JPH1033958A - Treatment by composite reverse osmosis membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method by which a solution containing cationic organic substances and/or amphoteric organic substances can be treated stably at high liquid filtering flow rate while employing a composite reverse osmosis membrane having a polyamide type skin layer which can be operated at low running cost. SOLUTION: A salt solution containing cationic organic substances and/or amphoteric organic substances is desalinated by a composite reverse osmosis membrane comprising a negative charge-bearing crosslinked polyamide type skin layer and a finely pours supporting body to support the skin layer and the surface of the skin layer is coated with an organic polymer layer having a positive charge-bearing group and the skin layer is synthesized by a multi- functional amine compound having two or more reactive amino groups and a multi-functional halogen compound having two or more reactive acid halide groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a treatment method using a composite reverse osmosis membrane for selectively separating components in a solution containing a cationic organic substance and / or an amphoteric organic substance. The present invention relates to a method for treating a solution using a composite reverse osmosis membrane in which the surface of a polyamide skin layer is coated with an organic polymer layer having a positively chargeable group.

[0002]

2. Description of the Related Art Using a conventional composite reverse osmosis membrane,
Desalination of solutions containing organic and / or amphoteric organics
When performing cellulose acetate reverse osmosis
Because it is difficult to adsorb equipment and / or amphoteric organic matter,
The amount of permeated water is relatively stable, but it is currently on the market
30 kgf / cm for cellulose acetate reverse osmosis membrane
^TwoOperating pressure before and after is required, and running costs such as electricity bills
High. On the other hand, 15kgf / cm^TwoOperate at operating pressures before and after
Composite reverse osmosis membrane with rollable polyamide skin layer
Is generally slightly negatively charged, so the cation
Organic and / or amphoteric organic substances adsorb to the membrane and
The operation was not possible due to a marked decrease in the amount of water. Especially ticks
Contains on- and / or amphoteric surfactants
In advanced treatment using complex reverse osmosis membrane of wastewater
Could not drive stably. Also, ultra pure
In water production applications, clicks from anion exchange resins
The same applies to the treatment of liquids in which
Since the amount of permeated water decreases significantly due to the absorption phenomenon,
First, increase the number of composite reverse osmosis
High costs were incurred, such as compensating for the decrease in the amount of water.
Accordingly, a composite reverse osmosis membrane having a polyamide skin layer is required.
Using these cationic organic substances and / or amphoteric
For desalting and concentrating solutions containing organic substances.
Processing methods are expected.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to use a composite reverse osmosis membrane having a polyamide-based skin layer having a low running cost to raise a solution containing a cationic organic substance and / or an amphoteric organic substance. It is an object of the present invention to provide a water treatment method effective for desalination and concentration of active ingredients that can be treated stably with a permeated water amount.

[0004]

Means for Solving the Problems In order to achieve the above object, a method for treating with a composite reverse osmosis membrane according to the present invention is a method for treating a solution containing a cationic organic substance and / or an amphoteric organic substance with a composite reverse osmosis membrane. The composite reverse osmosis membrane used for the treatment is a composite reverse osmosis membrane comprising a polyamide skin layer and a microporous support supporting the same, wherein the polyamide skin layer has two or more reactive amino groups. A negatively-charged crosslinked polyamide skin layer synthesized from a polyfunctional amine compound having a polyfunctional acid halide having two or more reactive acid halide groups, wherein the surface of the skin layer is positively charged. It is characterized by being coated with an organic polymer layer having a group. By coating the surface of the polyamide skin layer with an organic polymer layer having a positively chargeable group,
A cationic organic substance and / or an amphoteric organic substance can be prevented from being adsorbed to the polyamide skin layer, and a stable continuous operation can be performed without a decrease in the amount of permeated water of the composite reverse osmosis membrane.

[0005] In the treatment method using the composite reverse osmosis membrane of the present invention, the specific surface area of the polyamide skin layer of the composite reverse osmosis membrane is preferably 3 or more. By setting the specific surface area of the polyamide skin layer to 3 or more, it is possible to realize a good amount of permeated water, which is preferable. Although the upper limit of the specific surface area of the polyamide skin layer is not particularly limited, it is usually 1000.
The following is preferred. The specific surface area of the skin layer used in the present invention is defined by the following equation.

Specific surface area of skin layer = (surface area of skin layer) / (surface area of microporous support) The surface area of the skin layer is opposite to the surface in contact with the microporous support, ie, It indicates the surface area of the surface that comes into contact with the supplied liquid to be treated. On the other hand, the surface area of the microporous support represents the surface area of the surface in contact with the skin layer.

The method for determining the surface area and the specific surface area is as follows:
It can be obtained according to a general method for obtaining a surface area or a specific surface area, and the method is not particularly limited. For example, a surface area measuring device, a specific surface area measuring device, a scanning electron microscope (SEM, FE-SEM), a transmission electron microscope (TE
M) and the like.

[0008] In the treatment method using the composite reverse osmosis membrane of the present invention, the polyamide skin layer of the composite reverse osmosis membrane is preferably a wholly aromatic crosslinked polyamide. By using a skin layer made of a wholly aromatic cross-linked polyamide as the skin layer, compared to the case of using a skin layer made of an aliphatic polyamide, chemical resistance such as chemical resistance is excellent, and long-term use After removing the attached slime and scale by chemical cleaning,
When reused, it is preferable because there is no decrease in performance.

[0009] In the treatment method using the composite reverse osmosis membrane according to the present invention, the performance of the composite reverse osmosis membrane is set at an operating pressure of 1%.
5 kgf / cm ² , sodium chloride 15 at a temperature of 25 ° C.
When evaluated with an aqueous solution having a pH of 6.5 containing 00 ppm, the membrane permeation inhibition rate of the salt was 90% or more, and the amount of permeated water was 1 m.
It is preferably at least ³ / m ² · day. The higher the permeated water amount is, the lower the pressure can be operated, and the running cost such as electricity cost can be reduced, which is preferable. More preferably, the amount of permeated water is 1.2 m ³ / m ² · day or more.

Further, in the treatment method using the composite reverse osmosis membrane of the present invention, the organic polymer layer having a positively chargeable group covering the surface of the polyamide skin layer of the composite reverse osmosis membrane is crosslinked. It is preferred that By forming a crosslinked organic polymer layer, it is possible to prevent the organic polymer layer having a positively charged group covering the surface from being partially dropped off during continuous operation or washing with chemicals, and it is possible to prevent cationic organic substances. This is preferable because the effect of suppressing the decrease in the amount of permeated water due to the amphoteric organic material can be prevented.

[0011] In the method of treating with a composite reverse osmosis membrane according to the present invention, the organic polymer layer having a positively chargeable group and covering the surface of the polyamide skin layer of the composite reverse osmosis membrane comprises: It is preferably an intramolecular and / or intermolecular crosslinked organic polymer layer of a polymer having a quaternary ammonium group and a hydroxyl group. This crosslinked organic polymer layer is preferable because it can be easily produced and can efficiently exhibit the above-described processing performance.

Further, in the treatment method using the composite reverse osmosis membrane according to the present invention, the organic polymer layer having a positively chargeable group, which covers the surface of the polyamide skin layer of the composite reverse osmosis membrane, It is preferably an organic polymer layer obtained by crosslinking polyethyleneimine. This crosslinked organic polymer layer is preferable because it can be easily produced and can efficiently exhibit the above-mentioned performance.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing a reverse osmosis membrane used in the present invention is not particularly limited as long as a composite reverse osmosis membrane satisfying the above characteristics can be obtained. Can be produced by referring to various conventionally known methods for producing a composite reverse osmosis membrane having:

The polyamide skin layer of the composite reverse osmosis membrane used in the present invention includes, for example, a compound having two or more reactive amino groups and a polyamine having two or more reactive acid halide groups. During the interfacial polycondensation reaction with a functional acid halide compound, the solubility parameter is 8 to 14 (cal / c
m ³ ) ^1/2 compounds, such as alcohols, ethers,
It can be produced by the presence of at least one compound selected from ketones, esters, halogenated hydrocarbons, and sulfur-containing compounds. Examples of such alcohols include ethanol, propanol, butanol, butyl alcohol, 1-pentanol, 2-pentanol, t-amyl alcohol, isoamyl alcohol, isobutyl alcohol, isopropyl alcohol, undecanol, 2-ethylbutanol,
2-ethylhexanol, octanol, cyclohexanol, tetrahydrofurfuryl alcohol, neopentyl glycol, t-butanol, benzyl alcohol, 4-methyl-2-pentanol, 3-methyl-2-
Butanol, pentyl alcohol, allyl alcohol,
Examples include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and the like.

Examples of ethers include anisole, ethyl isoamyl ether, ethyl t-butyl ether, ethyl benzyl ether, crown ether,
Cresyl methyl ether, diisoamyl ether, diisopropyl ether, diethyl ether, dioxane,
Diglycidyl ether, cineol, diphenyl ether, dibutyl ether, dipropyl ether, dibenzyl ether, dimethyl ether, tetrahydropyran,
Tetrahydrofuran, trioxane, dichloroethyl ether, butylphenyl ether, furan, methyl-t
-Butyl ether, monodichlorodiethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene chlorohydrin and the like can be mentioned.

The ketones include, for example, ethyl butyyl ketone, diacetone alcohol, diisobutyl ketone, cyclohexanone, 2-heptanone, methyl isobutyl ketone, methyl ethyl ketone and the like.

Examples of the esters include methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, isoamyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, and isoamyl acetate.

Examples of the halogenated hydrocarbons include, for example, allyl chloride, amyl chloride, dichloromethane,
Dichloroethane and the like. Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiolan.

Of these, alcohols and ethers are particularly preferred. These compounds can be present alone or in combination. The amount of the compound having a solubility parameter of 8 to 14 (cal / cm ³ ) ^1/2 depends on the kind of the compound, the kind of the polyfunctional amine compound used for the interfacial polycondensation, and the kind of the polyfunctional acid halogen compound. It is particularly limited because it differs depending on whether it is added to a solution containing the polyfunctional amine compound (hereinafter referred to as solution X) or a solution containing the polyfunctional acid halide compound (hereinafter referred to as solution Y). If a substance having a solubility parameter of 8 to 14 (cal / cm ³ ) ^1/2 (hereinafter referred to as “substance Z”) is added to the solution X, the preferable addition amount is the total weight of the solution X and the substance Z. 10 to 50% by weight based on If the amount is less than 10% by weight, the effect of improving water permeability tends to be insufficient, and if it exceeds 50% by weight, the rate of inhibition of salt permeation through the membrane tends to decrease. When the substance Z is added to the solution Y, the preferable addition amount is 0.001 to 10% by weight based on the total weight of the solution Y and the substance Z. If the amount is less than 0.001% by weight, the effect of improving water permeability tends not to be sufficiently exhibited, and if it exceeds 10% by weight, the rate of inhibition of salt permeation through the membrane tends to decrease. The compound having a solubility parameter of 8 to 14 (cal / cm ³ ) ^1/2 is added to at least one or both of the solution containing the polyfunctional amine compound and the solution containing the polyfunctional acid halide compound. You may.

When the solubility parameter is 8 to 14 (cal
The specific surface area and the like of the polyamide-based skin layer can be adjusted by appropriately selecting the amount and type of the compound of (cm ³ ) ^1/2 .

As described above, the polyamide skin layer of the composite reverse osmosis membrane used in the present invention comprises a polyfunctional amine compound having two or more reactive amino groups,
It is synthesized by an interfacial polycondensation reaction with a polyfunctional acid halide compound having one or more reactive acid halide groups,
The polyfunctional amine compound to be used is not particularly limited as long as it is a polyfunctional amine having two or more reactive amino groups, and examples thereof include aromatic, aliphatic and alicyclic polyfunctional amines.

The aromatic polyfunctional amine includes, for example, an aromatic polyfunctional amine having 6 to 11 carbon atoms.
Specifically, m-phenylenediamine, p-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 8,5-diaminobenzoic acid, 2,4-diaminotoluene, Examples include 2,4-diaminoanisole, amidole, xylylenediamine and the like.

The aliphatic polyfunctional amine includes, for example, an aliphatic polyfunctional amine having 2 to 11 carbon atoms.
Specifically, ethylenediamine, propylenediamine,
Tris (2-aminoethyl) amine and the like can be mentioned.

The alicyclic polyfunctional amine includes, for example, an alicyclic polyfunctional amine having 4 to 11 carbon atoms.
Specific examples include 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, 4-aminomethylpiperazine and the like.

These amines may be used alone,
Two or more kinds may be used in combination. Among these polyfunctional amine compounds, aromatic polyfunctional amines are particularly preferred. Further, as the polyfunctional acid halide used in the present invention,
It is not particularly limited as long as it is a polyfunctional acid halide compound having two or more reactive acid halide groups, and examples thereof include aromatic, aliphatic, and alicyclic polyfunctional acid halides.

Examples of such aromatic polyfunctional acid halides include aromatic polyfunctional acid halides having 8 to 16 carbon atoms. Specific examples include trimesic acid chloride, terephthalic acid chloride, and isophthalic acid. Chloride, biphenyldicarboxylic acid chloride, naphthalenedicarboxylic acid dichloride, benzenetrisulfonic acid chloride, benzenedisulfonic acid chloride, chlorosulfonylbenzenedicarboxylic acid chloride and the like.

The aliphatic polyfunctional acid halide includes, for example, an aliphatic polyfunctional acid halide having 4 to 12 carbon atoms. Specifically, propanetricarboxylic acid chloride, butanetricarboxylic acid chloride, Pentanetricarboxylic acid chloride, glutaryl halide,
Adipoyl halide and the like can be mentioned.

Examples of the alicyclic polyfunctional acid halide include alicyclic polyfunctional acid halides having 6 to 14 carbon atoms. Specifically, cyclopropane tricarboxylic acid chloride, cyclobutane tetrachloride Carboxylic acid chloride, cyclopentanetricarboxylic acid chloride,
Examples thereof include cyclopentanetetracarboxylic acid chloride, cyclohexanetricarboxylic acid chloride, tetrahydrofurantetracarboxylic acid chloride, cyclopentanedicarboxylic acid chloride, cyclobutanedicarboxylic acid chloride, cyclohexanedicarboxylic acid chloride, and tetrahydrofurancarboxylic acid chloride.

These acid halides may be used alone or as a mixture of two or more. Among these polyfunctional acid halides, aromatic polyfunctional acid halides are particularly preferred.

Further, since the polyamide skin layer needs to be cross-linked, the polyfunctional amine compound and / or the polyfunctional acid halide may be trifunctional or higher polyfunctional as at least a part thereof. It is necessary to use amine compounds and / or trifunctional or higher polyfunctional acid halides. Of course, one or both of the polyfunctional amine compound and the polyfunctional acid halide may be a compound having three or more functions. The amount of the trifunctional or higher polyfunctional amine compound and / or the trifunctional or higher polyfunctional acid halide to be used may be appropriately selected depending on the desired degree of cross-linking. In the range of 10 mol% to 100 mol%, more preferably 20 mol% for each amount of polyfunctional acid halide.
It is used in the range of mol% to 100 mol%.

In the present invention, the negatively-charged cross-linked polyamide of the negatively-charged cross-linked polyamide-based skin layer has a pH of 7
In this case, the charge of the film composed of the polyamide skin layer is negative. Generally polyamides and -NH ₂ group -CO
Has a OH group, a tendency becomes strong showing a positive charge for -NH ₂ group is -NH ₃ ⁺ is at the acidic range,
Is In the alkaline region is -COOH group -COO ^- tends to exhibit a negative charge to become the stronger. Normal polyamide has a strong negative charge in a pH range of 7.

In the present invention, the polyfunctional amine compound and the polyfunctional acid halide are interfacially polymerized on a microporous support, whereby a crosslinked polyamide is mainly formed on the microporous support. A thin film as a component, that is, a composite reverse osmosis membrane having a polyamide skin layer formed thereon is obtained.

In the present invention, the microporous support for supporting the polyamide-based skin layer is not particularly limited as long as it can support a thin film composed of the polyamide-based skin layer. Various things used as a body are used. For example, polysulfone, polyarylethersulfone such as polyethersulfone,
Although various materials such as polyimide and polyvinylidene fluoride can be mentioned, in particular, a microporous support membrane made of polysulfone or polyarylethersulfone is preferably used because it is chemically, mechanically and thermally stable. . Such microporous supports usually have a thickness of about 25-125 μm.
m, preferably about 40-75 μm, but is not necessarily limited to these.

More specifically, a first layer comprising a solution (usually an aqueous solution) containing the polyfunctional amine compound (amine component) is formed on a microporous support, and then the first layer is formed. A layer comprising a solution containing a polyfunctional acid halide (acid halide component) (usually an organic solvent solution is used) is formed on the first layer, and interfacial polycondensation is carried out to form a crosslinked polyamide. It can be obtained by forming a thin film (polyamide skin layer) on a microporous support.

The solution containing the polyfunctional amine compound is
In order to facilitate membrane formation or to improve the performance of the obtained composite reverse osmosis membrane, for example, polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid, and polyhydric alcohols such as sorbitol and glycerin Can be contained in a small amount.

The amine salts described in JP-A-2-187135, for example, salts of tetraalkylammonium halides and trialkylamines with organic acids, can also be used to easily form a film. It is preferably used in terms of improving absorption into the body, accelerating the condensation reaction, and the like.

Further, a surfactant such as sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium lauryl sulfate and the like can be contained. These surfactants are effective in improving the wettability of the solution containing the polyfunctional amine compound on the microporous support.

Further, in order to promote the polycondensation reaction at the interface, sodium hydroxide or trisodium phosphate for removing hydrogen halide generated by the interfacial polycondensation reaction is used, or acyl catalyst is used as a catalyst. It is also advantageous to use a catalyst for conversion.

In the solution containing the polyfunctional acid halide and the solution containing the polyfunctional amine compound,
The concentration of the polyfunctional acid halide and the polyfunctional amine compound is not particularly limited, but the polyfunctional acid halide is usually 0.01 to 5% by weight, preferably 0.1 to 5% by weight.
The amount of the polyfunctional amine compound is usually 0.1 to 10% by weight, preferably 0.5 to 5% by weight.

In this way, the solution containing the polyfunctional amine compound is coated on the microporous support, and then the solution containing the polyfunctional acidic halide is coated thereon. And then usually about 20
~ 150 ° C, preferably about 70-130 ° C, about 1-1
Heat drying for 0 minute, preferably about 2 to 8 minutes, to form a water-permeable thin film made of a negatively charged crosslinked polyamide, that is, a negatively charged crosslinked polyamide skin layer. The thickness of this thin film is usually in the range of about 0.05 to 2 μm, preferably about 0.10 to 1 μm.

Next, in the present invention, the surface of the negatively chargeable crosslinked polyamide skin layer must be covered with an organic polymer layer having a positively chargeable group. If not coated with an organic polymer layer having a positively chargeable group, the amount of permeated water is remarkably reduced when a solution containing a cationic organic substance and / or an amphoteric organic substance is treated.

In the composite reverse osmosis membrane used in the present invention,
The surface of the negatively charged crosslinked polyamide-based skin layer may be any one coated with an organic polymer layer having a positively chargeable group, and the chemical structure of the organic polymer having the positively chargeable group is particularly limited. Not something. However, from the viewpoint of durability and long-term stability, it is preferable that the organic polymer be crosslinked.

In the present invention, from the viewpoints of workability and processability, it is desirable that the organic polymer itself is soluble in a solvent. Therefore, the organic polymer itself is three-dimensionally crosslinked after being coated on the polyamide skin layer of the composite reverse osmosis membrane. Are preferred. As such an organic polymer, a polymer having a positively chargeable group and a functional group which causes a cross-linking reaction in the molecule and itself soluble in a solvent is used. For example, as an example, a polymer having at least two hydroxyl groups and / or amino groups in a molecule together with a positively charged group (hereinafter referred to as polymer A), or at least two hydroxyl groups and / or amino groups in a molecule together with a positively charged group And a polymer having a group and two protected isocyanate groups (hereinafter referred to as polymer B).

Here, examples of the positively chargeable group include an ammonium group, a phosphonium group, a sulfonium group and the like. The protected isocyanate group is an isocyanate group blocked with a blocking agent,
Or an isocyanate group protected in the form of an amine imide group.

Various blocking agents are known for blocking the isocyanate group. Examples thereof include phenols such as phenol and cresol, alcohols such as methanol, ethanol and methyl cellosolve, methyl ethyl ketoxime, and acetaldehyde oxime. Oximes such as

Examples of the polymer A include homopolymers of hydroxypropyltrimethylammonium methacrylate and copolymers with other polymerizable monomers, and copolymers of ethyltrimethylammonium methacrylate and hydroxyethyl methacrylate. Coalescing,
Examples include quaternized copolymers of 4-vinylpyridine and hydroxyethyl methacrylate.

Further, as the polymer B, for example, 2-
Copolymer of isocyanate monomer obtained by blocking methacryloyloxyethylene isocyanate with an appropriate blocking agent and hydroxypropyltrimethylammonium methacrylate, copolymer of the above blocked isocyanate with 4-vinylpyridine and hydroxyethyl methacrylate A quaternized polymer, such as a copolymer of a vinyl monomer having an amine imide group such as 1,1-dimethyl-1- (2-hydroxypropyl) amine methacrylimide and hydroxypropyltrimethylammonium methacrylate, may be used. Can be mentioned.

The above polymers A and B are both soluble in water and alcohol. Therefore, in the present invention, the organic crosslinked polymer layer having a positively chargeable group can be formed on the polyamide skin layer of the composite reverse osmosis membrane by, for example, the following various methods.

In order to form a crosslinked polymer layer formed by crosslinking the polymer A, an aqueous solution or alcohol solution of the polymer A is applied on the polyamide skin layer of the composite reverse osmosis membrane,
The polymer A may be dried, contacted with a solution in which a polyisocyanate compound as a polyfunctional crosslinking agent is dissolved, and heated if necessary to crosslink the polymer A between the molecules.

As another method, a polyfunctional polyisocyanate compound blocked with a blocking agent as described above is added to an aqueous solution or alcohol solution of polymer A,
After applying the obtained solution to the polyamide skin layer of the composite reverse osmosis membrane, the solution is heated to a temperature equal to or higher than the dissociation temperature of the blocked polyisocyanate to release the polyisocyanate compound and cause a crosslinking reaction with the polymer A. Is also good.

The polyisocyanate compound as a crosslinking agent used here is not particularly limited. For example, tolylene diisocyanate, diphenylmethane diisocyanate, a polymer thereof, isophorone diisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate , Tris (p-isocyanatephenyl) thiophosphite, adducts of trimethylolpropane and tolylenediisocyanate, adducts of trimethylolpropane and xylylenediisocyanate, and the like.

In order to form the crosslinked polymer layer of the polymer B on the polyamide skin layer of the composite reverse osmosis membrane, for example, a water or alcohol solution of the polymer B is applied on the polyamide skin layer, What is necessary is just to heat to a temperature higher than the dissociation temperature of the blocked isocyanate to release the isocyanate group and to crosslink between and / or within the molecules.

In order to accelerate the above-mentioned crosslinking reaction between isocyanate groups and hydroxyl groups,
If necessary, a catalyst such as a tertiary amine or an organotin compound can be used.

Even if the organic polymer does not have a crosslinkable functional group as described above, after coating the organic polymer having a positively chargeable group on the polyamide skin layer of the composite reverse osmosis membrane, the electron beam is irradiated. Irradiation, or mixing peroxide in the organic polymer solution, by heating after coating on the polyamide skin layer of the composite reverse osmosis membrane to generate radicals on the organic polymer skeleton, Three-dimensional crosslinking can also be performed.

In the present invention, the thickness of the thus formed crosslinked organic polymer layer having a positively charged group is usually preferably in the range of 10 Å (1 nm) to 10 μm.

When polyethyleneimine is used as the organic polymer having a positively charged group and glutaraldehyde is used as a crosslinking agent, a polyethyleneimine crosslinked layer is formed by a reaction represented by the following formula (Formula 1).

[0057]

Embedded image

The average molecular weight of the polyethyleneimine used in the above is preferably 300 or more, more preferably 500 or more. Although the upper limit of the average molecular weight of polyethyleneimine is not particularly limited, it is usually 500,
It is about 000. The preferred thickness of the obtained crosslinked polyethyleneimine layer is in the range of 1 nm to 10 μm.

[0059]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

Reference Example 1 A synthesis example of one component of a monomer for forming an organic polymer having a positively chargeable group. 29 g of methyl ethyl ketoxime was dissolved in 50 g of benzene, and 2 g of this solution was added.
At a temperature of 5 ° C., 51.6 g of 2-methacryloyloxyethylene isocyanate was added dropwise over a period of about 40 minutes.
Stirred at 5 ° C for 2 hours. The obtained reaction product was analyzed by proton NMR to confirm that it was a blocked product in which methyl ethyl ketoxime was almost quantitatively added to 2-methacryloyloxyethylene isocyanate.

Reference Example 2 A synthesis example of an organic polymer having a positively chargeable group. 16 g of hydroxypropyltrimethylammonium methacrylate chloride and 8 g of the blocked isocyanate compound obtained in Reference Example 1 were mixed with 60 g of methanol.
Azobisisobutyronitrile 0.4
g was added and stirred at 60 ° C. for 6 hours under a nitrogen gas atmosphere to obtain a copolymer having a quaternary ammonium group and a hydroxyl group.

Example 1 m-phenylenediamine
An aqueous solution containing 3.0% by weight, 0.15% by weight of sodium lauryl sulfate, 3.0% by weight of triethylamine, 6.0% by weight of camphorsulfonic acid, and 5% by weight of isopropyl alcohol was used as a solution A to support a microporous polysulfone. By contacting with the membrane, excess solution A was removed to form a layer of the solution A on the support membrane.

Next, a hydrocarbon solvent “IP10” containing 0.20% by weight of trimesic acid chloride and 0.05% by weight of isopropyl alcohol was formed on the surface of the supporting film.
A solution consisting of 16 ″ (isoparaffinic hydrocarbon solvent manufactured by Idemitsu Chemical Co., Ltd.) was prepared as solution B, brought into contact with solution A, and then kept in a hot air drier at 120 ° C. for 3 minutes to form a solution on the support film. Polymer thin film (polyamide skin layer)
Was formed to obtain a composite reverse osmosis membrane. (Composite reverse osmosis membrane A) A part of the obtained composite reverse osmosis membrane was washed with water and dried, and then a cross section of the composite reverse osmosis membrane was analyzed with a transmission electron microscope (TEM) to determine the specific surface area of the polyamide skin layer. When measured,
The specific surface area was 4.3. This is because the surface shape of the reverse osmosis membrane was changed during the interfacial polycondensation reaction due to the addition of isopropyl alcohol to solution A. Even if it is other than isopropyl alcohol, the presence of a compound having a solubility parameter of 8 to 14 (cal / cm ³ ) ^1/2 during the interfacial polycondensation reaction similarly changes the surface shape of the reverse osmosis membrane. The inventors have confirmed.

1 g of the copolymer obtained in Reference Example 2 was dissolved in water to prepare a 1% by weight aqueous solution. As a crosslinking catalyst, 1,4-azabicyclo (2,2,2) octane 0.00
5 g were added. The solution thus obtained is applied on the polyamide skin layer of the composite reverse osmosis membrane A,
By heating at 150 ° C. for 10 minutes, the copolymer was crosslinked to obtain a composite reverse osmosis membrane having positive chargeability (composite reverse osmosis membrane B).

The composite reverse osmosis membrane B was treated with sodium chloride 1500
operating pressure 15k with pH 6.5 aqueous solution containing ppm
When evaluated at gf / cm ² and a temperature of 25 ° C., the membrane permeation inhibition rate of the salt was 99% or more, and the amount of permeated water was 1.5 m ³ / m ^2.
・ It was a day. Add 1 cationic surfactant to this evaluation solution.
000 ppm and further operated for 1 hour. After one hour,
When the amount of permeated water was measured by replacing the evaluation liquid with a new evaluation liquid having the same composition, the permeated water amount was 1.3 m ³ / m ² · day, which was about 10% lower than the initial value. Indicated.

(Comparative Example 1) A composite reverse osmosis membrane A was prepared in the same manner as in Example 1 except that the pH of the composite reverse osmosis membrane A contained 1500 ppm of sodium chloride.
Initial evaluation using an aqueous solution of 6.5 showed that the salt permeation inhibition rate of the salt was 99% and the amount of permeated water was 2.1 m ³ / m ² · day. Subsequently, the same operation as in Example 1 was performed using an evaluation liquid obtained by mixing the evaluation liquid having the composition with a cationic surfactant at 1000 ppm, and the amount of permeated water was measured.
About 70% of the permeated water amount was remarkably reduced from the initial value of 0.6 m ³ / m ² · day.

(Example 2) 1% by weight of polyethyleneimine was added to composite reverse osmosis membrane A in pure water for supply, and after reverse osmosis treatment, the inside of the system was washed with water and 1% of glutaraldehyde was added to pure water for supply. %, And the mixture was treated to crosslink polyethyleneimine to obtain a composite reverse osmosis membrane having a positively charged group (composite reverse osmosis membrane C).

When the composite reverse osmosis membrane C was initially evaluated in the same manner as in Example 1, the membrane permeation inhibition rate of the salt was 99% and the amount of permeated water was 1.2 m ³ / m ² · day. Subsequently, the same operation as in Example 1 was carried out using an evaluation solution obtained by further mixing a cationic surfactant at 1000 ppm with the evaluation solution having this composition, and the amount of permeated water was measured. As a result, 1.1 m ³ / m ² · day was obtained. A sufficiently high amount of permeated water was shown.

As described above, in the desalting treatment of a solution containing a cationic organic substance and / or an amphoteric organic substance in which the amount of permeated water is significantly reduced, if the treatment method using the composite reverse osmosis membrane of the present invention is used, Can be operated stably without remarkable decrease.

[0070]

According to the method for treating with a composite reverse osmosis membrane of the present invention, a solution containing a cationic organic substance and / or an amphoteric organic substance is produced by using a composite reverse osmosis membrane having a polyamide-based skin layer having a low running cost. In addition, it is possible to provide a water treatment method effective for desalting water, concentrating active ingredients, and the like, which can stably treat a large amount of permeated water.

From the above-mentioned effects, the method of the present invention provides
For example, it is suitably used for desalination of a solution containing a cationic organic substance and / or an amphoteric organic substance, and from stains and the like that cause pollution such as dyeing wastewater and electrodeposition paint wastewater,
The contaminants or effective substances contained therein are removed and collected, and the treated solution can be reused, which contributes to the reduction of wastewater and the closure of wastewater.
In addition, it can be used for advanced treatments such as concentration of active ingredients in food applications and the like and removal of harmful components in water purification and sewage applications.

The treatment method using such a composite reverse osmosis membrane can be operated with a solution containing a cationic organic substance and / or an amphoteric organic substance, which cannot be operated because the amount of permeated water is significantly reduced in the conventional composite reverse osmosis membrane. Is possible. For example,
It can be suitably used for treatment of wastewater containing a cationic surfactant or an amphoteric surfactant, treatment of a solution in which a cationic monomer is eluted from an anion exchange resin or the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C09D 179/02 PLT C09D 179/02 PLT

Claims (7)

[Claims] 1. A method of treating a solution containing a cationic organic substance and / or an amphoteric organic substance with a composite reverse osmosis membrane, wherein the composite reverse osmosis membrane used for the treatment comprises a polyamide skin layer and a microporous layer supporting the same. A composite reverse osmosis membrane comprising a support, wherein the polyamide skin layer has a polyfunctional amine compound having two or more reactive amino groups and a polyfunctional amine compound having two or more reactive acid halide groups; A negatively-charged crosslinked polyamide skin layer synthesized from an acid halide, wherein the surface of the skin layer is coated with an organic polymer layer having a positively-chargeable group; Method. 2. The method according to claim 1, wherein the specific surface area of the polyamide skin layer of the composite reverse osmosis membrane is 3 or more. 3. The method according to claim 1, wherein the polyamide skin layer of the composite reverse osmosis membrane comprises a wholly aromatic crosslinked polyamide. 4. The performance of the composite reverse osmosis membrane is set at an operating pressure of 15 k.
gf / cm ² , sodium chloride 1500 at a temperature of 25 ° C.
When evaluated with an aqueous solution having a pH of 6.5 containing ppm, the salt permeation inhibition rate of the salt was 90% or more and the amount of permeated water was 1 m ^3.
/ M ² · day or more, the treatment method using the composite reverse osmosis membrane according to any one of claims 1 to 3. 5. The composite reverse according to claim 1, wherein the organic polymer layer having a positively chargeable group covering the surface of the polyamide skin layer is a crosslinked organic polymer film. Treatment method using a permeable membrane. 6. An organic polymer layer having a positively chargeable group,
2. An intramolecular and / or intermolecular crosslinked organic polymer layer of a polymer having a quaternary ammonium group and a hydroxyl group.
A method for treating with a composite reverse osmosis membrane according to any one of claims 1 to 5. 7. The treatment method using a composite reverse osmosis membrane according to claim 1, wherein the organic polymer film having a positively chargeable group is an organic polymer layer obtained by crosslinking polyethyleneimine.