JP2007167725A - Method and apparatus for modifying separation membrane, and separation membrane modified by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for modifying a separation membrane capable of effectively modifying a separation membrane, when modifying the separation membrane and improving blocking performance, even raw water or the like is in an oxidizing atmosphere, and a separation membrane modified by the method. <P>SOLUTION: Provided are the method and the apparatus for modifying the separation membrane characterized by pressurizing an organic substance containing polyphenol and water containing a reducing agent to make them pass through the separation membrane, so as to improve and recover the blocking performance of the separation membrane, and the separation membrane modified by the method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus relating to a treatment for modifying a separation membrane, particularly a reverse osmosis membrane (RO membrane) or a nanofiltration membrane (NF membrane), and improving the performance with certainty, and a separation membrane modified by the method. It is about.

  Conventionally, as a method for obtaining seawater desalination, ultrapure water, and water for various production processes, for example, a method of separating ionic components and low molecular components from raw water using a module having an RO membrane or NF membrane as a separation membrane is known. It has been. Compared to before, the performance of RO membranes and NF membranes has been greatly improved, and membranes capable of high blocking performance and low pressure operation are also used.

  However, the level of ultrapure water required in recent years is extremely high, and the RO membrane alone is not sufficient. Of course, even when an electric regenerative desalinator (EDI) is installed in the subsequent stage, the RO membrane has 2 There were cases where it had to be used as a step.

  Patent Document 1 proposes a method for producing a membrane having both high desalting properties and high water permeability by immersing a semipermeable membrane in an organic acid at a high temperature. In this method, since processing is performed at a high temperature, it is difficult to perform processing in a module form, and depending on conditions, there is a case where the permeated water amount is significantly reduced.

Patent Document 2 proposes a method of reducing salt permeability by adding tannic acid to seawater at a pH of less than 5. However, this method is limited to seawater treatment, and groundwater, well water, river water, lake water, rainwater, industrial water, tap water, waste leachate, sewage treatment water, Desalination of raw water that has been turbidized as needed, such as agricultural wastewater and water recovered from various processes, is not included.
JP 2003-117360 A JP 58-109182 A

  Although the application has not yet been published, the applicant previously proposed in Japanese Patent Application No. 2005-39061 a method for improving the separation performance by modifying the separation membrane using an organic substance containing polyphenol. (Japanese Patent Application No. 2005-39061). However, with this method, it has been found that there are cases where the effect of the organic substance is insufficient when the raw water supplied to the separation membrane is an oxidizing atmosphere.

  Therefore, in view of such circumstances, the object of the present invention is to effectively improve the separation membrane even when the raw water or the like is in an oxidizing atmosphere when the separation membrane is modified to improve the blocking performance. It is an object of the present invention to provide a separation membrane modification method and apparatus, and a separation membrane modified by the method.

  In the above situation, as a result of intensive studies, the inventors have (1) raw water supplied to the separation membrane and water that dissolves the organic substance by using a certain kind of organic substance and reducing agent in combination. Even in the case of an oxidizing atmosphere, the blocking performance of existing separation membranes, particularly RO membranes and NF membranes, can be reliably improved and recovered. (2) As an injection method, an organic substance and a reducing agent are mixed. Alternatively, it has been found that a great effect can be obtained by adopting any of the methods of line injection in the order of reducing agent and organic substance, and the present invention has been completed.

  That is, the method for reforming a separation membrane according to the present invention is characterized in that water containing an organic substance containing a polyphenol and water containing a reducing agent is passed through the separation membrane to improve and recover the blocking performance of the separation membrane. It consists of a way to do. If the raw water supplied to the separation membrane or the water that dissolves the organic substance is in an oxidizing atmosphere, the organic substance may decompose before reaching the separation membrane, and the effect of modification may not be obtained. It was. By using this method, even when the raw water supplied to the separation membrane or the water for dissolving the organic substance is in an oxidizing atmosphere, the blocking performance of the separation membrane can be reliably improved and recovered.

  As a method for supplying the organic substance containing polyphenol and the water containing the reducing agent to the separation membrane, a mixed liquid in which the organic substance containing polyphenol and the reducing agent are mixed can be supplied to the separation membrane. By using this method, even when the raw water supplied to the separation membrane and the water for dissolving the organic substance are in an oxidizing atmosphere, the work is not complicated compared to the case of using the organic substance alone. The blocking performance of the separation membrane can be reliably improved and recovered.

  In addition, as a method of supplying the organic substance containing polyphenol and water containing the reducing agent to the separation membrane, water containing the reducing agent and water containing the organic substance containing polyphenol are sequentially supplied to the line supplying raw water to the separation membrane. It can be injected and supplied to the separation membrane. By using this method, even when the raw water supplied to the separation membrane is in an oxidizing atmosphere, for example, by utilizing an existing reducing agent injection line, the separation membrane blocking performance can be easily improved and recovered easily. Can be made.

  As the separation membrane, it is preferable to use a separation membrane having a performance of 99% or less of the rejection rate of the 500 mg / L sodium chloride aqueous solution before the modification treatment. A more preferable range of the blocking rate is 10% or more and 99% or less, more preferably 20% or more and 98.5% or less, still more preferably 98% or less, and further preferably 30% or more and 98% or less. By using this method, a reliable performance improvement of the separation membrane is realized. For membranes with a rejection rate exceeding 99%, the effect of modification is low. The rejection rate depends on the temperature and permeation flux at the time of measurement, so the manufacturer applies standard conditions for measuring the performance of the membrane, or in the case of a spiral membrane element, 25 ° C, 1.0 m / day It is better to measure with the permeation flux of as a guide. In the present application, the blocking rate refers to that measured by this method unless otherwise specified.

  In addition, the separation membrane having a performance of 99% or less of the blocking rate before “reforming treatment” as used herein means a membrane having the above performance when used as well as a membrane having the above performance when used as a new membrane. Also included are membranes that are brought into contact with an oxidant such as sodium hypochlorite to forcibly oxidize and deteriorate to achieve the above performance.

  Moreover, it is preferable to use a reverse osmosis membrane or a nanofiltration membrane as the separation membrane. By using this method, it is possible to improve the salt blocking performance of the membrane, the non-dissociation component blocking performance such as silica and boron, and the organic component blocking performance.

  Moreover, it is preferable to use a spiral membrane element as the separation membrane. Spiral membrane elements are inexpensive and have high versatility, so there are significant advantages to using membranes with this structure.

  Moreover, it is preferable to use a membrane containing at least an aromatic polyamide material as the separation membrane. More preferred materials are wholly aromatic polyamides, more preferably crosslinked wholly aromatic polyamides. By including a polyamide-based material in the separation membrane, the effect of modification is further increased.

  The average molecular weight of the organic substance is preferably 200 to 5000. A more preferable average molecular weight is 200 to 3000, and more preferably 200 to 2000. If the average molecular weight is less than 200, the organic substance may permeate the membrane, so the effect is weak. When the average molecular weight exceeds 5000, membrane fouling is caused and only the permeation flux is lowered, and it does not contribute to the improvement of the blocking performance.

  As the organic substance, tannic acid is preferably used. Among polyphenols, the effect of tannic acid is particularly high, and it is preferable to use this substance.

  As tannic acid, hydrolyzable tannin is preferably used. Tannic acid has a hydrolysis type and a condensation type, and the former is particularly effective.

  Further, as the tannic acid, it is preferable to use a pentonic acid made as a raw material. Tannic acid extracted from pentaploids generally has an average molecular weight of about 1700, and is estimated to be suitable for modification.

  As the reducing agent, a substance containing at least one of sodium sulfite and sodium hydrogen sulfite can be used. Although it does not specifically limit as a reducing agent to be used, Sodium sulfite and sodium hydrogen sulfite are general purpose reducing agents conventionally used, and since cost is cheap, it is preferable to use these.

  The present invention also provides a separation membrane modified by the method for modifying a separation membrane as described above.

  The apparatus for reforming a separation membrane according to the present invention is characterized in that the separation membrane has means for pressurizing water containing an organic substance containing polyphenol and a reducing agent to improve and recover the separation membrane blocking performance. It is made up of.

  The means for supplying the organic substance containing polyphenol and the water containing the reducing agent to the separation membrane may be a means for supplying a mixed liquid in which the organic substance containing polyphenol and the reducing agent are mixed to the separation membrane.

  Further, as means for supplying water containing the organic substance containing polyphenol and the reducing agent to the separation membrane, water containing the reducing agent and water containing the organic substance containing polyphenol are sequentially supplied to the line supplying raw water to the separation membrane. It can also be a means for injecting and supplying to the separation membrane.

  As the separation membrane, it is preferable to use a separation membrane having a performance of 99% or less of the rejection rate of the 500 mg / L sodium chloride aqueous solution before the modification treatment.

  In addition, a reverse osmosis membrane or a nanofiltration membrane is preferably used as the separation membrane.

  Moreover, it is preferable to use a spiral membrane element as the separation membrane.

  Moreover, it is preferable to use a membrane containing at least an aromatic polyamide material as the separation membrane.

  The average molecular weight of the organic substance is preferably 200 to 5000.

  Further, tannic acid is preferably used as the organic substance.

  As tannic acid, hydrolyzable tannin is preferably used.

  Moreover, it is preferable to use the tannic acid made from a pentaploid as a raw material.

  As the reducing agent, a substance containing at least one of sodium sulfite and sodium hydrogen sulfite is preferably used.

  According to the present invention, even when raw water or the like is in an oxidizing atmosphere, the separation membrane can be effectively modified, and the blocking performance is greatly and reliably improved by modifying the commercially available separation membrane. Thus, it is possible to provide a membrane that realizes further lower pressure while maintaining high blocking performance. In addition, there is a great effect on reliable performance recovery and stable operation of a deteriorated film, and the industrial utility value is very high.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below shows an example of this invention and does not restrict | limit the content of this invention.

  A method for reforming a separation membrane according to a first embodiment (off-line processing) of the present invention will be described with reference to FIG. FIG. 1 is an equipment system diagram of a membrane reforming apparatus for carrying out the treatment method of this example (a pressure gauge, a flow meter, a valve, etc. are omitted as appropriate). Reference numeral 1 denotes a separation membrane supply water tank (raw water tank), 2 denotes a pressure pump, 3 denotes a separation membrane module, 4 denotes a pressure control valve, and 5 to 9 denote valves composed of ball valves. The separation membrane module 3 includes a membrane element 31 that is the separation membrane itself and a vessel 32 that is a pressure-resistant container for storing the membrane element.

  After the membrane element 31 is loaded in the vessel 32, a sufficient amount of water is put into the tank 1 with the valve 5 closed, the valves 6, 8, 9 are closed, the valves 5, 7 are opened, and the valve 4 is opened appropriately. The pump 2 is started. Water is passed for a while without applying pressure, and the separation membrane module 3 is washed with water while supplying water to the tank 1 if necessary. In addition, the state which does not apply the pressure said by this invention means the state of the low pressure which cannot permeate.

  Next, after the pump 2 is stopped, the valve 5 is closed, a predetermined amount of water is put into the tank 1, and a predetermined amount of organic substances and reducing agents as reforming chemicals are added to sufficiently dissolve. The valves 2 and 9 are closed, the valves 5, 6 and 8 are opened, and the valve 4 is opened to a predetermined pressure, and the pump 2 is started.

  After a predetermined time has elapsed, the pump 2 is stopped, the valve 9 is opened, and the chemical solution in the tank 1 is discharged. After washing the tank 1 with water, the valve 9 is closed and water is stored. The valves 2, 8 and 9 are closed, the valves 5 and 7 are opened, the valve 4 is opened as appropriate, and the pump 2 is started. Water is passed for a while without applying pressure, and the separation membrane module 3 is washed with water while supplying water to the tank 1 if necessary. Further, the valve 6 is also opened, and the circulation line is appropriately washed with water.

  The separation membrane after the reforming treatment can be used in the entire system of the water treatment apparatus. For example, the raw water can be subjected to a turbidity treatment by a method such as coagulation sedimentation, sand filtration, membrane filtration, etc., and then a modified separation membrane can be used, or EDI can be used in the subsequent stage.

  The water supplied to the tank 1 is preferably pure water. However, when pure water cannot be used, turbid water having an SDI value of 5 or less may be used. In this method, since the reducing agent is added, even water in an oxidizing atmosphere can be used other than pure water as long as it is turbid water that does not affect the separation membrane. Even when pure water is used, since oxygen in the air dissolves in the solution in the long term, an oxidizing atmosphere is created and the effect of the organic substance may be reduced. It is more preferable to add.

  The treatment time is not particularly limited, but it is preferably 5 minutes to 24 hours, preferably 10 minutes to 6 hours, for efficient treatment. If it is less than 5 minutes, the effect of the treatment is weak, and if it exceeds 24 hours, fouling may occur or further improvement of the treatment effect may not be expected.

  As a method of confirming the effect of the treatment before and after the modification treatment, an aqueous electrolyte solution such as sodium chloride, calcium chloride, magnesium sulfate is used to evaluate the salt blocking performance, silica (sodium silicate) and alcohols. It is preferable to evaluate the blocking performance of TOC components such as Usually, an electrolyte aqueous solution is often used for performance evaluation of RO and NF. However, since the blocking performance of non-electrolyte components is improved by the modification treatment, it is preferable to use silica or TOC as an index.

  A method for reforming a separation membrane according to a second embodiment (on-line processing) of the present invention will be described with reference to FIG. FIG. 2 is an equipment system diagram of the separation membrane device for carrying out the operation method of this example (pressure gauge, flow meter, valve and the like are omitted as appropriate). 1 is a separation membrane supply water tank (raw water tank), 2 is a pressurizing pump, 3 is a separation membrane module, 4 is a pressure control valve, 4 to 9 are valves consisting of ball valves, 10 and 20 are chemical tanks, 11 and 21 Indicates a chemical injection pump, respectively. The separation membrane module 3 includes a membrane element 31 that is the separation membrane itself and a vessel 32 that is a pressure-resistant container for storing the membrane element.

  During normal operation, the feed water tank 1 receives water from the previous stage, for example, raw water subjected to turbidity treatment. The valves 5 and 7 are opened, the valve 4 is opened to a predetermined pressure, the valves 6, 8 and 9 are closed, and the raw water pressurized by the pressure pump 2 is converted into concentrated water by the separation membrane module 3. The water is separated into permeated water, the concentrated water is blown, and the permeated water is sent to the subsequent apparatus. In some cases, the ball valves 6 and 7 are appropriately adjusted to partially circulate the concentrated water.

  The chemical solution tank 10 stores a reducing agent aqueous solution having a predetermined concentration in advance, and the chemical solution tank 20 stores an organic substance aqueous solution having a predetermined concentration in advance. When the water quality meter 12 falls below a certain reference value, an electric signal is sent to the chemical injection pumps 11 and 21, and the pump is started. The medicinal pumps 11 and 21 are set in advance to have a predetermined injection amount.

  When the water quality meter 12 exceeds a certain reference value after the start of injection, an electric signal is sent to the medicinal pumps 11 and 21, and the pump is stopped.

  In addition, in the case of adding intermittently and when adding at regular intervals, no electrical signal from the water quality meter is required, and the dosing pumps 11 and 21 are started automatically or manually at regular intervals. That's fine. Moreover, when adding continuously, the chemical injection pumps 11 and 21 are always started. Note that when the reducing agent is added for the purpose of reducing the oxidizing agent contained in the raw water, the chemical injection pump 11 is turned on regardless of whether the organic substance is added intermittently or continuously. Always start and add the reducing agent continuously.

  During the addition of organic substances, normal operation does not need to be stopped if there is no hindrance to the subsequent stage. When leakage of organic substances into the permeated water is observed and there is a possibility that the latter stage may be hindered, the permeated water can be blown with the valve 5 closed and the valve 9 opened during the addition. It is also possible to circulate the permeate by closing 5 and opening the valve 8. In the case of circulation, the concentrated water may be circulated by closing the valve 7 and opening the valve 6. In this case, the drug injection pumps 11 and 21 are stopped when the chemical solution concentration reaches a certain concentration.

  In the above-described embodiment, the form of one module is exemplified, but the present invention can also be applied to a separation membrane device constituted by a plurality of modules including a plurality of elements such as a Christmas tree-like arrangement and a two-stage RO.

  The concentration of the organic substance that is the modifying chemical is not particularly limited, but is preferably 0.1 to 200 mg / L, preferably 0.5 to 100 mg / L, at the inlet of the separation membrane module for efficient treatment. Less than 0.1 mg / L is less effective, and more than 200 mg / L may cause fouling, which is not preferable.

  The concentration of the reducing agent is not particularly limited, but is preferably 0.1 to 200 mg / L, preferably 0.2 to 100 mg / L, at the inlet of the separation membrane module for efficient treatment. If it is less than 0.1 mg / L, the effect is weak, and if it exceeds 200 mg / L, the chemical cost is increased, which is not preferable.

  In order to obtain a suitable reforming effect, it is desirable that the permeation flux during pressurized water flow is in the range of 0.3 to 5.0 m / day. A more preferable permeation flux range is 0.5 to 3.0 m / day, and even more preferably 0.7 to 2.0 m / day. If it is less than 0.3 m / day, the effect of adsorbing organic substances is low, and improvement in the blocking performance cannot be expected. If it exceeds 5.0m / day, fouling may occur, which is not preferable. Conventionally, there has been a case where tannic acid treatment is performed with a hollow fiber RO membrane for seawater, but the permeation flux during the treatment is very low, and the effect is insufficient. In the method of the present invention, a high reforming effect can be realized by performing the treatment with a high permeation flux of 0.3 to 5.0 m / day.

  An acid may be added to water containing the organic substance to adjust the pH to 1-5. By controlling the pH within the above range, precipitation of organic substances can be prevented and reforming can be carried out appropriately. The acid is not particularly limited, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, citric acid, oxalic acid, carboxylic acid, and the like can be used. In particular, citric acid is easy to use because it is easily available and has low toxicity. Good operability.

  The polyphenol as used in the field of this invention refers to the general polyphenol which named generically the aromatic compound which the some hydroxyl group couple | bonded. Examples of the polyphenol include anthocyanins, catechins, tannins, rutin, quercetin, isoflavones, flavonoids, humins, and fulvic acids, but are not particularly limited.

  Tannins are also called tannic acid and tannins, and are used confusedly, but are all used synonymously in the present application. In addition, pentaploid tannin is sometimes called gallotannin. In addition, a quintuplet is an insect cob of the genus Nurde.

  Tannic acid has a hydrolysis type and a condensation type. Examples of the former ingredients include pentaploid, gallic, chestnut, oak wood, eucalyptus, divi-divi, tara, sumac, myrabolam , Algarobilla, Valonea, walnuts, chestnuts, mallet, gummy, pomegranate, red-crowned whale, urchinaceae, sanshuyu, genokosho. Examples of the latter raw materials include Keebracho, Burma Cutch, Wattle, Mimosa, Spruse, Hemlock, Mangrove, Oak bark , Abalam, Gambier, tea, persimmon astringent, cypress, grape, apple, lotus root, coffee, perilla, bokeh, persimmon, rosemary, parsley, salvia flower, sunflower, and the like. The hydrolysis type is also called pyrogallol type (Hydrolyzable Tannin), and the condensation type is also called catechol type (Condensel Tannin).

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

Example 1
The reforming process was performed by the method shown in the first embodiment in the apparatus shown in FIG. 1 using pentaploid tannin as an organic substance and sodium hydrogen sulfite as a reducing agent. The membrane used was a new LES90-D8 manufactured by Nitto Denko Corporation. The chemical solution concentration was 50 mg / L at the inlet of the separation membrane, and the dissolved water used was turbidity water with an oxidation tendency with an ORP of +600 mV. The treatment time was 1 hour, and the permeation flux during the treatment was 1.0 m / day.

Comparative Example 1-1
In Example 1, the treatment was performed in the same manner as in Example 1 except that the reducing agent was not used and only the reforming treatment with pentaploid tannin was performed.

Comparative Example 1-2
In Example 1, the treatment was performed in the same manner as in Example 1 except that no organic substance was used and only sodium bisulfite was added.

Before and after the treatment, the NaCl permeability (salt permeability) and Ca ²⁺ permeability of each film were measured to evaluate the performance. In addition, the salt permeability was evaluated by electrical conductivity. The permeation flux at the time of performance evaluation was 1.0 m / day. The results are shown in Table 1.

  In Comparative Example 1-1 in which the reducing agent was not used and only the modification treatment with pentaploid tannin was performed, the effect was insufficient as compared with Example 1, although there was a slight modification effect. It is presumed that the organic material was decomposed before the organic material reached the separation membrane. In Comparative Example 1-2 in which no addition of sodium hydrogen sulfite was performed without using an organic substance, no performance improvement was observed. On the other hand, in Example 1 using a mixed liquid of an organic substance and a reducing agent, a significant performance improvement was observed and the effect of the modification was great.

Example 2
The treatment was performed by the method shown in the second embodiment using the apparatus shown in FIG. 2 using pentaploid tannin as an organic substance and sodium sulfite as a reducing agent. The raw water received in tank 1 was groundwater that was turbidized by the membrane turbidizer in the previous stage, and the conductivity during the operation period was stable at an average of around 20 mS / m. The ORP averaged +600 mV, and it was water with an oxidation tendency. The membrane used was Nitto Denko ES-10-D8. The organic substance and reducing agent concentrations were adjusted to 10 mg / L at the inlet of the separation membrane module. The conductivity of the permeated water was monitored with a water quality meter, and the organic substance was set to be added under the following conditions.
・ 1mS / m or more: Start of addition ・ 0.7mS / m or less: Stop of addition

Comparative Example 2-1
In Example 2, the treatment was performed in the same manner as in Example 2, except that the reducing agent was not used and only the treatment with pentaploid tannin was performed.

Comparative Example 2-2
In Example 2, the treatment was performed in the same manner as in Example 2 except that no organic substance was used and only sodium sulfite was added.

  Continuous operation was carried out under the above conditions, and the performance was evaluated in the initial operation, after 1 month, 2 months, and 3 months. The permeated water amount is shown as a relative value with the initial operation being 100. The results are shown in Table 2.

  In Comparative Example 2-1, in which only the treatment with pentaploid tannin was carried out without using a reducing agent, although a slight treatment effect was seen, the effect was insufficient as compared with Example 2, and the performance over time Degradation has happened. It is presumed that the organic material was decomposed before the organic material reached the separation membrane. In Comparative Example 2-2 in which an organic substance was not used and only sodium sulfite was added, performance was not recovered at all, and significant performance degradation occurred. On the other hand, in Example 2 in which the organic substance and the reducing agent were used together, stable operation was possible and the effect of the treatment was great.

  The separation membrane reforming method and apparatus according to the present invention and the separation membrane treated by the method can be used in any application that requires effective modification of the separation membrane even when raw water or the like is in an oxidizing atmosphere. In particular, it is suitable for modifying reverse osmosis membranes and nanofiltration membranes.

It is an equipment distribution diagram of a reforming device of a separation membrane concerning a 1st embodiment of the present invention. It is an equipment distribution diagram of a reforming device of a separation membrane concerning a 2nd embodiment of the present invention.

Explanation of symbols

1 Separation membrane supply water tank (raw water tank)
2 Pressurizing pump 3 Separation membrane module 4, 5, 6, 7, 8, 9 Valve 10 Chemical tank (reducing agent aqueous solution storage)
11, 21 Chemical pump 20 Chemical tank (organic substance aqueous solution storage)
31 Membrane element 32 Vessel as pressure vessel

Claims (25)

  A method for reforming a separation membrane, wherein water containing an organic substance containing polyphenol and a reducing agent is passed through the separation membrane under pressure to improve and recover the blocking performance of the separation membrane.   The method of supplying water containing the organic substance containing polyphenol and the reducing agent to the separation membrane is characterized in that a mixed liquid obtained by mixing the organic substance containing polyphenol and the reducing agent is supplied to the separation membrane. 2. A method for modifying a separation membrane according to 1.   As a method of supplying the organic substance containing polyphenol and the water containing the reducing agent to the separation membrane, the water containing the reducing agent and the water containing the organic substance containing the polyphenol are injected into the line for supplying the raw water to the separation membrane in this order. The method for reforming a separation membrane according to claim 1, wherein the method is supplied to the separation membrane.   The separation membrane according to any one of claims 1 to 3, wherein a separation membrane having a performance of 99% or less is used as the separation membrane. Separation membrane modification method.   The method for reforming a separation membrane according to any one of claims 1 to 4, wherein a reverse osmosis membrane or a nanofiltration membrane is used as the separation membrane.   The method for reforming a separation membrane according to any one of claims 1 to 5, wherein a spiral membrane element is used as the separation membrane.   The method for reforming a separation membrane according to any one of claims 1 to 6, wherein a membrane containing at least an aromatic polyamide material is used as the separation membrane.   The method for reforming a separation membrane according to any one of claims 1 to 7, wherein an average molecular weight of the organic substance is 200 to 5,000.   The method for modifying a separation membrane according to any one of claims 1 to 8, wherein tannic acid is used as the organic substance.   The method for modifying a separation membrane according to claim 9, wherein hydrolyzable tannin is used as the tannic acid.   11. The method for reforming a separation membrane according to claim 9, wherein the tannic acid is made from a pentaploid as a raw material.   The method for reforming a separation membrane according to any one of claims 1 to 11, wherein a substance containing at least one of sodium sulfite and sodium hydrogen sulfite is used as the reducing agent.   A separation membrane modified by the method for modifying a separation membrane according to claim 1.   An apparatus for reforming a separation membrane, comprising means for pressurizing water containing an organic substance containing polyphenol and a reducing agent through the separation membrane to improve and recover the blocking performance of the separation membrane.   The means for supplying water containing the organic substance containing polyphenol and the reducing agent to the separation membrane comprises a means for supplying a mixed liquid in which the organic substance containing polyphenol and the reducing agent are mixed to the separation membrane, The apparatus for reforming a separation membrane according to claim 14.   As means for supplying water containing the organic substance containing polyphenol and reducing agent to the separation membrane, water containing reducing agent and water containing organic substance containing polyphenol are injected into the line for supplying raw water to the separation membrane in this order. The apparatus for reforming a separation membrane according to claim 14 or 15, comprising means for supplying to the separation membrane.   The separation membrane according to any one of claims 14 to 16, wherein a separation membrane having a performance of 99% or less of a rejection rate of a 500 mg / L sodium chloride aqueous solution before the reforming treatment is used as the separation membrane. Separation membrane reformer.   The apparatus for reforming a separation membrane according to any one of claims 14 to 17, wherein a reverse osmosis membrane or a nanofiltration membrane is used as the separation membrane.   The apparatus for reforming a separation membrane according to any one of claims 14 to 18, wherein a spiral membrane element is used as the separation membrane.   The apparatus for reforming a separation membrane according to any one of claims 14 to 19, wherein a membrane containing at least an aromatic polyamide material is used as the separation membrane.   21. The apparatus for reforming a separation membrane according to claim 14, wherein an average molecular weight of the organic substance is 200 to 5,000.   The apparatus for reforming a separation membrane according to any one of claims 14 to 21, wherein tannic acid is used as the organic substance.   The apparatus for reforming a separation membrane according to claim 22, wherein hydrolyzable tannin is used as the tannic acid.   The apparatus for reforming a separation membrane according to claim 22 or 23, wherein the tannic acid is made from a pentaploid as a raw material.   The apparatus for reforming a separation membrane according to any one of claims 14 to 24, wherein a substance containing at least one of sodium sulfite and sodium hydrogen sulfite is used as the reducing agent.

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