Method for treating polyamide-based semipermeable membrane, method and device for manufacturing semipermeable membrane element, and method and device for treating fluid using semipermeable membrane element

Abstract

The purpose of the present invention is to improve the removal performance of a semipermeable membrane in which the removal performance does not reach a desired level or has decreased. This treatment method is a method for treating a semipermeable membrane provided with a separation function layer containing a polyamide, the method comprising: (a) a step for bonding a polyfunctional amine to the polyamide; and (b) a step for bonding at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to the polyamide.

Description

Technical Field

[0001] The present invention relates to a method for treating a semipermeable membrane useful for the selective separation of liquid mixtures, and more particularly, to a method for treating a semipermeable membrane having a separation functional layer containing polyamide. Background Art

[0002] Semipermeable membranes for separating liquid mixtures include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, etc. These membranes are used, for example, for producing drinking water from water containing salts or harmful substances, producing industrial ultrapure water, wastewater treatment, or recovering valuable substances.

[0003] Most of the currently commercially available reverse osmosis membranes and nanofiltration membranes are composite semipermeable membranes. A representative composite semipermeable membrane has a microporous support membrane and a separation functional layer, and has high permeability and selective separation properties. Among them, the separation functional layer is formed of a crosslinked aromatic polyamide obtained by a polycondensation reaction of a polyfunctional amine and a polyfunctional acyl halide and covers the microporous support membrane.

[0004] However, during the use of the semipermeable membrane, due to organic fouling, inorganic fouling (scale), and biological fouling caused by organic substances, inorganic substances, microorganisms, etc. present in the liquid mixture, the water permeability of the semipermeable membrane decreases. In order to restore the water permeability decreased due to fouling, the membrane is cleaned with a chemical solution containing an acid or a base. In addition, an oxidizing agent such as chlorine is sometimes supplied for cleaning pipes, etc., and since these oxidizing agents are also mixed into the liquid supplied to the semipermeable membrane, the semipermeable membrane sometimes comes into contact with the oxidizing agent. Therefore, even if the causative substances of fouling are removed by cleaning with an acid or a base and the water permeability is restored, there is a case where the removal performance of the semipermeable membrane decreases due to contact of the semipermeable membrane with a chemical solution such as an oxidizing agent.

[0005] In Patent Document 1, as the reason for the deterioration of the polyamide membrane due to an oxidizing agent, it is cited that the sieving structure collapses due to the cleavage of the C-N bond (amide bond). In addition, in Patent Document 1, as a method for increasing the rejection rate of such deteriorated membrane, it is disclosed that an amino compound is bonded to the carboxyl group generated at the cleavage portion of the amide bond. The method for increasing the rejection rate described in Patent Document 1 includes a step of passing a first organic compound having a molecular weight of less than 200, a second organic compound having a molecular weight of 200 or more and less than 500, and a third organic compound having a molecular weight of 500 or more through the polyamide membrane.

[0006] As the first and second organic compounds, aromatic amino compounds such as aniline and diaminobenzene, aliphatic amino compounds such as methylamine and 1,9-diaminononane, etc. can be cited. As the third organic compound, a substance having a carboxyl group, an amino group, a hydroxyl group or a cyclic structure can be cited. As an example, tannic acid and peptides can be cited.

[0007] According to Patent Document 1, it is considered that low-molecular-weight first and second organic compounds have high solubility in water, react with the carboxyl groups of the membrane, bind to the reverse osmosis membrane, form insoluble salts, and block the pores generated by membrane deterioration. The third organic compound blocks large deteriorated parts of the membrane, both of which improve the rejection rate of the membrane.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-187469 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] An object of the present invention is to provide a treatment method that can improve the removal performance of a semipermeable membrane whose removal performance does not reach the desired level or whose removal performance has decreased.

[0013] Means for Solving the Problems

[0014] In order to solve the above problems, the treatment method of a semipermeable membrane, the manufacturing method of a semipermeable membrane element, the treatment device, and the fluid treatment method and fluid treatment device using the semipermeable membrane element have any of the following configurations.

[0015] [1] A treatment method, which is a treatment method of a semipermeable membrane having a separation functional layer containing polyamide, and the treatment method has:

[0016] (a) A step of bonding a polyfunctional amine to the polyamide; and

[0017] (b) A step of bonding at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to the polyamide.

[0018] [2] The treatment method according to the above [1], wherein the step (b) is performed after the step (a).

[0019] [3] The treatment method according to the above [1] or [2], wherein the bonding in the step (a) and the bonding in the step (b) are both covalent bondings.

[0020] [4] The treatment method according to any one of the above [1] to [3], wherein the step (a) includes covalently bonding the polyfunctional amine to the polyamide using a condensing agent.

[0021] [5] The treatment method according to any one of the above [1] to [4], wherein the step (b) includes covalently bonding the polyfunctional carboxylic acid to the polyamide using a condensing agent.

[0022] [6] The treatment method according to any one of [1] to [5] above, wherein the foregoing step (a) and the foregoing step (b) are alternately repeated two or more times.

[0023] [7] The treatment method according to [6] above, wherein the repetition of the foregoing step (a) and the foregoing step (b) is ended with the foregoing step (b).

[0024] [8] The treatment method according to any one of [1] to [7] above, wherein the foregoing semipermeable membrane is assembled in a semipermeable membrane element, and the foregoing step (a) and the foregoing step (b) are performed on the foregoing semipermeable membrane element that exhibits at least one of a salt permeability rate 10% or more higher than the initial value and a neutral molecule permeability rate 10% or more higher than the initial value.

[0025] [9] The treatment method according to any one of [1] to [8] above, wherein the foregoing step (a) and the foregoing step (b) are performed on a semipermeable membrane that has been contacted with at least one agent selected from the group consisting of an acid with a pH of 4 or less, a base with a pH of 10 or more, and an oxidizing agent.

[0026]

[10] A treatment method, which is a treatment method of a semipermeable membrane having a separation functional layer containing polyamide, and the treatment method includes:

[0027] (A) A step of bringing an aqueous solution containing a polyfunctional amine and a condensing agent into contact with the foregoing separation functional layer; and

[0028] (B) A step of bringing at least one of an aqueous solution containing a polyfunctional carboxylic acid and an organic solvent solution containing a polyfunctional acyl halide into contact with the foregoing separation functional layer.

[0029]

[11] The treatment method according to

[10] above, wherein the foregoing step (B) is performed after the foregoing step (A).

[0030]

[12] The treatment method according to [4], [5],

[10] , or

[11] above, wherein the foregoing condensing agent is a carbodiimide-based condensing agent or a triazine-based condensing agent.

[0031]

[13] A method for manufacturing a semipermeable membrane element, which is a method for manufacturing a semipermeable membrane element equipped with a semipermeable membrane having a separation functional layer containing polyamide, and the manufacturing method includes a step of treating the foregoing semipermeable membrane by using the treatment method according to any one of [1] to

[12] above.

[0032]

[14] A treatment device for a semipermeable membrane element that implements the treatment method according to any one of [1] to

[12] above, and the treatment device includes:

[0033] A first tank that stores an aqueous solution containing a polyfunctional amine;

[0034] A second tank that stores at least one of an aqueous solution containing a polyfunctional carboxylic acid and an organic solvent solution containing a polyfunctional acyl halide;

[0035] A component mounting section that mounts at least one semipermeable membrane element equipped with a semipermeable membrane having a separation functional layer containing polyamide;

[0036] A pipe connecting the first tank to the component mounting section;

[0037] A pipe connecting the second tank to the component mounting section;

[0038] A first pump between the first tank and the component mounting section; and

[0039] A second pump between the second tank and the component mounting section.

[0040]

[15] A fluid processing device that processes a fluid using a semipermeable membrane element obtained by the method for manufacturing a semipermeable membrane element described in the above

[13] .

[0041]

[16] A fluid processing method that processes a fluid using a semipermeable membrane element obtained by the method for manufacturing a semipermeable membrane element described in the above

[13] .

[0042] Effects of the Invention

[0043] According to the present invention, it is possible to improve the removal performance of a semipermeable membrane whose removal performance does not reach the desired level or whose removal performance has deteriorated. Detailed Description of the Invention

[0044] Hereinafter, the present invention will be described in more detail.

[0045] It should be noted that in this specification, "mass" and "weight" have the same meaning.

[0046] <Processing Method>

[0047] (1) Outline

[0048] The following describes a processing method, which is a processing method of a semipermeable membrane (polyamide-based semipermeable membrane) having a separation functional layer containing polyamide, and has:

[0049] (a) A step of bonding a polyfunctional amine to the polyamide; and

[0050] (b) A step of bonding at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to the polyamide.

[0051] By this processing method, it is possible to improve the performance of a semipermeable membrane that does not meet the desired performance or whose performance does not meet the desired performance due to contact with a liquid medicine.

[0052] The polyamide contained in the separation functional layer of the semipermeable membrane according to this embodiment can be hydrolyzed by contacting with an oxidant mixed in the raw water supplied to the semipermeable membrane. The hydrolyzed part becomes large pores through which the substance to be removed can pass. In addition, in the large pores, carboxyl groups are exposed due to the hydrolysis of polyamide.

[0053] By bonding a polyfunctional amine to functional groups such as carboxyl groups in the polyamide separation functional layer, the large pores can be reduced. Here, the so-called bonding refers to any one of ionic bonding, covalent bonding, and intermolecular forces (van der Waals forces, hydrogen bonds).

[0054] In addition, by bonding at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to functional groups such as amino groups in the polyamide separation functional layer, the large pores can also be reduced.

[0055] In the treatment method of the semipermeable membrane according to this embodiment, by bonding a polyfunctional amine and at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to polyamide, the large pores can be reduced and the performance of the semipermeable membrane can be improved.

[0056] More specifically, an amide bond can be formed between the polyfunctional amine and the terminal carboxyl group in the polyamide separation functional layer, and the polyfunctional carboxylic acid and the polyfunctional acyl halide can form an amide bond with the terminal amino group in the polyamide separation functional layer.

[0057] In addition, by repeating the step of bonding at least one of a polyfunctional amine, a polyfunctional carboxylic acid, and a polyfunctional acyl halide, the large pores can be further reduced.

[0058] (2) Bonding step of polyfunctional amine (a)

[0059] Examples of the polyfunctional amine include polyfunctional aromatic amines and polyfunctional aliphatic amines.

[0060] The polyfunctional aromatic amine refers to an aromatic amine having at least one of two or more primary amino groups and secondary amino groups in one molecule, and at least one of the amino groups is a primary amino group. Examples of the polyfunctional aromatic amine include compounds in which two amino groups are bonded to an aromatic ring in any positional relationship of ortho, meta, or para, such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, o-xylenediamine, m-xylenediamine, p-xylenediamine, o-diaminopyridine, m-diaminopyridine, p-diaminopyridine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 3-aminobenzylamine, 4-aminobenzylamine, etc. In particular, from the viewpoint of obtaining a semipermeable membrane with excellent selective separation performance, permeability, and heat resistance, m-phenylenediamine, p-phenylenediamine, or 1,3,5-triaminobenzene can be suitably used.

[0061] A polyfunctional aliphatic amine refers to an aliphatic amine having two or more amino groups in one molecule. Examples of the polyfunctional aliphatic amine include piperazine and its derivatives, and ethylenediamine.

[0062] Piperazine and its derivatives are specifically represented by the following general formula (I).

[0063] [Chemical formula 1]

[0064]

[0065] (R 1 , R 2 are each -H or -(CH2) n -CH3, and n is an integer from 0 to 3.)

[0066] Examples of piperazine and its derivatives include piperazine, 2,5-dimethylpiperazine, 2-methylpiperazine, 2,6-dimethylpiperazine, 2,3,5-trimethylpiperazine, 2,5-diethylpiperazine, 2,3,5-triethylpiperazine, 2-n-propylpiperazine, 2,5-di-n-butylpiperazine, etc. Piperazine or dimethylpiperazine is particularly preferably used.

[0067] In this step, at least one polyfunctional amine can be used, and two or more compounds can be selected from polyfunctional aromatic amines and polyfunctional aliphatic amines for use.

[0068] The above step (a) may include covalently bonding a polyfunctional amine to a polyamide using a condensing agent. Specifically, this step can be carried out as step (A) of bringing an aqueous solution containing a polyfunctional amine and a condensing agent into contact with the separation functional layer. The contact with the separation functional layer is carried out by bringing the aqueous solution into contact with the surface of the separation functional layer.

[0069] Regarding the contact time between the polyfunctional amine aqueous solution and the surface of the separation functional layer, for one treatment, it is preferably 1 minute or more and 72 hours or less, more preferably 30 minutes or more and 48 hours or less, and further preferably 1 hour or more and 24 hours or less.

[0070] The concentration of the polyfunctional amine in the polyfunctional amine aqueous solution is preferably 0.005% by mass or more and 0.5% by mass or less, more preferably 0.01% by mass or more and 0.3% by mass or less.

[0071] The concentration of the condensing agent in the polyfunctional amine aqueous solution is preferably 0.001% by mass or more and 1.0% by mass or less, more preferably 0.005% by mass or more and 0.3% by mass or less. By making the concentration of the condensing agent 0.001% by mass or more, the bonding between the terminal carboxyl groups present in the polyamide separation functional layer and the polyfunctional amine can be sufficiently generated.

[0072] Regarding the type of the condensing agent, it will be described later.

[0073] When the supply temperature of the polyfunctional amine aqueous solution is high, the bonding between the carboxyl group and the polyfunctional amine is likely to be promoted. However, if it is too high, the semipermeable membrane is easily affected by heat. Therefore, it is preferably 10°C or higher and 50°C or lower, and more preferably 20°C or higher and 45°C or lower.

[0074] In addition, in order to promote the bonding between the carboxyl group and the polyfunctional amine, the pH of the polyfunctional amine aqueous solution can be 10 or higher and 13 or lower.

[0075] (3) Bonding step of polyfunctional carboxylic acid or polyfunctional acyl halide (b)

[0076] Polyfunctional carboxylic acid refers to a carboxylic acid having two or more carboxyl groups in one molecule. Examples of polyfunctional carboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, glutaric acid, 1,3,5-cyclohexanetricarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3,5-benzenetricarboxylic acid (hereinafter referred to as "trimellitic acid"), 1,2,4-benzenetricarboxylic acid, 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, etc. Among polyfunctional carboxylic acids, 1,3,5-benzenetricarboxylic acid is preferred. As polyfunctional carboxylic acids, only one compound can be used, or two or more compounds can be combined.

[0077] Polyfunctional acyl halide refers to an acyl halide having two or more halocarbonyl groups in one molecule. Polyfunctional acyl halides can form amide bonds through reaction with terminal amino groups.

[0078] Examples of polyfunctional acyl halides that can be used include halides of oxalic acid, malonic acid, maleic acid, fumaric acid, glutaric acid, 1,3,5-cyclohexanetricarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, trimellitic acid, 1,2,4-benzenetricarboxylic acid, 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, etc. Among acyl halides, acyl chlorides are preferred.

[0079] Polyfunctional acyl halides are preferably polyfunctional aromatic acyl halides. Specifically, polyfunctional aromatic acyl halides refer to aromatic acyl halides having at least two, preferably 2 to 4, carbonyl chloride groups in one molecule (i.e., polyfunctional aromatic acyl chlorides). For example, as trifunctional acyl halides, trimellitoyl chloride, etc. can be cited, and as difunctional acyl chlorides, phthaloyl chloride, azophthaloyl chloride, terephthaloyl chloride, isophthaloyl chloride, naphthalenedicarbonyl chloride, etc. can be cited. These polyfunctional aromatic acyl halides can be used alone or in combination of two or more compounds.

[0080] In step (b), the polyfunctional carboxylic acid is used in the form of an aqueous solution, and the polyfunctional acyl halide is used in the form of an organic solvent solution. That is, this step can be carried out as step (B) of bringing at least one of the aqueous solution containing the polyfunctional carboxylic acid and the organic solvent solution containing the polyfunctional acyl halide into contact with the separation functional layer. Similar to step (A), the contact with the separation functional layer is carried out by bringing the aqueous solution or the organic solvent solution into contact with the surface of the separation functional layer.

[0081] Regarding the contact time of the polyfunctional carboxylic acid aqueous solution or the organic solvent solution containing the polyfunctional acyl halide (hereinafter, also referred to as the polyfunctional acyl halide solution) with the membrane surface, for one treatment, it is preferably 1 minute or more and 6 hours or less, more preferably 10 minutes or more and 3 hours or less.

[0082] The concentration of the polyfunctional carboxylic acid in the polyfunctional carboxylic acid aqueous solution is preferably 0.005% by mass or more and 0.5% by mass or less, more preferably 0.01% by mass or more and 0.3% by mass or less.

[0083] Step (b) may include covalently bonding the aforementioned polyfunctional carboxylic acid to the aforementioned polyamide using a condensing agent. The concentration of the condensing agent in the polyfunctional carboxylic acid aqueous solution is preferably 0.001% by mass or more and 1.0% by mass or less, more preferably 0.005% by mass or more and 0.3% by mass or less. By making the concentration of the condensing agent 0.001% by mass or more, the bonding between the terminal amino group present in the polyamide separation functional layer and the polyfunctional carboxylic acid can be sufficiently generated.

[0084] In order to promote the bonding between the amino group and the polyfunctional carboxylic acid and to suppress the influence of heat on the semipermeable membrane, the temperature of the polyfunctional carboxylic acid aqueous solution is preferably 10°C or more and 50°C or less, more preferably 20°C or more and 45°C or less.

[0085] In addition, in order to promote the bonding between the amino group and the polyfunctional carboxylic acid, the pH of the polyfunctional carboxylic acid aqueous solution can be 10 or more and 13 or less.

[0086] As the organic solvent for dissolving the polyfunctional acyl halide, an organic solvent that is immiscible with water and has a solubility parameter (SP value) of 15.2 (MPa) 1 / 2 or more and an octanol / water partition coefficient (logP) of 3.2 or more is used. In addition, the organic solvent preferably does not damage the support, especially the porous support layer. As a representative example of the organic solvent that satisfies the above conditions, octane, nonane, decane, undecane, dodecane, isododecane, tridecane, tetradecane, heptadecane, hexadecane, isodecane, cyclooctane, isooctane, ethylcyclohexane, 1-octene, 1-decene, etc. monomers or their mixtures can be preferably used.

[0087] The concentration of the polyfunctional acyl halide in the organic solvent solution containing the polyfunctional acyl halide is preferably 0.005% by mass or more and 0.5% by mass or less, more preferably 0.01% by mass or more and 0.3% by mass or less.

[0088] When the temperature of the organic solvent solution containing the polyfunctional acyl halide is high, the bonding between the amino group and the polyfunctional acyl halide is likely to be promoted. However, if it is too high, the semipermeable membrane is affected by heat. Therefore, it is preferably 10°C or higher and 50°C or lower, more preferably 20°C or higher and 45°C or lower.

[0089] Regarding steps (a) and (b), it is preferred to perform step (b) after step (a). In the large pores, carboxyl groups are exposed due to the hydrolysis of the polyamide. Therefore, by performing step (b) after step (a), the polyfunctional amine and the polyfunctional carboxylic acid or polyfunctional acyl halide can be efficiently bonded to the polyamide. Similarly, regarding steps (A) and (B), it is preferred to perform step (B) after step (A).

[0090] In addition, steps (a) and (b) are alternately repeated two or more times, whereby the effect of improving the removal performance can be enhanced. The repetition of steps (a) and (b) is preferably ended with step (b). The reason is that by modifying the amino group with a carboxyl group, the removal performance and the water permeability can be stabilized. Similarly, steps (A) and (B) are also preferably alternately repeated two or more times, and the repetition of steps (A) and (B) is preferably ended with step (B).

[0091] The contact between the polyfunctional amine aqueous solution, the polyfunctional carboxylic acid aqueous solution or the polyfunctional acyl halide solution and the separation functional layer can be carried out in a state where the polyamide-based semipermeable membrane is assembled in a semipermeable membrane element (sometimes simply referred to as "element"). These solutions can be continuously supplied to the element, or the solution can be allowed to stand after being supplied to the element, whereby the semipermeable membrane is immersed in these solutions, or the element can be immersed in the solution. By allowing the solution to flow into the supply-side flow path of the semipermeable membrane in the element, the solution can be brought into contact with the separation functional layer.

[0092] It should be noted that the polyfunctional amine aqueous solution, the polyfunctional carboxylic acid aqueous solution and the condensing agent can be supplied to the element simultaneously, or an aqueous solution containing only the condensing agent can be first supplied to the semipermeable membrane element, and then the polyfunctional amine aqueous solution or the polyfunctional carboxylic acid aqueous solution can be supplied.

[0093] In addition, the contact time of the polyfunctional amine aqueous solution with the surface of the separation functional layer is preferably longer than the contact time of the polyfunctional carboxylic acid aqueous solution or the organic solvent solution containing the polyfunctional acyl halide with the surface of the separation functional layer. By making the contact time of the polyfunctional amine aqueous solution with the surface of the separation functional layer longer than the contact time of the polyfunctional carboxylic acid aqueous solution or the organic solvent solution containing the polyfunctional acyl halide with the surface of the separation functional layer, the total treatment time can be shortened.

[0094] In the present embodiment, the semipermeable membrane is assembled in the semipermeable membrane element. Preferably, the above-mentioned steps (a) and (b) are performed on a semipermeable membrane element having a salt permeability of 10% or more higher than the initial value and / or a neutral molecule permeability of 10% or more higher than the initial value. The same applies to steps (A) and (B).

[0095] Here, the so-called "initial value" refers to the salt permeability or neutral molecule permeability calculated based on the standard salt rejection rate or standard neutral molecule rejection rate described in the specification of the element. The salt permeability and neutral molecule permeability of the element are calculated by the following formulas.

[0096] Salt permeability (%) = 100 - Salt rejection rate (%)

[0097] Neutral molecule permeability (%) = 100 - Neutral molecule rejection rate (%)

[0098] (4) Bonding based on covalent bonding

[0099] In the present embodiment, the bonding in step (a) and the bonding in step (b) are preferably both covalent bondings. By performing bonding with covalent bonding, a bonding with a high bonding force can be formed. Therefore, even when operating for a long time or after contacting chemical solutions such as acids and alkalis, the membrane performance can be maintained more stably. In order to make the bonding in step (a) a covalent bonding, for example, a condensing agent can be used. In order to make the bonding in step (b) a covalent bonding, a condensing agent or a polyfunctional acyl halide solution can be used. The same applies to steps (A) and (B).

[0100] (5) Condensing agent

[0101] Examples of the condensing agent used in the above step (a) and step (b), or step (A) and step (B) include carbodiimide-based condensing agents such as N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (hereinafter referred to as "EDC-HCl"), imidazole-based condensing agents such as N,N'-carbonyldiimidazole, 1,1'-carbonylbis(1,2,4-triazole), 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (hereinafter referred to as "DMT-MM"), 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, O-(3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, triazine-based condensing agents such as trifluoromethanesulfonic acid (4,6-dimethoxy-1,3,5-triazin-2-yl)-(2-octyloxy-2-oxoethyl)dimethylammonium, phosphonium-based condensing agents such as 1H-benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, (7-azabenzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate, bromotris(dimethylamino)phosphonium hexafluorophosphate, chlorotripyrrolidinophosphonium hexafluorophosphate, urea-based condensing agents such as O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, O-(N-succinimidyl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(N-succinimidyl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, S-(1-oxido-2-pyridyl)-N,N,N',N'-tetramethylthiuronium tetrafluoroborate, O-[2-oxo-1(2H)-pyridyl]-N,N,N',N'-tetramethyluronium tetrafluoroborate, {[(1-cyano-2-ethoxy-2-oxoethylidene)amino]oxy}-4-morpholinomethylidene dimethylammonium hexafluorophosphate, 2-chloro-1,3-dimethylimidazolium hexafluorophosphate, 1-(chloro-1-pyrrolidinomethylene)pyrrolidinium hexafluorophosphate, 2-fluoro-1,3-dimethylimidazolium hexafluorophosphate, fluoro-N,N,N',N'-tetramethylformamidinium hexafluorophosphate, sulfuric acid, etc.

[0102] Among the above, a condensing agent that is preferably a carbodiimide-based condensing agent or a triazine-based condensing agent. Considering that it is preferable for condensation in an aqueous system, if it is a carbodiimide-based condensing agent, EDC-HCl can be preferably used, and if it is a triazine-based condensing agent, DMT-MM can be preferably used.

[0103] (6) Other elements

[0104] In an aqueous solution of a polyfunctional amine and an organic solvent of an aqueous solution of a polyfunctional carboxylic acid or a polyfunctional acyl halide, if necessary, each may contain compounds such as an acylation catalyst, a polar solvent, an acid scavenger, and an antioxidant.

[0105] <Cleaning>

[0106] Before performing the treatments based on the above-mentioned steps (a) and (b), and the above-mentioned steps (A) and (B), the polyamide-based semipermeable membrane can be cleaned using a chemical solution. By cleaning, substances (fouling) accumulated on the membrane surface can be removed.

[0107] For cleaning inorganic fouling (scale), acids are mainly used, and examples include hydrochloric acid, nitric acid, sulfuric acid, citric acid, oxalic acid, etc. The lower the pH of the acid, the greater the cleaning effect, but the deterioration of the semipermeable membrane also becomes larger. Therefore, the pH is preferably 0 or more and 4 or less, and more preferably 1 or more and 3 or less.

[0108] For cleaning organic fouling, alkalis are mainly used, and examples include sodium hydroxide, potassium hydroxide, etc. The higher the pH of the alkali, the higher the cleaning effect. Therefore, it is preferably 10 or more and 14 or less, and more preferably 11 or more and 13 or less.

[0109] In addition, when an oxidizing agent such as chlorine is used for cleaning biological fouling, examples of the oxidizing agent include hypochlorite, chlorinated isocyanurate, percarbonate, ozone, potassium permanganate, etc.

[0110] The chemicals used in cleaning can be used singly or in combination.

[0111] <Semipermeable membrane>

[0112] The above-mentioned treatment method can be widely applied to a semipermeable membrane (polyamide-based semipermeable membrane) having a separation functional layer containing polyamide. The semipermeable membrane preferably has separation performance as a reverse osmosis membrane or a nanofiltration membrane.

[0113] The semipermeable membrane may also be used in the form of a composite membrane with a support. The support may have a substrate and a porous support layer, or may be composed of only a porous support.

[0114] The substrate is preferably a nonwoven fabric (including long-fiber nonwoven fabric and short-fiber nonwoven fabric) or a fabric. The substrate is composed of, for example, a polyester-based polymer, a polyamide-based polymer, a polyolefin-based polymer, and their mixtures or copolymers.

[0115] The porous support layer is a porous layer having a denser structure than the substrate. The separation functional layer is formed on the porous support layer, and the pore diameter of the surface on the separation functional layer side in the porous support layer is, for example, 0.1 nm or more and 100 nm or less.

[0116] Examples of materials constituting the porous support layer include polysulfone, polyethersulfone, polyamide, polyester, cellulose-based polymers, vinyl polymers, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenyl sulfone, and polyphenylene ether. Here, examples of cellulose-based polymers include cellulose acetate and cellulose nitrate, and examples of vinyl polymers include polyethylene, polypropylene, polyvinyl chloride, and polyacrylonitrile.

[0117] The separation functional layer preferably contains crosslinked aromatic polyamide as the main component. The main component means a component that accounts for 50% by mass or more of the components of the separation functional layer. The content rate of the crosslinked aromatic polyamide in the separation functional layer is preferably 80% by mass or more, and more preferably 90% by mass or more.

[0118] Crosslinked aromatic polyamide refers to a polymer of polyfunctional aromatic amine and polyfunctional aromatic acyl chloride.

[0119] As the polyfunctional aromatic amine and polyfunctional aromatic acyl chloride, the compounds exemplified for steps (a) and (b) of the above-described treatment method can be preferably used.

[0120] The separation functional layer is preferably formed by interfacial polymerization using an aqueous solution containing polyfunctional aromatic amine and an organic solvent solution containing polyfunctional aromatic acyl chloride. The steps of interfacial polymerization include: (i) a step of coating the aqueous solution containing polyfunctional aromatic amine on the support (when the support has a substrate and a porous support layer, on the porous support layer); (ii) a step of coating the organic solvent solution containing polyfunctional aromatic acyl chloride on the support after step (i) (when the support has a substrate and a porous support layer, on the porous support layer).

[0121] In steps (i) and (ii), examples of the coating means include dipping, spraying, and coating.

[0122] As the organic solvent in step (ii), the solvent exemplified in step (b) of the above-described treatment method can be preferably used.

[0123] <Semipermeable membrane element>

[0124] The semipermeable membrane is wound around a tubular water collecting pipe provided with a plurality of holes together with a supply-side flow path material such as a plastic net, a permeate-side flow path material such as a tricot knitted fabric, and a membrane used as needed to improve pressure resistance, and is suitable for use as a spiral semipermeable membrane element. Further, a semipermeable membrane module in which the elements are connected in series or parallel and housed in a pressure vessel can also be produced.

[0125] In addition, the semipermeable membrane, its components, and assemblies can be combined with a pump for supplying water to them, a device for pre-treating the supplied water, etc. to form a fluid separation device. By using this separation device, the supplied water can be separated into permeated water such as drinking water and concentrated water that has not permeated through the membrane, obtaining water that meets the requirements.

[0126] <Treatment device>

[0127] Regarding the treatment device for the semipermeable membrane element according to the present embodiment, in order to perform the above-described treatment method of the semipermeable membrane, it includes: a first tank that stores an aqueous solution containing a polyfunctional amine; a second tank that stores at least one of an aqueous solution containing a polyfunctional carboxylic acid and an organic solvent solution containing a polyfunctional acyl halide; an element mounting portion that mounts at least one semipermeable membrane element equipped with a semipermeable membrane having a separation functional layer containing polyamide; a pipe that connects the aforementioned first tank and the aforementioned element mounting portion; a pipe that connects the aforementioned second tank and the aforementioned element mounting portion; a first pump between the aforementioned first tank and the aforementioned element mounting portion; and a second pump between the aforementioned second tank and the aforementioned element mounting portion. Specifically, the treatment device for the semipermeable membrane element according to the present embodiment is configured to include: a semipermeable membrane unit that includes a container for loading the semipermeable membrane element serving as the element mounting portion; pipes that connect the semipermeable membrane unit to each tank; and pumps connected to these pipes.

[0128] The pipes connecting the first tank and the second tank to the semipermeable membrane element are preferably connected in such a way that each solution is supplied from the separation functional layer side of the semipermeable membrane.

[0129] The treatment device may further include a storage tank, a pump, and a piping system for the solution for cleaning.

[0130] The polyamide-based semipermeable membrane treated by the treatment method of the present invention is a semipermeable membrane whose removal performance does not reach the desired level or whose removal performance has deteriorated. For example, if the above-described steps (a) and (b), or steps (A) and (B) are performed on the semipermeable membrane that has undergone the above-described cleaning treatment, specifically, a semipermeable membrane that has come into contact with at least one chemical selected from the group consisting of acids with a pH of 4 or less, alkalis with a pH of 10 or more, and oxidants, the removal performance is improved. That is, according to the present invention, a method for improving the removal performance of a polyamide-based semipermeable membrane is also provided.

[0131] In addition, through the present invention, a method for manufacturing a semipermeable membrane element is provided, which includes a step of treating a polyamide-based semipermeable membrane using the treatment method having the above-described steps (a) and (b), or steps (A) and (B).

[0132] <Utilization of the semipermeable membrane element>

[0133] The semipermeable membrane elements obtained by the above manufacturing method are connected in series or in parallel and housed in a pressure vessel, and thus used as a semipermeable membrane module. The semipermeable membrane element and the semipermeable membrane module can be combined with a pump for supplying fluid to them, a device for pre-treating the fluid, etc. to form a fluid treatment device.

[0134] The fluid treatment method of the present invention uses the semipermeable membrane element obtained by the above manufacturing method to treat a fluid. For example, it is suitable for treating water containing salts or harmful substances, industrial wastewater, domestic wastewater, etc.

[0135] Examples

[0136] Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited thereto.

[0137] (Membrane permeation flux)

[0138] Regarding the membrane permeation water volume of the feed water (seawater) after membrane filtration treatment for 24 hours with seawater (TDS concentration 3.5%, boron concentration about 5 ppm) adjusted to pH 6.5 supplied to the element at an operating pressure of 5.5 MPa and a recovery rate of 8%, the membrane permeation flux (m 3 / m 2 / day) is expressed as the water permeation volume (cubic meters) per square meter of membrane surface per day.

[0139] (Desalination (TDS) rate, boron removal rate)

[0140] Regarding the feed water and permeate water at the time point after 24 hours of membrane filtration treatment with seawater (TDS concentration 3.5%, boron concentration about 5 ppm) adjusted to pH 6.5 supplied to the element at an operating pressure of 5.5 MPa and a recovery rate of 8%, the salt (TDS) concentration is obtained by conductivity measurement, and the boron concentration is obtained using an ICP emission analyzer (5110 ICP-OES manufactured by Agilent Technologies). The desalination (TDS) rate and boron removal rate are calculated according to the following formula.

[0141] Desalination rate (%) = 100 × {1 - (salt concentration in permeate water / salt concentration in feed water)}

[0142] Boron removal rate (%) = 100 × {1 - (boron concentration in permeate water / boron concentration in feed water)}

[0143] (Acid immersion test)

[0144] For the element after membrane filtration treatment for 24 hours with seawater (TDS concentration 3.5%, boron concentration about 5 ppm) adjusted to pH 6.5 supplied to the element at an operating pressure of 5.5 MPa and a recovery rate of 8%, a solution containing sulfuric acid with pH 1.0 is supplied at 25°C, and it is left standing and immersed for 24 hours. Then, the inside of the element is replaced with pure water.

[0145] (Alkali immersion test)

[0146] For the element after membrane filtration treatment for 24 hours with seawater (TDS concentration 3.5%, boron concentration about 5 ppm) adjusted to pH 6.5 supplied to the element at an operating pressure of 5.5 MPa and a recovery rate of 8%, a solution containing an aqueous sodium hydroxide solution with pH 13.0 is supplied at 25°C, and it is left standing and immersed for 24 hours. Then, the inside of the element is replaced with pure water.

[0147] (Ratio of membrane permeation flux, ratio of salt (TDS) permeation rate, ratio of boron permeation rate)

[0148] The ratio of membrane permeation flux, the ratio of salt (TDS) permeation rate, and the ratio of boron permeation rate are calculated according to the following formulas respectively.

[0149] Ratio of membrane permeation flux = (membrane permeation flux after acid immersion test, alkali immersion test, or accelerated degradation treatment) / (membrane permeation flux before acid immersion test, alkali immersion test, or accelerated degradation treatment)

[0150] Ratio of salt permeation rate = {100 - (salt rejection rate after acid immersion test, alkali immersion test, or accelerated degradation treatment)} / {100 - (salt rejection rate before acid immersion test, alkali immersion test, or accelerated degradation treatment)}

[0151] Ratio of boron permeation rate = {100 - (boron rejection rate after acid immersion test, alkali immersion test, or accelerated degradation treatment)} / {100 - (boron rejection rate before acid immersion test, alkali immersion test, or accelerated degradation treatment)}

[0152] [Reference Example 1]

[0153] Perform performance evaluation (measurement of membrane permeation flux, salt rejection rate, and boron rejection rate) of the reverse osmosis membrane element TM810V for seawater desalination manufactured by Toray Industries, Inc. Then, for the element subjected to the acid immersion test or the alkali immersion test, perform performance evaluation in the same manner.

[0154] [Reference Example 2]

[0155] For the reverse osmosis membrane element TM810V for seawater desalination manufactured by Toray Industries, Inc., a solution containing an aqueous sodium hydroxide solution with a pH of 13.0 was supplied at 25°C for 24 hours, and then a solution containing sulfuric acid with a pH of 1.0 was supplied at 25°C for 24 hours, thereby performing an accelerated deterioration treatment of the membrane. Then, the performance evaluation of the element was carried out.

[0156] [Reference Example 3]

[0157] In the same manner as in Reference Example 2, for the reverse osmosis membrane element TM810V for seawater desalination manufactured by Toray Industries, Inc., after performing an accelerated deterioration treatment of the membrane using an acid and a base, an aqueous solution containing sodium hypochlorite with a chlorine concentration adjusted to 100 ppm was supplied at 25°C for 24 hours, thereby further performing an accelerated deterioration treatment of the membrane. Then, the performance evaluation of the element was carried out.

[0158] [Example 1]

[0159] The following treatment was performed on the accelerated deteriorated semipermeable membrane element obtained in Reference Example 2: An aqueous solution containing 0.05% by mass of m-phenylenediamine and 0.10% by mass of DMT-MM was supplied at 25°C for 1.5 hours, and then an aqueous solution containing 0.05% by mass of trimesic acid and 0.10% by mass of DMT-MM was supplied at 25°C for 1.5 hours. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was performed again.

[0160] [Example 2]

[0161] Except for supplying the aqueous m-phenylenediamine solution and the aqueous trimesic acid solution twice respectively, the treatment was carried out in the same manner as in Example 1. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was performed again. By repeating the treatment twice, the performance of the treated semipermeable membrane element was further improved compared to Example 1.

[0162] [Example 3]

[0163] Except for supplying the aqueous m-phenylenediamine solution and the aqueous trimesic acid solution three times respectively, the treatment was carried out in the same manner as in Example 1. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was performed again. By repeating the treatment three times, the performance of the treated semipermeable membrane element was further improved compared to Example 2 and was improved to near the performance of Reference Example 1.

[0164] [Example 4]

[0165] Except for changing the supply order of the m-phenylenediamine aqueous solution and the trimesic acid aqueous solution and performing the supply three times separately, the treatment was carried out in the same manner as in Example 1. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. When the treatment was carried out in the order of step (b) and step (a), the performance improvement effect was lower than that of Example 3.

[0166] [Example 5]

[0167] Except for alternately supplying the m-phenylenediamine aqueous solution and the trimesic acid aqueous solution twice and then supplying the m-phenylenediamine aqueous solution, the treatment was carried out in the same manner as in Example 1. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. Through the treatment, the performance of the semipermeable membrane element was sufficiently improved. However, since the end of the polyamide was an amino group, the performance deterioration after acid immersion and alkali immersion was greater than that of Example 2 and Example 3 where the end of the polyamide was a carboxyl group.

[0168] [Example 6]

[0169] Except for changing the supply order of m-phenylenediamine and the trimesic acid aqueous solution, performing the supply twice and then supplying the trimesic acid aqueous solution, the treatment was carried out in the same manner as in Example 1. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. The performance improvement effect was lower than that of Example 4. However, since the end of the polyamide was a carboxyl group, the performance deterioration after acid immersion and alkali immersion was lower than that of Example 4.

[0170] [Example 7]

[0171] Except for supplying a decane solution containing 0.05% by mass of trimellitic acid chloride at 25°C for 1.5 hours instead of an aqueous solution containing 0.05% by mass of trimesic acid and 0.10% by mass of DMT-MM, the treatment was carried out in the same manner as in Example 3. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. Even when using a decane solution containing trimellitic acid chloride instead of an aqueous solution containing trimesic acid and DMT-MM, the performance of the treated semipermeable membrane element was improved in the same manner as in Example 3.

[0172] [Example 8]

[0173] Except for using the accelerated-deteriorated semipermeable membrane element obtained in Reference Example 3, the treatment was carried out in the same manner as in Example 3. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. For the further deteriorated semipermeable membrane element, under the present treatment conditions, the performance improvement effect was insufficient.

[0174] [Example 9]

[0175] Except for increasing the concentrations of m-phenylenediamine, trimesic acid, and DMT-MM to 2 times, the treatment was carried out in the same manner as in Example 8. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. By making the supply concentration of each treatment 2 times, the reaction rate in each treatment became higher, and the performance of the treated semipermeable membrane element was improved compared to Example 8.

[0176] [Example 10]

[0177] Except for changing the supply time of each treatment to 4 hours, the treatment was carried out in the same manner as in Example 8. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. By making the supply time of each treatment 4 hours, the reaction rate in each treatment became higher, and the performance of the treated semipermeable membrane element was improved compared to Example 8.

[0178] [Example 11]

[0179] Except for changing the supply temperature of each treatment to 40 °C, the treatment was carried out in the same manner as in Example 8. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. By making the supply temperature of each treatment 40 °C, the reaction rate in each treatment became higher, and the performance of the treated semipermeable membrane element was improved compared to Example 8.

[0180] [Example 12]

[0181] The supply time of each treatment was changed to 4 hours, and the supply temperature was changed to 40 °C. Except for this, the treatment was carried out in the same manner as in Example 8. After the performance evaluation of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance evaluation of the semipermeable membrane element was carried out again. By making the supply concentration of each treatment 2 times, the supply time 4 hours, and the supply temperature 40 °C, the reaction rate in each treatment became higher, and the performance of the treated semipermeable membrane element was significantly improved compared to Example 8 and was improved to near the performance of Reference Example 1.

[0182] [Comparative Example 1]

[0183] The following treatment was performed on the accelerated deteriorated semipermeable membrane element obtained in Reference Example 2: At 25°C, an aqueous solution containing 0.05% by mass of m-phenylenediamine and 0.10% by mass of DMT-MM was supplied for 1.5 hours. After evaluating the performance of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance of the semipermeable membrane element was evaluated again. When only process (a) was carried out, the performance deterioration after acid immersion and alkali immersion was greater compared to Example 3.

[0184] [Comparative Example 2]

[0185] The following treatment was performed on the accelerated deteriorated semipermeable membrane element described in Reference Example 2: At 25°C, an aqueous solution containing 0.05% by mass of trimellitic acid and 0.10% by mass of DMT-MM was supplied for 1.5 hours. After evaluating the performance of the treated semipermeable membrane element, an acid immersion test or an alkali immersion test was carried out, and the performance of the semipermeable membrane element was evaluated again. When only process (b) was carried out, the effect of improving the performance of the treated semipermeable membrane element was low.

[0186] The treatment methods of Examples 1 to 12 and Comparative Examples 1 to 2 are shown in Table 1, the properties of the semipermeable membrane elements obtained in Reference Examples 1 to 3 are shown in Table 2, and the performances of the semipermeable membrane elements obtained in Reference Example 1, Examples 1 to 12 and Comparative Examples 1 to 2 are shown in Table 3.

[0187] As shown in Examples 1 to 12, it can be seen that the performance of the semipermeable membrane element to which the treatment method according to the present embodiment is applied is close to the initial performance before accelerated deterioration, and has an excellent performance improvement effect in a short time.

[0188] [Table 1]

[0189]

[0190] [Table 2]

[0191] Table 2

[0192]

[0193] [Table 3]

[0194]

[0195] The present invention has been described in detail using a specific method, but those skilled in the art will understand that various changes and modifications can be made without departing from the spirit and scope of the present invention. It should be noted that this application is based on the Japanese Patent Application (Japanese Patent Application No. 2022-204061) filed on December 21, 2022, the entire content of which is incorporated herein by reference.

Claims

1. A treatment method, which is a treatment method of a semipermeable membrane having a separation functional layer containing polyamide, the treatment method comprising: (a) a step of bonding a polyfunctional amine to the polyamide; and (b) a step of bonding at least one of a polyfunctional carboxylic acid and a polyfunctional acyl halide to the polyamide.

2. The processing method according to claim 1, wherein, The step (b) is carried out after the step (a).

3. The processing method according to claim 1 or 2, wherein, The bonding in the step (a) and the bonding in the step (b) are both covalent bondings.

4. The processing method according to claim 1 or 2, wherein, The step (a) includes covalently bonding the polyfunctional amine to the polyamide by using a condensing agent.

5. The processing method according to claim 1 or 2, wherein The step (b) includes covalently bonding the polyfunctional carboxylic acid to the polyamide by using a condensing agent.

6. The processing method according to claim 1 or 2, wherein, The steps (a) and (b) are alternately repeated two or more times.

7. The processing method according to claim 6, wherein, The repetition of the steps (a) and (b) is ended with the step (b).

8. The processing method according to claim 1 or 2, wherein The semipermeable membrane is assembled in a semipermeable membrane element, The steps (a) and (b) are carried out on the semipermeable membrane element showing at least one of a salt permeability more than 10% higher than the initial value and a neutral molecule permeability more than 10% higher than the initial value.

9. The processing method according to claim 1 or 2, wherein, The steps (a) and (b) are carried out on a semipermeable membrane that has been contacted with at least one agent selected from the group consisting of an acid with a pH of 4 or less, a base with a pH of 10 or more, and an oxidizing agent.

10. A treatment method, which is a treatment method of a semipermeable membrane having a separation functional layer containing polyamide, the treatment method comprising: (A) a step of bringing an aqueous solution containing a polyfunctional amine and a condensing agent into contact with the separation functional layer; and (B) a step of bringing at least one of an aqueous solution containing a polyfunctional carboxylic acid and an organic solvent solution containing a polyfunctional acyl halide into contact with the separation functional layer.

11. The processing method according to claim 10, wherein, The step (B) is carried out after the step (A).

12. The processing method according to claim 4, wherein, The condensing agent is a carbodiimide-based condensing agent or a triazine-based condensing agent.

13. The processing method according to claim 5, wherein The condensing agent is a carbodiimide-based condensing agent or a triazine-based condensing agent.

14. The processing method according to claim 10 or 11, wherein The condensing agent is a carbodiimide-based condensing agent or a triazine-based condensing agent.

15. A method for manufacturing a semipermeable membrane element, which is a method for manufacturing a semipermeable membrane element equipped with a semipermeable membrane having a separation functional layer containing polyamide, the manufacturing method comprising a step of treating the semipermeable membrane by using the treatment method according to claim 1 or 10.

16. A treatment device for a semipermeable membrane element implementing the treatment method according to claim 1 or 2, the treatment device comprising: a first tank for storing an aqueous solution containing a polyfunctional amine; a second tank for storing at least one of an aqueous solution containing a polyfunctional carboxylic acid and an organic solvent solution containing a polyfunctional acyl halide; an element mounting part for mounting at least one semipermeable membrane element equipped with a semipermeable membrane having a separation functional layer containing polyamide; a pipe connecting the first tank and the element mounting part; a pipe connecting the second tank and the element mounting part; a first pump between the first tank and the element mounting part; and a second pump between the second tank and the element mounting part.

17. A fluid treatment device, which uses a semipermeable membrane element obtained by the method for manufacturing a semipermeable membrane element according to claim 15 to treat a fluid.

18. A fluid treatment method, which uses a semi-permeable membrane element obtained by the manufacturing method of the semi-permeable membrane element described in claim 15 to treat a fluid.

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