treatment process. The amounts of the organic ammonium compound having an organic ammonium salt structure and the dithiocarbamate to be added can be determined appropriately depending on the concentration of the target element or its compound in the wastewater, the concentration of salts coexisting in the wastewater, etc.

[0102] Furthermore, when adding a dithiocarbamate, the timing of adding the dithiocarbamate may be simultaneous with or separate from the addition of the organic ammonium compound having an organic ammonium salt structure. For example, the treatment agent of the present invention may be added after the addition of the dithiocarbamate, or before the addition of the dithiocarbamate, or they may be premixed and added simultaneously. Since the treatment agent of the present invention can be effective even with a small amount added and the number of treatment steps can be reduced, it is preferable to premix the dithiocarbamate and the treatment agent of the present invention and add them. The same applies when the treatment agent is an aqueous solution. To effectively treat the target substance in the water to be treated, the dithiocarbamate is preferably added to water to be treated with a pH of 3.5 or higher, and more preferably to water to be treated with a pH of 4 or higher. The organic ammonium compound and dithiocarbamate of the present invention can efficiently treat a wide range of target substances simultaneously in a single operation without interfering with the effects of either compound. The mass ratio of the compound to the dithiocarbamate is not particularly limited. For example, good treatment can be achieved by adding the dithiocarbamate / compound at a mass ratio of 1000 to 0.01. When the compound is of formula (I), the mass ratio is preferably 1000 to 0.1, more preferably 1000 to 10, and even more preferably 1000 to 100, due to the high flocculation effect. When the compound is of formula (II) or (III), the mass ratio is preferably 1000 to 0.1, more preferably 100 to 0.1. When the organic ammonium compound of the present invention and the dithiocarbamate are mixed in advance and added, a mixed solution of the compound represented by formulas (I) to (III) and the dithiocarbamate can be used. While not particularly limited, for example, an aqueous solution or aqueous dispersion containing the compound represented by formulas (I) to (III) and the dithiocarbamate can be used. From the viewpoint of industrial convenience, an aqueous solution is preferred. When using both, the pH of the wastewater can be adjusted to 3 to 7, and after treatment in a process including the addition of a wastewater treatment agent, the pH can be further adjusted. For example, the pH of the wastewater can be adjusted to 7 to 10 by adding an acid or alkali.

[0103] If necessary, a flocculant is added and the resulting flocs are separated by stirring, thereby removing the target element or its compound, particularly its complex, contained in the wastewater.

[0104] Adding a flocculant together with the treatment agent of the present invention can further improve the settling properties of the flocs.

[0105] The flocculant is not particularly limited, but examples thereof include polymer flocculants, inorganic flocculants, minerals, etc. The polymer flocculant is not particularly limited, but anionic, cationic, nonionic, and amphoteric flocculants can be used, for example, anionic flocculants such as polyacrylamide, sodium polyacrylate, and polyacrylic acid, cationic flocculants such as polymethacrylic acid esters, polyacrylic acid esters, polyamines, polydadomac, and dicyandiamide, nonionic flocculants such as polyacrylamide, polyethylene glycol, and polyvinyl alcohol, and amphoteric flocculants such as polyacrylic acid ester-acrylic acid copolymers. Specific examples include sodium polyacrylate, sodium alginate, copolymers of acrylamide and sodium acrylate, copolymers of acrylamide and sodium acrylamido-2-methylpropanesulfonate, polyacrylamide, and polyethylene oxide. Examples of inorganic flocculants include, but are not limited to, ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, polytetrafluoroethylene, aluminum sulfate, polyaluminum chloride, aluminum chloride, calcium chloride, potassium aluminate, and magnesium hydroxide. Examples of minerals include, but are not limited to, carbonate minerals such as hydrotalcite, magnesite, and limestone; silicate minerals such as zeolite, montmorillonite, kaolin, bentonite, and silica; oxide minerals such as alumina; sulfate minerals such as gypsum; and phosphate minerals such as hydroxyapatite. Flocculants may be used alone or in combination of two or more, and may be used once or twice or more times. Among these, polymer flocculants are preferred from the viewpoint of floc settling properties, and anionic ones are preferred, with weakly anionic copolymers of acrylamide and sodium acrylate being more preferred. It is also preferable to use an inorganic flocculant, with ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, polytetrafluoroethylene, aluminum sulfate, polyaluminum chloride, and aluminum chloride being more preferred, and ferric chloride, aluminum sulfate, and polyaluminum chloride being even more preferred. A preferred embodiment is to use an inorganic flocculant and a polymer flocculant in combination.

[0106] The inorganic flocculant may be added at any time, but is preferably added before the addition of the organic ammonium compound and dithiocarbamate, particularly when it is zinc, copper, or a compound thereof.

[0107] The polymer flocculant may be added at any time, but is preferably added after the organic ammonium compound and the dithiocarbamate have been added.

[0108] When an inorganic flocculant and a polymer flocculant are used, they may be added at any time. However, it is preferable to add the inorganic flocculant, then add the organic ammonium compound and dithiocarbamate, and then add the polymer flocculant.

[0109] In the wastewater treatment process, the order of pH adjustment and addition of the flocculant is not particularly limited. For example, it is preferable to adjust the pH of the wastewater to 3 to 7, then add an inorganic flocculant, add an organic ammonium compound and a dithiocarbamate, then adjust the pH, and add a polymer flocculant.

[0110] As described above, the wastewater treatment agent and wastewater treatment method of the present invention can simply and efficiently remove a target element or its compound from wastewater, even if the target element is complexed with a multidentate ligand. Furthermore, even if the wastewater contains the target element or its compound, particularly salts such as sulfates, nitrates, carbonates, and phosphates that inhibit the separation of the complex, the target element or its compound can be efficiently removed.

[0111] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. [Example]

[0112] In the examples, organic ammonium compounds having the following organic ammonium salt structures, dithiocarbamates, and amines were used. The dithiocarbamates were produced according to conventional methods. In the notations below, "water-insoluble" refers to a solubility in water of less than 1% by mass at 20°C, and "water-soluble" refers to a solubility in water of 1% by mass or more at 20°C. The solubility in water was determined by dissolving various organic ammonium compounds at 20°C to a concentration of 1% by mass, and visually checking for dissolution.

[0113] [Organic ammonium compounds] Organic ammonium compound A (water-insoluble) Di-n-alkyldimethylammonium chloride (a mixture of alkyl chains with 16 and 18 carbon atoms) (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0114] Organic ammonium compound B (water-insoluble) Purolite A500 (polyvinylbenzyltrimethylammonium chloride, manufactured by Purolite Co., Ltd.) (Formula I: l≧0.1 mol%, m=0 mol%, n≧0 mol%)

[0115] Organic ammonium compound C (water-soluble) Diafloc KP201G (polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride, molecular weight 3 million, manufactured by Mitsubishi Chemical Corporation) (Formula I: l = 100 mol%, m = 0 mol%, n = 0 mol%)

[0116] Organic ammonium compound D (water-soluble) Diaflock KP7000 (acrylamide-acrylonitrile-N-vinylacrylamidine hydrochloride-N-vinylacrylamide-vinylamine hydrochloride-N-vinylformamide copolymer, molecular weight 3,000,000, manufactured by Mitsubishi Chemical Corporation) (Formula I: l≧0.1 mol%, m=0 mol%, n≧0 mol%)

[0117] Organic ammonium compound E (water-soluble) Chitosan hydrochloride 10 mmol of Daichitosan H (chitosan, molecular weight 200,000 to 10,000,000, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was reacted with 10 mmol of hydrochloric acid (reagent, manufactured by Kokusan Chemical Co., Ltd.), and the resulting product was purified and used. (Formula I: l ≥ 0.1 mol%, m = 0 mol%, n ≥ 0 mol%)

[0118] Organic ammonium compound F (water-soluble) Diacatch CH1405 (dicyandiamide-ammonium chloride-formaldehyde polycondensate, manufactured by Mitsubishi Chemical Corporation)

[0119] Organic ammonium compound G (water-soluble) Diaflock KA804E (acrylamide-acrylic acid-2-(acryloyloxy)ethyltrimethylammonium chloride-2-(methacryloyloxy)ethyltrimethylammonium chloride copolymer, molecular weight 6 million, manufactured by Mitsubishi Chemical Corporation) (Formula I: l≧0.1 mol%, m=0 mol%, n≧0 mol%)

[0120] Organic ammonium compound H (water-soluble) Tetrabutylammonium bromide (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0121] Organic ammonium compounds I (water-soluble) Triethylamine hydrochloride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0122] Organic ammonium compounds (water-soluble) Diethylenetriamine trihydrochloride An aqueous solution containing 10 mmol of diethylenetriamine (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.) was reacted with 30 mmol of hydrochloric acid (reagent, manufactured by Kokusan Chemical Co., Ltd.), and the resulting product was purified and used.

[0123] Organic ammonium compound K (water-soluble) Choline chloride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0124] Organic ammonium compounds (water-soluble) DL-Carnitine hydrochloride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0125] Organic ammonium compound M (water-soluble) Trimethylglycine hydrochloride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0126] Organic ammonium compound N (water-soluble) Acetyl-L-carnitine hydrochloride (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0127] Organic ammonium compounds (water-soluble) Catinal LC-100 (O-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethylcellulose chloride (polyquaternium-10), manufactured by Toho Chemical Industry Co., Ltd.) (Formula I: l≧0.1 mol%, m=0 mol%, n≧0 mol%)

[0128] The compound names and structures of the organic ammonium compounds used in this example are shown in Table 1.

[0129] [Table 1-1]

[0130] [Table 1-2]

[0131] [Table 1-3]

[0132] [Table 1-4]

[0133] [Dithiocarbamate] The synthesis method of the dithiocarbamate or the ratio of raw materials used is not particularly limited, but as an example, the following synthesis was used.

[0134] Dithiocarbamate A A sample (40% aqueous solution) prepared by reacting 128 mmol of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), 256 mmol of carbon disulfide, and 256 mmol of potassium hydroxide in 403 g of ion-exchanged water was used.

[0135] Dithiocarbamate B A sample (55% aqueous solution) prepared by reacting 293 mmol of diethylamine (Tokyo Chemical Industry Co., Ltd.), 293 mmol of carbon disulfide, and 293 mmol of potassium hydroxide in 233 g of ion-exchanged water was used.

[0136] Dithiocarbamate C A sample (40% aqueous solution) prepared by reacting 68.7 mmol of tetraethylenepentamine (Dow Chemical Japan Co., Ltd.), 274 mmol of carbon disulfide, and 274 mmol of sodium hydroxide in 441 g of ion-exchanged water was used.

[0137] Dithiocarbamate D A carbon disulfide-caustic soda modified polyethyleneimine-benzyl chloride condensate (30% aqueous solution) was synthesized in the same manner as above and used.

[0138] In the comparative examples, the following amines and dithiocarbamates were used. The dithiocarbamates were the same as those used in the examples.

[0139] [Amines] Amines A Diaflock KP000M1 (polymer of 2-(methacryloyloxy)ethyldimethylamine, molecular weight 3 million, manufactured by Mitsubishi Chemical Corporation)

[0140] Amines B Purolite A100 (polyvinylbenzyldimethylamine, manufactured by Purolite Co., Ltd.)

[0141] Amines C Diethylenetriamine (reagent, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0142] The following reagents were used to prepare the test solutions to be treated, and were added to the concentrations shown in the tables. Furthermore, aqueous hydrochloric acid or aqueous sodium hydroxide was used to adjust the pH during the preparation of the test solutions.

[0143] Chromium(III) chloride hexahydrate (Kanto Chemical Co., Ltd.) Cobalt(II) chloride hexahydrate (Fujifilm Wako Pure Chemical Industries, Ltd.) Copper(II) chloride dihydrate (Kokusan Chemical Co., Ltd.) Zinc(II) chloride (Kokusan Chemical Co., Ltd.) Aluminum sulfate 14-18 hydrate (Fujifilm Wako Pure Chemical Industries, Ltd.) Cadmium(II) chloride (Fujifilm Wako Pure Chemical Industries, Ltd.) Lead(II) chloride (Kanto Chemical Co., Ltd.) Selenious acid (Fujifilm Wako Pure Chemical Industries, Ltd.) 0.5 mol / L-EDTA solution (Nacalai Tesque, Inc.)

[0144] [Copper-containing wastewater treatment-1] An aqueous solution containing 50 mg / L copper, 500 mg / L EDTA (ethylenediaminetetraacetic acid), and 500 mg / L sodium sulfate (NaSO) was prepared as test wastewater, and the wastewater was treated and evaluated according to the procedure described below. In Example 27, 100 mg / L EDTA was used. In some examples, test wastewater containing neither EDTA nor sodium sulfate was used.

[0145] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted to the pre-treatment pH shown in Table 2 with aqueous hydrochloric acid and stirred for 5 minutes. An organic ammonium compound was then added in the amount shown in Table 2 and stirred for 5 minutes. A dithiocarbamate was then added in the amount shown in Table 2 and stirred for 10 minutes. The pH was then adjusted to the post-treatment pH shown in Table 2 with aqueous sodium hydroxide. In Examples 1, 2, and 3, the pH was adjusted to the pre-treatment pH, the organic ammonium compound was added, and the mixture was stirred for 5 minutes. The mixture was then stirred for 10 minutes without adding the dithiocarbamate or adjusting the pH after the addition of the treatment. In Examples 13 and 14, the dithiocarbamate was added to the organic ammonium compound in advance, and the resulting mixture was added to the test wastewater and stirred for 15 minutes.

[0146] In Example 28, an aqueous solution of ferric chloride was added as an inorganic flocculant in the amount shown in Table 2 before adding the organic ammonium compound, and the mixture was stirred for 5 minutes. In Example 29, after adding the dithiocarbamate, an aqueous solution of ferric chloride was added in the amount shown in Table 2, and the mixture was stirred for 5 minutes. The order of addition of the inorganic flocculants is shown in Table 2 as the order of addition of inorganic flocculants (vs. treatment agent).

[0147] Next, a polymer flocculant (a copolymer of acrylamide and sodium acrylate) was added and stirred at 20 rpm for 2 minutes. After stirring, the mixture was left to stand for 10 minutes, and the solid matter (floc) was filtered off using filter paper (JIS P3801 Type 5A). The copper concentration of the filtrate was measured using an ICP emission spectrometer (ICPE-9820, Shimadzu Corporation).

[0148] As comparative examples, only dithiocarbamate was added (Comparative Example 1), only amines were added (Comparative Examples 2 and 3), and amines and dithiocarbamate were added (Comparative Examples 4 and 5). In addition, as a conventional coagulation and sedimentation method for separating and removing target metals as hydroxides, slaked lime was used and the pH was adjusted to 10 shown in Table 2 (Comparative Example 6). Wastewater treatment was carried out in the same manner as in the Examples.

[0149] [Floc formation] The treated water was visually inspected for water-soluble organic ammonium compounds and evaluated according to the following criteria. Evaluation criteria ◎: Flocs have completely settled ○: Flocs have settled ×: Flocs are dispersed or solubilized The results are shown in Table 2.

[0150] [Table 2-1]

[0151] [Table 2-2]

[0152] [Table 2-3]

[0153] [Table 2-4]

[0154] [result] In all Comparative Examples that did not use an organic ammonium compound having an organic ammonium salt structure, the effect of removing the EDTA and copper complex (copper complex) was insufficient or absent, whereas in Examples 1 to 24 and 27 to 29 that used an organic ammonium compound having an organic ammonium salt structure, the effect of removing the copper complex was observed. In Examples 25 and 26, the effect of removing copper was observed.

[0155] In particular, comparisons between Example 3 and Comparative Example 3, Example 7 and Comparative Example 4, and Example 20 and Comparative Example 5, which are relatively similar in structure except for the presence or absence of an organic ammonium salt structure, show that in Example 3, which used organic ammonium compound B (polyvinylbenzyltrimethylammonium chloride), the copper concentration after treatment was 0.89 mg / L, whereas in Comparative Example 3, which used amines B (polyvinylbenzyldimethylamine), the copper concentration after treatment was 42.2 mg / L, and in Example 7, which used organic ammonium compound C (polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride), the copper concentration after treatment was 0.02 In Example 20, using organic ammonium compound J (diethylenetriamine trihydrochloride), the copper concentration after treatment was less than 0.02 mg / L, whereas in Comparative Example 4, using amine A (polymer of 2-(methacryloyloxy)ethyldimethylamine), the copper concentration after treatment was 25.7 mg / L. In Example 20, using organic ammonium compound J (diethylenetriamine trihydrochloride), the copper concentration after treatment was less than 0.02 mg / L, whereas in Comparative Example 5, using amine C (diethylenetriamine), the copper concentration after treatment was 38.3 mg / L. These results confirm that the use of organic ammonium compounds having the organic ammonium salt structure of the present invention can enhance the treatment effect of copper complex-containing wastewater. Furthermore, in Examples 25 and 26, the copper removal effect was observed even for copper that did not form a complex with EDTA. This demonstrates that the use of the organic ammonium compounds of the present invention can efficiently treat wastewater containing the above elements or their compounds.

[0156] Furthermore, in Examples 7 and 27, the copper removal effect was confirmed both when the molar ratio of EDTA was less than that of the copper to be treated and when it was in excess. This confirmed that the use of the organic ammonium compound of the present invention can suitably treat wastewater to which a complexing agent has been added in excess of the element to be treated.

[0157] Furthermore, comparison of Examples 1 and 2, and Examples 4 and 5 confirmed that when the wastewater contained sodium sulfate as a coexisting salt, the effect of separating the copper complex was reduced. However, in all Examples containing sodium sulfate, the copper complex was able to be removed more efficiently than in Comparative Examples 3 and 5, which did not contain sulfate. This suggests that the organic ammonium compound of the present invention has a high treatment effect and can suitably treat wastewater containing the element or its compound, particularly a complex, even when the wastewater contains a coexisting salt.

[0158] A comparison of Example 5 with Examples 15 and 21 to 24, which use organic ammonium compounds in which no hydrogen atoms are bonded to the nitrogen cation, shows that Examples 15 and 21 to 24, which use organic ammonium compounds H, K, L, M, and N in which the alkyl group has 1 to 8 carbon atoms, have a higher copper complex treatment effect than Example 5, which uses organic ammonium compound A in which the alkyl group has more than 8 carbon atoms. This suggests that when using an organic ammonium compound in which no hydrogen atoms are bonded to the nitrogen cation, the treatment effect of the element or its compound, particularly its complex, can be further enhanced by using an organic ammonium compound in which the hydrocarbon group has 1 to 8 carbon atoms.

[0159] Comparison of Examples 1 and 4, and Examples 2 and 5, showed that Examples 4 and 5, in which the organic ammonium compound of the present invention and a dithiocarbamate were used in combination, had a higher copper complex treatment effect than Examples 1 and 2, in which no combination was used. This suggests that the combined use of the organic ammonium compound of the present invention and a dithiocarbamate enables more efficient treatment of wastewater containing the element or its compound, particularly a complex.

[0160] A comparison of Example 5 with Examples 15, 21-24 showed that when a dithiocarbamate was used in combination, Examples 15, 21-24, which used water-soluble organic ammonium compounds H, K, L, M, and N, were more effective in treating copper complexes than Example 5, which used water-insoluble organic ammonium compound A. This suggests that when a dithiocarbamate was used in combination, the use of a water-soluble organic ammonium compound can more efficiently treat wastewater containing the element or its compound, particularly complexes. Furthermore, a comparison of Example 6 with Examples 7, 8, and 10, which used an organic ammonium compound consisting only of cationic repeating units in formula (I), showed that when a dithiocarbamate was used in combination, Examples 7, 8, and 10, which used water-soluble organic ammonium compounds C, D, and E, were more effective in treating copper complexes than Example 6, which used water-insoluble organic ammonium compound B. This also suggests that when a dithiocarbamate was used in combination, the use of a water-soluble organic ammonium compound can more efficiently treat wastewater containing the element or its compound, particularly complexes.

[0161] A comparison of Examples 7, 8, 10, and 12, which used polymeric organic ammonium compounds, with Example 11 confirmed that Examples 7, 8, 10, and 12, which used organic ammonium compounds C, D, E, and G in which the bond adjacent to the nitrogen cation is a single bond, had lower copper concentrations after treatment and were more effective in treating wastewater containing copper complexes than Example 11, which used organic ammonium compound F in which the bond adjacent to the nitrogen cation is not a single bond. This suggests that when the organic ammonium compound of the present invention is a polymer, the use of an organic ammonium compound in which the bond adjacent to the nitrogen cation is a single bond provides a higher treatment effect for wastewater containing the element or its compound, particularly a complex, than an organic ammonium compound in which the bond adjacent to the nitrogen cation is not a single bond.

[0162] A comparison of Examples 7 to 10, 12, and 14 with Examples 15 to 24 showed that floc formation was easier with a smaller amount of the organic ammonium compound represented by formula (I) than with the organic ammonium compounds represented by formulas (II) and (III). This suggests that the use of the organic ammonium compound represented by formula (I) allows for efficient treatment of the elements or their compounds, particularly complexes, with a small amount of the organic ammonium compound.

[0163] A comparison of Examples 7, 8, and 10 with Example 12, which used organic ammonium compounds represented by formula (I), confirmed that Examples 7, 8, and 10, which used organic ammonium compounds C, D, and E consisting only of cationic repeating units, had lower copper concentrations after treatment and were more effective in treating wastewater containing copper complexes than Example 12, which used organic ammonium compound G having anionic repeating units. This suggests that when using organic ammonium compounds represented by formula (I), the use of organic ammonium compounds consisting only of cationic repeating units provides a higher treatment effect for wastewater containing the element or its compounds, particularly complexes, than the use of organic ammonium compounds having anionic repeating units.

[0164] In Examples 6, 7, 8, and 10, which used organic ammonium compounds represented by formula (I), the copper concentration after treatment was low in all cases: Example 6, which used organic ammonium compound B, had a copper concentration of 0.50 mg / L; Example 7, which used organic ammonium compound C, and Example 8, which used organic ammonium compound D, had a copper concentration of less than 0.02 mg / L; and Example 10, which used organic ammonium compound E, had a copper concentration of 0.44 mg / L. In particular, Example 7, which used organic ammonium compound C, and Example 8, which used organic ammonium compound D, had even lower copper concentrations. These results suggest that among the organic ammonium compounds represented by formula (I), polyvinylbenzyltrimethylammonium chloride, polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride, copolymer of acrylamide-acrylonitrile-N-vinylacrylamidine hydrochloride-N-vinylacrylamide-vinylamine hydrochloride-N-vinylformamide, and chitosan hydrochloride can be used to efficiently treat wastewater containing the above elements or their compounds, especially complexes. In particular, polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride and copolymer of acrylamide-acrylonitrile-N-vinylacrylamidine hydrochloride-N-vinylacrylamide-vinylamine hydrochloride-N-vinylformamide can be used to efficiently treat wastewater containing the above elements or their compounds, especially complexes.

[0165] A comparison of Example 19, which used an organic ammonium compound represented by formula (III), with Examples 15 and 21 to 24 showed that the copper concentration after treatment was lower in Examples 15 and 21 to 24, which used organic ammonium compounds H, K, M, and N, in which only a hydrocarbon group is bonded to the nitrogen cation, than in Example 19, which used organic ammonium compound I, in which a hydrogen atom is bonded to the nitrogen cation. This suggests that when an organic ammonium compound represented by formula (III) is used, the use of an organic ammonium compound in which only a hydrocarbon group is bonded to the nitrogen cation will result in a higher treatment effect for wastewater containing the element or its compound, particularly a complex.

[0166] A comparison of Example 21 with Examples 22 to 24 confirmed that, compared with Example 21, which used organic ammonium compound K having only a hydroxyl group on the alkyl group, Examples 22 to 24, which used organic ammonium compound L having both a hydroxyl group and a carboxyl group on the alkyl group, organic ammonium compound M having a carboxyl group on the alkyl group, and organic ammonium compound N having an ester group on the alkyl group, had lower copper concentrations after treatment and were more effective in treating copper complexes. This suggests that the use of organic ammonium compounds having an ester or carboxyl group on the hydrocarbon group provides a higher treatment effect for wastewater containing the element or its compound, particularly its complex, than the use of organic ammonium compounds having only a hydroxyl group on the hydrocarbon group.

[0167] A comparison of Examples 15 to 18 shows that Example 15, which used dithiocarbamate A, and Example 17, which used dithiocarbamate C, were able to reduce the copper concentration to less than 0.02 mg / L with smaller addition amounts than Example 16, which used dithiocarbamate B, and Example 18, which used dithiocarbamate D. This suggests that when the organic ammonium compound of the present invention is used in combination with a dithiocarbamate, using piperazine dithiocarbamate or tetraethylenepentamine dithiocarbamate as the dithiocarbamate enables more efficient treatment of wastewater containing the element or a compound thereof, in particular a complex thereof.

[0168] Comparison of Examples 5 and 13 and Examples 7 and 14 shows that when the organic ammonium compound of the present invention and a dithiocarbamate were used in combination, Example 13, in which organic ammonium compound A and a dithiocarbamate were mixed and added in advance, had a higher copper complex treatment effect than Example 5, in which they were added separately. Furthermore, Example 14, in which organic ammonium compound C and a dithiocarbamate were mixed in advance and added in advance, was able to treat the copper concentration to less than 0.02 mg / L with a smaller addition amount than Example 7, in which they were added separately. This suggests that when the organic ammonium compound of the present invention and a dithiocarbamate are used in combination, pre-mixing and adding the organic ammonium compound and dithiocarbamate enables more efficient treatment of wastewater containing the element or its compound, particularly a complex.

[0169] From Examples 28 and 29, it was confirmed that even when an inorganic flocculant was further added, the copper removal effect was achieved regardless of the order of addition of the inorganic flocculants.

[0170] Examples 7 to 12 and 14 to 29, in which flocs were formed, were evaluated as having a higher ease of floc formation than Comparative Examples 1, 2, and 4 to 6. This confirms that the use of the organic ammonium compound of the present invention facilitates the formation of flocs and enables the easy treatment of wastewater containing the element or its compound, particularly a complex.

[0171] Furthermore, in Examples 4 to 29 in which dithiocarbamate salts were used, no irritating odor was observed.

[0172] [Zinc-containing wastewater treatment-1] An aqueous solution containing 10 mg / L of zinc, 25 or 100 mg / L of EDTA, and 100 mg / L of sodium sulfate was prepared as test wastewater, and the wastewater was treated and evaluated according to the following procedure. In Examples 30 and 36, test wastewater containing no EDTA was used.

[0173] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted with an aqueous hydrochloric acid solution to the pH before the addition of the treatment agent listed in Table 3, and the mixture was stirred for 5 minutes. Next, an aqueous ferric chloride solution or an aqueous aluminum sulfate solution (aluminum sulfate) was added as an inorganic coagulant in the amount listed in Table 3 and stirred for 5 minutes. A dithiocarbamate salt was added to an organic ammonium compound in advance, mixed, and added in the amount listed in Table 3, and the mixture was stirred for 10 minutes. Then, an aqueous sodium hydroxide solution was used to adjust the pH to the pH after the addition of the treatment agent listed in Table 3. The inorganic coagulants were added in the order shown in Table 3 (to the treatment agent). In Example 34, the dithiocarbamate salt was added to an organic ammonium compound in advance, mixed, and then the inorganic coagulant was added. A polymer coagulant (a copolymer of acrylamide and sodium acrylate) was then added and stirred at 20 rpm for 2 minutes. In Example 33, no polymer coagulant was added. After stirring, the mixture was left to stand for 10 minutes, and the solid matter (floc) was filtered off using filter paper (JIS P3801 Type 5A), and the zinc concentration in the filtrate was measured using an ICP emission spectrometer. The results are shown in Table 3.

[0174] [Table 3]

[0175] As shown in Table 3, Examples 30 to 37, which used the treatment agent of the present invention and ferric chloride or aluminum sulfate as an inorganic coagulant, had lower zinc concentrations after treatment than Comparative Examples 7 to 10, which used the conventional coagulation and sedimentation method. This confirms the effectiveness of the organic ammonium compound of the present invention in treating zinc and zinc complexes. This suggests that the use of the organic ammonium compound of the present invention can more efficiently treat wastewater containing the elements or their compounds, especially complexes.

[0176] Furthermore, even when no complexing agent was included (Examples 30 and 36), zinc could be treated effectively, and even when the molar ratio of EDTA was lower than that of the zinc to be treated (Examples 31 and 37), or even when it was in excess (Examples 32 to 35), the zinc removal effect was confirmed. From these results, it was confirmed that the use of the organic ammonium compound of the present invention allows for the effective treatment of wastewater to which a complexing agent has been added in excess of the element to be treated.

[0177] Examples 32 and 33, which differ only in the presence or absence of a polymer flocculant, demonstrate the effect of removing zinc complexes in both cases, and it was confirmed that one or two types of flocculants could be used, and that the zinc removal effect could be confirmed whether the number of times was one or two. This suggests that the use of one or more types of flocculants, whether the number of times was one or two or more, can more efficiently treat wastewater containing the element or its compounds, especially complexes.

[0178] In Examples 32 and 34, which differ only in the order of addition of the inorganic flocculant, both were found to be effective in removing zinc complexes, but Example 32, in which the inorganic flocculant was added before the organic ammonium compound, was more effective in removing zinc complexes. This suggests that adding an inorganic flocculant before adding the organic ammonium compound and dithiocarbamate of the present invention can more efficiently treat wastewater containing the elements or their compounds, especially complexes.

[0179] In Examples 32 and 35, which differ only in pH before the addition of the treating agent of the present invention, both were found to be effective in removing zinc complexes. This suggests that wastewater containing the element or its compound, especially its complex, can be treated more efficiently by adjusting the pH to 4 to 6 before the addition of the organic ammonium compound of the present invention and then adjusting the pH after the addition.

[0180] [Treatment of wastewater containing other elements-1] As test wastewater, aqueous solutions containing 10 mg / L each of chromium, cobalt, cadmium, aluminum, lead, and selenium, and 100 mg / L of EDTA were prepared, and the wastewater was treated and evaluated according to the procedure described below.

[0181] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted with aqueous hydrochloric acid to the pH before the addition of the treatment agent listed in Table 4 and stirred for 5 minutes. Next, an organic ammonium compound was added in the amount listed in Table 4 and stirred for 5 minutes. A dithiocarbamate was added in the amount listed in Table 4 and stirred for 10 minutes. The pH was then adjusted with aqueous sodium hydroxide to the pH after the addition of the treatment agent listed in Table 4. A polymer flocculant (a copolymer of acrylamide and sodium acrylate) was then added and stirred at 20 rpm for 2 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the solids (flocs) were filtered off using filter paper (JIS P3801 Type 5A). The element concentrations in the filtrate were measured using an ICP atomic emission spectrometer. The results are shown in Table 4.

[0182] [Table 4]

[0183] In Examples 38 to 43, which used wastewater containing complexes of chromium, cobalt, cadmium, aluminum, lead, and selenium, which are Group 6 to 16 elements other than copper, zinc, and nickel, the concentrations of each element in the wastewater were reduced by treating with the organic ammonium compound of the present invention, confirming that the use of the organic ammonium compound of the present invention can suitably treat wastewater containing complexes of elements from Periods 3 to 6 of Groups 6 to 16.

[0184] Furthermore, among the complexes of chromium, cobalt, cadmium, aluminum, lead, and selenium, lead, which belongs to Group 14, Period 6, was particularly favorably treated. As described above, copper, which belongs to Group 11, Period 4, and zinc, which belongs to Group 12, Period 4, were also particularly favorably treated. This confirms that the use of the organic ammonium compound of the present invention enables favorable treatment of wastewater containing complexes of elements belonging to Groups 11 to 14, Periods 4 to 6.

[0185] [Copper-containing wastewater treatment-2] An aqueous solution containing 50 mg / L of copper, 500 mg / L of EDTA (ethylenediaminetetraacetic acid), and 500 mg / L of sodium sulfate (NaSO) was prepared as test wastewater, and the wastewater was treated and evaluated according to the procedure described below. In Example 64, the EDTA concentration was 100 mg / L. In some examples, test wastewater containing neither EDTA nor sodium sulfate was used.

[0186] The test wastewater was placed in a 500 mL beaker and, while stirring at 100 rpm, adjusted with an aqueous hydrochloric acid solution to the pH before the addition of the treating agent shown in Table 5 and stirred for 5 minutes. Next, an organic ammonium compound was added in the amount shown in Table 5 and stirred for 5 minutes. Further, a dithiocarbamate was added in the amount shown in Table 5 and stirred for 10 minutes. Thereafter, an aqueous sodium hydroxide solution was used to adjust the pH to the pH after the addition of the treating agent shown in Table 5. In addition, in Examples 52, 53, 69 to 71, and 74 to 76, a dithiocarbamate was added to the organic ammonium compound in advance, and the mixture was added to the test wastewater and stirred for 15 minutes.

[0187] In Examples 65, 70, and 75, an aqueous solution of ferric chloride was added as an inorganic coagulant in the amount shown in Table 5 before adding the organic ammonium compound, and the mixture was stirred for 5 minutes. In Examples 66, 71, and 76, an aqueous solution of ferric chloride was added in the amount shown in Table 5 after adding the dithiocarbamate, and the mixture was stirred for 5 minutes. The order of addition of the inorganic coagulants is shown in Table 5 as the order of addition of inorganic coagulants (vs. treatment agent).

[0188] A polymer flocculant (a copolymer of acrylamide and sodium acrylate) was then added and stirred at 20 rpm for 2 minutes. After stirring, the mixture was left to stand for 10 minutes, and the solid matter (floc) was filtered off using filter paper (JIS P3801 Type 5A). The copper concentration of the filtrate was measured using an ICP emission spectrometer (ICPE-9820, Shimadzu Corporation). The results are shown in Table 5.

[0189] [Table 5-1]

[0190] [Table 5-2]

[0191] [Table 5-3]

[0192] From Table 5, it was confirmed that the copper complex was removed effectively in Examples 44 to 61, 64 to 66, 68 to 71, and 73 to 76, which used organic ammonium compounds having an organic ammonium salt structure. In Examples 62, 63, 67, and 72, the copper was removed effectively.

[0193] In particular, comparisons between Example 47 and Comparative Example 4, and Example 57 and Comparative Example 5, which are relatively similar in structure except for the presence or absence of the organic ammonium salt structure, show that in Example 47, which used organic ammonium compound C (polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride), the copper concentration after treatment was less than 0.02 mg / L, while in Comparative Example 4, which used amines A (polymer of 2-(methacryloyloxy)ethyldimethylamine), the copper concentration after treatment was 25.7 mg / L. In Example 57, which used organic ammonium compound J (diethylenetriamine trihydrochloride), the copper concentration after treatment was less than 0.02 mg / L, while in Comparative Example 5, which used amines C (diethylenetriamine), the copper concentration after treatment was 38.3 mg / L. These results confirm that the use of organic ammonium compounds having the organic ammonium salt structure of the present invention can enhance the treatment efficiency of copper complex-containing wastewater. Furthermore, in Examples 62, 63, 67, and 72, the copper removal effect was observed even for copper that was not complexed with EDTA. This demonstrates that wastewater containing the above elements or compounds thereof can be efficiently treated by using the organic ammonium compound of the present invention.

[0194] Furthermore, in Examples 47 and 64, the copper removal effect was confirmed both when the molar ratio of EDTA was less than that of the copper to be treated and when it was in excess. This confirmed that the use of the organic ammonium compound of the present invention can suitably treat wastewater to which a complexing agent has been added in excess of the element to be treated.

[0195] Furthermore, a comparison between Example 44 and Example 45 confirmed that when the wastewater contained sodium sulfate as a coexisting salt, the separation effect of the copper complex decreased, but in all Examples containing sodium sulfate, the copper complex was able to be removed more efficiently than in Comparative Examples 3 and 5, which did not contain sulfate. This suggests that the organic ammonium compound of the present invention has a high treatment effect and can suitably treat wastewater containing the element or its compound, particularly a complex, even when the wastewater contains a coexisting salt.

[0196] A comparison of Example 45 with Examples 54 and 58 to 61, which used organic ammonium compounds in which no hydrogen atoms are bonded to the nitrogen cation, showed that Examples 54 and 58 to 61, which used organic ammonium compounds H, K, L, M, and N in which the alkyl group had 1 to 8 carbon atoms, had a higher copper complex treatment effect than Example 45, which used organic ammonium compound A in which the alkyl group had more than 8 carbon atoms. This suggests that when using an organic ammonium compound in which no hydrogen atoms are bonded to the nitrogen cation, using an organic ammonium compound in which the hydrocarbon group had 1 to 8 carbon atoms would further enhance the treatment effect of the element or its compound, particularly its complex.

[0197] Comparison of Example 1 with Example 44 and Example 2 with Example 45 showed that Examples 44 and 45, in which the organic ammonium compound of the present invention and a dithiocarbamate were used in combination, had a higher copper complex treatment effect than Examples 1 and 2, in which no combination was used. This suggests that the combined use of the organic ammonium compound of the present invention and a dithiocarbamate enables more efficient treatment of wastewater containing the element or its compound, particularly a complex.

[0198] A comparison of Example 45 with Examples 54, 58-61 shows that when a dithiocarbamate was used in combination, Examples 54, 58-61, which used water-soluble organic ammonium compounds H, K, L, M, and N, showed a higher copper complex treatment effect than Example 45, which used water-insoluble organic ammonium compound A. This suggests that the use of a water-soluble organic ammonium compound when a dithiocarbamate was used in combination can more efficiently treat wastewater containing the element or its compound, particularly its complex. Furthermore, a comparison of Example 46 with Examples 47, 48, 49, and 73, which used organic ammonium compounds consisting only of cationic repeating units in formula (I), shows that when a dithiocarbamate was used in combination, Examples 47, 48, 49, and 73, which used water-soluble organic ammonium compounds C, D, E, and O, showed a higher copper complex treatment effect than Example 46, which used water-insoluble organic ammonium compound B. This also suggests that when a dithiocarbamate is used in combination, the use of a water-soluble organic ammonium compound can more efficiently treat wastewater containing the above elements or their compounds, especially complexes.

[0199] A comparison of Examples 47, 48, 49, 51, and 73, which used polymeric organic ammonium compounds, with Example 50 confirmed that Examples 47, 48, 49, 51, and 73, which used organic ammonium compounds C, D, E, G, and O in which the bond adjacent to the nitrogen cation is a single bond, had lower copper concentrations after treatment and were more effective in treating wastewater containing copper complexes than Example 50, which used organic ammonium compound F in which the bond adjacent to the nitrogen cation is not a single bond. This suggests that when the organic ammonium compound of the present invention is a polymer, the use of an organic ammonium compound in which the bond adjacent to the nitrogen cation is a single bond provides a higher treatment effect for wastewater containing the element or its compound, particularly a complex, than an organic ammonium compound in which the bond adjacent to the nitrogen cation is not a single bond.

[0200] A comparison of Examples 47 to 49, 51, 53, and 73 with Examples 54 to 61 showed that floc formation was easier with a smaller amount of the organic ammonium compound represented by formula (I) than with the organic ammonium compounds represented by formulas (II) and (III). This suggests that the use of the organic ammonium compound represented by formula (I) allows for efficient treatment of the elements or their compounds, particularly complexes, with a small amount of the organic ammonium compound.

[0201] A comparison of Examples 47-49 and 73, which used organic ammonium compounds represented by formula (I), with Example 51 confirmed that Examples 47-49 and 73, which used organic ammonium compounds C, D, E, and O consisting only of cationic repeating units, had lower copper concentrations after treatment and were more effective in treating wastewater containing copper complexes than Example 51, which used organic ammonium compound G having anionic repeating units. This suggests that when using organic ammonium compounds represented by formula (I), the use of organic ammonium compounds consisting only of cationic repeating units provides a higher treatment effect for wastewater containing the element or its compounds, particularly complexes, than the use of organic ammonium compounds having anionic repeating units.

[0202] In Examples 46 to 49 and 73, which used organic ammonium compounds represented by formula (I), the copper concentration after treatment was 0.46 mg / L in Example 46, which used organic ammonium compound B; less than 0.02 mg / L in Example 47, which used organic ammonium compound C, Example 48, which used organic ammonium compound D, and Example 73, which used organic ammonium compound O; and 0.39 mg / L in Example 49, which used organic ammonium compound E. In particular, the copper concentrations after treatment were even lower in Example 47, which used organic ammonium compound C, Example 48, which used organic ammonium compound D, and Example 73, which used organic ammonium compound O. These results suggest that wastewater containing the above elements or their compounds, especially their complexes, can be efficiently treated using the organic ammonium compounds represented by formula (I), such as polyvinylbenzyltrimethylammonium chloride, polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride, copolymer of acrylamide-acrylonitrile-N-vinylacrylamidine hydrochloride-N-vinylacrylamide-vinylamine hydrochloride-N-vinylformamide, copolymer of chitosan hydrochloride, and (O-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethylcellulose chloride. Furthermore, the use of polymer of 2-(methacryloyloxy)ethyltrimethylammonium chloride, copolymer of acrylamide-acrylonitrile-N-vinylacrylamidine hydrochloride-N-vinylacrylamide-vinylamine hydrochloride-N-vinylformamide, and copolymer of (O-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethylcellulose chloride, is particularly effective in treating wastewater.

[0203] A comparison of Example 56, which used an organic ammonium compound represented by formula (III), with Examples 54, 58 to 61, showed that the copper concentration after treatment was lower in Examples 54, 58 to 61, which used organic ammonium compounds H, K, M, and N, in which only hydrocarbon groups are bonded to the nitrogen cation, than in Example 56, which used organic ammonium compound I, in which a hydrogen atom is bonded to the nitrogen cation. This suggests that when using an organic ammonium compound represented by formula (III), the use of an organic ammonium compound in which only hydrocarbon groups are bonded to the nitrogen cation will result in a higher treatment effect for wastewater containing the element or its compound, particularly a complex.

[0204] A comparison of Example 58 with Examples 59 to 61 confirmed that, compared to Example 58, which used organic ammonium compound K having only a hydroxyl group on the alkyl group, Examples 59 to 61, which used organic ammonium compound L having both a hydroxyl group and a carboxyl group on the alkyl group, organic ammonium compound M having a carboxyl group on the alkyl group, and organic ammonium compound N having an ester group on the alkyl group, had lower copper concentrations after treatment and were more effective in treating copper complexes. This suggests that the use of organic ammonium compounds having an ester or carboxyl group on the hydrocarbon group is more effective in treating wastewater containing the element or its compounds, especially complexes, than the use of organic ammonium compounds having only a hydroxyl group on the hydrocarbon group.

[0205] Comparison of Examples 45 and 52 and Examples 47 and 53 shows that when the organic ammonium compound of the present invention and a dithiocarbamate were used in combination, Example 52, in which organic ammonium compound A and a dithiocarbamate were mixed and added in advance, showed a higher copper complex treatment effect than Example 45, in which they were added separately. Furthermore, Example 53, in which organic ammonium compound C and a dithiocarbamate were mixed in advance and added in advance, was able to treat the copper concentration to less than 0.02 mg / L with a smaller addition amount than Example 47, in which they were added separately. This suggests that when the organic ammonium compound of the present invention and a dithiocarbamate are used in combination, pre-mixing and adding the organic ammonium compound and dithiocarbamate enables more efficient treatment of wastewater containing the element or its compound, particularly its complex.

[0206] From Examples 65, 66, 70, 71, 75 and 76, it was confirmed that even when an inorganic flocculant was further added, the copper removal effect was achieved regardless of the order of addition of the inorganic flocculants.

[0207] Examples 47 to 51 and 53 to 76, in which flocs were formed, were evaluated as being more favorable in terms of ease of floc formation than Comparative Examples 1, 2, and 4 to 6. This confirms that the use of the organic ammonium compound of the present invention facilitates the formation of flocs and enables the easy treatment of wastewater containing the element or its compound, particularly a complex.

[0208] Furthermore, in Examples 44 to 76, in which dithiocarbamate salts were used, no irritating odor was observed.

[0209] [Zinc-containing wastewater treatment-2] An aqueous solution containing 10 mg / L of zinc, 25 or 100 mg / L of EDTA, and 100 mg / L of sodium sulfate was prepared as test wastewater, and the wastewater was treated and evaluated according to the procedure described below. In Examples 77, 83, 85, 91, 93, and 99, test wastewater containing no EDTA was used.

[0210] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted with an aqueous hydrochloric acid solution to the pH before the addition of the treatment agent listed in Table 6, and the mixture was stirred for 5 minutes. Next, an inorganic coagulant, either an aqueous ferric chloride solution or an aqueous aluminum sulfate solution (aluminum sulfate), was added in the amounts listed in Table 6 and stirred for 5 minutes. A mixture of an organic ammonium compound and a dithiocarbamate was added in the amounts listed in Table 6 and stirred for 10 minutes. The pH was then adjusted to the pH after the addition of the treatment agent listed in Table 6 using an aqueous sodium hydroxide solution. The inorganic coagulants were added in the order shown in Table 6 (relative to the treatment agent). In Examples 81, 89, and 97, the organic ammonium compound and a dithiocarbamate were added in advance, followed by the inorganic coagulant. A polymer coagulant (a copolymer of acrylamide and sodium acrylate) was then added and stirred at 20 rpm for 2 minutes. In Examples 80, 88, and 96, no polymer coagulant was added. After stirring, the mixture was left to stand for 10 minutes, and the solid matter (floc) was filtered off using filter paper (JIS P3801 Type 5A), and the zinc concentration in the filtrate was measured using an ICP emission spectrometer.

[0211] The results are shown in Table 6.

[0212] [Table 6-1]

[0213] [Table 6-2]

[0214] As shown in Table 6, Examples 77 to 100, which used the treatment agent of the present invention and ferric chloride or aluminum sulfate as an inorganic coagulant, had lower zinc concentrations after treatment than Comparative Examples 7 to 10, which used the conventional coagulation and sedimentation method. This confirms the effectiveness of the organic ammonium compound of the present invention in treating zinc and its complexes. This suggests that the use of the organic ammonium compound of the present invention can more efficiently treat wastewater containing the element or its compounds, especially complexes.

[0215] Furthermore, even when no complexing agent was included (Examples 77, 83, 85, 91, 93, 99), zinc could be treated effectively, and even when the molar ratio of EDTA was lower than the zinc to be treated (Examples 78, 84, 86, 92, 94, 100), or even when it was in excess (Examples 79-82, 87-90, 95-98), the zinc removal effect was confirmed. From these results, it was confirmed that the use of the organic ammonium compound of the present invention allows for the effective treatment of wastewater to which a complexing agent has been added in excess of the element to be treated.

[0216] Examples 79 and 80, 87 and 88, and 95 and 96, which differ only in the presence or absence of a polymer flocculant, all showed an effect of removing zinc complexes, and it was confirmed that one or two types of flocculants could be used, and that the zinc removal effect could be confirmed whether the number of times was one or two. This suggests that the use of one or more types of flocculants, whether the number of times was one or two or more, can more efficiently treat wastewater containing the element or its compounds, especially complexes.

[0217] Examples 79 and 81, 87 and 89, and 95 and 97, which differ only in the order of addition of the inorganic coagulant, all showed an effect of removing zinc complexes, but Examples 79, 87, and 95, in which the inorganic coagulant was added before the organic ammonium compound, were more effective in removing zinc complexes. This suggests that adding an inorganic coagulant before adding the organic ammonium compound and dithiocarbamate of the present invention can more efficiently treat wastewater containing the elements or their compounds, especially complexes.

[0218] Examples 79 and 82, 87 and 90, and 95 and 98, which differ only in pH before the addition of the treatment agent of the present invention, all showed an effect of removing zinc complexes. This suggests that wastewater containing the element or its compound, especially its complex, can be treated more efficiently by adjusting the pH before the addition of the organic ammonium compound of the present invention to 4 to 6 and then adjusting the pH after the addition.

[0219] [Nickel-containing wastewater treatment] An aqueous solution containing 10 mg / L of nickel, 100 mg / L of EDTA, and 100 mg / L of sodium sulfate was prepared as test wastewater, and the wastewater was treated and evaluated according to the procedure described below.

[0220] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted with an aqueous hydrochloric acid solution to the pH before the addition of the treatment agent listed in Table 7 and stirred for 5 minutes. Next, an organic ammonium compound was added in the amount listed in Table 7 and stirred for 5 minutes. A dithiocarbamate salt was added in the amount listed in Table 7 and stirred for 10 minutes. An aqueous ferric chloride solution was then added as an inorganic flocculant and stirred for 5 minutes. Then, an aqueous sodium hydroxide solution was used to adjust the pH to the pH after the addition of the treatment agent listed in Table 7. A polymer flocculant (a copolymer of acrylamide and sodium acrylate) was then added and stirred for 2 minutes at 20 rpm. After stirring, the mixture was allowed to stand for 10 minutes, and the solids (flocs) were filtered off using filter paper (JIS P3801 Type 5A). The nickel concentration of the filtrate was measured. The nickel concentration in the filtrate was measured using an ICP atomic emission spectrometer.

[0221] The results are shown in Table 7.

[0222] [Table 7]

[0223] As shown in Table 7, Examples 101 to 104, which used the treatment agent of the present invention and ferric chloride as an inorganic coagulant, had lower nickel concentrations after treatment than Comparative Example 11, which used a conventional coagulation and sedimentation method. This confirmed the effectiveness of the organic ammonium compound of the present invention in treating nickel and its complexes. This suggests that the use of the organic ammonium compound of the present invention can more efficiently treat wastewater containing the element or its compound, especially its complex.

[0224] [Treatment of wastewater containing other elements-2] As test wastewater, aqueous solutions containing 10 mg / L each of chromium, cobalt, cadmium, aluminum, lead, and selenium, and 100 mg / L of EDTA were prepared, and the wastewater was treated and evaluated according to the procedure described below.

[0225] The test wastewater was placed in a 500 mL beaker and stirred at 100 rpm. The pH was adjusted with aqueous hydrochloric acid to the pH before the addition of the treatment agent listed in Table 8 and stirred for 5 minutes. Next, an organic ammonium compound was added in the amount listed in Table 8 and stirred for 5 minutes. A dithiocarbamate was added in the amount listed in Table 8 and stirred for 10 minutes. The pH was then adjusted with aqueous sodium hydroxide to the pH after the addition of the treatment agent listed in Table 8. A polymer flocculant (a copolymer of acrylamide and sodium acrylate) was then added and stirred at 20 rpm for 2 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the solids (flocs) were filtered off using filter paper (JIS P3801 Type 5A). The element concentrations in the filtrate were measured using an ICP atomic emission spectrometer.

[0226] The results are shown in Table 8.

[0227] [Table 8-1]

[0228] [Table 8-2]

[0229] In Examples 105 to 122, which used wastewater containing complexes of chromium, cobalt, cadmium, aluminum, lead, and selenium, which are Group 6 to 16 elements other than copper, zinc, and nickel, the concentrations of each element in the wastewater were reduced by treating with the organic ammonium compound of the present invention, confirming that the use of the organic ammonium compound of the present invention can suitably treat wastewater containing complexes of elements from the third to sixth periods of Group 6 to 16.

[0230] Furthermore, among the complexes of chromium, cobalt, cadmium, aluminum, lead, and selenium, lead, which belongs to Group 14, Period 6, was particularly favorably treated. As described above, copper, which belongs to Group 11, Period 4, and zinc, which belongs to Group 12, Period 4, were also particularly favorably treated. This confirms that the use of the organic ammonium compound of the present invention enables favorable treatment of wastewater containing complexes of elements belonging to Groups 11 to 14, Periods 4 to 6.

Claims

1. A wastewater treatment agent for removing a complex of a Group 6 to 16 element from wastewater containing the complex, the wastewater treatment agent comprising an organic ammonium compound having at least one or more organic ammonium salt structures, the organic ammonium compound being represented by any one of the following formulas (I) to (III), and the wastewater treatment agent removes the complex by reacting the organic ammonium compound with the complex: 【Chemistry 1】 (In formula (I), the numbers in parentheses l, m, and n represent repeating units of the polymer, and the bonding order is arbitrary. l, m, and n represent the mol % of the repeating units in the polymer. The total of l, m, and n is 100 mol %, l and m are 0 mol % or more, and at least one of them is 0.1 mol % or more, and n is 0 mol % or more. In the repeating unit enclosed in parentheses l, X represents a main skeleton of the repeating unit derived from the raw material monomer, and may have two or more types of repeating units. R 1 represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent. R 2 to R 4 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent. A - represents an anion. o is 0 or 1. In the repeating unit enclosed in parentheses m, R 5 and R 7 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent. represents a divalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and B - represents an anion. p and q are 0 or 1. In the repeating unit enclosed in parentheses of n, Y represents a repeating unit derived from the raw material monomer. Y may have two or more types of repeating units. When R 2 to R 4 , R 5 and R 7 are hydrocarbon groups, they may be joined to the adjacent group via a nitrogen atom to form a ring. 【Chemistry 2】 (In formula (II), R 9 to R 11 and R 13 to R 15 each independently represent a hydrogen atom or a monovalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent; R 12 represents a divalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent; C - and D - represent an anion; r and s represent integers, r is 1 or more, s is 0 or more, and the sum of r and s is 2 or more. The bonding order of r and s (repeating units) is arbitrary; t and u are 0 or 1, and the sum of t and u is 1 or more. When t and u are 0, N has no charge; when t and u are 1, N is a nitrogen cation. When R 9 to R 11 and R 13 to R 15 are hydrocarbon groups, they may be joined to an adjacent group via a nitrogen atom to form a ring.) 【Transformation 3】 (In formula (III), R 16 to R 19 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and E − represents an anion. When R 16 to R 19 are hydrocarbon groups, they may be joined with an adjacent group via a nitrogen atom to form a ring.)

2. The wastewater treatment agent according to claim 1, wherein the organic ammonium compound has a solubility in water at 20°C of less than 1 mass%.

3. The wastewater treatment agent according to claim 1, wherein the organic ammonium compound has a solubility in water at 20°C of 1 mass% or more.

4. The wastewater treatment agent according to any one of claims 1 to 3, which contains a dithiocarbamate.

5. A wastewater treatment method for removing a Group 6 to 16 complex from wastewater containing the complex, the method comprising the step of adding to the wastewater a wastewater treatment agent containing an organic ammonium compound having at least one or more organic ammonium salt structures, the organic ammonium compound being represented by any one of the following formulas (I) to (III), and the wastewater treatment agent removes the complex by reacting the organic ammonium compound with the complex: 【Chemistry 4】 (In formula (I), the numbers in parentheses l, m, and n represent repeating units of the polymer, and the bonding order is arbitrary. l, m, and n represent the mol % of the repeating units in the polymer. The total of l, m, and n is 100 mol %, with at least one of l and m being 0.1 mol % or more and n being 0 mol % or more. In the repeating units enclosed in parentheses l, X represents a main skeleton of the repeating units derived from the raw material monomers and may have two or more types of repeating units. R 1 represents a divalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent. R 2 to R 4 each independently represent a hydrogen atom or a monovalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent. A - represents an anion. o is 0 or 1.) In the repeating unit enclosed in parentheses m, R 5 and R 7 each independently represent a hydrogen atom or an optionally substituted monovalent hydrocarbon group of 1 to 22 carbon atoms, R 6 and R 8 represent an optionally substituted divalent hydrocarbon group of 1 to 22 carbon atoms, and B - represents an anion. p and q are 0 or 1. In the repeating unit enclosed in parentheses n, Y represents a repeating unit derived from the raw material monomer. Y may have two or more types of repeating units. When R 2 to R 4 , R 5 , and R 7 are hydrocarbon groups, they may be joined to an adjacent group via a nitrogen atom to form a ring. 【Transformation 5】 (In formula (II), R 9 to R 11 and R 13 to R 15 each independently represent a hydrogen atom or a monovalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent; R 12 represents a divalent hydrocarbon group of 1 to 22 carbon atoms which may have a substituent; C - and D - represent an anion; r and s represent integers, r is 1 or more, s is 0 or more, and the sum of r and s is 2 or more. The bonding order of r and s (repeating units) is arbitrary; t and u are 0 or 1, and the sum of t and u is 1 or more. When t and u are 0, N has no charge; when t and u are 1, N is a nitrogen cation. When R 9 to R 11 and R 13 to R 15 are hydrocarbon groups, they may be joined to an adjacent group via a nitrogen atom to form a ring.) 【Transformation 6】 (In formula (III), R 16 to R 19 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 22 carbon atoms which may have a substituent, and E − represents an anion. When R 16 to R 19 are hydrocarbon groups, they may be joined with an adjacent group via a nitrogen atom to form a ring.)

6. 6. The wastewater treatment method according to claim 5, wherein the organic ammonium compound has a solubility in water at 20°C of less than 1% by mass.

7. 6. The wastewater treatment method according to claim 5, wherein the organic ammonium compound has a solubility in water at 20°C of 1% by mass or more.

8. 8. The wastewater treatment method according to claim 5, comprising a step of adding at least one organic ammonium compound having an organic ammonium salt structure and a dithiocarbamate, either separately or as a mixture in advance, to wastewater.

9. 9. The wastewater treatment method according to claim 8, wherein the pH is further adjusted after the treatment in the steps including adjusting the pH to 3 to 7, adding the organic ammonium compound, and adding a dithiocarbamate.

10. The wastewater treatment method according to any one of claims 5 to 9, further comprising the step of adding an inorganic flocculant.

11. 11. The wastewater treatment method according to claim 10, wherein the step of adding the inorganic flocculant is performed before the step of adding the organic ammonium compound and the dithiocarbamate.

12. 12. The wastewater treatment method according to claim 11, wherein the wastewater is adjusted to a pH of 3 to 7, the inorganic flocculant is added, the organic ammonium compound and the dithiocarbamate are then added, the pH is adjusted, and the polymer flocculant is added.

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