AU2013365015B2 - Method for hydrophilizing reverse osmosis membrane - Google Patents
Method for hydrophilizing reverse osmosis membrane Download PDFInfo
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- AU2013365015B2 AU2013365015B2 AU2013365015A AU2013365015A AU2013365015B2 AU 2013365015 B2 AU2013365015 B2 AU 2013365015B2 AU 2013365015 A AU2013365015 A AU 2013365015A AU 2013365015 A AU2013365015 A AU 2013365015A AU 2013365015 B2 AU2013365015 B2 AU 2013365015B2
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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
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- 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
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- 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
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- 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
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- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Materials Applied To Surfaces To Minimize Adherence Of Mist Or Water (AREA)
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
HYDROPHILIC TREATMENT METHOD FOR REVERSE OSMOSIS MEMBRANE
Field of Invention [0001]
The present invention relates to a hydrophilic treatment method for a reverse osmosis (RO) membrane, the method using a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain; an RO membrane provided by being subjected to a hydrophilic treatment by this method; and a hydrophilic treatment agent for an RO membrane.
Background of Invention [0002] RO membranes, which have unique properties, are practically used in wide-ranging fields relating to various water treatments for the purpose of desalinization, concentration, or the like.
[0003]
In order to suppress a decrease in permeation flux (flux) and a decrease in salt rejection over the use of RO membranes, there is a known technique of bringing poly(vinyl alcohol) (PVA) into contact with RO membranes (for example, Patent Literatures 1 to 3).
[0004]
By bringing PVA into contact with an RO membrane, the RO membrane is made hydrophilic, which allows the permeability of the RO membrane to be maintained. Specifically, PVA has a large number of OH groups and is highly hydrophilic. Accordingly, by making PVA adhere to an RO membrane, the RO membrane is made hydrophilic and adsorption of proteins and the like on the RO membrane is suppressed, which is enhancement of the fouling resistance. As a result, the permeability can be maintained.
[0005]
The conventional hydrophilic treatments for RO membranes using PVA have the following problems: (1) PVA becomes separated from RO membranes over use for a long period of time, which results in loss of the hydrophilic effect, and (2) adhesion of PVA to RO membranes causes a considerable decrease in the flux of the RO membranes.
Patent Literature [0006]
Patent Literature 1: Japanese Patent Publication 5113388 A
Patent Literature 2: Japanese Patent Publication 5328083 A
Patent Literature 3: Japanese Patent Publication 1128466 A
Summary of Invention [0007]
It would be advantageous if at least preferred embodiments of the present invention were to provide an RO membrane that addresses the above-described conventional problems, can maintain a hydrophilic effect for a long period of time, and can also maintain a relatively high flux; and a hydrophilic treatment method and a hydrophilic treatment agent for providing the RO membrane.
[0008]
The inventors of the present invention performed thorough studies, and on the basis of the finding that polyethylene glycol is highly adsorbable on RO membranes, the inventors have found that a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain has higher adsorbability on RO membranes than conventionally used PVA, and that hence the modified poly(vinyl alcohol) allows the fouling resistance to be maintained for a longer period of time than PVA.
[0009]
The present invention has been accomplished on the basis of these findings. The gist of the present invention is as follows.
[0010] [1] A hydrophilic treatment method for a reverse osmosis membrane, comprising passing an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain by application of pressure through a reverse osmosis membrane [2] The hydrophilic treatment method for a reverse osmosis membrane according to [1], wherein the modified poly(vinyl alcohol) has a degree of saponification of 80% or more.
[0012] [3] The hydrophilic treatment method for a reverse osmosis membrane according to [1] or [2], wherein the poly(alkylene oxide) chain is a poly(ethylene oxide) chain.
[0013] [4] The hydrophilic treatment method for a reverse osmosis membrane according to any one of [1] to [3], wherein the modified poly(vinyl alcohol) is passed by application of pressure through the reverse osmosis membrane in a manner in which, in a container having a liquid inlet and a liquid outlet and partitioned with the reverse osmosis membrane, an aqueous solution containing the modified poly(vinyl alcohol) is passed by being introduced through the liquid inlet, made to permeate the reverse osmosis membrane, and discharged through the liquid outlet.
[0014] [5] The hydrophilic treatment method for a reverse osmosis membrane according to [4], wherein a pressure applied to the solution being passed is 0.1 to 0.5 MPa and the solution is passed at a flux of 0.1 to 1.0 m/day.
[0015] [6] The hydrophilic treatment method for a reverse osmosis membrane according to any one of [1] to [5], wherein the aqueous solution containing the modified poly(vinyl alcohol) has a concentration of the modified poly(vinyl alcohol) of 0.1 to 5000 mg/L.
[0016] [7] A reverse osmosis membrane provided by being subjected to a hydrophilic treatment by the hydrophilic treatment method for a reverse osmosis membrane according to any one of [1] to [6].
[0017] [8] A hydrophilic treatment agent for a reverse osmosis membrane, comprising a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain.
[0017a]
The present invention as claimed herein is defined by the following items 1 to 8: 1 A hydrophilic treatment method for a polyamide reverse osmosis membrane, comprising bringing a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain into contact with a polyamide reverse osmosis membrane. 2 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to item 1, wherein the modified poly(vinyl alcohol) has a degree of saponification of 80% or more. 3 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to item 1 or 2, wherein the poly(alkylene oxide) chain is a poly(ethylene oxide) chain . 4 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of items 1 to 3, wherein the modified poly(vinyl alcohol) is brought into contact with the reverse osmosis membrane in a manner in which, in a container having a liquid inlet and a liquid outlet and partitioned with the reverse osmosis membrane, an aqueous solution containing the modified poly(vinyl alcohol) is passed by being introduced through the liquid inlet, made to permeate the reverse osmosis membrane, and discharged through the liquid outlet. 5 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to item 4, wherein a pressure applied to the solution being passed is 0.1 to 2.0 MPa and the solution is passed at a flux of 0.1 to 1.0 m/day. 6 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of items 1 to 5, wherein the aqueous solution containing the modified poly(vinyl alcohol) has a concentration of the modified poly(vinyl alcohol) of 0.1 to 5000 mg/L. 7 A polyamide reverse osmosis membrane provided by being subjected to a hydrophilic treatment by the hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of items 1 to 6. 8 A hydrophilic treatment agent when used in the treatment of a polyamide reverse osmosis membrane, wherein the hydrophilic treatment agent is in the form of an aqueous solution comprising a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, and wherein the hydrophilic treatment agent is passed through the polyamide reverse osmosis membrane by application of pressure.
Advantageous Effects of Invention [0018]
According to the present invention, by treating an RO membrane with a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, hydrophilicity can be imparted to the RO membrane and this hydrophilic effect can be maintained for a long period of time. In this case of using a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, a decrease in the flux of the RO membrane caused by the hydrophilic treatment can be suppressed and an aqueous solution of the modified poly(vinyl alcohol) is more easily prepared than that of conventional PVA.
Brief Description of Drawing [0019]
Fig. 1 is a graph illustrating changes in flux over time in Examples 1 to 3 and Comparative examples 1 and 2. Description of Embodiments [0020]
Hereinafter, embodiments of the present invention will be described in detail.
[0021] <R0 membrane>
The present invention is applicable to RO membranes that are polyamide RO membranes having aromatic polyamide dense layers. The present invention is also applicable to polyamide nanofiltration membranes. That is, RO membranes to be treated by the present invention are RO membranes in a broad sense that encompass nanofiltration membranes. The present invention is applicable to, without problems, new membranes, used membranes, deteriorated membranes, and the like.
[0022]
Such RO membranes are also not particularly limited in terms of structures, and structures such as flat membrane modules, spiral modules, and hollow fiber modules can be used.
[0023] <Modified poly{vinyl alcohol) having poly(alkylene oxide) chain>
In the present invention, a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain used for a hydrophilic treatment for an RO membrane includes a vinyl alcohol unit and a unit having a poly(alkylene oxide) group and optionally further includes a vinyl acetate unit.
[0024]
In the unit having a poly(alkylene oxide) group, the poly(alkylene oxide) group is preferably a poly(alkylene oxide) group in which the alkylene group has 2 to 4 carbons, such as a poly(ethylene oxide) group, a poly(propylene oxide) group, or a poly(butylene oxide) group; most preferably, a poly(ethylene oxide) group. The number of an alkylene oxide group repeated in a poly(alkylene oxide) group is preferably 2 to 300, in particular, 4 to 150. In a case where this repeating number is excessively small, the effect of enhancing adsorbability on RO membranes due to the poly(alkylene oxide) group cannot be sufficiently provided. In a case where this number is excessively large, the hydrophilic treatment causes a considerable decrease in the flux of RO membranes.
[0025]
In the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, the molar fraction of the unit having a poly(alkylene oxide) group is preferably 0.1 to 50 mol%, more preferably 0.3 to 40 mol%, particularly preferably 0.5 to 30 mol%. In a case where the molar fraction of the unit having a poly(alkylene oxide) group is lower than such a range, advantages according to the present invention due to introduction of the poly(alkylene oxide) chain into poly(vinyl alcohol), such as enhancement of adsorbability on RO membranes and suppression of a decrease in flux, tend not to be sufficiently provided. Conversely, in a case where the molar fraction is higher than the range, the molar fraction of the vinyl alcohol unit correspondingly decreases, which tends to result in reduction in the hydrophilic treatment effect.
[0026]
In the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, the molar fraction of the vinyl alcohol unit is preferably 50 to 99.9 mol%, more preferably 60 to 99.7 mol%, particularly preferably 70 to 99.5 mol%.
In a case where the molar fraction of the vinyl alcohol unit is lower than such a range, the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain has a small number of hydroxy groups, which may result in insufficient hydrophilic treatment effect and flux stability. Conversely, in a case where the molar fraction is higher than the range, the molar fraction of the unit having a poly(alkylene oxide) group correspondingly decreases, so that the advantages due to introduction of a poly(alkylene oxide) chain into poly(vinyl alcohol) may be insufficiently provided.
[0027]
In the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, the molar fraction of the vinyl acetate unit is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, particularly preferably 0 to 5 mol%.
[0028]
An index of a property of poly(vinyl alcohol) is a degree of saponification. The degree of saponification is calculated by dividing the molar fraction of a vinyl alcohol unit by the total molar fraction of the vinyl alcohol unit and a vinyl acetate unit. In the present invention, a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain preferably has a degree of saponification of 80% or more, particularly 85% or more, especially 95% or more. In a case where the degree of saponification is less than 80%, because of a small number of hydroxy groups and low hydrophilicity, the hydrophilic treatment effect and flux stability tend not to be sufficiently provided.
[0029]
The degree of polymerization of the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, that is, the total number of the above-described units is not particularly limited and is preferably 20 to 20,000. An excessively low degree of polymerization results in low adsorbability on membranes and an excessively high degree of polymerization results in a considerable decrease in the flux of RO membranes due to the hydrophilic treatment, which are not preferred.
[0030]
Such a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain can be obtained by a publicly known synthesis method. Alternatively, commercially available products such as "Ecomaty WO-320N" and "Ecomaty WO-32QR" manufactured by The Nippon Synthetic Chemical Industry Co., Ltd. can be used.
[0031]
The modified poly(vinyl alcohol) having a poly(alkylene oxide) chain is preferably synthesized by a method in which a monomer having a poly(alkylene oxide) group is polymerized with vinyl acetate and subsequently vinyl acetate is partially or entirely saponified to provide the modified poly(vinyl alcohol). Alternatively, other synthesis methods may be used.
[0032]
Examples of the monomer having a poly(alkylene oxide) group include poly(ethylene oxide) monovinyl ether, poly(propylene oxide) monovinyl ether, poly(ethylene 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) monomethacrylate, and methoxypolyethylene glycol-polypropylene glycol monoacrylate.
These may be used alone or in combination of two or more thereof.
[0033]
In the present invention, only one modified poly(vinyl alcohol) having a poly(alkylene oxide) chain may be used; alternatively, two or more modified poly(vinyl alcohol)s having a poly(alkylene oxide) chain may be used in combination, the poly(vinyl alcohol)s being different in terms of poly(alkylene oxide) group, molar fractions of units, or degree of polymerization, for example.
[0034]
Such a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain is used, for a hydrophilic treatment for an RO membrane, in the form of an aqueous solution having a concentration of normally about 0.1 to about 5000 rag/L, preferably about 1 to about 1000 mg/L, of the modified poly(vinyl alcohol). Regarding this concentration, an excessively low concentration results in a long treatment time required for providing the intended hydrophilic effect, which is inefficient; and, conversely, an excessively high concentration results in a high viscosity of the aqueous solution, which is not preferred in terms of handling of the aqueous solution to be brought into contact with an RO membrane.
[0035]
Unlike normal poly(vinyl alcohol), a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain used in the present invention is sufficiently soluble in water even at about 40°C to about 60°C. Accordingly, an aqueous solution of the modified poly(vinyl alcohol) can be prepared by simple procedures so as to have a predetermined concentration.
[0036] A water used for preparation of an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain is not particularly limited and may be a water having a low ion load such as desalted water. Alternatively, the treatment can be carried out by adding a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain directly to water to be fed to an RO membrane.
[0037] CHydrophilic treatment method>
The method for bringing a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain into contact with an RO membrane is not particularly limited; preferably, an aqueous solution of the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain is passed by application of pressure through an RO membrane to thereby be brought into contact with the RO membrane.
[0038]
An example of the method is as follows: in a container having a liquid inlet and a liquid outlet and partitioned with an RO membrane to be treated, an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain is introduced through the liquid inlet, made to permeate the RO membrane, and discharged through the liquid outlet. In this case, as described above, the hydrophilic treatment can be carried out by adding the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain directly to RO feed water for an RO membrane module in a normal RO membrane separation apparatus. In summary, a hydrophilic treatment according to the present invention can be carried out for an RO membrane module of an existing RO membrane separation apparatus, during RO membrane separation treatment, by adding a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain directly to water to be treated by the RO membrane; alternatively, the hydrophilic treatment can be carried out while the RO membrane separation treatment is interrupted.
[0039]
The pressure applied to an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain during passing of the aqueous solution through an RO membrane is not particularly limited and is preferably in the range of 0.1 to 2.0 MPa. In order to pass an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain through an RO membrane, a pump used to wash the RO membrane is normally used. In this case, the performance of the pump determines the pressure for passing the solution, to be in the range of 0.1 to 0.5 MPa. The flux during passing of the solution is not particularly limited and Is preferably about 0.1 to about 1.0 m/day. Regarding this condition for passing the solution, an excessively low condition may result in insufficient hydrophilic effect and an excessively high condition may cause a considerable decrease in the flux.
[0040]
The time for the treatment is not particularly limited but preferably 10 minutes or more and less than 48 hours, more preferably 1 hour or more and less than 24 hours. A short treatment time may result in insufficient hydrophilic effect. A long treatment time may cause an excessive decrease in the flux of the RO membrane.
[0041]
The temperature {water temperature) during the hydrophilic treatment is preferably 10°C to 35°C. An excessively low water temperature causes a decrease in the flux, resulting in decreased contact efficiency. An excessively high water temperature may cause problems including degeneration of the membrane material.
[0042] RO membranes having been treated by a hydrophilic treatment method according to the present invention can be suitably used for ultrapure water production systems, wastewater reclamation systems, and other water-treatment systems .
EXAMPLES
[0043]
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative examples.
[0044] [Example 1]
An RO membrane "ES20" (flat membrane, diameter: φ32 mm) manufactured by Nitto Denko Corporation was subjected to a hydrophilic treatment under conditions below. A modified poly(vinyl alcohol) having a poly(alkylene oxide) chain and serving as a hydrophilic treatment agent was used by being dissolved in ultrapure water (60°C). The RO membrane having been subjected to the hydrophilic treatment was evaluated for flux stability by a water-flow test using a water having been subjected to biological treatment in a wastewater reclamation system of Kurita Global Technology Center of Kurita Water Industries Ltd.
[0045] CHydrophilic treatment>
Hydrophilic treatment agent: "Ecomaty WO-320N", manufactured by The Nippon Synthetic Chemical Industry Co., Ltd. (modified poly(vinyl alcohol) having poly(ethylene oxide) chain, degree of saponification: 98.5% or more) Concentration: 100 mg/L Water-flow time: 5 hours Inlet pressure: 0.75 MPa Flux: 1.0 m/day Water temperature: 25°C
[0046] <Water-flow test>
Raw water for water-flow evaluation: water having been subjected to biological treatment in wastewater reclamation system of Kurita Global Technology Center of Kurita Water
Industries Ltd. (in order to control slime, 3 mg/L of "Kuriverter EC-503" manufactured by Kurita Water Industries Ltd. was added; pH 6.5)
Inlet pressure: 0.75 MPa Recovery ratio: 60%
Water temperature: 25°C
[0047]
The RO membrane was subjected to the hydrophilic treatment: the aqueous solution of the modified poly(vinyl alcohol) having a poly(alkylene oxide) chain was passed through the RO membrane under application of pressure under the above-described hydrophilic treatment conditions. Subsequently, the above-described raw water for water-flow evaluation was passed, during which changes in the flux over time were determined (relative values with respect to a water-flow initiation flux defined as 1). The results are illustrated in Fig. 1.
[0048] [Example 2]
An evaluation for flux stability was carried out by the same test as in Example 1 except that the hydrophilic treatment agent used was "Ecomaty WO-320R", manufactured by The Nippon Synthetic Chemical Industry Co., Ltd. (modified poly(vinyl alcohol) having poly(ethylene oxide) chain, degree of saponification: 86.5% to 89.5%). The results are illustrated in Fig. 1.
[0049] [Example 3]
An evaluation for flux stability was carried out by the same test as in Example 1 except that the inlet pressure during the hydrophilic treatment was changed to 0.2 MPa.
The results are illustrated in Fig. 1.
[0050] [Comparative example 1]
An "£320" manufactured by Nitto Denko Corporation (flat membrane, diameter: φ32 mm) without being subjected to the hydrophilic treatment was evaluated for flux stability by the water-flow test. The results are illustrated in Fig. 1.
[0051] [Comparative example 2]
An evaluation for flux stability was carried out by the same test as in Example 1 except that the hydrophilic treatment agent used was poly(vinyl alcohol) (degree of polymerization: 2,000, degree of saponification: 99%). The results are illustrated in Fig. 1.
[0052]
Fig. 1 indicates that, by bringing a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain into contact with an RO membrane, enhanced flux stability is achieved and enhanced persistence of the fouling resistance effect is achieved, compared with the conventional PVA treatment.
[0053]
The present invention has been described in detail with reference to specific embodiments. However, it is obvious for those skilled in the art to understand that various modifications can be made without departing from the spirit and scope of the present invention.
The present application is based on Japanese Patent Application No. 2012-279590 filed on December 21, 2012, the entire contents of which are incorporated herein by reference .
It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
Claims (8)
- CLAIMS 1 A hydrophilic treatment method for a polyamide reverse osmosis membrane, comprising passing an aqueous solution of a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain by application of pressure through a polyamide reverse osmosis membrane.
- 2 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to Claim 1, wherein the modified poly(vinyl alcohol) has a degree of saponification of 80% or more.
- 3 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to Claim 1 or 2, wherein the poly(alkylene oxide) chain is a poly(ethylene oxide) chain .
- 4 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of Claims 1 to 3, wherein the modified poly(vinyl alcohol) is passed by application of pressure through the reverse osmosis membrane in a manner in which, in a container having a liquid inlet and a liquid outlet and partitioned with the reverse osmosis membrane, an aqueous solution containing the modified poly(vinyl alcohol) is passed by being introduced through the liquid inlet, made to permeate the reverse osmosis membrane, and discharged through the liquid outlet.
- 5 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to Claim 4, wherein a pressure applied to the solution being passed is 0.1 to 2.0 MPa and the solution is passed at a flux of 0.1 to 1.0 m/day.
- 6 The hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of Claims 1 to 5, wherein the aqueous solution containing the modified poly(vinyl alcohol) has a concentration of the modified poly(vinyl alcohol) of 0.1 to 5000 mg/L.
- 7 A polyamide reverse osmosis membrane provided by being subjected to a hydrophilic treatment by the hydrophilic treatment method for a polyamide reverse osmosis membrane according to any one of Claims 1 to 6.
- 8 A hydrophilic treatment agent when used in the treatment of a polyamide reverse osmosis membrane, wherein the hydrophilic treatment agent is in the form of an aqueous solution comprising a modified poly(vinyl alcohol) having a poly(alkylene oxide) chain, and wherein the hydrophilic treatment agent is passed through the polyamide reverse osmosis membrane by application of pressure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012-279590 | 2012-12-21 | ||
| JP2012279590A JP2014121681A (en) | 2012-12-21 | 2012-12-21 | Treating method of hydrophilizing reverse osmosis membrane |
| PCT/JP2013/083697 WO2014098059A1 (en) | 2012-12-21 | 2013-12-17 | Method for hydrophilizing reverse osmosis membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2013365015A1 AU2013365015A1 (en) | 2015-06-11 |
| AU2013365015B2 true AU2013365015B2 (en) | 2017-11-02 |
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| AU2013365015A Ceased AU2013365015B2 (en) | 2012-12-21 | 2013-12-17 | Method for hydrophilizing reverse osmosis membrane |
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| Country | Link |
|---|---|
| JP (1) | JP2014121681A (en) |
| CN (1) | CN104994937B (en) |
| AU (1) | AU2013365015B2 (en) |
| TW (1) | TWI605070B (en) |
| WO (1) | WO2014098059A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US11612860B2 (en) * | 2016-08-22 | 2023-03-28 | Trevi Systems Inc. | Osmotic fluid purification and draw compounds thereof |
| CN108939923B (en) * | 2018-07-16 | 2019-07-02 | 安徽智泓净化科技股份有限公司 | A kind of reverse osmosis functional membrane of RO of high-throughput strong anti-pollution |
| US11919986B2 (en) | 2019-03-01 | 2024-03-05 | Nanyang Technological University | Fouling prevention ability-imparting agent and water treatment membrane manufactured using same |
| CN112108009B (en) * | 2020-10-13 | 2022-04-22 | 上海希沃环境科技有限公司 | Polytetrafluoroethylene membrane and hydrophilic treatment method and application thereof |
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| WO2012124745A1 (en) * | 2011-03-14 | 2012-09-20 | 日本ゴア株式会社 | Filter for water treatment filtering and method for producing same |
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| JPS5328083A (en) * | 1976-08-10 | 1978-03-15 | Kurita Water Ind Ltd | Long term maintaining method for inverse osmotic membrane efficiency |
| JP2000024471A (en) * | 1998-07-09 | 2000-01-25 | Daicel Chem Ind Ltd | Solid-liquid separation membrane |
| JP5151152B2 (en) * | 2006-03-29 | 2013-02-27 | 栗田工業株式会社 | Nanofiltration membrane or reverse osmosis membrane rejection rate improver, rejection rate improvement method, nanofiltration membrane or reverse osmosis membrane, water treatment method, and water treatment apparatus |
| JP5644328B2 (en) * | 2009-09-30 | 2014-12-24 | 東レ株式会社 | Hollow fiber membrane module and method for producing hollow fiber membrane module |
-
2012
- 2012-12-21 JP JP2012279590A patent/JP2014121681A/en active Pending
-
2013
- 2013-12-17 CN CN201380067336.3A patent/CN104994937B/en active Active
- 2013-12-17 WO PCT/JP2013/083697 patent/WO2014098059A1/en active Application Filing
- 2013-12-17 AU AU2013365015A patent/AU2013365015B2/en not_active Ceased
- 2013-12-20 TW TW102147510A patent/TWI605070B/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030037914A1 (en) * | 2001-03-27 | 2003-02-27 | Nippon Paint Co., Ltd. | Hydrophilic modification method and heat exchanger treated thereby |
| US20110168626A1 (en) * | 2007-10-01 | 2011-07-14 | Kurita Water Industries Ltd. | Reverse osmosis membrane, reverse osmosis membrane apparatus, and hydrophilic treatment method for reverse osmosis membrane |
| WO2012124745A1 (en) * | 2011-03-14 | 2012-09-20 | 日本ゴア株式会社 | Filter for water treatment filtering and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104994937B (en) | 2017-03-22 |
| JP2014121681A (en) | 2014-07-03 |
| AU2013365015A1 (en) | 2015-06-11 |
| WO2014098059A1 (en) | 2014-06-26 |
| TW201434873A (en) | 2014-09-16 |
| TWI605070B (en) | 2017-11-11 |
| CN104994937A (en) | 2015-10-21 |
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