JP2017094259A - Membrane fouling inhibitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane fouling inhibitor which, while having excellent adsorptivity for materials such as a biopolymer and the like which cause membrane fouling, can easily elute the material adsorbed which causes membrane fouling, and can be recycled repeatedly.SOLUTION: The membrane fouling inhibitor contains a polymer compound (C) based on a cationic group-containing polymer compound (A) and a compound (B) containing at least one functional group having reactivity with the cationic group of the polymer compound (A), where the membrane fouling inhibitor has a region where a density of the cationic group is 8.5 to 15 mmol/g.SELECTED DRAWING: None

Description

  The present invention relates to a membrane fouling suppressing material having adsorptivity to a causative substance that causes membrane fouling, and a water treatment method using the same.

  In the field of water treatment for raw water obtained from natural or man-made environments, various types such as ultrafiltration (UF) membrane, microfiltration (MF) membrane, nanofiltration (NF) membrane and reverse osmosis (RO) membrane Advanced water treatment is performed by membrane filtration using a membrane. In these water treatments by membrane filtration, membrane fouling occurs in the membrane used for water treatment with the passage of operating time, the membrane cleaning frequency increases, the membrane replacement frequency increases due to membrane deterioration due to membrane degradation, and the pump Problems such as increased running costs due to increased energy often occurred.

  In recent years, it has been found that biopolymers such as polysaccharides and proteins, which are organic carbons with relatively high hydrophilicity, are the main causes of irreversible membrane fouling, and water treatment with excellent adsorptivity to biopolymers Hydrophilic polymer adsorbents for use have been proposed. For example, Patent Document 1 discloses a hydrophilic polymer adsorbent having a hydrophilic polymer as a main skeleton and having a functional group capable of forming a bond with at least a part of organic carbon in water to be treated. A water treatment method using the same is disclosed.

International Publication No. 2015/076371 Pamphlet

  When using adsorbents for membrane fouling-causing substances in the field of water treatment, it is generally easy to remove the membrane fouling-causing substances adsorbed on the adsorbents from the viewpoint of reducing the adsorbent replacement frequency and running costs. It is a great advantage that it can be eluted and the adsorbent can be repeatedly recycled. However, although the hydrophilic polymer adsorbent described in the above-mentioned patent document is excellent in the adsorptivity to the biopolymer, its adsorption performance is too high, so the elution property of the adsorbed biopolymer and the recyclability of the adsorbent are It was not always satisfactory.

  The present invention can easily elute adsorbed membrane fouling-causing substances and can be reused repeatedly while having excellent adsorption performance for membrane fouling-causing substances such as biopolymers. It aims at providing a film | membrane fouling suppression material. In addition, the present invention uses such a membrane fouling suppression material to ensure a high water treatment capacity and can easily regenerate the membrane fouling suppression material with a simple procedure. An object is to provide a processing method.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a membrane fouling-suppressing material includes a reaction product of a cationic group-containing polymer compound and a compound containing a specific functional group. When it has a region of 8.5 to 15 mmol / g cationic group density, it is found that it exhibits high adsorptivity to the biopolymer and that the adsorbed biopolymer can be easily eluted by contacting with the cleaning fluid; The present invention has been reached. That is, the present invention provides the following embodiment [1] and preferred embodiments [2] to [17].
[1] A polymer compound (C) based on a cationic group-containing polymer compound (A) and a compound (B) containing at least one functional group having reactivity with the cationic group of the polymer compound (A) ) And a membrane fouling inhibitor having a region having a cationic group density of 8.5 to 15 mmol / g.
[2] In the above [1], the cationic group of the polymer compound (A) is at least one selected from the group consisting of an amino group, an imino group, an amidine group, a guanidino group, an imidazole group, and a pyridyl group. The film | membrane fouling suppression material of description.
[3] The above-mentioned [1], wherein the polymer compound (A) is at least one selected from the group consisting of polyethyleneimine, polyallylamine, polyvinylamine, polyamidine, polyguanidine, polyamino acid, polypyridine, and salts thereof. Or the film | membrane fouling suppression material as described in [2].
[4] The functional group of the compound (B) is an epoxy group, a carboxyl group, a halogen group, an acid anhydride group, an acid halide group, a formyl group, an N-chloroformyl group, a chloroformate group, an isocyanate group, or an aldehyde group. The film fouling suppressing material according to any one of [1] to [3], which is at least one selected from the group consisting of azetidine groups and carbodiimide groups.
[5] The film fouling suppression material according to any one of [1] to [4], wherein the compound (B) is a compound having at least one epoxy group.
[6] The film fouling suppression material according to any one of [1] to [5], further including a hydrophilic polymer compound (D).
[7] The film fouling suppressing material according to [6], wherein the polymer compound (C) is dispersed in the hydrophilic polymer compound (D).
[8] The film fouling suppression material according to [6] or [7], wherein the hydrophilic polymer compound (D) is an ethylene-vinyl alcohol copolymer.
[9] The film fouling suppressing material according to any one of [1] to [8], wherein the swelling degree in 25 ° C. water is 20 to 500%.
[10] The membrane fouling suppression material according to any one of [1] to [9], which has biopolymer adsorption ability.
[11] For use in water treatment by at least one membrane selected from the group consisting of an ultrafiltration (UF) membrane, a microfiltration (MF) membrane, a nanofiltration (NF) membrane and a reverse osmosis (RO) membrane The film fouling suppressing material according to any one of [1] to [10].
[12] The treated water is brought into contact with the membrane fouling suppressing material according to any one of [1] to [11], and the membrane fouling-causing substance contained in the treated water is adsorbed to the membrane fouling suppressing material. A water treatment method including a step of causing
[13] The water treatment method according to [12], wherein the water to be treated contains 0.1% by mass or more of salts.
[14] A method for regenerating a membrane fouling suppression material, comprising the step of bringing the membrane fouling suppression material according to any one of [1] to [11] into contact with water to be treated and then contacting with a cleaning fluid. .
[15] The method for regenerating a membrane fouling suppression material according to [14], wherein the cleaning fluid is a metal ion-containing aqueous solution.
[16] A group consisting of an ultrafiltration (UF) membrane, a microfiltration (MF) membrane, a nanofiltration (NF) membrane, and a reverse osmosis (RO) membrane for water to be treated after being brought into contact with the membrane fouling suppression material The water treatment method according to [12], including a step of membrane filtration with at least one membrane selected from
[17] The water treatment method according to [12] or [16], including the regeneration method according to [14] or [15].

  According to the present invention, the adsorbed membrane fouling-causing substance can be easily eluted and reused repeatedly while having excellent adsorption performance for the membrane fouling-causing substances such as biopolymers. The film | membrane fouling suppression material which can be provided can be provided. Moreover, by using such a membrane fouling suppression material, a high water treatment capability can be ensured, and a water treatment method capable of regenerating the membrane fouling suppression material by a simple procedure can be provided.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

[Membrane fouling inhibitor]
The membrane fouling-suppressing material of the present invention includes a cationic group-containing polymer compound (A), and a compound (B) containing at least one functional group having reactivity with the cationic group of the polymer compound (A). The high molecular compound (C) based on this is included.

  The cationic group-containing polymer compound (A) (hereinafter sometimes referred to as “polymer compound (A)”) is a polymer compound containing at least one cationic group. Examples of the cationic groups include nitrogen atom-containing cationic groups such as amino groups (primary amino groups, secondary amino groups, and tertiary amino groups), imino groups, amidine groups, guanidino groups, imidazole groups, and pyridyl groups. , Sulfonium group, phosphonium group and the like. These may exist in a salt state. In the polymer compound (A), one type of cationic group may be present, or two or more types of cationic groups may be present. Among these, from the viewpoints of reactivity and versatility, the cationic group contained in the polymer compound (A) is preferably a nitrogen atom-containing cationic group, and is an amino group, imino group, amidine group, guanidino group, imidazole. A group selected from the group consisting of a group and a pyridyl group is more preferable, and an amino group is particularly preferable.

  In the polymer compound (A), the compound produced by the reaction with the compound (B) containing at least one functional group having reactivity with a cationic group described later is used in a membrane fouling region. It is not specifically limited as long as it can comprise in a ring suppression material, The high molecular compound containing a well-known cationic group may be sufficient. The polymer compound (A) may be, for example, a compound composed of typical elements, and is composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms and oxygen atoms. It is preferable that it is composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms and oxygen atoms.

  Examples of the polymer compound (A) include polyethyleneimine, polyallylamine, polyvinylamine, polyamidine, polyguanidine, polyamino acid, polypyridine, and salts thereof. These may be used alone or in combination of two or more. The polymer compound (A) may be a copolymer obtained by copolymerizing two or more monomers corresponding to the repeating units constituting the polymer compound. Among them, the polymer compound (A) is preferably selected from the group consisting of polyethyleneimine, polyallylamine, polyvinylamine, polyamidine, polyguanidine, polyamino acid, polypyridine, and salts thereof. In particular, the polymer compound (A) is more preferably polyethyleneimine, polyallylamine, or polyvinylamine because it is easily available and has a high amino group density and is easily adjusted to a desired cationic group density. Polyethyleneimine is particularly preferred.

  The weight average molecular weight (Mw) of the polymer compound (A) is preferably 300 to 3000000, more preferably 400 to 300000, still more preferably 500 to 200000, and 600 to 150,000. Is particularly preferred. In addition, the weight average molecular weight of a high molecular compound (A) can be calculated | required, for example using gel permeation chromatography (GPC).

The polymer compound (A) preferably has a cationic group density of 10 to 30 mmol / g, and more preferably has a cationic group density of 11 to 28 mmol / g. When the density of the cationic group is less than 10 mmol / g, the cationic group cannot function cooperatively in the water to be treated (especially, the water to be treated containing salts). The adsorption rate of the filter becomes insufficient, and the water permeability of the filtration membrane may be inferior. When it exceeds 30 mmol / g, it may be difficult to produce the cationic group-containing polymer compound.
In the present invention, the cationic group density refers to the content of cationic groups per gram of dry weight.

The cationic group density of the polymer compound (A) is calculated according to the following formula based on the number of cationic groups (N) per molecular weight (M) (g / mol) of the repeating units constituting the polymer compound (A). be able to.
Cationic group density = (N / M) × 1000 (mmol / g)
For example, in the case of polyethyleneimine, the cationic group density can be calculated based on the composition formula (C ₂ H ₅ N ₁ : molecular weight 43.07) of aziridine as a constituent unit. That is, the number of cationic groups (N) present in the unit structure is 1, and the cationic group density can be calculated by the following formula.
Polyethyleneimine cationic group density =
(1 / 43.07) x 1000 (mmol / g) = 23.218 (mmol / g)

  In the present invention, the compound (B) containing at least one functional group having reactivity with the cationic group of the polymer compound (A) (hereinafter sometimes referred to as “compound (B)”) It is a compound that can control the cationic group density of the polymer compound (A) by reacting with and binding to the cationic group contained in the molecular compound (A). For this reason, the compound (B) contains at least one functional group having reactivity with the cationic group contained in the polymer compound (A).

In the present invention, the compound (B) may be appropriately determined according to the kind of the cationic group contained in the polymer compound (A), the desired cationic group density, and the like. The compound (B) is a compound that can control the cationic group density of the polymer compound (A) by reacting with and binding to the cationic group contained in the polymer compound (A), for example, One selected from epoxy group, carboxyl group, halogen group, acid anhydride group, acid halide group, formyl group, N-chloroformyl group, chloroformate group, isocyanate group, aldehyde group, azetidine group, carbodiimide group, etc. Or the compound containing at least 1 of 2 or more types of functional groups is mentioned.
Examples of the epoxy group-containing compound include alkylene oxide (eg, ethylene oxide, propylene oxide), haloalkylene oxide (eg, chloropropylene oxide), styrene oxide, epoxy alkene (eg, 1,3-butadiene monoepoxide), glycidol, Alkyl glycidyl ether (eg, glycidyl methyl ether, i-propyl glycidyl ether, n-propyl glycidyl ether, t-butyl glycidyl ether, i-butyl glycidyl ether, etc.), aryl glycidyl ether (eg, phenyl glycidyl ether), benzyl Glycidyl ether, allyl glycidyl ether, glycidyl alkylate (eg glycidyl methacrylate), glycidyl benzoate, Alkoxyalkylsilyl), diepoxyalkanes (eg, diepoxybutane, diepoxyoctane, etc.), alkylene glycol diglycidyl ethers (eg, ethylene glycol diglycidyl ether), and the like. The alkyl group and aryl group may have a substituent as appropriate.
Examples of the compound having a carboxyl group include an alkyl carboxylic acid and an aryl carboxylic acid, and the alkyl group and the aryl group may have a substituent as appropriate.
Examples of the compound having a halogen group include an alkyl halide and an aryl halide, and the alkyl group and the aryl group may have a substituent as appropriate.
Examples of the compound having an acid anhydride group include alkyl carboxylic acid anhydrides (for example, acetic anhydride), succinic anhydrides (for example, alkyl succinic anhydride, alkenyl succinic anhydride, aryl succinic anhydride, etc. ), Maleic anhydride (eg, alkyl maleic anhydride, arylmaleic anhydride, etc.), glutaric anhydride, itaconic anhydride, aryl acid anhydride (eg, benzoic anhydride), cycloalkane Examples thereof include tetracarboxylic acid anhydride, phthalic acid anhydride (for example, alkylphthalic acid anhydride), pyromellitic acid anhydride, and the like. The alkyl group and aryl group may have a substituent as appropriate.
Examples of the compound having an acid halide group include alkyl carboxylic acid halides and aryl carboxylic acid halides, and the alkyl group and aryl group may have a substituent as appropriate.
Examples of the compound having a formyl group include alkyl aldehydes (for example, acetaldehyde, butyraldehyde, etc.), aryl aldehydes (for example, phenyl aldehyde, etc.), and the alkyl group and aryl group appropriately have a substituent. May be.
Examples of the compound having an N-chloroformyl group include N-chloroformylalkylamine (for example, N-butylcarbamoyl chloride) and the like, which may have a substituent as appropriate.
Examples of the compound having a chloroformate group include alkyl chloroformate (for example, methyl chloroformate, ethyl chloroformate, etc.), aryl chloroformate (for example, phenyl chloroformate, etc.), and the like. The alkyl group and aryl group may have a substituent as appropriate.
Examples of the compound having an isocyanate group include alkyl isocyanate (for example, methyl isocyanate), aryl isocyanate (for example, phenyl isocyanate), and the like. The alkyl group or aryl group has a substituent as appropriate. Also good.
Examples of the compound having an aldehyde group include alkyl aldehyde (for example, formaldehyde, butyraldehyde, etc.), aryl aldehyde (for example, phenyl aldehyde, etc.), and the alkyl group and aryl group have a substituent as appropriate. (Eg, glutaraldehyde).
Examples of the compound having an azetidine group include alkyl azetidine (for example, methyl azetidine) and aryl azetidine (for example, phenyl azetidine), and the alkyl group and the aryl group appropriately have a substituent. It may be.
Examples of the compound having a carbodiimide group include alkyl carbodiimide (for example, N, N-bismethylcarbodiimide), aryl carbodiimide (for example, N, N-bisphenylcarbodiimide), and the like. You may have a substituent suitably. These compounds (B) may be used alone or in combination of two or more.

  In the present invention, from the viewpoint of reactivity with a cationic group, the compound (B) comprises an epoxy group, a carboxyl group, a halogen group, an acid anhydride group, an acid halide group, a formyl group, an N-chloroformyl group, a chlorophore. It is preferably a compound containing at least one functional group selected from the group consisting of a mate group, an isocyanate group, an aldehyde group, an azetidine group, and a carbodiimide group, an epoxy group, a halogen group, an acid anhydride group, More preferably, it is a compound containing at least one functional group selected from the group consisting of an acid halide group, a formyl group, an isocyanate group, an azetidine group and a carbodiimide group. Among these, from the viewpoint of the stability and handleability of the compound, the compound (B) is more preferably a compound containing an epoxy group. In addition, as the compound (B), a compound prepared by a method known in the art may be used, or a commercially available product may be used.

  The membrane fouling-suppressing material of the present invention includes a polymer compound (C) (hereinafter sometimes referred to as “polymer compound (C)”) based on the polymer compound (A) and the compound (B). . In the present invention, the polymer compound based on the polymer compound (A) and the compound (B) is a reaction product of the polymer compound (A) and the compound (B). It means a polymer compound in which the compound (B) is bonded to the cationic group portion of the polymer compound (A) by reacting the contained cationic group with the functional group contained in the compound (B). In the present invention, the specific cationic group density region of the membrane fouling inhibitor is mainly derived from the cationic group density of the polymer compound (C). Therefore, the polymer compound (C) is usually This is a polymer compound in which the compound (B) is bonded to a part of the cationic group of the polymer compound (A). For example, when the polymer compound (A) is polyethyleneimine and the compound (B) is glycidol, the polymer compound (C) has glycidol bonded to at least a part of amino groups of polyethyleneimine by an addition reaction. It becomes a polymer compound. For example, when glycidol is added to a secondary amine contained in polyethyleneimine, the structure of the moiety can be represented by the following formula, but polyethyleneimine is a polymer of aziridine and is a primary amine, secondary amine, and tertiary amine. In fact, glycidol can be added to each of these amines.

Examples of the polymer compound (C) contained in the membrane fouling-suppressing material of the present invention include a compound based on polyethyleneimine and glycidol, a compound based on polyethyleneimine and glycidylmethyl ether, and based on polyethyleneimine and isopropylglycidyl ether. Examples thereof include compounds, compounds based on polyethyleneimine and t-butyl glycidyl ether, compounds based on polyethyleneimine and ethylene glycol diglycidyl ether, compounds based on polyallylamine and ethylene glycol diglycidyl ether, and the like. Among these, from the viewpoint of not reducing the hydrophilicity of the polyamine, the polymer compound (C) is preferably a compound based on polyethyleneimine and glycidol, or a compound based on polyethyleneimine and ethylene glycol diglycidyl ether.
The membrane fouling suppressing material of the present invention may contain only one type of compound based on the polymer compound (A) and the compound (B), or may contain two or more types in combination.

  The polymer compound (C) can be prepared, for example, by adding the compound (B) to the polymer compound (A) dissolved in ion-exchanged water or isopropanol and mixing them. The blending amount and mixing ratio of the polymer compound (A) and the compound (B), and the type of the solvent are determined according to the type of the polymer compound (A) and the compound (B) to be used. What is necessary is just to determine suitably so that the desired cationic group density which a ring inhibitor has may be obtained.

  The membrane fouling suppressing material of the present invention has a region where the cationic group density is 8.5 to 15 mmol / g. By having a region in which the cationic group density is 8.5 to 15 mmol / g, the membrane fouling suppressing material of the present invention has high adsorptivity to membrane fouling-causing substances, particularly biopolymers, and membrane fouling. After adsorbing the ring-causing substance, the membrane fouling-causing substance can be easily eluted by contacting with the cleaning fluid, and the membrane fouling suppressing material can be repeatedly recycled. The membrane fouling suppressing material of the present invention preferably has a region having a cationic group density of 8.6 to 14 mmol / g, particularly preferably 8.7 to 13 mmol / g.

  The area | region which has the said specific cationic group density originates in all the compounds which have a cationic group contained in a membrane fouling suppression material. That is, in one embodiment, the membrane fouling inhibitor of the present invention has a region where the cationic group density of the polymer compound (C) is 8.5 to 15 mmol / g. Therefore, for example, when the compound having a cationic group contained in the membrane fouling suppressing material is only one kind of polymer compound (C), the polymer compound (C) is 8.5 to 15 mmol / g of cation. It has a sex group density. When a plurality of polymer compounds (C) that are compatible with each other are included, they have a cationic group density of 8.5 to 15 mmol / g when they are completely compatible.

  In the membrane fouling-suppressing material of the present invention, when a plurality of polymer compounds (C) that are incompatible with each other are contained, the polymer compound (C) having the specific cationic group density relative to the total polymer compound (C) The content ratio is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. Increasing the adsorptivity of the membrane fouling inhibitor to the membrane fouling-causing substance by containing the polymer compound (C) having the specific cationic group density in the above range with respect to the total polymer compound (C). Can do.

The cationic group density of the polymer compound (C) is determined mainly in relation to the type of the polymer compound (A) [cationic group density of the polymer compound (A)] and the addition amount of the compound (B). . Specifically, the cationic group density of the polymer compound (A) X A _g to Compound (B) X B _g additional polymerized compounds produced by (C) can be calculated according to the following formula .
Cationic group density (mmol / g) of polymer compound (C) =
Cationic group density of polymer compound (A) × X _A / (X _A + X _B )
Therefore, for example, when 10 g of glycidol is added to 20 g of polyethyleneimine having a cationic group density of 23.2 mmol / g, the cationic group density can be calculated from the following calculation, which is about 15.5 mmol / g.
Cationic group density of polymer compound (C) =
23.2 × 20 / (20 + 10) = 15.46 (mmol / g)

The cationic group density can be calculated based on the skeleton structure of the compound having a cationic group as described above as a method for calculating the cationic group density of the polymer compound (A). When the skeleton structure is unknown or complicated, and when a plurality of compounds having a cationic group are contained, the calculation can be performed by the following procedure. For example, a predetermined amount of a membrane fouling suppressing material is added to a 4% NaOH aqueous solution, and after stirring, the cationic group is exchanged with an OH ^- type cationic group. Next, the inhibitor after the exchange to the OH ⁻ type is thoroughly washed with ion exchange water, and then this inhibitor is added to a 4% HCl aqueous solution. After stirring, the cationic group is exchanged with the Cl ⁻ type cationic group. To do. After thoroughly exchanging the suppressor with ion-exchanged water, the cross-section of the suppressor is cut out to produce a section having a predetermined size. The section was analyzed by transmission electron microscope (TEM) -energy dispersive X-ray spectroscopy (EDX) (for example, JEM-2100F, JED-2300T manufactured by JEOL), and when Cl was mapped, the distribution of Cl If it is uniform, arbitrary 5 points are selected, and if it is a phase-separated structure, 5 high-density phases are selected at random, and the Cl / C molar ratio is calculated.

Regarding the elements other than carbon atoms in the membrane fouling suppression material sample, the molar ratio of each atom to carbon atom is grasped at the above-mentioned 5 points (or 5 points corresponding to the selected site), and based on these molar ratios. The cationic group density per unit molecular weight may be calculated by the following formula.
Cationic group density =
1 / [(1 / X) × (atomic weight of carbon atom) + {(total ratio of target atom to carbon atom) × (atomic weight of target atom)}]

  For elements other than carbon atoms, various analysis methods may be used as long as the molar ratio of the target atom to carbon atoms can be calculated. For example, in addition to TEM-EDX, mass spectrometry, red You may determine the molar ratio of the object atom with respect to a carbon atom by various analyzes, such as an external absorption spectrum, a Raman scattering spectrum, and NMR.

For example, when the Cl / C molar ratio is X, the N / C molar ratio is Y, the O / C molar ratio is Z, and the H / C molar ratio is W, the cationic group density is It can be approximated by a formula.
Cationic group density =
1 / {(1 / X) × C _C + (Y / X) × C _N + (Z / X) × C _O + (W / X) × C _H } × 1000
(Wherein C _C is the atomic weight of the carbon atom, C _N is the atomic weight of the nitrogen atom, C 2 _O is the atomic weight of the oxygen atom, and C _H is the atomic weight of the hydrogen atom)
It is possible to estimate with.

When the distribution of Cl is uniform, the cationic group density may be calculated by the following formula using the ion exchange capacity of the membrane fouling suppression material, and may be used as an alternative value.
Cationic group density = ion exchange capacity (meq / ml) × resin dry weight per volume (ml / g)

  In the present invention, for example, by controlling the cationic group density of the polymer compound (C), it is possible to bring a desired cationic group density region to the membrane fouling suppressing material. As described above, the cationic group density of the polymer compound (C) is determined mainly in relation to the type of the polymer compound (A) and the amount of the compound (B) added. The desired cationic group density can be controlled.

  The form of the membrane fouling-suppressing material of the present invention is particularly limited as long as it contains the polymer compound (C) and has at least part of a region having a cationic group density of 8.5 to 15 mmol / g. Is not to be done. For example, the polymer compound (C) itself may constitute a membrane fouling suppressing material as a simple substance. As such a membrane fouling suppressing material, for example, a liquid or solid containing the polymer compound (C) may be insolubilized by crosslinking or the like. In this case, the crosslinking can be performed by a known method, for example, using a crosslinking agent described later.

  Moreover, the film | membrane fouling suppression material of this invention may be comprised from the said high molecular compound (C) and another component (substance). In this case, the form may be, for example, a mixture of the polymer compound (C) and other components as long as a predetermined cationic group density can be achieved. (C) may be introduced. Other components that can be included in the membrane fouling suppressing material of the present invention are not particularly limited as long as they can be combined with the polymer compound (C), and may be inorganic components, for example, organic It may be a component.

  Examples of the inorganic component include silica, alumina, hydroxyapatite, clay, molecular sieves, and the like. You may use these individually or in combination of 2 or more types. Silica is more preferable as the inorganic component. When an inorganic component is used, for example, the polymer compound (C) can be introduced into the inorganic component as a base material by coating or impregnation. Moreover, you may fix a high molecular compound (C) with a chemical bond with respect to an inorganic type component using a silane coupling agent, a crosslinking agent, etc. as needed.

  Examples of the organic component include various organic polymer compounds, and the organic polymer compound may be either a hydrophobic polymer compound or a hydrophilic polymer compound.

In the present invention, the hydrophobic polymer compound has a solubility calculated by the Fedor's estimation method according to the formula using cohesive energy density (Ecoh) and molar molecular volume (V): δ = [ΣEcoh / ΣV] ^1/2. It means a polymer compound having a parameter (δ) of less than 22. Examples of such hydrophobic polymer compounds include styrene polymer compounds such as polystyrene; polyolefin polymer compounds such as polyethylene and polypropylene; poly (meth) acrylate esters such as polymethyl methacrylate; polysulfone and poly Examples thereof include polysulfone-based polymer compounds such as ether sulfones; halogen-based vinyl polymers such as polyvinylidene fluoride. These hydrophobic polymer compounds may be used alone or in combination of two or more. As the hydrophobic polymer compound, styrene polymer compounds and poly (meth) acrylic acid esters are preferable.

  The weight average molecular weight of the hydrophobic polymer compound may be appropriately selected according to the type of the compound, and may be, for example, at least 5000 or more (for example, 5000 to 100,000), for example, 10,000 or more. Good. The weight average molecular weight of the hydrophobic polymer compound can be determined using, for example, gel permeation chromatography (GPC).

  In the present invention, the hydrophilic polymer compound means a polymer compound having a solubility parameter (δ) of 22 or more. Since such a hydrophilic polymer compound is particularly excellent in adsorptivity to biopolymers such as polysaccharides and proteins, the membrane fouling suppressing material of the present invention is hydrophilic in addition to the polymer compound (C). It preferably contains a polymer compound (hereinafter sometimes referred to as “hydrophilic polymer compound (D)”). In the present invention, it is more preferable to include a hydrophilic polymer compound having a solubility parameter (δ) of 23 or more, more preferably 24 or more, and particularly preferably 25 or more. Includes molecular compounds.

  The hydrophilic polymer compound (D) has a solubility parameter (δ) in the above range. For example, a hydroxyl group, an ether group, a cationic group, an anionic property in a repeating unit constituting the hydrophilic polymer compound. And a polymer compound having a hydrophilic group such as a group or an amide group.

Examples of the hydrophilic polymer compound (D) include acetic acid such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl acetal (for example, polyvinyl alcohol acetalized products with various aldehydes such as formaldehyde, acetaldehyde, butyraldehyde). Polyvinylalkyl alcohol; Polyalkylene glycol; Polyvinylalkyl ether; Polyalkylene oxide; Poly (meth) acrylamide; Polyacrylonitrile; Polystyrene sulfonic acid, polyvinyl sulfate, poly (meth) acrylic acid, polymaleic acid and polyamic acid, etc. Anionic polymer; phenol resin; polyamide; polyvinyl pyrrolidone; cellulose derivative; dextrin and chitin.
These polymers may have other comonomer units (for example, monomer units having unsaturated carboxylic acid units such as maleic acid, itaconic acid, acrylic acid, silanol groups, aldehyde groups, or sulfonic acid groups). .

  Particularly preferred hydrophilic polymer compounds (D) include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl acetal (for example, polyvinyl formal, polyvinyl butyral), polyvinyl alkyl alcohol, polyalkylene glycol, polyvinyl alkyl ether, poly Examples include alkylene oxides, anionic polymers, phenolic resins, polyvinyl pyrrolidone, dextrin and chitin. Among them, polyvinyl alcohol, ethylene-vinyl alcohol copolymer and polyvinyl acetal are more preferable, and polyvinyl alcohol, ethylene-vinyl alcohol copolymer and polyvinyl formal are particularly preferable. From the viewpoint of not only water resistance but also excellent durability, moldability and hydrophilicity, the hydrophilic polymer compound (D) is most preferably an ethylene-vinyl alcohol copolymer.

  The weight average molecular weight of the hydrophilic polymer compound (D) may be appropriately selected according to the type of the compound, and may be, for example, at least 5000 or more (for example, 5000 to 100,000), for example, 10,000 or more. There may be. In addition, the weight average molecular weight of hydrophilic polymer compound (D) can be calculated | required, for example using gel permeation chromatography (GPC).

  When the membrane fouling suppressing material of the present invention contains polyvinyl alcohol as the hydrophilic polymer compound (D), the molecular weight thereof may be defined by the viscosity average degree of polymerization, and the viscosity average obtained from the viscosity of the 30 ° C. aqueous solution. The degree of polymerization can be selected from a wide range of about 100 to 15000, for example. From the viewpoint of improving the durability of the membrane fouling suppressant, it is preferable to use a material having a high degree of polymerization. In this case, for example, the viscosity average degree of polymerization is preferably about 800 to 13000, more preferably about 1000 to 10,000. is there. The saponification degree of polyvinyl alcohol may be, for example, 88 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more. In particular, from the viewpoint of improving the durability of the membrane fouling suppressing material, those having a saponification degree of 98 mol% or more are preferable.

  When the membrane fouling-suppressing material of the present invention contains an ethylene-vinyl alcohol copolymer as the hydrophilic polymer compound (D), the ethylene unit content is 20 to 60 mol% in all monomer units. Is more preferable, and it is 25-55 mol% more preferably. When there is too little content of an ethylene unit, there exists a possibility that durability of a film | membrane fouling suppression material may worsen. On the other hand, when there is too much content of an ethylene unit, there exists a possibility that the hydrophilicity of a film | membrane fouling suppression material may fall.

  When the film | membrane fouling suppression material of this invention contains the said hydrophilic high molecular compound (D), it is preferable that a hydrophilic high molecular compound (D) is included as a base material. By including the hydrophilic polymer compound (D) as the base material, the retention of the polymer compound (C) can be enhanced. In this case, for example, the membrane fouling suppressing material is introduced into the hydrophilic polymer compound (D) by copolymerization or alloying with the hydrophilic polymer compound (D) as the base material. It may be in the form.

  For the copolymerization of the polymer compound (C) and the hydrophilic polymer compound (D) as a base material, a conventionally known method can be adopted in this field, and for example, preferably a block copolymer or a graft copolymer is used. The polymer compound (C) can be introduced into the hydrophilic polymer compound (D) as a substrate by polymerization. The alloying may also be performed by, for example, a method of preparing a mixed solution using (i) the polymer compound (C) and the hydrophilic polymer compound (D), and optionally using an optional component and an appropriate solvent. Alternatively, (ii) the polymer compound (C), the hydrophilic polymer compound (D) and, if necessary, an optional component may be melt-kneaded using a kneader or the like (solution molding).

  In a preferred embodiment of the present invention, the polymer compound (C) is dispersed in the hydrophilic polymer compound (D). By dispersing the polymer compound (C) in the hydrophilic polymer compound (D), a membrane fouling suppressing material having excellent adsorptivity of the membrane fouling-causing substance can be obtained. The reason for this is not clear, but the hydrophilic polymer compound (D) as a base material increases the wettability to water, and at least some of the components causing membrane fouling, particularly biopolymers such as polysaccharides and proteins. This is presumably because the polymer compound (C) containing a cationic group effectively penetrates into the membrane fouling suppressing material.

  In the membrane fouling-suppressing material of the present invention, the polymer compound (C) is in a mass ratio [polymer compound (C): hydrophilic polymer compound (D)] in the hydrophilic polymer compound (D). It is preferably dispersed at a ratio of 99 to 70:30, more preferably dispersed at a ratio of 5:95 to 65:35, and dispersed at a ratio of 8:92 to 60:40. Is particularly preferred. By dispersing the polymer compound (C) in the hydrophilic polymer compound (D) at a ratio in the above range, the water resistance of the membrane fouling inhibitor and the adsorptivity to the membrane fouling-causing substance can be enhanced.

In the membrane fouling suppressing material of the present invention, the polymer compound (C) and the hydrophilic polymer compound (D) may be post-modified by introducing a crosslinked structure using a crosslinking agent as necessary. Good.
Examples of the crosslinking agent include crosslinks capable of forming a crosslink between the polymer compounds (C), between the hydrophilic polymer compounds (D), and / or between the polymer compound (C) and the hydrophilic polymer compound (D). Although it will not specifically limit if it is an agent, For example, an epoxy group, a carboxyl group, a halogen group, an acid anhydride group, an acid halide group, a formyl group, a N-chloroformyl group, a chloroformate group, an isocyanate group, Examples thereof include compounds containing at least two functional groups selected from an aldehyde group, an azetidine group, a carbodiimide group, and the like. Among these, a compound containing at least two functional groups selected from an epoxy group, a halogen group, an isocyanate group, an aldehyde group, an azetidine group, and a carbodiimide group is preferable. Also, zirconyl-based crosslinking agents (zirconyl nitrate, zirconium ammonium carbonate, zirconyl chloride, zirconyl acetate, zirconyl sulfate), titanium-based crosslinking agents [titanium-based crosslinking agents, titanium lactate, titanium diisopropoxybis (triethanolamate)], etc. May be used. As such a crosslinking agent, various commercially available crosslinking agents can be used.

  The membrane fouling-suppressing material of the present invention includes, for example, a polymer compound (C), a hydrophilic polymer compound (D) prepared from the polymer compound (A) and the compound (B) according to a known method, and if necessary And other components constituting the film fouling inhibitor (for example, additives such as antioxidants, stabilizers, lubricants, processing aids, antistatic agents, colorants, antifoaming agents and dispersing agents) It can manufacture by mixing.

  For example, a method (melt kneading method) of melt kneading using a biaxial kneader can be mentioned. According to this method, a film fouling suppressing material in which each component is uniformly dispersed can be easily obtained. For example, the hydrophilic polymer compound (D) is melt-kneaded by a twin screw extruder, and a predetermined amount of the polymer compound (C) is added from the side feeder to mix them. The melt-kneaded product can be extruded to form molded bodies of various shapes, and then immersed in a solution containing a cross-linking agent and subjected to a cross-linking treatment. In addition, a crosslinking agent may be added during kneading to melt and knead the polymer compound and introduce crosslinking. Further, the molded body can be pulverized to form a particulate film fouling suppressing material.

  Further, for example, a mixed liquid of a polymer compound (C), a hydrophilic polymer compound (D), and optional components as necessary is prepared. As the solvent, water is usually used, but an organic solvent may be used. A solution having good properties can be obtained by adding both polymer compounds to a solvent and raising the temperature while stirring. The mixed solution of the polymer compound (C) and the hydrophilic polymer compound (D) is extruded through a spinning nozzle by a wet or dry / wet method and solidified in a coagulation bath, or is extruded into an air bath by dry spinning. Thereafter, according to a conventional method, wet stretching, drying, and dry heat stretching are performed to crystallize to form a fibrous molded body, and further immersed in a solution containing a crosslinking agent to perform a crosslinking treatment.

  The shape of the membrane fouling-suppressing material of the present invention is not particularly limited as long as it can be used for the adsorption treatment of biopolymers such as membrane fouling-causing substances contained in the water to be treated, particularly polysaccharides and proteins, For example, it may be in the form of particles, flakes, fibers, sheets, fabrics, or three-dimensional shapes. From the viewpoint of improving the adsorption performance, it is preferably particulate or fibrous. When used in a column, it is more preferably particulate from the viewpoint of volume filling rate.

  The membrane fouling suppression material of the present invention preferably has a degree of swelling in water of 25 ° C. of 20 to 500%, for example, from 30 to 450%, from the viewpoint of permeability of treated water and handleability. Is more preferable, and 40 to 350% is particularly preferable. When the degree of swelling is within the above range, the water permeability of the water to be treated containing the substance causing the membrane fouling is good and the contact with the water to be treated can be sufficiently performed. Performance is good. Here, the degree of swelling was determined by immersing 1 g of the membrane fouling suppression material in 25 ° C. water for 12 hours, then centrifugally dewatering the membrane fouling suppression material and weighing it at 105 ° C. for 4 hours. Calculated using dried and weighed values. In detail, it can measure with the measuring method in the Example mentioned later, for example.

  The degree of swelling of the membrane fouling suppression material can be appropriately controlled by the types, combinations, and contents of various components constituting the membrane fouling suppression material, and the types and amounts of the crosslinking agent. For example, the polymer compound (C) can be controlled by crosslinking with a crosslinking agent. The polymer compound (C) may be a hydrophobic polymer compound or a hydrophilic polymer (e.g., ethylene- It can also be controlled by introducing it into a base material such as vinyl alcohol copolymer and polyamide).

When the membrane fouling-suppressing material of the present invention is packed in a column and used, it is preferable that the volume change rate at a high temperature of 80 ° C. is low, for example, the volume change rate is 1.2 times or less. More preferred. The lower the volume change rate, the less the influence on the column and the better the packing property. The volume change rate was measured by filling a sufficiently swollen membrane fouling suppressant into a 15.4 mm inner diameter chromatographic column tube (manufactured by Shibata Kagaku Co., Ltd.) to a height of 5 cm and passing the acid solution through. And after washing | cleaning, it can calculate according to a following formula from the height of the film | membrane fouling suppression material before and behind immersion when the whole chromatographic column is immersed in the water bath heated at 80 degreeC for 1 hour.
Volume change rate (times) = height (cm) / 5 cm of membrane fouling suppression material after heating at 80 ° C.

  Various raw materials causing membrane fouling are present in the raw water. With the film fouling suppressing material of the present invention, it is possible to adsorb and remove film fouling-causing substances that have been difficult to adsorb. In particular, the membrane fouling suppression material of the present invention efficiently uses organic substances having a particle size of 0.45 μm or less (for example, aromatic-containing organic substances such as humic acid and fulvic acid, synthetic chemical substances such as surfactants, biopolymers, etc.). It can adsorb well.

In the present specification, the membrane fouling-causing substance means a substance that causes fouling. Membrane fouling-causing substances include, for example, organic carbon, various bacteria, inorganic particles, and the like.
In the present specification, organic carbon means carbon constituting organic substances existing in water [for example, dissolved organic carbon (DOC): particulate organic carbon (POC) such as TEP]. To do. Organic carbon includes, for example, biopolymers such as polysaccharides and proteins, humic acid, fulvic acid, uronic acid, cuturonic acid, and odor components (geosmin, 2-methylisoborneol).

Further, the membrane fouling-causing substance may be a substance that is difficult to remove by means such as physical backwashing when performing membrane filtration. Although the specific causative substance is still under study, the treated water that has undergone the adsorption process for adsorbing the fouling causative substance in the treated water using the membrane fouling suppression material of the present invention is supplied to the membrane treatment process. Compared with the case where the water to be treated is supplied to the membrane treatment step without going through the adsorption step, the lifetime of the membrane in the membrane treatment step can be improved.
Therefore, even if not all the causative substances are specifically identified, it is possible to confirm that the amount of causative substances that cause physically irreversible membrane fouling can be reduced by the adsorption process.

  The membrane fouling-suppressing material of the present invention is particularly excellent in biopolymer adsorption ability with high hydrophilicity among membrane fouling-causing substances. A biopolymer is a kind of organic carbon present in various raw waters, and is generally a polysaccharide and protein having an apparent molecular weight of 100,000 Da or more.

In the present invention, as an index for distinguishing other organic carbons from biopolymers, for example, in LC-OCD in which a wet total organic carbon measuring instrument is connected to high performance liquid chromatography, from a retention time at which a humic signal peak appears. It can be defined as a substance that exhibits a signal peak in a short holding time.
More particularly, the biopolymers are described in Stefan A.M. A fraction measured by the method described in Huber et al., Water Research 45 (2011), pages 879-885, for example, a retention time by LC-OCD may be a component of 25 minutes to 38 minutes. Further, the humic substance may be a B fraction in the measurement under the same conditions, for example, a component having a retention time exceeding 38 minutes and 50 minutes or less.

  Biopolymers are mainly composed of organic substances with few hydrophobic structures such as benzene rings and mainly high hydrophilicity. For example, biopolymers are composed of organic substances exhibiting an SUVA value of 1.0 [L / (m · mg)] or less. May be. On the other hand, since the humic substance contains a benzene ring and the like, it not only has a UV-absorbing structure, but also has a high hydrophobicity. For example, the SUVA value is 2.0 [L / (m · mg)] or more. It may be composed of an organic material showing.

The SUVA value is obtained by the following formula.
SUVA (L / mg-C · m) = UV (m ⁻¹ ) / DOC (mg-C / L)
Here, each parameter for calculating the SUVA value is Stefan A.M. It is measured by the method described in Water Research 45 (2011) pp. 879-885 by Huber et al. "Area value" represents the area value obtained by LC-OCD, "UV" Absorbance at a wavelength of 254 nm, “DOC”, indicates the DOC concentration (mg-C / L) in the test sample.

UV value calculation method (i) UV of biopolymer = UV of entire test sample × area value of biopolymer in spectrum (holding time tb: 25 minutes ≦ tb ≦ 38 minutes) / area value of entire spectrum (ii) Humin Quality UV = UV of the entire test sample × humin quality in the spectrum (holding time th: 38 minutes <th ≦ 50 minutes) / area value of the whole spectrum

DOC value calculation method (i) DOC of biopolymer = DOC of the entire test sample x area value of biopolymer in the spectrum (holding time tb: 25 minutes ≤ tb ≤ 38 minutes) / area value of the whole spectrum (ii) Humin DOC of the quality = DOC of the entire test sample × Area value of humic substance in the spectrum (holding time th: 38 minutes <th ≦ 50 minutes) / Area value of the whole spectrum

  In the membrane fouling suppressing material of the present invention, for example, the adsorption rate of the biopolymer from the treated water (raw water) may be, for example, 15% or more, preferably 20% or more, more preferably 30% or more, Preferably it may be 50% or more, more preferably 80% or more, still more preferably 85% or more, and particularly preferably 90% or more.

  The membrane fouling-suppressing material of the present invention is a biopolymer model water at 25 ° C. (sodium alginate concentration: 4.0 mg-C / L sodium alginate aqueous solution) or model seawater (sodium alginate concentration: 4.0 mg-C / L). L (sodium alginate, NaCl concentration 3.5% solution), the sodium alginate adsorption rate (A) may be, for example, 30% or more (for example, 30 to 100%), preferably 35% or more. More preferably, it may be 45% or more, more preferably 60% or more, and particularly preferably 80% or more. About the adsorption rate, the value measured by the method described in the Example mentioned later is shown.

The mechanism by which the membrane fouling-suppressing material of the present invention exhibits high adsorptivity to membrane fouling-causing substances such as biopolymers is not clear, but is presumed as follows.
Normally, many organic substances in water that are present in nature are negatively charged and can be removed with an adsorbent having a cationic group. Since the material does not have a high cationic group density, organic substances in water cannot be removed efficiently even if the material has a cationic group. On the other hand, since the membrane fouling suppression material of the present invention has a region in which cationic groups are distributed at high density, the cationic groups function cooperatively in this region, and cause membrane fouling such as biopolymers. Substances can be adsorbed efficiently. In particular, the existence of such a region having a high cationic group density enables the cationic group to function cooperatively even in treated water containing salts and in which ionic components compete for adsorption. It is thought that the ring causative substance can be adsorbed efficiently.

  Therefore, in a particularly preferred embodiment, the membrane fouling suppression material of the present invention is also in water to be treated containing 0.1% by weight or more, for example, 1% by weight or more of salts with respect to 100% by weight of water to be treated. Membrane fouling-causing substances can be efficiently adsorbed. Examples of the salts include alkali metal salts such as sodium chloride and potassium chloride; alkaline earth metal salts such as magnesium chloride, magnesium sulfate, calcium chloride, and calcium sulfate.

  The membrane fouling-suppressing material of the present invention has a high adsorptivity to a membrane fouling-causing substance, while the polymer compound (C) in which the compound (B) is bonded to the cationic group of the polymer compound (A). , Because it has a region in which the cationic group density is 8.5 to 15 mmol / g, it can be used for membrane fouling-causing substances such as biopolymers that could not be adsorbed and removed by conventional adsorbents with low cationic group density. It also has high adsorbability, and also has high elution properties that can easily elute the adsorbed membrane fouling-causing substances. For this reason, the membrane fouling suppression material of the present invention is excellent in reproducibility (reusability) and can be used repeatedly for a long period of time by performing a simple regeneration treatment. Replacement of the membrane fouling suppression material in water treatment It is possible to reduce the frequency and running cost.

  For adsorbents with high adsorptivity to hydrophilic polymers, if the total adsorption capacity of the adsorbent cannot be used even after exposure to treated water containing membrane fouling-causing substances such as biopolymers for a certain period of time There is. In this case, although the elution property to the substance that causes membrane fouling is actually low, the remaining adsorption capacity causes the membrane fouling cause even if it is exposed to the treated water for a certain time after the regeneration treatment. May exhibit high adsorptivity to substances. Therefore, in the present invention, in order to accurately evaluate the reproducibility of the membrane fouling suppression material, the membrane fouling suppression material adsorbing the membrane fouling-causing substance is immersed in the cleaning fluid and actually eluted in the cleaning fluid. The elution rate based on the concentration of the substance causing the membrane fouling is used as an index of the reproducibility of the membrane fouling suppression material.

Specifically, the elution rate is calculated by the following method.
The membrane fouling suppression material adsorbing sodium alginate in the biopolymer model water or model seawater is immersed in an aqueous sodium chloride solution (NaCl concentration: 25 mass%) at 25 ° C. and shaken for 1 hour. The supernatant after shaking is analyzed by LC-OCD, and is calculated from the sodium alginate concentration before and after being immersed in an aqueous sodium chloride solution according to the following formula.
Biopolymer elution rate = sodium alginate concentration in eluent / (concentration of sodium alginate in stock solution during adsorption test-sodium alginate concentration after adsorption) x 100 (%)
More specifically, it can be measured by the method described in Examples described later.

  In the membrane fouling suppressing material of the present invention, the biopolymer elution rate is preferably 5% or more, more preferably 7% or more, and particularly preferably 10% or more. When the elution rate is 5% or more, the membrane fouling-causing substance can be easily eluted, and high reusability can be realized.

  The membrane fouling-suppressing material of the present invention includes an ultrafiltration membrane (UF membrane), a microfiltration membrane (MF membrane), a nanofiltration membrane (NF membrane), and a reverse osmosis membrane (RO membrane) depending on the purpose of water treatment. It can use suitably for the water treatment which used suitably.

[Water treatment method and regeneration method]
The present invention also relates to a water treatment method and a regeneration method using the membrane fouling suppression material of the present invention. In the water treatment method of the present invention, the membrane fouling inhibitor of the present invention is brought into contact with the treated water containing the membrane fouling-causing substance, and the membrane fouling-causing substance contained in the treated water is used as the membrane fouling-suppressing material. A process of adsorbing (hereinafter, referred to as “adsorption process” in some cases).

  The water treatment method of the present invention can be used for various raw waters obtained in a natural environment or an artificial environment, for example, seawater, general river water, lake water, brackish water, soil elution water, irrigation water, It can be used for biologically treated water, biologically treated water in sewage treatment and human waste treatment facilities, advanced treated water such as tertiary treatment, and various factory effluents. It is preferable to perform a pretreatment for removing contaminants such as foreign matters having a relatively large size (for example, a particle diameter of about 1 μm to 2 mm) on the water to be treated before the adsorption step. The pretreatment can be performed by, for example, sand filtration treatment, rough filtration treatment using a water treatment membrane, coagulation sedimentation treatment, ozone treatment, adsorption treatment using an existing adsorbent or activated carbon, or the like.

  The water treatment method of the present invention contains membrane fouling-causing substances, particularly biopolymers such as polysaccharides and proteins that are considered to cause physically irreversible membrane fouling, and for example 0.1% by mass It can utilize suitably also with respect to the raw | natural water containing the above salts. Such raw water is, for example, seawater (sodium chloride concentration of 2 to 4% by mass), brackish water (sodium chloride concentration of 0.5 to 2% by mass), and accompanying water generated when mining oil and gas fields. Or water containing a higher concentration of sodium chloride obtained by treating them, or water containing various salts obtained from raw water in the natural environment. Good. Examples of the salts include, in addition to sodium chloride, alkali metal salts such as potassium chloride; alkaline earth metal salts such as magnesium chloride, magnesium sulfate, calcium chloride, and calcium sulfate. The concentration of the salt may be, for example, 0.1% by mass or more, 1% by mass or more, or 2% by mass or more, for example, a concentration of about 30% by mass.

  In the adsorption step, the method is not particularly limited as long as the treated water and the membrane fouling suppressing material can be brought into contact with each other. For example, as a batch type, the membrane fouling suppressing material is added to the treated water, Accordingly, the adsorption treatment may be carried out by stirring in a known manner; the adsorption treatment is carried out by allowing the water to be treated to flow through the column filled with the membrane fouling suppression material as a continuous type. Also good. Further, the adsorption step may be a single step or a multi-step.

  The amount of the membrane fouling suppression material used for the water to be treated can be appropriately selected according to the type of the water to be treated, the form of the membrane fouling suppression material, etc. The amount of the fouling suppressing material may be about 0.05 to 30 g, preferably about 0.1 to 10 g, per liter of water to be treated.

  When the membrane fouling suppression material is immersed in the water to be treated for adsorption treatment, the membrane fouling suppression material may be stirred by mechanical stirring, bubble stirring, or the like. When mechanical stirring is performed, the peripheral speed may be, for example, about 0.1 to 20 m / s, or about 0.3 to 15 m / s.

When the membrane treatment is performed continuously, the flow rate of the water to be treated with respect to the membrane fouling suppression material packed in the column is, for example, a superficial velocity that is a value obtained by dividing the treatment water flow rate by the membrane fouling suppression material volume. 0.5 to 200 h ⁻¹ may be used, and preferably about ¹ to 150 h ⁻¹ may be used.

  The temperature of the to-be-processed water in an adsorption | suction process is not specifically limited, For example, it may be room temperature vicinity, for example, 0 degreeC or more and less than 40, Preferably it may be 5-38 degreeC, More preferably, it may be 10-35 degreeC.

  By performing adsorption treatment using the membrane fouling suppression material of the present invention, membrane fouling-causing substances in the water to be treated can be efficiently adsorbed. In particular, the adsorption of the biopolymer as described above can be performed efficiently. In the adsorption process of the water treatment method of the present invention, the biopolymer adsorption rate from the water to be treated may be, for example, 15% or more, preferably 20% or more, more preferably 25% or more. . In addition, an adsorption rate shows the value measured by the method described in the Example mentioned later. When the adsorption rate is equal to or higher than the above value, when the treated water after the adsorption treatment is supplied to the membrane filtration step which is a subsequent step, the effect of suppressing membrane contamination is sufficiently obtained.

  In the water treatment method of the present invention, the water to be treated after being brought into contact with the membrane fouling suppressing material is subjected to ultrafiltration membrane (UF membrane), microfiltration membrane (MF membrane), depending on the purpose of water treatment, It includes a step of membrane filtration with a membrane such as a nanofiltration membrane (NF membrane) and a reverse osmosis (RO) membrane (hereinafter sometimes referred to as “membrane filtration step”). The membrane filtration step may be a single step or multiple steps. About the kind of film | membrane of a membrane filtration process, the same film | membrane may be used and a different kind of film | membrane may be combined. For example, when a plurality of types of membranes are combined, water to be treated supplied by a microfiltration membrane or an ultrafiltration membrane may be subjected to membrane filtration treatment, and then further membrane filtration treatment may be performed using a nanofiltration membrane or a reverse osmosis membrane. . Membrane filtration may be combined to purify water according to the application.

  The membrane material of the filtration membrane in the membrane filtration step is not particularly limited, and a known material can be used. For example, examples of membrane materials for ultrafiltration membranes and microfiltration membranes include cellulose acetate, polyacrylonitrile, polyethylene, polyethersulfone, polysulfone, polypropylene, polyvinylidene fluoride, and ceramic. Examples of the membrane material for the nanofiltration membrane include polyamide-based, polypiperazine amide-based, polyester amide-based, and water-soluble vinyl polymer crosslinked. Examples of the membrane material for the reverse osmosis membrane include cellulose acetate and polyamide.

  The form of the membrane is not particularly limited, and may be any shape such as a flat membrane, a tubular membrane, and a hollow fiber membrane. The film thickness may be, for example, in the range of 10 μm to 1 mm. In the case of a hollow fiber membrane, the inner diameter may be about 0.2 to 2 mm and the outer diameter may be about 0.4 to 5 mm. The filtration membrane may have a fine porous structure such as a network structure, a honeycomb structure, or a fine gap structure.

  These filtration membranes may be modularized. For example, in the case of a flat membrane, a spiral type, a pleat type, a plate-and-frame type, or a disc type in which discs are stacked may be used. It may be a hollow fiber membrane type bundled in an I shape and stored in a container.

The filtration flow rate can be appropriately set according to the type of water to be treated, the type of filtration membrane, and the like. For example, when filtration is performed by a cross flow method, the filtration flow rate is from flux 0.5 to 5.0. ^(m 3 / ^{m 2} / day) at a even better, preferably may be Flux1.0~4.0 ^(m 3 / m ² / day).

  In addition, since the membrane fouling suppression material of the present invention functions effectively even if the water to be treated contains salts, the water to be treated containing salts is adsorbed with the membrane fouling suppression material of the present invention. Alternatively, it may be supplied to a membrane treatment using a reverse osmosis membrane or the like to remove salts in the water to be treated.

In the water treatment method of the present invention, the membrane fouling-causing substances in the water to be treated before the membrane filtration step, particularly biopolymers such as polysaccharides and proteins, are reduced by the adsorption step using the membrane fouling inhibitor of the present invention. Can be made. As a result, it prevents membrane fouling (especially physically irreversible membrane fouling) from occurring in the membrane during the membrane filtration process, and prevents the filtration membrane from declining due to clogging of the membrane. I can do it.
Furthermore, since the amount of the membrane fouling-causing substance in the water to be treated before the membrane filtration step can be reduced, it is possible to suppress deterioration of the filtration membrane due to membrane fouling. Thereby, the service life of the filtration membrane can be extended. In addition, the frequency of cleaning the filtration membrane and the amount of cleaning chemicals used can be reduced.

  The water treatment method of the present invention can be combined with an existing water treatment method as necessary, as long as the effects of the present invention are not impaired. Examples of the existing water treatment method include sand filtration treatment, coarse filtration treatment, coagulation sedimentation treatment, ozone treatment, adsorption treatment using an existing membrane fouling inhibitor or activated carbon, biological treatment, and the like. You may perform these processes individually or in combination of 2 or more types. These water treatments may be appropriately performed before the adsorption treatment and / or after the adsorption treatment.

  The membrane fouling suppression material that has adsorbed the membrane fouling-causing substance in the adsorption step is separated by a known filtering means as necessary, and subjected to a regeneration treatment according to a regeneration method described later, for example, to thereby provide the membrane fouling of the present invention. The ring-suppressing material can be used again in the adsorption process. On the other hand, the to-be-processed water solid-liquid-separated by filtering a membrane fouling suppression material may be membrane-filtered in a membrane filtration process as needed.

  The method for regenerating a membrane fouling suppression material of the present invention includes a step of contacting the membrane fouling suppression material after being brought into contact with the water to be treated with a cleaning fluid (hereinafter sometimes referred to as “regeneration step”). . The regeneration method of the present invention may be independent as the regeneration step, or may be performed in combination with the water treatment method of the present invention. In the regeneration method of the present invention, for example, the membrane fouling inhibitor adsorbing the membrane fouling causative agent is brought into contact with an appropriate cleaning fluid, and the membrane fouling causative agent adsorbed on the membrane fouling inhibitor is eluted. The membrane fouling suppressing material can be regenerated.

  The cleaning fluid may be, for example, a medium composed of a liquid containing water as a main component (for example, 60% by mass or more). For example, purified water (water that has been cleaned by an appropriate treatment operation on raw water). , For example, tap water), pure water (RO water, deionized water, distilled water, etc.), various raw waters described above in the adsorption process or related water thereof may be used, and the chemicals may be used as these water (purified water, pure water, An aqueous solution added to raw water or related water) may be used. As the drug, for example, various acidic substances and salts thereof, various alkaline substances and the like can be used.

  As the raw water, various raw waters described above in the adsorption step may be used. When performing in combination with the water treatment method of the present invention, raw water used in the adsorption process may be partly used in the regeneration process, and raw water different from the raw water used in the adsorption process is used as a regeneration medium. Also good. Examples of raw water-related water include non-permeate water (for example, concentrated water obtained after RO membrane treatment) generated when various membrane treatments of raw water, treated water obtained after the raw water adsorption step, and the like.

  For example, as an acidic substance, various inorganic acids (for example, hydrochloric acid, hypochlorous acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, carbonic acid, phosphoric acid, hypobromous acid, hypoiodous acid, etc.), various organic acids ( For example, formic acid, acetic acid, propionic acid, butyric acid, stearic acid, citric acid, oxalic acid, lactic acid, maleic acid, tartaric acid, fumaric acid, malonic acid, succinic acid, malic acid, adipic acid, oleic acid, linoleic acid, linolenic acid And benzoic acid). The acidic substance salt may be, for example, an alkali metal salt such as a sodium salt or a potassium salt, or an organic salt such as an ammonium salt. Examples of the alkaline substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and ammonia water. These drugs may be used alone or in combination of two or more. The concentration of the drug in the cleaning fluid may be, for example, 0.1 to 60% by mass, preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, as a solute ratio with respect to water. It may be.

  The cleaning fluid is not limited to a liquid, and may be a gas such as air or heated steam, for example. That is, the cleaning fluid only needs to be a fluid that can clean the membrane fouling suppressing material of the present invention and elute the fouling-causing substance adhering to the surface. Further, the contact with the cleaning fluid in the regeneration step may be one stage or multiple stages. In the case of multiple stages, a plurality of types of cleaning fluids may be used separately.

  In the regeneration method of the present invention, it is preferable to use a metal ion-containing aqueous solution as the cleaning fluid. The metal ion contained in the metal ion-containing aqueous solution is not particularly limited as long as it can desorb a membrane fouling-causing substance, but typically an alkali metal such as lithium ion, sodium ion, or potassium ion. The aqueous solution containing metal ions may be, for example, an aqueous solution containing an alkali metal hydroxide, an alkali metal organic acid salt, or an alkali metal inorganic acid salt. As the alkali metal hydroxide, organic acid and inorganic acid, various substances used as the above-mentioned chemicals may be used. Preferable metal ion-containing aqueous solutions include alkali metal salt aqueous solutions of inorganic acids, and examples include sodium chloride aqueous solution, potassium chloride aqueous solution, lithium chloride aqueous solution, sodium carbonate aqueous solution, potassium carbonate aqueous solution, and lithium carbonate aqueous solution. The cleaning fluid may be a metal ion-containing aqueous solution containing the same type of metal ions as the salts present in the water to be treated.

  The concentration of the metal ion-containing aqueous solution may be, for example, 0.1 to 60% by weight, preferably 0.1 to 40% by weight, more preferably 0.5 to 30% by weight, as the ratio of the solute to water. There may be. For example, the aqueous medium as the cleaning fluid may have a sodium chloride concentration of 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more. Moreover, sodium chloride concentration may be 27 mass% or less, for example, and may be 20 mass% or less. In addition to sodium chloride, the cleaning fluid may contain alkali metal salts such as potassium chloride; alkaline earth metal salts such as magnesium chloride, magnesium sulfate, calcium chloride, and calcium sulfate.

  The pH of the cleaning fluid may be, for example, 5 to 14, preferably 5.5 to 12, more preferably 6 to 11. When the pH is in the neutral region (pH 6 to 8), it is preferable for disposal of the cleaning fluid after the regeneration treatment, and when the pH is weakly basic (pH 8 to 11), the regeneration performance is good.

  The temperature of the cleaning fluid used in the regeneration step is not particularly limited as long as the membrane fouling suppressing material can be regenerated. Depending on the type of cleaning fluid, it may be near room temperature or at the same temperature as the water to be treated. You may heat-process as needed. The temperature of the cleaning fluid in the present invention may be, for example, 0 to 90 ° C, preferably 10 to 80 ° C, more preferably 20 to 70 ° C.

  The contact method in the regeneration step is not particularly limited as long as the cleaning fluid and the membrane fouling suppression material can be brought into contact with each other. For example, as a batch type, the membrane fouling suppression material is added to the cleaning fluid, and if necessary The regeneration process may be performed by stirring by a known method; or the regeneration process may be performed by passing a cleaning fluid through a column filled with a membrane fouling suppression material as a continuous type. Further, the regeneration step may be a single step or multiple steps.

  The amount of the cleaning fluid used for the membrane fouling suppression material can be appropriately selected according to the type of the cleaning fluid, the form of the membrane fouling suppression material, the type of the regeneration process (batch type or continuous type), and the like. . In addition, when the membrane fouling suppression material is immersed in the cleaning fluid for the regeneration treatment, the membrane fouling suppression material may be stirred by mechanical stirring or bubble stirring. When performing mechanical stirring, for example, the peripheral speed may be about 0.1 to 20 m / s, or about 0.3 to 18 m / s.

  The treatment time in the regeneration step is not particularly limited as long as the membrane fouling suppressing material can be regenerated, and can be appropriately set according to the state of the membrane fouling suppressing material, the type and amount of the cleaning fluid, and the like. The reproduction processing time may be, for example, 30 seconds to 24 hours, or 1 minute to 3 hours.

  The membrane fouling suppression material regenerated by the regenerating step can be separated by a known filtering means if necessary, and then used again in the water treatment adsorption step.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples. In the examples and comparative examples, “%” and “parts” represent “% by mass” and “parts by mass”, respectively, unless otherwise specified.

  Analysis of physical properties and characteristics in Examples and Comparative Examples was performed according to the following methods.

(Calculation of cationic group density of polymer compound (A))
The cationic group density of the polymer compound (A) is the number of cationic groups per molecular weight (M) (g / mol) of the repeating unit constituting the polymer compound (A) from the skeleton structure of the polymer compound (A). Based on (N), it calculated according to the following formula.
Cationic group density of polymer compound (A) = (N / M) × 1000 (mmol / g)

(Calculation of cationic group density of polymer compound (C))
Cationic-group density of the polymer compound (A) X A _g to Compound (B) the X _{B g} added so polymer compound formed by (C) was calculated according to the following equation.
Cationic group density of polymer compound (C) = Cationic group density of polymer compound (A) × X _A / (X _A + X _B )

(Adsorption rate of biopolymer)
Adsorption evaluation of sodium alginate (manufactured by Wako Pure Chemical Industries, Ltd., model number: 199-09961) was carried out as a biopolymer model substance. 100 g of model fresh water (concentration of sodium alginate: 4) was obtained from 0.5 g of the membrane fouling suppression material obtained in each production example (the mass in the state dried in a vacuum dryer for 12 hours and the same in the following description). 0.0 mg-C / L) or model seawater (concentration of sodium alginate: 4.0 mg-C / L, NaCl: 3.5%), and shaken with a shaker at a temperature of 25 ° C. 20 ml of supernatant liquid before and after shaking for 18 hours was evaluated by liquid chromatography-organic carbon detector (LC-OCD), and the adsorption rate of the biopolymer by the membrane fouling inhibitor was evaluated as follows.
Biopolymer adsorption rate = (sodium alginate concentration before adsorption evaluation−sodium alginate concentration after adsorption evaluation) / sodium alginate concentration before adsorption evaluation × 100 (%)

(Biopolymer elution rate (regeneration of membrane fouling suppression material))
After adsorbing sodium alginate, it was filtered off, immersed in 100 mL of 25 mass% NaCl aqueous solution at 25 ° C., and shaken for 1 hour. 20 mL of the supernatant after shaking was analyzed by LC-OCD, and the elution rate of sodium alginate was calculated by the following formula.
Biopolymer elution rate = sodium alginate concentration in eluent / (concentration of sodium alginate in stock solution during adsorption test-sodium alginate concentration after adsorption) x 100 (%)

(Evaluation of swelling degree)
After 1 g of membrane fouling suppression material is immersed in water at 25 ° C. for 12 hours, the membrane fouling suppression material is subjected to centrifugal dehydration and weighed (A), then dried at 105 ° C. for 4 hours and weighed (B). The degree of swelling was determined from the following formula.
Swelling degree = [(A−B) / (B)] × 100 (%)

(Volume change rate of membrane fouling suppression material)
Membrane fouling suppression material 5.0 g was immersed in water at 25 ° C. for 12 hours, and then the membrane fouling suppression was performed so that the height was 5 cm in a 15.4 mm inner diameter chromatographic column tube (manufactured by Shibata Kagaku) Filled with material. After passing 1N HCl through 3BV, ion-exchanged water was passed through 3BV. After stopping the flow of liquid, the volume change rate of the membrane fouling suppression material before and after the immersion when the entire chromatographic column was immersed in a water bath heated to 80 ° C. for 1 hour was calculated according to the following formula. Here, BV (bed volume) is a numerical value representing the liquid passing magnification when the product of the column cross-sectional area and the resin filling height is 1 BV.
Volume change rate (times) = height of membrane fouling suppression material after heating at 80 ° C (cm) / 5cm
A case where the volume change rate was 1.2 times or less was evaluated as A, and a case where the volume change rate exceeded 1.2 times was evaluated as B.

(Elution rate at the 5th cycle)
The elution rate at the 5th cycle when the adsorption in the model fresh water described above and the elution with the 25 mass% NaCl aqueous solution were repeated 5 cycles was calculated as follows.
Elution rate of biopolymer in the 5th cycle = sodium alginate concentration in the eluent in the 5th cycle / (concentration of sodium alginate in the stock solution during the 5th cycle adsorption test−sodium alginate concentration after the 5th cycle adsorption) × 100 (%)

Each component used in the examples and comparative examples is as follows.
Polymer compound (A)
Polyethyleneimine: “Epomin SP-200” (manufactured by Nippon Shokubai Co., Ltd.), cationic group density 23.2 (mmol / g), weight average molecular weight 100,000
Polyallylamine: “PAA-15C” (manufactured by Nitto Bo Medical Co., Ltd.), cationic group density 17.5 (mmol / g), weight average molecular weight 150,000
Chitosan: “Kimikachitosan F” (manufactured by Kimika Co., Ltd.), cationic group density 6.2 (mmol / g)
Compound (B)
Ethylene glycol diglycidyl ether: “Denacol EX-810” (manufactured by Nagase ChemteX Corporation)
Glycidol (manufactured by Sigma-Aldrich)
Isopropyl glycidyl ether (manufactured by Sigma-Aldrich)
Hydrophilic polymer (D)
Ethylene-vinyl alcohol copolymer (D-1): “E-105” (manufactured by Kuraray Co., Ltd.), solubility parameter δ = 28
Ethylene-vinyl alcohol copolymer (D-2): “G-156” (manufactured by Kuraray Co., Ltd.), solubility parameter δ = 25
Ethylene-vinyl alcohol copolymer (D-3): “F-101” (manufactured by Kuraray Co., Ltd.), solubility parameter δ = 28

[Production Example 1] (Membrane fouling suppression material 1)
63 parts by mass of polyethyleneimine was dissolved in ion-exchanged water to obtain a 30% solution. To the place sufficiently cooled with ice water, 37 parts by mass of ethylene glycol diglycidyl ether was added, and the temperature was raised to room temperature with sufficient stirring. After 24 hours, the obtained gelled product was pulverized, and the obtained pulverized product was washed with hot water at 80 ° C. to obtain the target film fouling suppressing material 1. The cationic group density (amino group density) of the obtained membrane fouling suppression material 1 was calculated. The results are shown in Table 1.

[Production Example 2] (Membrane fouling suppression material 2)
46 parts by mass of polyethyleneimine was dissolved in ion-exchanged water to obtain a 30% solution. To the place sufficiently cooled with ice water, 54 parts by mass of ethylene glycol diglycidyl ether was added, and the temperature was raised to room temperature with sufficient stirring. After 24 hours, the obtained gelled product was pulverized, and the obtained pulverized product was washed with a large amount of hot water at 80 ° C. to obtain the target film fouling suppressing material 2. The cationic group density (amino group density) of the obtained membrane fouling suppression material 2 was calculated. The results are shown in Table 1.

[Production Example 3] (Membrane fouling suppression material 3)
After dissolving 51 parts by mass of polyethyleneimine in ion exchange water to make a 30% solution, the temperature was raised to 80 ° C. There, 49 mass parts of glycidol was dripped, and it was made to react for 2 hours. After allowing to cool to room temperature, the reaction solution was concentrated with an evaporator to obtain glycidol-added polyethyleneimine. The cationic group density of the obtained glycidol-added polyethyleneimine was calculated. Next, 25 parts by mass of the obtained glycidol-added polyethyleneimine and 75 parts by mass of a hydrophilic polymer, ethylene-vinyl alcohol copolymer (D-1), were melt-kneaded at 180 ° C. for 5 minutes in a lab plast mill. The obtained kneaded product was cooled and then pulverized to obtain particles. Further, this particle was subjected to a crosslinking treatment with a solution of ethylene glycol diglycidyl ether 2% at 25 ° C. for 1 hour, filtered and then stirred and washed with a large amount of hot water at 80 ° C. to obtain a membrane fouling suppressing material 3. It was.

[Production Example 4] (Film Fouling Inhibiting Material 4)
60 parts by mass of polyallylamine was dissolved in ion-exchanged water to obtain a 30% solution. 40 mass parts of ethylene glycol diglycidyl ether was added to the place cooled enough with ice water, and it heated up to room temperature, fully stirring. After 24 hours, the gelled product obtained was pulverized, and the pulverized product was washed with a large amount of hot water at 80 ° C. to obtain the target film fouling suppressing material 4. The cationic group density (amino group density) of the obtained membrane fouling suppression material 4 was calculated. The results are shown in Table 1.

[Production Example 5] (Film Fouling Inhibiting Material 5)
After dissolving 48 parts by mass of polyethyleneimine in isopropanol to obtain a 30% solution, the temperature was raised to 80 ° C. There, 52 mass parts of isopropyl glycidyl ether (IPGE) was dripped, and it was made to react for 2 hours. After allowing to cool to room temperature, the reaction solution was concentrated with an evaporator to obtain IPGE-added polyethyleneimine. The cationic group density (amino group density) of the obtained IPGE-added polyethyleneimine was calculated. Next, 30 parts by mass of the obtained IPGE-added polyethyleneimine and 70 parts by mass of a hydrophilic polymer, ethylene-vinyl alcohol copolymer (D-2), were melt-kneaded at 180 ° C. for 5 minutes in a lab plast mill. The obtained kneaded product was cooled and then pulverized to obtain particles. Further, this particle was subjected to a crosslinking treatment for 1 hour with a solution of ethylene glycol diglycidyl ether 2% at 25 ° C., and after filtration, the membrane fouling inhibitor 5 was obtained by stirring and washing with a large amount of hot water at 80 ° C. It was.

[Production Example 6] (Film Fouling Inhibiting Material 6)
After dissolving 38 parts by mass of polyethyleneimine in ion exchange water to make a 30% solution, the temperature was raised to 80 ° C. There, 62 mass parts of glycidol was dripped, and it was made to react for 2 hours. After allowing to cool to room temperature, the reaction solution was concentrated with an evaporator to obtain glycidol-added polyethyleneimine. The cationic group density (amino group density) of the obtained glycidol-added polyethyleneimine was calculated. Next, 20 parts by mass of the obtained glycidol-added polyethyleneimine and 80 parts by mass of a hydrophilic polymer, ethylene-vinyl alcohol copolymer (D-3), were melt-kneaded at 180 ° C. for 5 minutes in a lab plast mill. The obtained kneaded product was cooled and then pulverized to obtain particles. Further, this particle was subjected to a crosslinking treatment with a solution of ethylene glycol diglycidyl ether 2% at 25 ° C. for 1 hour, and after filtration, the membrane fouling inhibitor 6 was obtained by stirring and washing with a large amount of hot water at 80 ° C. It was.

[Production Example 7] (Membrane fouling suppression material 7)
After dissolving 69 parts by mass of polyethyleneimine in ion exchange water to make a 30% solution, the temperature was raised to 80 ° C. There, 31 mass parts of glycidol was dripped, and it was made to react for 2 hours. After allowing to cool to room temperature, the reaction solution was concentrated with an evaporator to obtain glycidol-added polyethyleneimine. The cationic group density of the obtained glycidol-added polyethyleneimine was calculated. Next, 25 parts by mass of the obtained glycidol-added polyethyleneimine and 75 parts by mass of a hydrophilic polymer, ethylene-vinyl alcohol copolymer (D-1), were melt-kneaded at 180 ° C. for 5 minutes in a lab plast mill. The obtained kneaded product was cooled and then pulverized to obtain particles. Further, this particle was subjected to a crosslinking treatment with a solution of ethylene glycol diglycidyl ether 2% at 25 ° C. for 1 hour, filtered and then stirred and washed with a large amount of hot water at 80 ° C. to obtain a membrane fouling suppressing material 7. It was.

[Production Example 8] (Membrane fouling suppression material 8)
20 parts by mass of polyethyleneimine was dissolved in ion-exchanged water to obtain a 30% solution. 80 parts by mass of ethylene glycol diglycidyl ether was added to the place sufficiently cooled with ice water, and the temperature was raised to room temperature with sufficient stirring. After 24 hours, the obtained gelled product was pulverized, and the obtained pulverized product was washed with a large amount of hot water at 80 ° C. to obtain the target film fouling suppressing material 8. The cationic group density (amino group density) of the obtained membrane fouling suppression material 8 was calculated. The results are shown in Table 1.

[Production Example 9] (Membrane fouling suppression material 9)
30 parts by mass of polyallylamine was dissolved in ion-exchanged water to obtain a 30% solution. 70 mass parts of ethylene glycol diglycidyl ether was added to the place cooled enough with ice water, and it heated up to room temperature, fully stirring. After 24 hours, the obtained gelled product was pulverized, and the obtained pulverized product was washed with a large amount of hot water at 80 ° C. to obtain the target film fouling suppressing material 9. The cationic group density (amino group density) of the obtained membrane fouling suppression material 9 was calculated. The results are shown in Table 1.

[Production Example 10] (Membrane fouling suppression material 10)
25 parts by mass of polyethyleneimine and 75 parts by mass of ethylene-vinyl alcohol copolymer (D-1), which is a hydrophilic polymer, were melt-kneaded at 180 ° C. for 5 minutes in a lab plast mill, and the resulting kneaded product was After cooling, pulverization was performed to obtain particles. Further, the particles were subjected to a crosslinking treatment with a solution of ethylene glycol diglycidyl ether 2% at 25 ° C. for 1 hour, and after filtration, the membrane fouling inhibitor 10 was obtained by stirring and washing with a large amount of hot water at 80 ° C. It was.

[Production Example 11] (Membrane fouling suppression material 11)
The membrane fouling suppression material 11 was obtained by immersing the chitosan crosslinked particles in a large amount of 80 ° C. hot water and washing with stirring. The cationic group density (amino group density) of the obtained membrane fouling suppression material 11 was calculated. The results are shown in Table 1.

[Examples 1-6 and Comparative Examples 1-5]
Using the film fouling suppression material shown in Table 1, the various physical properties described above were evaluated. The results are shown in Table 2. The elution rate at the fifth cycle was evaluated for Example 3 and Comparative Example 4.

  Table 1 shows the compositions of the membrane fouling suppressing materials prepared in Production Examples 1 to 11. In addition, the quantity of the high molecular compound (A) and the compound (B) in Table 1 shows the quantity with respect to 100 mass parts of total amounts of a high molecular compound (A) and a compound (B), and high molecular compound (C) and group The amount of the material indicates an amount with respect to 100 parts by mass of the total amount of the polymer compound (C) and the base material. Moreover, the evaluation results of the adsorption rate, elution rate, swelling degree, volume change rate, and elution rate of the fifth cycle of each membrane fouling suppression material in Examples 1-6 and Comparative Examples 1-5 in fresh water and seawater are shown. It is shown in 2.

As shown in Table 2, the polymer compound based on the cationic group-containing polymer compound (A) and the compound (B) containing a functional group having reactivity with the cationic group of the polymer compound (A). The membrane fouling-suppressing material of the present invention containing (C) and containing a region where the cationic group density of the polymer compound (C) is 8.5 to 15 mmol / g has a high adsorption rate in model fresh water and model sea water. It was confirmed that the elution rate was 10% or more (Examples 1 to 6). On the other hand, it does not include a region having a cationic group density of 8.5 to 15 mmol / g and has a high adsorption rate when it includes a region having a cationic group density higher than 15 mmol / g. It was confirmed that the reproducibility was inferior (Comparative Examples 1 and 4). In addition, when only the region where the cationic group density is lower than 8.5 mmol / g is included, although the elution rate is high, the adsorption rate in the model seawater is 0%, and especially in the treated water containing salts. Inferiority was confirmed (Comparative Examples 2, 3 and 5).
Similarly, as shown in Table 2, the membrane fouling-suppressing material of the present invention containing a region having a cationic group density of 8.5 to 15 mmol / g can be used even after 5 cycles of adsorption and elution are repeated. It has been suggested that a good elution rate is maintained and repeated use is possible (Example 3). On the other hand, those containing a region where the cationic group density was higher than 15 mmol / g still had an elution rate of less than 5%, and were confirmed to be unsuitable for repeated use (Comparative Example 4).

Claims (17)

  A polymer compound (C) based on a cationic group-containing polymer compound (A) and a compound (B) containing at least one functional group having reactivity with the cationic group of the polymer compound (A). A membrane fouling suppression material having a region where the cationic group density is 8.5 to 15 mmol / g.   The membrane fau according to claim 1, wherein the cationic group of the polymer compound (A) is at least one selected from the group consisting of an amino group, an imino group, an amidine group, a guanidino group, an imidazole group, and a pyridyl group. Ring suppression material.   The polymer compound (A) is at least one selected from the group consisting of polyethyleneimine, polyallylamine, polyvinylamine, polyamidine, polyguanidine, polyamino acid, polypyridine, and salts thereof. Film fouling suppression material.   The functional group of the compound (B) is epoxy group, carboxyl group, halogen group, acid anhydride group, acid halide group, formyl group, N-chloroformyl group, chloroformate group, isocyanate group, aldehyde group, azetidine group. The film fouling suppressing material according to claim 1, which is at least one selected from the group consisting of carbodiimide groups.   The film fouling suppressing material according to any one of claims 1 to 4, wherein the compound (B) is a compound having at least one epoxy group.   The membrane fouling suppression material according to any one of claims 1 to 5, further comprising a hydrophilic polymer compound (D).   The membrane fouling suppression material according to claim 6, wherein the polymer compound (C) is dispersed in the hydrophilic polymer compound (D).   The film fouling suppression material according to claim 6 or 7, wherein the hydrophilic polymer compound (D) is an ethylene-vinyl alcohol copolymer.   The film | membrane fouling suppression material in any one of Claims 1-8 whose swelling degree in 25 degreeC water is 20 to 500%.   The membrane fouling suppression material according to any one of claims 1 to 9, which has biopolymer adsorption ability.   Claims for use in water treatment with at least one membrane selected from the group consisting of ultrafiltration (UF) membranes, microfiltration (MF) membranes, nanofiltration (NF) membranes and reverse osmosis (RO) membranes The film | membrane fouling suppression material in any one of 1-10.   Water that includes a step of bringing the water to be treated into contact with the membrane fouling suppressing material according to any one of claims 1 to 11 and adsorbing the membrane fouling-causing substance contained in the water to be treated to the membrane fouling suppressing material. Processing method.   The water treatment method according to claim 12, wherein the water to be treated contains 0.1% by mass or more of salts.   A method for regenerating a membrane fouling suppression material, comprising the step of bringing the membrane fouling suppression material according to any one of claims 1 to 11 into contact with water to be treated and then bringing it into contact with a cleaning fluid.   The method for regenerating a membrane fouling suppression material according to claim 14, wherein the cleaning fluid is a metal ion-containing aqueous solution.   The treated water after contacting with the membrane fouling suppression material is selected from the group consisting of ultrafiltration (UF) membrane, microfiltration (MF) membrane, nanofiltration (NF) membrane and reverse osmosis (RO) membrane The water treatment method according to claim 12, comprising a step of membrane filtration with at least one kind of membrane.   The water treatment method according to claim 12 or 16, comprising the regeneration method according to claim 14 or 15.