WO2014098059A1 - Method for hydrophilizing reverse osmosis membrane - Google Patents

Method for hydrophilizing reverse osmosis membrane Download PDF

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Publication number
WO2014098059A1
WO2014098059A1 PCT/JP2013/083697 JP2013083697W WO2014098059A1 WO 2014098059 A1 WO2014098059 A1 WO 2014098059A1 JP 2013083697 W JP2013083697 W JP 2013083697W WO 2014098059 A1 WO2014098059 A1 WO 2014098059A1
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polyvinyl alcohol
reverse osmosis
modified polyvinyl
osmosis membrane
membrane
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PCT/JP2013/083697
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French (fr)
Japanese (ja)
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邦洋 早川
孝博 川勝
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栗田工業株式会社
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Priority to AU2013365015A priority Critical patent/AU2013365015B2/en
Priority to CN201380067336.3A priority patent/CN104994937B/en
Publication of WO2014098059A1 publication Critical patent/WO2014098059A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/08—Prevention of membrane fouling or of concentration polarisation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0081—After-treatment of organic or inorganic membranes
    • B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/56—Polyamides, e.g. polyester-amides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/02—Hydrophilization
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/36—Hydrophilic membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration

Definitions

  • the present invention relates to a hydrophilic treatment method for a reverse osmosis (RO) membrane using a modified polyvinyl alcohol having a polyalkylene oxide chain, an RO membrane subjected to a hydrophilic treatment by this method, and a hydrophilic treatment agent for the RO membrane. .
  • RO reverse osmosis
  • RO membranes have been widely put into practical use in various water treatment fields for the purpose of desalination and concentration, taking advantage of their characteristics.
  • PVA polyvinyl alcohol
  • the RO membrane When the PVA is brought into contact with the RO membrane, the RO membrane becomes hydrophilic and the permeation performance of the RO membrane is maintained. That is, since PVA has many OH groups and high hydrophilicity, by attaching PVA to the RO membrane, the RO membrane is hydrophilized, and adsorption of proteins and the like to the RO membrane is suppressed, thereby improving the stain resistance. As a result, the transmission performance can be maintained.
  • the present invention solves the above-mentioned conventional problems, can maintain a hydrophilization effect for a long period of time, and can maintain a relatively high flux, and a hydrophilization treatment method and hydrophilization treatment therefor It is an object to provide an agent.
  • the present inventors have been conventionally used by using modified polyvinyl alcohol having a polyalkylene oxide chain, based on the knowledge that polyethylene glycol has high adsorptivity with RO membranes. It has been found that the adsorptivity to the RO membrane is improved as compared with PVA, and therefore, the contamination resistance can be maintained for a long time as compared with PVA.
  • the present invention has been achieved on the basis of such knowledge, and the gist thereof is as follows.
  • a method of hydrophilizing a reverse osmosis membrane comprising bringing a modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the reverse osmosis membrane.
  • a container having a liquid inlet and a liquid outlet is partitioned by the reverse osmosis membrane, and the aqueous solution containing the modified polyvinyl alcohol introduced from the liquid inlet is permeated through the reverse osmosis membrane to allow the liquid outlet.
  • the method for hydrophilizing a reverse osmosis membrane according to any one of [1] to [3], wherein the modified polyvinyl alcohol is brought into contact with the reverse osmosis membrane by draining it from water and passing it through.
  • a hydrophilic treatment agent for a reverse osmosis membrane containing a modified polyvinyl alcohol having a polyalkylene oxide chain containing a modified polyvinyl alcohol having a polyalkylene oxide chain.
  • the present invention by treating the RO membrane with a modified polyvinyl alcohol having a polyalkylene oxide chain, it is possible to impart hydrophilicity and maintain the hydrophilic effect over a long period of time. And if it is a modified polyvinyl alcohol which has a polyalkylene oxide chain, the fall of the flux of RO membrane by a hydrophilic treatment can be suppressed, and the preparation of the aqueous solution is easy compared with conventional PVA. .
  • RO membrane to which the present invention is applied examples include a polyamide-based RO membrane having an aromatic polyamide as a dense layer, but a polyamide-based nanofiltration membrane may also be used. That is, the RO membrane to be treated in the present invention is a broad RO membrane containing a nanofiltration membrane. Also, it can be applied to new films, used films, and deteriorated films without problems.
  • the structure of the RO membrane is not particularly limited, and a flat membrane module, a spiral type module, a hollow fiber module, or the like can be used.
  • the modified polyvinyl alcohol having a polyalkylene oxide chain used for the hydrophilic treatment of the RO membrane is composed of a vinyl alcohol unit and a unit to which a polyalkylene oxide group is bonded, and optionally further includes a vinyl acetate unit.
  • a polyalkylene oxide group having 2 to 4 carbon atoms of an alkylene group such as a polyethylene oxide group, a polypropylene oxide group, or a polybutylene oxide group is preferable.
  • the oxide group is most preferred.
  • the number of repeating alkylene oxide groups in the polyalkylene oxide group is preferably 2 to 300, particularly 4 to 150. If the number of repetitions is too small, the effect of improving the adsorptivity to the RO membrane by the polyalkylene oxide group cannot be sufficiently obtained, and if it is too large, the decrease in the flux of the RO membrane due to the hydrophilization treatment becomes large.
  • the molar fraction of the unit to which the polyalkylene oxide group is bonded in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 0.1 to 50 mol%, more preferably 0.3 to 40 mol%, and 0 Particularly preferred is 5 to 30 mol%.
  • the present invention such as improvement of the adsorptivity to the RO membrane and suppression of flux reduction by introducing the polyalkylene oxide chain into the polyvinyl alcohol. If the amount is too large, the molar fraction of the vinyl alcohol unit is relatively small, and the hydrophilization effect tends to be reduced.
  • the molar fraction of the vinyl alcohol unit in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 50 to 99.9 mol%, more preferably 60 to 99.7 mol%, and particularly preferably 70 to 99.5 mol%. preferable. If the molar fraction of the vinyl alcohol unit is less than this range, the number of hydroxyl groups in the modified polyvinyl alcohol having a polyalkylene oxide chain is reduced, and sufficient hydrophilization effect and flux stability cannot be obtained. If the amount is too large, the molar fraction of the unit to which the polyalkylene oxide group is bonded is relatively small, and the above-described effect due to the introduction of the polyalkylene oxide chain into polyvinyl alcohol may not be sufficiently obtained.
  • the molar fraction of vinyl acetate units in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, and particularly preferably 0 to 5 mol%.
  • Saponification degree is an index indicating the properties of polyvinyl alcohol.
  • the saponification degree is obtained by dividing the molar fraction of the vinyl alcohol unit by the sum of the molar fractions of the vinyl alcohol unit and the vinyl acetate unit.
  • the degree of saponification of the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 80% or more, particularly 85% or more, particularly 95% or more.
  • the degree of saponification is less than 80%, the number of hydroxyl groups is small, the hydrophilicity is lowered, and sufficient hydrophilization treatment effect and flux stability tend not to be obtained.
  • the polymerization degree of the modified polyvinyl alcohol having a polyalkylene oxide chain that is, the total number of units is not particularly limited, but is preferably 20 to 20,000. If the degree of polymerization is too low, the adsorptivity to the membrane is deteriorated, and if the degree of polymerization is too large, the RO membrane flux decreases due to the hydrophilic treatment, which is not preferable.
  • Such a modified polyvinyl alcohol having a polyalkylene oxide chain can be obtained by a known synthesis method.
  • Commercial products such as “Ecomati WO-320N” and “Ecomati WO-320R” manufactured by Nippon Synthetic Chemical Industry can also be used.
  • a method for synthesizing a modified polyvinyl alcohol having a polyalkylene oxide chain is a method in which a monomer having a polyalkylene oxide group is polymerized with vinyl acetate, and then a part or all of the vinyl acetate is saponified to obtain a modified polyvinyl alcohol.
  • a monomer having a polyalkylene oxide group is polymerized with vinyl acetate, and then a part or all of the vinyl acetate is saponified to obtain a modified polyvinyl alcohol.
  • other synthetic methods may be used.
  • modified polyvinyl alcohol having a polyalkylene oxide chain only one kind may be used, and two or more kinds having different polyalkylene oxide groups, molar fractions of units, polymerization degree, and the like may be used. You may use it in combination.
  • Such modified polyvinyl alcohol having a polyalkylene oxide chain is usually used for the hydrophilization treatment of the RO membrane as an aqueous solution having a concentration of about 0.1 to 5000 mg / L, preferably about 1 to 1000 mg / L. If this concentration is too low, it takes a long processing time to obtain the desired hydrophilization effect, which is inefficient. Conversely, if this concentration is too high, the viscosity of the aqueous solution increases and the RO membrane is contacted at the time of contact processing. It is not preferable in terms of handling.
  • the modified polyvinyl alcohol having a polyalkylene oxide chain used in the present invention has sufficient solubility in water of about 40 to 60 ° C. unlike simple polyvinyl alcohol, so that an aqueous solution having a predetermined concentration can be prepared by a simple operation. Can do.
  • the water used for preparing the aqueous solution of the modified polyvinyl alcohol having a polyalkylene oxide chain is not particularly limited, and water having a low ion load such as desalted water is used.
  • the RO membrane feed water has a polyalkylene oxide chain. It is also possible to perform treatment by directly adding polyvinyl alcohol.
  • ⁇ Hydrophilic treatment method> There is no particular limitation on the method of bringing the modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the RO membrane, but it is preferable to contact the RO membrane with an aqueous solution of the modified polyvinyl alcohol having a polyalkylene oxide chain under pressure. .
  • a container having a liquid inlet and a liquid outlet is partitioned by a RO membrane to be treated, and an aqueous solution of modified polyvinyl alcohol having a polyalkylene oxide chain is introduced from the liquid inlet and permeated through the RO membrane.
  • the method of discharging is mentioned.
  • the modified polyvinyl alcohol having a polyalkylene oxide chain can be directly added to the RO supply water of the RO membrane module of the normal RO membrane separation apparatus to perform the hydrophilic treatment. That is, in the hydrophilization treatment according to the present invention, a modified polyvinyl alcohol having a polyalkylene oxide chain is added to the RO membrane treatment water during the RO membrane separation treatment to the RO membrane module of the existing RO membrane separation apparatus.
  • the RO membrane separation process can be interrupted.
  • the pressure when an aqueous solution of a modified polyvinyl alcohol having a polyalkylene oxide chain is passed through the RO membrane under pressure but a range of 0.1 to 2.0 MPa is preferable.
  • cleaning of RO membrane is normally used for the water flow to the RO membrane of the modified polyvinyl alcohol aqueous solution which has a polyalkylene oxide chain.
  • the water flow pressure is The range is from 0.1 to 0.5 MPa.
  • the flux when passing water but it is preferably about 0.1 to 1.0 m / day. If this water flow condition is too low, a sufficient hydrophilic effect cannot be obtained, and if it is too high, there is a concern that the flux will decrease greatly.
  • the treatment time is not particularly limited, but is preferably 10 minutes or more and less than 48 hours, more preferably 1 hour or more and less than 24 hours. If the treatment time is short, a sufficient hydrophilic effect cannot be obtained. If the treatment time is long, there is a concern that the RO membrane flux is too low.
  • the temperature (water temperature) during the hydrophilization treatment is preferably 10 to 35 ° C. If the water temperature is too low, the flux decreases and the contact efficiency deteriorates. If the water temperature is too high, problems such as denaturation of the membrane material may occur.
  • the RO membrane treated by the hydrophilization treatment method of the present invention can be suitably used for an ultrapure water production system, a wastewater collection system, and other water treatment systems.
  • Example 1 The RO membrane “ES20” (flat membrane, diameter 32 mm ⁇ ) manufactured by Nitto Denko Corporation was hydrophilized under the following conditions.
  • the modified polyvinyl alcohol having a polyalkylene oxide chain as a hydrophilic treatment agent was used after being dissolved in ultrapure water (60 ° C.). After hydrophilization treatment, we conducted a water flow test using biologically treated water from the wastewater recovery system of Kurita Industrial Co., Ltd., and verified flux stability.
  • Hydrophilization treatment agent “Ecomati WO-320N” manufactured by Nippon Synthetic Chemical Industry Co., Ltd. (modified polyvinyl alcohol having a polyethylene oxide chain, saponification degree of 98.5% or more) Concentration: 100 mg / L Water flow time: 5 hours Inlet pressure: 0.75 MPa Flux: 1.0m / day Water temperature: 25 ° C
  • Raw water evaluation raw water Biologically treated water from the wastewater collection system of Kurita Kogyo Co., Ltd. Development Center ("Kuribata EC-503" manufactured by Kurita Kogyo Co., Ltd. added as a countermeasure against slime, 3 mg / L, pH 6.5) Inlet pressure: 0.75 MPa Recovery rate: 60% Water temperature: 25 ° C
  • an aqueous solution of a modified polyvinyl alcohol having a polyalkylene oxide chain is subjected to hydrophilization by passing water through the RO membrane under pressure, and then the above water-flow evaluation raw water is passed through.
  • the change with time (relative value when the flux at the start of water flow is 1) was examined, and the results are shown in FIG.
  • Example 2 The same as in Example 1 except that “Ecomati WO-320R” (modified polyvinyl alcohol having a polyethylene oxide chain, saponification degree: 86.5 to 89.5%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used as the hydrophilic treatment agent. A test was conducted to verify the flux stability. The results are shown in FIG.
  • Example 3 Except that the inlet pressure during the hydrophilization treatment was 0.2 MPa, the same test as in Example 1 was performed to verify the flux stability. The results are shown in FIG.
  • Example 2 Except that polyvinyl alcohol (polymerization degree 2,000, saponification degree 99%) was used as the hydrophilic treatment agent, the same test as in Example 1 was performed to verify the flux stability. The results are shown in FIG.

Abstract

Provided is a method for hydrophilizing an RO membrane, the method being excellent in terms of the persistence of the hydrophilization effect and flux stability. An RO membrane is brought into contact with a modified polyvinyl alcohol having a polyalkylene oxide chain. The modified polyvinyl alcohol has a degree of saponification of preferably 80% or higher, and the polyalkylene oxide chain preferably is a polyethylene oxide chain. The modified polyvinyl alcohol having a polyalkylene oxide chain has higher adsorbability onto RO membranes than conventional PVAs, and the antifouling properties can hence be maintained over a long period.

Description

逆浸透膜の親水化処理方法Method of hydrophilizing reverse osmosis membrane
　本発明は、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを用いた逆浸透（ＲＯ）膜の親水化処理方法、及びこの方法で親水化処理を行ったＲＯ膜と、ＲＯ膜の親水化処理剤に関する。 The present invention relates to a hydrophilic treatment method for a reverse osmosis (RO) membrane using a modified polyvinyl alcohol having a polyalkylene oxide chain, an RO membrane subjected to a hydrophilic treatment by this method, and a hydrophilic treatment agent for the RO membrane. .
　ＲＯ膜は、その特性を生かして、脱塩や濃縮などの目的で各種の水処理分野で広く実用化されている。 RO membranes have been widely put into practical use in various water treatment fields for the purpose of desalination and concentration, taking advantage of their characteristics.
　従来、使用によるＲＯ膜の透過水量（フラックス）の低下、脱塩率の低下を防止するために、ＲＯ膜にポリビニルアルコール（ＰＶＡ）を接触させることが知られている（例えば、特許文献１～３）。 Conventionally, it is known that polyvinyl alcohol (PVA) is brought into contact with the RO membrane in order to prevent a decrease in permeated water amount (flux) of the RO membrane and a decrease in desalination rate due to use (for example, Patent Documents 1 to 4). 3).
　ＰＶＡをＲＯ膜に接触させることにより、ＲＯ膜が親水化し、ＲＯ膜の透過性能が維持されるようになる。即ち、ＰＶＡはＯＨ基が多く、親水性が高いため、ＰＶＡをＲＯ膜に付着させることにより、ＲＯ膜が親水化され、ＲＯ膜への蛋白質等の吸着が抑制されて耐汚染性が向上する結果、透過性能を維持することが可能となる。 When the PVA is brought into contact with the RO membrane, the RO membrane becomes hydrophilic and the permeation performance of the RO membrane is maintained. That is, since PVA has many OH groups and high hydrophilicity, by attaching PVA to the RO membrane, the RO membrane is hydrophilized, and adsorption of proteins and the like to the RO membrane is suppressed, thereby improving the stain resistance. As a result, the transmission performance can be maintained.
　ＰＶＡを用いる従来のＲＯ膜の親水化処理では、
　(1)　ＰＶＡが、長期の使用においてＲＯ膜から剥離し、親水化効果が失われてしまう。
　(2)　ＰＶＡをＲＯ膜に付着させることで、付着前に比べてＲＯ膜のフラックスが大きく低下する。
といった問題があった。 In the conventional hydrophilization treatment of RO membrane using PVA,
(1) PVA peels off from the RO membrane in long-term use, and the hydrophilic effect is lost.
(2) By attaching PVA to the RO membrane, the flux of the RO membrane is greatly reduced compared to before the attachment.
There was a problem.
特開昭５１－１３３８８号公報Japanese Patent Laid-Open No. 51-13388 特開昭５３－２８０８３号公報JP-A-53-28083 特開平１１－２８４６６号公報Japanese Patent Laid-Open No. 11-28466
　本発明は、上記従来の問題点を解決し、親水化効果を長期間維持することができ、しかも、比較的高いフラックスを維持することができるＲＯ膜及びそのための親水化処理方法と親水化処理剤を提供することを課題とする。 The present invention solves the above-mentioned conventional problems, can maintain a hydrophilization effect for a long period of time, and can maintain a relatively high flux, and a hydrophilization treatment method and hydrophilization treatment therefor It is an object to provide an agent.
　本発明者らは上記課題を解決すべく鋭意検討の結果、ポリエチレングリコールがＲＯ膜との吸着性が高いという知見から、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを用いることで、従来用いられてきたＰＶＡよりもＲＯ膜への吸着性が向上すること、このため、ＰＶＡと比較して耐汚染性を長期間維持できることを見出した。 As a result of intensive studies to solve the above problems, the present inventors have been conventionally used by using modified polyvinyl alcohol having a polyalkylene oxide chain, based on the knowledge that polyethylene glycol has high adsorptivity with RO membranes. It has been found that the adsorptivity to the RO membrane is improved as compared with PVA, and therefore, the contamination resistance can be maintained for a long time as compared with PVA.
　本発明はこのような知見に基いて達成されたものであり、以下を要旨とする。 The present invention has been achieved on the basis of such knowledge, and the gist thereof is as follows.
［１］　逆浸透膜に、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを接触させることを特徴とする逆浸透膜の親水化処理方法。 [1] A method of hydrophilizing a reverse osmosis membrane, comprising bringing a modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the reverse osmosis membrane.
［２］　前記変性ポリビニルアルコールのけん化度が８０％以上であることを特徴とする、［１］に記載の逆浸透膜の親水化処理方法。 [2] The method for hydrophilizing a reverse osmosis membrane according to [1], wherein the degree of saponification of the modified polyvinyl alcohol is 80% or more.
［３］　前記ポリアルキレンオキサイド鎖がポリエチレンオキサイド鎖であることを特徴とする、［１］又は［２］に記載の逆浸透膜の親水化処理方法。 [3] The method for hydrophilizing a reverse osmosis membrane according to [1] or [2], wherein the polyalkylene oxide chain is a polyethylene oxide chain.
［４］　液導入口と液排出口とを有する容器内を前記逆浸透膜で仕切り、該液導入口から導入した前記変性ポリビニルアルコールを含む水溶液を該逆浸透膜に透過させて該液排出口から排出させて通水することにより、該逆浸透膜に該変性ポリビニルアルコールを接触させることを特徴とする、［１］ないし［３］のいずれかに記載の逆浸透膜の親水化処理方法。 [4] A container having a liquid inlet and a liquid outlet is partitioned by the reverse osmosis membrane, and the aqueous solution containing the modified polyvinyl alcohol introduced from the liquid inlet is permeated through the reverse osmosis membrane to allow the liquid outlet. The method for hydrophilizing a reverse osmosis membrane according to any one of [1] to [3], wherein the modified polyvinyl alcohol is brought into contact with the reverse osmosis membrane by draining it from water and passing it through.
［５］　前記通水時の圧力が０．１～０．５ＭＰａであることを特徴とする、［４］に記載の逆浸透膜の親水化処理方法。 [5] The method for hydrophilizing a reverse osmosis membrane according to [4], wherein the water-passing pressure is 0.1 to 0.5 MPa.
［６］　前記変性ポリビニルアルコールを含む水溶液の変性ポリビニルアルコール濃度が０．１～５０００ｍｇ／Ｌであることを特徴とする、［１］ないし［５］のいずれかに記載の逆浸透膜の親水化処理方法。 [6] The hydrophilization of the reverse osmosis membrane according to any one of [1] to [5], wherein the concentration of the modified polyvinyl alcohol in the aqueous solution containing the modified polyvinyl alcohol is 0.1 to 5000 mg / L Processing method.
［７］　［１］ないし［６］のいずれかに記載の逆浸透膜の親水化処理方法により親水化処理されてなる逆浸透膜。 [7] A reverse osmosis membrane that is hydrophilized by the method of hydrophilizing a reverse osmosis membrane according to any one of [1] to [6].
［８］　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを含有する逆浸透膜の親水化処理剤。 [8] A hydrophilic treatment agent for a reverse osmosis membrane containing a modified polyvinyl alcohol having a polyalkylene oxide chain.
　本発明によれば、ＲＯ膜を、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールで処理することにより、親水性を付与すると共に、その親水化効果を長期に亘って維持することができる。しかも、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールであれば、親水化処理によるＲＯ膜のフラックスの低下を抑制することができる上に、従来のＰＶＡと比較して、その水溶液の調製が容易である。 According to the present invention, by treating the RO membrane with a modified polyvinyl alcohol having a polyalkylene oxide chain, it is possible to impart hydrophilicity and maintain the hydrophilic effect over a long period of time. And if it is a modified polyvinyl alcohol which has a polyalkylene oxide chain, the fall of the flux of RO membrane by a hydrophilic treatment can be suppressed, and the preparation of the aqueous solution is easy compared with conventional PVA. .
実施例１～３及び比較例１，２におけるフラックスの経時変化を示すグラフである。6 is a graph showing changes in flux over time in Examples 1 to 3 and Comparative Examples 1 and 2.
　以下に本発明の実施の形態を詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
＜ＲＯ膜＞
　本発明が適用されるＲＯ膜としては、芳香族ポリアミドを緻密層とするポリアミド系ＲＯ膜が挙げられるが、ポリアミド系のナノ濾過膜を対象としてもかまわない。すなわち、本発明で処理対象とするＲＯ膜はナノ濾過膜を含有する広義のＲＯ膜である。また、新しい膜や使用後の膜、劣化した膜などにも問題なく適用が可能である。 <RO membrane>
Examples of the RO membrane to which the present invention is applied include a polyamide-based RO membrane having an aromatic polyamide as a dense layer, but a polyamide-based nanofiltration membrane may also be used. That is, the RO membrane to be treated in the present invention is a broad RO membrane containing a nanofiltration membrane. Also, it can be applied to new films, used films, and deteriorated films without problems.
　ＲＯ膜の構造についても特に制限はなく、平膜モジュール、スパイラル型モジュール、中空糸モジュールなどを用いることができる。 The structure of the RO membrane is not particularly limited, and a flat membrane module, a spiral type module, a hollow fiber module, or the like can be used.
＜ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコール＞
　本発明において、ＲＯ膜の親水化処理に用いるポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールは、ビニルアルコールユニットと、ポリアルキレンオキサイド基が結合したユニットとからなり、場合により、更に酢酸ビニルユニットを含む。 <Modified polyvinyl alcohol having a polyalkylene oxide chain>
In the present invention, the modified polyvinyl alcohol having a polyalkylene oxide chain used for the hydrophilic treatment of the RO membrane is composed of a vinyl alcohol unit and a unit to which a polyalkylene oxide group is bonded, and optionally further includes a vinyl acetate unit.
　ポリアルキレンオキサイド基が結合したユニットのポリアルキレンオキサイド基としては、ポリエチレンオキサイド基、ポリプロピレンオキサイド基、ポリブチレンオキサイド基等のアルキレン基の炭素数が２～４のポリアルキレンオキサイド基が好適であり、ポリエチレンオキサイド基が最も好適である。ポリアルキレンオキサイド基のアルキレンオキサイド基の繰り返し数は２～３００、特に４～１５０であることが好ましい。この繰り返し数が小さ過ぎると、ポリアルキレンオキサイド基によるＲＯ膜への吸着性の向上効果を十分に得ることができず、大きすぎると、親水化処理によるＲＯ膜のフラックスの低下が大きくなる。 As the polyalkylene oxide group of the unit to which the polyalkylene oxide group is bonded, a polyalkylene oxide group having 2 to 4 carbon atoms of an alkylene group such as a polyethylene oxide group, a polypropylene oxide group, or a polybutylene oxide group is preferable. The oxide group is most preferred. The number of repeating alkylene oxide groups in the polyalkylene oxide group is preferably 2 to 300, particularly 4 to 150. If the number of repetitions is too small, the effect of improving the adsorptivity to the RO membrane by the polyalkylene oxide group cannot be sufficiently obtained, and if it is too large, the decrease in the flux of the RO membrane due to the hydrophilization treatment becomes large.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコール中のポリアルキレンオキサイド基が結合しているユニットのモル分率としては、０．１～５０モル％が好ましく、０．３～４０モル％がより好ましく、０．５～３０モル％が特に好ましい。この範囲よりもポリアルキレンオキサイド基が結合しているユニットのモル分率が少ないと、ポリビニルアルコールにポリアルキレンオキサイド鎖を導入することによるＲＯ膜への吸着性の向上、フラックス低下の抑制といった本発明の効果を十分に得ることができず、逆に多いと相対的にビニルアルコールユニットのモル分率が少なくなって親水化処理効果が低減する傾向にある。 The molar fraction of the unit to which the polyalkylene oxide group is bonded in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 0.1 to 50 mol%, more preferably 0.3 to 40 mol%, and 0 Particularly preferred is 5 to 30 mol%. When the molar fraction of the unit to which the polyalkylene oxide group is bonded is smaller than this range, the present invention such as improvement of the adsorptivity to the RO membrane and suppression of flux reduction by introducing the polyalkylene oxide chain into the polyvinyl alcohol. If the amount is too large, the molar fraction of the vinyl alcohol unit is relatively small, and the hydrophilization effect tends to be reduced.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコール中のビニルアルコールユニットのモル分率は、５０～９９．９モル％が好ましく、６０～９９．７モル％がより好ましく、７０～９９．５モル％が特に好ましい。この範囲よりもビニルアルコールユニットのモル分率が少ないと、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコール中の水酸基数が少なくなって、十分な親水化処理効果、フラックス安定性が得られず、逆に、多いと相対的にポリアルキレンオキサイド基が結合しているユニットのモル分率が少なくなって、ポリビニルアルコールにポリアルキレンオキサイド鎖を導入することによる上記効果を十分に得ることができないおそれがある。 The molar fraction of the vinyl alcohol unit in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 50 to 99.9 mol%, more preferably 60 to 99.7 mol%, and particularly preferably 70 to 99.5 mol%. preferable. If the molar fraction of the vinyl alcohol unit is less than this range, the number of hydroxyl groups in the modified polyvinyl alcohol having a polyalkylene oxide chain is reduced, and sufficient hydrophilization effect and flux stability cannot be obtained. If the amount is too large, the molar fraction of the unit to which the polyalkylene oxide group is bonded is relatively small, and the above-described effect due to the introduction of the polyalkylene oxide chain into polyvinyl alcohol may not be sufficiently obtained.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコール中の酢酸ビニルユニットのモル分率は、０～２０モル％が好ましく、０～１０モル％がより好ましく、０～５モル％が特に好ましい。 The molar fraction of vinyl acetate units in the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, and particularly preferably 0 to 5 mol%.
　ポリビニルアルコールの性状を示す指標としてけん化度がある。けん化度はビニルアルコールユニットのモル分率をビニルアルコールユニットと酢酸ビニルユニットのモル分率の合計で除したものである。本発明における、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールのけん化度は８０％以上、特に８５％以上、とりわけ９５％以上であることが好ましい。けん化度が８０％未満であると水酸基の数が少なく、親水性が低くなり、十分な親水化処理効果、フラックス安定性が得られない傾向にある。 Saponification degree is an index indicating the properties of polyvinyl alcohol. The saponification degree is obtained by dividing the molar fraction of the vinyl alcohol unit by the sum of the molar fractions of the vinyl alcohol unit and the vinyl acetate unit. In the present invention, the degree of saponification of the modified polyvinyl alcohol having a polyalkylene oxide chain is preferably 80% or more, particularly 85% or more, particularly 95% or more. When the degree of saponification is less than 80%, the number of hydroxyl groups is small, the hydrophilicity is lowered, and sufficient hydrophilization treatment effect and flux stability tend not to be obtained.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの重合度、即ち、上記の合計のユニット数としては特に制限はないが、２０～２０，０００が好ましい。重合度が低すぎると膜への吸着性が悪くなり、重合度が大きすぎると、親水化処理によるＲＯ膜のフラックス低下が大きくなるため、好ましくない。 The polymerization degree of the modified polyvinyl alcohol having a polyalkylene oxide chain, that is, the total number of units is not particularly limited, but is preferably 20 to 20,000. If the degree of polymerization is too low, the adsorptivity to the membrane is deteriorated, and if the degree of polymerization is too large, the RO membrane flux decreases due to the hydrophilic treatment, which is not preferable.
　このようなポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールは、公知の合成方法で得ることができる。また、日本合成化学工業社製「エコマティＷＯ－３２０Ｎ」、「エコマティＷＯ－３２０Ｒ」といった市販品を用いることもできる。 Such a modified polyvinyl alcohol having a polyalkylene oxide chain can be obtained by a known synthesis method. Commercial products such as “Ecomati WO-320N” and “Ecomati WO-320R” manufactured by Nippon Synthetic Chemical Industry can also be used.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの合成方法としては、ポリアルキレンオキサイド基を有する単量体を酢酸ビニルと共に重合した後、酢酸ビニルの一部又は全てをけん化して変性ポリビニルアルコールとする方法が好ましいが、その他の合成方法を用いてもよい。 A method for synthesizing a modified polyvinyl alcohol having a polyalkylene oxide chain is a method in which a monomer having a polyalkylene oxide group is polymerized with vinyl acetate, and then a part or all of the vinyl acetate is saponified to obtain a modified polyvinyl alcohol. Although preferred, other synthetic methods may be used.
　上記のポリアルキレンオキサイド基を有する単量体としては、ポリエチレンオキサイドモノビニルエーテル、ポリプロピレンオキサイドモノビニルエーテル、ポリエチレンオキサイドモノアリルエーテル、ポリエチレングリコールモノメタクリレート、ポリエチレングリコールモノアクリレート、ポリプロピレングリコールモノメタクリレート、ポリプロピレングリコールモノアクリレート、ポリエチレングリコール－ポリプロピレングリコールモノメタクリレート、ポリエチレングリコール－ポリプロピレングリコールモノアクリレート、ポリ（エチレングリコール－テトラメチレングリコール）モノメタクリレート、ポリ（エチレングリコール－テトラメチレングリコール）モノアクリレート、ポリ（エチレングリコール－プロピレングリコール）モノメタクリレート、メトキシポリエチレングリコール－ポリプロピレングリコールモノアクリレート等が挙げられる。
　これらは１種を単独で用いてもよく、２種以上を併用してもよい。 As the monomer having the above polyalkylene oxide group, polyethylene oxide monovinyl ether, polypropylene oxide monovinyl ether, polyethylene oxide monoallyl ether, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polypropylene glycol monomethacrylate, polypropylene glycol monoacrylate, Polyethylene glycol-polypropylene glycol monomethacrylate, polyethylene glycol-polypropylene glycol monoacrylate, poly (ethylene glycol-tetramethylene glycol) monomethacrylate, poly (ethylene glycol-tetramethylene glycol) monoacrylate, poly (ethylene glycol-propylene glycol) Call) monomethacrylate, methoxy polyethylene glycol - and polypropylene glycol monoacrylate and the like.
These may be used alone or in combination of two or more.
　本発明において、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールとしては、１種のみを用いてもよく、また、ポリアルキレンオキサイド基や、各ユニットのモル分率、重合度等の異なるものを２種以上組み合わせて用いてもよい。 In the present invention, as the modified polyvinyl alcohol having a polyalkylene oxide chain, only one kind may be used, and two or more kinds having different polyalkylene oxide groups, molar fractions of units, polymerization degree, and the like may be used. You may use it in combination.
　このようなポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールは、通常０．１～５０００ｍｇ／Ｌ、好ましくは１～１０００ｍｇ／Ｌ程度の濃度の水溶液としてＲＯ膜の親水化処理に用いられる。この濃度が低過ぎると目的とする親水化効果を得るための処理時間を長く要し非効率であり、逆にこの濃度が高過ぎると水溶液の粘性が高くなり、ＲＯ膜への接触処理時の取り扱いの面で好ましくない。 Such modified polyvinyl alcohol having a polyalkylene oxide chain is usually used for the hydrophilization treatment of the RO membrane as an aqueous solution having a concentration of about 0.1 to 5000 mg / L, preferably about 1 to 1000 mg / L. If this concentration is too low, it takes a long processing time to obtain the desired hydrophilization effect, which is inefficient. Conversely, if this concentration is too high, the viscosity of the aqueous solution increases and the RO membrane is contacted at the time of contact processing. It is not preferable in terms of handling.
　本発明で用いるポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールは、単なるポリビニルアルコールと異なり４０～６０℃程度の水にも十分な溶解性を示すため、簡易な操作で所定の濃度の水溶液を調製することができる。 The modified polyvinyl alcohol having a polyalkylene oxide chain used in the present invention has sufficient solubility in water of about 40 to 60 ° C. unlike simple polyvinyl alcohol, so that an aqueous solution having a predetermined concentration can be prepared by a simple operation. Can do.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液の調製に用いる水としては、特に制限はなく、脱塩水などのイオン負荷の低い水が用いられるが、ＲＯ膜供給水にポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを直接添加して処理を行うことも可能である。 The water used for preparing the aqueous solution of the modified polyvinyl alcohol having a polyalkylene oxide chain is not particularly limited, and water having a low ion load such as desalted water is used. However, the RO membrane feed water has a polyalkylene oxide chain. It is also possible to perform treatment by directly adding polyvinyl alcohol.
＜親水化処理方法＞
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールをＲＯ膜に接触させる方法には特に制限はないが、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液をＲＯ膜に加圧通水して接触させることが好ましい。 <Hydrophilic treatment method>
There is no particular limitation on the method of bringing the modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the RO membrane, but it is preferable to contact the RO membrane with an aqueous solution of the modified polyvinyl alcohol having a polyalkylene oxide chain under pressure. .
　例えば、液導入口と液排出口を有する容器内を被処理ＲＯ膜で仕切り、液導入口からポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液を導入してＲＯ膜を透過させて液排出口から排出させる方法が挙げられる。この場合、通常のＲＯ膜分離装置のＲＯ膜モジュールのＲＯ供給水に対して、前述の如く、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを直接添加して親水化処理を行うこともできる。即ち、本発明による親水化処理は、既存のＲＯ膜分離装置のＲＯ膜モジュールに対して、ＲＯ膜分離処理中に、ＲＯ膜の被処理水にポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを添加して実施することもできるし、ＲＯ膜分離処理を中断して実施することもできる。 For example, a container having a liquid inlet and a liquid outlet is partitioned by a RO membrane to be treated, and an aqueous solution of modified polyvinyl alcohol having a polyalkylene oxide chain is introduced from the liquid inlet and permeated through the RO membrane. The method of discharging is mentioned. In this case, as described above, the modified polyvinyl alcohol having a polyalkylene oxide chain can be directly added to the RO supply water of the RO membrane module of the normal RO membrane separation apparatus to perform the hydrophilic treatment. That is, in the hydrophilization treatment according to the present invention, a modified polyvinyl alcohol having a polyalkylene oxide chain is added to the RO membrane treatment water during the RO membrane separation treatment to the RO membrane module of the existing RO membrane separation apparatus. The RO membrane separation process can be interrupted.
　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液をＲＯ膜に加圧通水する際の圧力に特に制限はないが、０．１～２．０ＭＰａの範囲が好ましい。なお、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液のＲＯ膜への通水には、通常、ＲＯ膜の洗浄で使用するポンプが用いられ、この場合にはポンプの能力から、通水圧力は０．１～０．５ＭＰａの範囲となる。通水する際のフラックスに特に制限はないが、０．１～１．０ｍ／ｄａｙ程度が好ましい。この通水条件が低すぎると十分な親水化効果が得られず、高すぎるとフラックスの低下が大きくなる懸念がある。 There is no particular limitation on the pressure when an aqueous solution of a modified polyvinyl alcohol having a polyalkylene oxide chain is passed through the RO membrane under pressure, but a range of 0.1 to 2.0 MPa is preferable. In addition, the pump used for the washing | cleaning of RO membrane is normally used for the water flow to the RO membrane of the modified polyvinyl alcohol aqueous solution which has a polyalkylene oxide chain. In this case, from the capability of the pump, the water flow pressure is The range is from 0.1 to 0.5 MPa. There is no particular limitation on the flux when passing water, but it is preferably about 0.1 to 1.0 m / day. If this water flow condition is too low, a sufficient hydrophilic effect cannot be obtained, and if it is too high, there is a concern that the flux will decrease greatly.
　処理時間としては特に制限はないが、１０分以上、４８時間未満が好ましく、１時間以上２４時間未満がさらに好ましい。処理時間が短いと十分な親水化効果が得られず、長いとＲＯ膜のフラックスが低下しすぎる懸念がある。 The treatment time is not particularly limited, but is preferably 10 minutes or more and less than 48 hours, more preferably 1 hour or more and less than 24 hours. If the treatment time is short, a sufficient hydrophilic effect cannot be obtained. If the treatment time is long, there is a concern that the RO membrane flux is too low.
　親水化処理中の温度（水温）は１０～３５℃であることが好ましい。水温が低すぎるとフラックスが低下し、接触効率が悪化する。水温が高すぎると膜素材の変性等の問題が出てくることが考えられる。 The temperature (water temperature) during the hydrophilization treatment is preferably 10 to 35 ° C. If the water temperature is too low, the flux decreases and the contact efficiency deteriorates. If the water temperature is too high, problems such as denaturation of the membrane material may occur.
　本発明の親水化処理方法で処理されたＲＯ膜は、超純水製造システム、排水回収システム、その他水処理システムに好適に使用することができる。 The RO membrane treated by the hydrophilization treatment method of the present invention can be suitably used for an ultrapure water production system, a wastewater collection system, and other water treatment systems.
　以下、実施例及び比較例を挙げて本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
［実施例１］
　日東電工社製ＲＯ膜「ＥＳ２０」（平膜、直径３２ｍｍφ）に対して、以下条件で親水化処理を行った。親水化処理剤のポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールは超純水（６０℃）に溶解させて使用した。親水化処理後に栗田工業（株）開発センターの排水回収装置の生物処理水を用いて通水試験を行い、フラックス安定性を検証した。 [Example 1]
The RO membrane “ES20” (flat membrane, diameter 32 mmφ) manufactured by Nitto Denko Corporation was hydrophilized under the following conditions. The modified polyvinyl alcohol having a polyalkylene oxide chain as a hydrophilic treatment agent was used after being dissolved in ultrapure water (60 ° C.). After hydrophilization treatment, we conducted a water flow test using biologically treated water from the wastewater recovery system of Kurita Industrial Co., Ltd., and verified flux stability.
＜親水化処理＞
　親水化処理剤：日本合成化学工業社製「エコマティＷＯ－３２０Ｎ」（ポリエチレンオキサイド鎖を有する変性ポリビニルアルコール、けん化度９８．５％以上）
　濃度：１００ｍｇ／Ｌ
　通水時間：５時間
　入口圧力：０．７５ＭＰａ
　フラックス：１．０ｍ／ｄａｙ
　水温：２５℃ <Hydrophilic treatment>
Hydrophilization treatment agent: “Ecomati WO-320N” manufactured by Nippon Synthetic Chemical Industry Co., Ltd. (modified polyvinyl alcohol having a polyethylene oxide chain, saponification degree of 98.5% or more)
Concentration: 100 mg / L
Water flow time: 5 hours Inlet pressure: 0.75 MPa
Flux: 1.0m / day
Water temperature: 25 ° C
＜通水試験＞
　通水評価原水：栗田工業（株）開発センターの排水回収装置の生物処理水（スライム対策として栗田工業（株）製「クリバーターＥＣ－５０３」を３ｍｇ／Ｌ添加、ｐＨ６．５）
　入口圧力：０．７５ＭＰａ
　回収率：６０％
　水温：２５℃ <Water flow test>
Raw water evaluation raw water: Biologically treated water from the wastewater collection system of Kurita Kogyo Co., Ltd. Development Center ("Kuribata EC-503" manufactured by Kurita Kogyo Co., Ltd. added as a countermeasure against slime, 3 mg / L, pH 6.5)
Inlet pressure: 0.75 MPa
Recovery rate: 60%
Water temperature: 25 ° C
　上記の親水化処理条件でポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールの水溶液をＲＯ膜に加圧通水して親水化処理した後、上記の通水評価原水を通水し、そのときのフラックスの経時変化（通水開始時のフラックスを１とした場合の相対値）を調べ、結果を図１に示した。 Under the above-mentioned hydrophilization treatment conditions, an aqueous solution of a modified polyvinyl alcohol having a polyalkylene oxide chain is subjected to hydrophilization by passing water through the RO membrane under pressure, and then the above water-flow evaluation raw water is passed through. The change with time (relative value when the flux at the start of water flow is 1) was examined, and the results are shown in FIG.
［実施例２］
　親水化処理剤として、日本合成化学工業社製「エコマティＷＯ－３２０Ｒ」（ポリエチレンオキサイド鎖を有する変性ポリビニルアルコール、けん化度８６．５～８９．５％）を用いた以外は実施例１と同様の試験を行い、フラックス安定性を検証した。結果を図１に示す。 [Example 2]
The same as in Example 1 except that “Ecomati WO-320R” (modified polyvinyl alcohol having a polyethylene oxide chain, saponification degree: 86.5 to 89.5%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used as the hydrophilic treatment agent. A test was conducted to verify the flux stability. The results are shown in FIG.
［実施例３］
　親水化処理時の入口圧力を０．２ＭＰａとした以外は実施例１と同様の試験を行い、フラックス安定性を検証した。結果を図１に示す。 [Example 3]
Except that the inlet pressure during the hydrophilization treatment was 0.2 MPa, the same test as in Example 1 was performed to verify the flux stability. The results are shown in FIG.
［比較例１］
　日東電工社製「ＥＳ２０」（平膜、直径３２ｍｍφ）を親水化処理を行わずに通水試験を行い、フラックス安定性を検証した。結果を図１に示す。 [Comparative Example 1]
Nitto Denko's “ES20” (flat membrane, 32 mm diameter) was subjected to a water flow test without hydrophilization, and the flux stability was verified. The results are shown in FIG.
［比較例２］
　親水化処理剤としてポリビニルアルコール（重合度２，０００、けん化度９９％）を用いた以外は実施例１と同様の試験を行い、フラックス安定性を検証した。結果を図１に示す。 [Comparative Example 2]
Except that polyvinyl alcohol (polymerization degree 2,000, saponification degree 99%) was used as the hydrophilic treatment agent, the same test as in Example 1 was performed to verify the flux stability. The results are shown in FIG.
　図１より、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールをＲＯ膜に接触させることで、フラックス安定性が向上し、従来のＰＶＡ処理と比較して耐汚染性効果の持続性が向上することが分かる。 From FIG. 1, it can be seen that by bringing modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the RO membrane, the flux stability is improved and the durability of the stain resistance effect is improved as compared with the conventional PVA treatment. .
　本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更が可能であることは当業者に明らかである。
　本出願は、２０１２年１２月２１日付で出願された日本特許出願２０１２－２７９５９０に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2012-279590 filed on Dec. 21, 2012, which is incorporated by reference in its entirety.

Claims (8)

  1. 　逆浸透膜に、ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを接触させることを特徴とする逆浸透膜の親水化処理方法。 A method for hydrophilizing a reverse osmosis membrane, comprising bringing a modified polyvinyl alcohol having a polyalkylene oxide chain into contact with the reverse osmosis membrane.
  2. 　前記変性ポリビニルアルコールのけん化度が８０％以上であることを特徴とする、請求項１に記載の逆浸透膜の親水化処理方法。 The method for hydrophilizing a reverse osmosis membrane according to claim 1, wherein the degree of saponification of the modified polyvinyl alcohol is 80% or more.
  3. 　前記ポリアルキレンオキサイド鎖がポリエチレンオキサイド鎖であることを特徴とする、請求項１又は２に記載の逆浸透膜の親水化処理方法。 The method for hydrophilizing a reverse osmosis membrane according to claim 1 or 2, wherein the polyalkylene oxide chain is a polyethylene oxide chain.
  4. 　液導入口と液排出口とを有する容器内を前記逆浸透膜で仕切り、該液導入口から導入した前記変性ポリビニルアルコールを含む水溶液を該逆浸透膜に透過させて該液排出口から排出させて通水することにより、該逆浸透膜に該変性ポリビニルアルコールを接触させることを特徴とする、請求項１ないし３のいずれか１項に記載の逆浸透膜の親水化処理方法。 A container having a liquid inlet and a liquid outlet is partitioned by the reverse osmosis membrane, and an aqueous solution containing the modified polyvinyl alcohol introduced from the liquid inlet is permeated through the reverse osmosis membrane and discharged from the liquid outlet. The method of hydrophilizing a reverse osmosis membrane according to any one of claims 1 to 3, wherein the modified polyvinyl alcohol is brought into contact with the reverse osmosis membrane by passing water through the membrane.
  5. 　前記通水時の圧力が０．１～２．０ＭＰａであり、通水フラックスが０．１～１．０ｍ／ｄａｙであることを特徴とする、請求項４に記載の逆浸透膜の親水化処理方法。 The hydrophilization of a reverse osmosis membrane according to claim 4, wherein the pressure during water flow is 0.1 to 2.0 MPa, and the water flow flux is 0.1 to 1.0 m / day. Processing method.
  6. 　前記変性ポリビニルアルコールを含む水溶液の変性ポリビニルアルコール濃度が０．１～５０００ｍｇ／Ｌであることを特徴とする、請求項１ないし５のいずれか１項に記載の逆浸透膜の親水化処理方法。 The method for hydrophilizing a reverse osmosis membrane according to any one of claims 1 to 5, wherein the concentration of the modified polyvinyl alcohol in the aqueous solution containing the modified polyvinyl alcohol is 0.1 to 5000 mg / L.
  7. 　請求項１ないし６のいずれか１項に記載の逆浸透膜の親水化処理方法により親水化処理されてなる逆浸透膜。 A reverse osmosis membrane which is hydrophilized by the hydrophilization method of a reverse osmosis membrane according to any one of claims 1 to 6.
  8. 　ポリアルキレンオキサイド鎖を有する変性ポリビニルアルコールを含有する逆浸透膜の親水化処理剤。 A hydrophilic treatment agent for a reverse osmosis membrane containing a modified polyvinyl alcohol having a polyalkylene oxide chain.
PCT/JP2013/083697 2012-12-21 2013-12-17 Method for hydrophilizing reverse osmosis membrane WO2014098059A1 (en)

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