JP2014050783A

JP2014050783A - Check ratio improvement method of reverse osmotic membrane

Info

Publication number: JP2014050783A
Application number: JP2012196245A
Authority: JP
Inventors: Kunihiro Hayakawa; 邦洋早川; Takahiro Kawakatsu; 孝博川勝
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2012-09-06
Filing date: 2012-09-06
Publication date: 2014-03-20

Abstract

PROBLEM TO BE SOLVED: To provide a check ratio improvement method of a reverse osmotic membrane capable of effectively improving the check ratio without largely reducing a permeation flux even in a considerably deteriorated membrane.SOLUTION: The check ratio improvement method of the reverse osmotic membrane is provided for contacting a first aqueous solution including an organic compound having an amino group of molecular weight less than 500 and a second aqueous solution having a polyphenol compound of molecular weight of 500 or more with the reverse osmotic membrane. The check ratio improvement method of the reverse osmotic membrane executes one time or more of treatment for alternately contacting the first aqueous solution and the second aqueous solution with the reverse osmotic membrane, by contacting the second aqueous solution with the reverse osmotic membrane after contacting the first aqueous solution with the reverse osmotic membrane.

Description

本発明は、逆浸透膜（ＲＯ膜）の阻止率（脱塩率、除去率）向上方法に係り、特に劣化したＲＯ膜を修復して、その阻止率を効果的に向上させる方法に関する。 The present invention relates to a method for improving a rejection rate (desalting rate, removal rate) of a reverse osmosis membrane (RO membrane), and more particularly to a method for repairing a deteriorated RO membrane and effectively improving the rejection rate.

ＲＯ膜は、超純水製造プラント、排水回収プラント、海水淡水化プラントなどで使用されており、ＲＯ膜処理により、水中の有機物、無機物などの大部分を除去することができる。 RO membranes are used in ultrapure water production plants, wastewater collection plants, seawater desalination plants, and the like, and most of organic substances and inorganic substances in water can be removed by RO membrane treatment.

しかし、ＲＯ膜は水中に存在する酸化性物質や還元性物質の影響を受けたり、酸・アルカリ洗浄、経年劣化などから、阻止率（脱塩率、除去率）が徐々に低下し、必要な透過水（処理水）水質が得られなくなることがある。また、予期せぬトラブルにより阻止率が低下することもあるし、また、製品としてのＲＯ膜の阻止率自体が要求されるレベルに達していない場合もある。 However, RO membranes are affected by the effects of oxidizing substances and reducing substances present in water, acid / alkali cleaning, aging, etc., and the blocking rate (desalting rate, removal rate) gradually decreases, and is necessary. Permeate (treated water) water quality may not be obtained. In addition, the blocking rate may decrease due to an unexpected trouble, and the blocking rate itself of the RO membrane as a product may not reach a required level.

特に、ＲＯ膜を用いた水処理システムにおいては、系内でのスライムの繁殖によるバイオファウリングを防止するために、前処理工程において塩素（次亜塩素酸ソーダなど）による原水の処理が行われているが、塩素は強力な酸化剤であり、残留塩素を十分に還元しないままＲＯ膜に供給すると、塩素がＲＯ膜に接触し、ＲＯ膜が劣化する。 In particular, in a water treatment system using an RO membrane, raw water is treated with chlorine (such as sodium hypochlorite) in a pretreatment process in order to prevent biofouling due to the propagation of slime in the system. However, chlorine is a strong oxidant, and when residual chlorine is supplied to the RO membrane without sufficiently reducing it, the chlorine comes into contact with the RO membrane and the RO membrane deteriorates.

また、残留塩素を分解するために、重亜硫酸ナトリウムなどの還元剤を添加することがあるが、重亜硫酸ナトリウムが過剰に添加されている還元性環境下において、ＣｕやＣｏ、Ｍｎ、Ｆｅなどの重金属が共存すると、ＲＯ膜が劣化することも知られている（特許文献１、非特許文献２）。 In order to decompose residual chlorine, a reducing agent such as sodium bisulfite may be added. In a reducing environment where sodium bisulfite is added excessively, Cu, Co, Mn, Fe, etc. It is also known that when a heavy metal coexists, the RO membrane deteriorates (Patent Document 1, Non-Patent Document 2).

従来、ＲＯ膜等の透過膜の阻止率向上方法としては、以下のようなものが提案されている。 Conventionally, the following methods have been proposed as methods for improving the rejection rate of permeable membranes such as RO membranes.

(1) アニオン又はカチオンのイオン性高分子化合物を膜表面に付着させることにより、透過膜の阻止率を向上させる方法（特許文献２）。
(2) ポリアルキレングリコール鎖を有する化合物を膜表面に付着させることにより、ナノ濾過膜やＲＯ膜の阻止率を向上させる方法（特許文献３）。
(3) タンニン酸などを劣化膜に付着させて脱塩率を改善させる方法（非特許文献２）。 (1) A method for improving the blocking rate of a permeable membrane by attaching an anionic or cationic ionic polymer compound to the membrane surface (Patent Document 2).
(2) A method for improving the blocking rate of a nanofiltration membrane or RO membrane by attaching a compound having a polyalkylene glycol chain to the membrane surface (Patent Document 3).
(3) A method of improving the desalination rate by attaching tannic acid or the like to a deteriorated film (Non-patent Document 2).

しかし、これらの従来法は、透過流束の低下が大きく、阻止率を回復させても、透過流束が処理前の２０％以上低下する場合があったり、非常に劣化の大きな膜に対しては十分に回復させることが困難である、といった問題があった。 However, these conventional methods have a large decrease in the permeation flux, and even when the rejection rate is recovered, the permeation flux may decrease by 20% or more before the treatment, or for a film with a very large deterioration. Had a problem that it was difficult to fully recover.

これら従来法の問題を解決するものとして、本発明者は、分子量２００未満の第１の有機化合物と、分子量２００以上５００未満の第２の有機化合物と、分子量５００以上の第３の有機化合物とを含む水溶液を逆浸透膜に通水する方法を提案した（特許文献４）。この方法は、従来法よりも阻止率向上効果が高く、透過流束も低下しにくい方法であるが、膜の劣化状態によっては、阻止率向上効果が十分でない場合があった。 In order to solve the problems of these conventional methods, the present inventor has developed a first organic compound having a molecular weight of less than 200, a second organic compound having a molecular weight of 200 or more and less than 500, and a third organic compound having a molecular weight of 500 or more. A method of passing an aqueous solution containing water through a reverse osmosis membrane was proposed (Patent Document 4). This method has a higher rejection rate improvement effect than the conventional method and is less likely to reduce the permeation flux. However, depending on the deterioration state of the film, the rejection rate improvement effect may not be sufficient.

特開平７−３０８６７１号公報JP-A-7-308671 特開２００６−１１０５２０号公報JP 2006-110520 A 特開２００７−２８９９２２号公報JP 2007-289922 A 特願２０１１−５１５３０Japanese Patent Application No. 2011-51530

Nagai et al. Desalination, Vol.96(1994),291-301Nagai et al. Desalination, Vol.96 (1994), 291-301 佐藤、田村、化学工学論文集、Vol.34(2008),493-498Sato, Tamura, Chemical Engineering, Vol.34 (2008), 493-498

本発明は、著しい劣化膜であっても透過流束を大きく低下させることなく従来方法よりも効果的に阻止率を向上させることができる方法を提供することを課題とする。 It is an object of the present invention to provide a method capable of improving the rejection rate more effectively than the conventional method without greatly reducing the permeation flux even with a significantly deteriorated film.

本発明者は、上記課題を解決すべく、鋭意検討を重ね、次のような知見を得た。 In order to solve the above-mentioned problems, the present inventor has made extensive studies and obtained the following knowledge.

１）従来法のように、膜の劣化で膜にあいた穴を、新たな物質（例えば、ノニオン系界面活性剤やカチオン系界面活性剤などの化合物）を膜に付着させることにより塞ぐ方法では、膜の疎水化や、高分子物質の付着による膜の透過流束の低下が著しく、水量の確保が困難である。
２）ＲＯ膜、例えばポリアミド膜は、酸化剤による劣化で、ポリアミドのＣ−Ｎ結合が分断され、膜本来のふるい構造が崩壊する。膜の劣化箇所においては、アミド結合の分断でアミド基は消失してしまうものの、カルボキシル基が一部残存する。
３）この劣化膜のカルボキシル基にアミノ化合物を効率良く付着・結合させることにより、劣化膜を修復して阻止率を回復させることができる。カルボキシル基に結合させるアミノ化合物として、分子量５００未満の低分子量化合物を用いることにより、膜劣化で形成された穴の大きさに応じて、劣化部分を効率よく修復し、除去率を回復させることができる。また、分子量５００以上の物質を用いて大きな穴を修復することができる。
４）これらの物質が一度では修復できない大きな劣化部位も、分子量の異なる有機化合物を交互に用いて繰り返し処理することで、大小さまざまな劣化部位を徐々に緻密化し、最終的には穴を修復する補修層を形成することができると考えられ、阻止率向上効果に優れたものとなる。 1) As in the conventional method, in a method of closing a hole formed in a film by deterioration of the film by attaching a new substance (for example, a compound such as a nonionic surfactant or a cationic surfactant) to the film, It is difficult to ensure the amount of water because the membrane is hydrophobized and the permeation flux of the membrane is significantly reduced due to the adhesion of polymer substances.
2) RO membranes, such as polyamide membranes, are deteriorated by an oxidizing agent, so that the CN bond of polyamide is broken and the original sieve structure of the membrane is destroyed. In the degraded part of the film, the amide group disappears due to the amide bond breakage, but a part of the carboxyl group remains.
3) By efficiently attaching and bonding an amino compound to the carboxyl group of the deteriorated film, the deteriorated film can be repaired and the blocking rate can be recovered. By using a low molecular weight compound having a molecular weight of less than 500 as the amino compound to be bonded to the carboxyl group, the degraded portion can be efficiently repaired and the removal rate can be restored according to the size of the hole formed by the film degradation. it can. In addition, a large hole can be repaired using a substance having a molecular weight of 500 or more.
4) Even large degradation sites that cannot be repaired at once by these substances are treated repeatedly using organic compounds with different molecular weights, and the degradation sites of various sizes are gradually refined and finally the holes are repaired. It is considered that the repair layer can be formed, and the effect of improving the rejection rate is excellent.

このような知見をもとに、本発明者は分子量５００未満のアミノ基を有する有機化合物を含有する第一の水溶液と、分子量５００以上のポリフェノール化合物を含有する第二の水溶液とを用い、これらを交互に複数回ＲＯ膜に接触させる阻止率向上処理であれば、従来法より、阻止率向上効果に優れたものとなることを見出し、本発明を完成させた。 Based on such knowledge, the present inventor uses a first aqueous solution containing an organic compound having an amino group having a molecular weight of less than 500 and a second aqueous solution containing a polyphenol compound having a molecular weight of 500 or more. The present invention has been completed by finding that the blocking rate improving treatment in which the substrate is alternately brought into contact with the RO membrane a plurality of times is superior to the conventional method in improving the blocking rate.

即ち、本発明は以下を要旨とする。 That is, the gist of the present invention is as follows.

［１］分子量５００未満のアミノ基を有する有機化合物を含有する第一の水溶液と、分子量５００以上のポリフェノール化合物を含有する第二の水溶液を逆浸透膜に接触させる逆浸透膜の阻止率向上方法であって、前記第一の水溶液を逆浸透膜に接触させた後、前記第二の水溶液を該逆浸透膜に接触させ、更に第一の水溶液と第二の水溶液を交互に該逆浸透膜に接触させる処理を１回以上行うことを特徴とする逆浸透膜の阻止率向上方法。 [1] A reverse osmosis membrane blocking rate improving method in which a first aqueous solution containing an organic compound having an amino group having a molecular weight of less than 500 and a second aqueous solution containing a polyphenol compound having a molecular weight of 500 or more are brought into contact with the reverse osmosis membrane. The first aqueous solution is brought into contact with the reverse osmosis membrane, the second aqueous solution is brought into contact with the reverse osmosis membrane, and the first aqueous solution and the second aqueous solution are alternately brought into contact with the reverse osmosis membrane. A method for improving the rejection rate of a reverse osmosis membrane, characterized in that the treatment of contacting with water is performed once or more.

［２］［１］において、前記分子量５００未満のアミノ基を有する有機化合物がアミノ基を２つ以上有する化合物であることを特徴とする逆浸透膜の阻止率向上方法。 [2] The method for improving the rejection of a reverse osmosis membrane according to [1], wherein the organic compound having an amino group having a molecular weight of less than 500 is a compound having two or more amino groups.

［３］［１］又は［２］において、前記第一の水溶液における前記分子量５００未満のアミノ基を有する有機化合物の濃度が１．０〜５００ｍｇ／Ｌであり、前記第二の水溶液における前記分子量５００以上のポリフェノール化合物の濃度が１．０〜５００ｍｇ／Ｌであることを特徴とする逆浸透膜の阻止率向上方法。 [3] In [1] or [2], the concentration of the organic compound having an amino group having a molecular weight of less than 500 in the first aqueous solution is 1.0 to 500 mg / L, and the molecular weight in the second aqueous solution is A method for improving the rejection rate of a reverse osmosis membrane, wherein the concentration of 500 or more polyphenol compounds is 1.0 to 500 mg / L.

［４］［１］ないし［３］のいずれかにおいて、下記式で定義される膜単位面積当りの有機化合物接触量が、前記分子量５００未満のアミノ基を有する有機化合物及び分子量５００以上のポリフェノール化合物のそれぞれについて２，５００ｍｇ／ｍ^２以上となるように、前記第一の水溶液及び第二の水溶液をそれぞれ逆浸透膜に通水することを特徴とする逆浸透膜の阻止率向上方法。
有機化合物接触量（ｍｇ／ｍ^２）＝［水溶液中の有機化合物濃度（ｍｇ／Ｌ）×処理時間（ｈｒ）×処理時透過水量（ｍ^３／ｈｒ）／膜面積（ｍ^２）］×１０００
（ここで、水溶液中の有機化合物濃度は、前記第一の水溶液中における分子量５００未満のアミノ基を有する有機化合物の濃度、又は前記第二の水溶液中における分子量５００以上のポリフェノール化合物の濃度である。） [4] In any one of [1] to [3], the organic compound contact amount per unit film area defined by the following formula is an organic compound having an amino group having a molecular weight of less than 500 and a polyphenol compound having a molecular weight of 500 or more. A method for improving the blocking rate of a reverse osmosis membrane, wherein each of the first aqueous solution and the second aqueous solution is passed through the reverse osmosis membrane so that each of the aqueous solutions is 2,500 mg / m ² or more.
Contact amount of organic compound (mg / m ² ) = [concentration of organic compound in aqueous solution (mg / L) × treatment time (hr) × permeated water amount during treatment (m ³ / hr) / membrane area (m ² )] × 1000
(Here, the concentration of the organic compound in the aqueous solution is the concentration of the organic compound having an amino group having a molecular weight of less than 500 in the first aqueous solution, or the concentration of the polyphenol compound having a molecular weight of 500 or more in the second aqueous solution. .)

［５］［１］ないし［４］のいずれかに記載の逆浸透膜の阻止率向上方法により阻止率向上処理が施されたことを特徴とする逆浸透膜。 [5] A reverse osmosis membrane, which has been subjected to a rejection improvement process by the method for improving the rejection of a reverse osmosis membrane according to any one of [1] to [4].

本発明によれば、分子量５００未満のアミノ基を有する有機化合物を含有する第一の水溶液と、分子量５００以上のポリフェノール化合物を含有する第二の水溶液を用い、これらを交互に２回以上ＲＯ膜に接触させることにより、透過流束を大きく低下させることなく、著しい劣化膜であっても阻止率を効果的に向上させることができる。 According to the present invention, a first aqueous solution containing an organic compound having an amino group having a molecular weight of less than 500 and a second aqueous solution containing a polyphenol compound having a molecular weight of 500 or more are alternately used twice or more. By contacting the film, the rejection rate can be effectively improved even for a significantly deteriorated film without greatly reducing the permeation flux.

以下に、本発明による劣化膜の修復のメカニズムを図１を参照して説明する。 Hereinafter, a mechanism for repairing a deteriorated film according to the present invention will be described with reference to FIG.

ＲＯ膜、例えば、ポリアミド膜の正常なアミド結合は図１の正常膜に示すような構造をとっている。この膜が塩素などの酸化剤で劣化した場合、アミド結合のＣ−Ｎ結合が分断され、最終的には図１の劣化膜に示すような構造となる。
図１の劣化膜に示されるように、アミド結合の分断で、アミノ基は消失することがあるが、この分断部分の少なくとも一部にカルボキシル基が形成される。そして、劣化が進行すると、間隙（劣化部分）が大きくなり、様々な大きさの間隙が形成される。 The normal amide bond of an RO membrane, for example, a polyamide membrane has a structure as shown in the normal membrane of FIG. When this film is deteriorated by an oxidizing agent such as chlorine, the amide bond C—N bond is broken, and finally the structure shown in the deteriorated film of FIG. 1 is obtained.
As shown in the deteriorated film in FIG. 1, the amino group may disappear due to the amide bond breakage, but a carboxyl group is formed in at least a part of the breakage portion. As the deterioration progresses, the gap (deteriorated portion) increases, and gaps of various sizes are formed.

本発明では、分子量５００未満の低分子量アミノ化合物と、分子量５００以上のポリフェノール化合物とを交互に接触させることにより、大小様々な間隙にこれらの化合物が定着して徐々に緻密化され、安定的な補修層が形成されることにより、膜性能の向上効果に優れたものとなる。 In the present invention, by alternately contacting a low molecular weight amino compound having a molecular weight of less than 500 and a polyphenol compound having a molecular weight of 500 or more, these compounds are fixed and gradually densified in large and small gaps. By forming the repair layer, the effect of improving the film performance is excellent.

正常膜と劣化膜を示す、化学構造式の説明図である。It is explanatory drawing of a chemical structural formula which shows a normal film | membrane and a deterioration film | membrane. 実施例で用いた平膜試験装置を示す模式図である。It is a schematic diagram which shows the flat film test apparatus used in the Example.

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.

本発明のＲＯ膜の阻止率向上方法は、分子量５００未満のアミノ基を有する有機化合物を含有する第一の水溶液と、分子量５００以上のポリフェノール化合物を含有する第二の水溶液を逆浸透膜に接触させる逆浸透膜の阻止率向上方法であって、前記第一の水溶液を逆浸透膜に接触させた後、前記第二の水溶液を該逆浸透膜に接触させ、更に第一の水溶液と第二の水溶液を交互に該逆浸透膜に接触させる処理を１回以上行うことを特徴とする。 In the RO membrane rejection rate improving method of the present invention, a first aqueous solution containing an organic compound having an amino group having a molecular weight of less than 500 and a second aqueous solution containing a polyphenol compound having a molecular weight of 500 or more are contacted with a reverse osmosis membrane. A reverse osmosis membrane blocking rate improving method comprising: bringing the first aqueous solution into contact with the reverse osmosis membrane; then bringing the second aqueous solution into contact with the reverse osmosis membrane; It is characterized in that the treatment of alternately bringing the aqueous solution into contact with the reverse osmosis membrane is performed once or more.

＜第一の水溶液＞
本発明において、第一の水溶液に溶解させる、分子量５００未満のアミノ基を有する有機化合物（以下、「低分子量アミノ化合物」と称す場合がある。）としては、例えば、次のようなものが挙げられる。 <First aqueous solution>
In the present invention, examples of the organic compound having an amino group having a molecular weight of less than 500 (hereinafter sometimes referred to as “low molecular weight amino compound”) dissolved in the first aqueous solution include the following. It is done.

芳香族アミノ化合物：例えば、アニリン（分子量９３）、ジアミノベンゼン（分子量１０８）などのベンゼン骨格とアミノ基を有するもの。 Aromatic amino compounds: For example, those having a benzene skeleton and an amino group such as aniline (molecular weight 93) and diaminobenzene (molecular weight 108).

芳香族アミノカルボン酸化合物：例えば、３，５−ジアミノ安息香酸（分子量１５２）、３，４−ジアミノ安息香酸（分子量１５２）、２，４−ジアミノ安息香酸（分子量１５２）、２，５−ジアミノ安息香酸（分子量１５２）、２，４，６−トリアミノ安息香酸（分子量１６７）などのベンゼン骨格と２つ以上のアミノ基とアミノ基の数より少ないカルボキシル基を有するもの。 Aromatic aminocarboxylic acid compounds: for example, 3,5-diaminobenzoic acid (molecular weight 152), 3,4-diaminobenzoic acid (molecular weight 152), 2,4-diaminobenzoic acid (molecular weight 152), 2,5-diamino Those having a benzene skeleton such as benzoic acid (molecular weight 152) and 2,4,6-triaminobenzoic acid (molecular weight 167), two or more amino groups, and a carboxyl group less than the number of amino groups.

脂肪族アミノ化合物：例えば、メチルアミン（分子量３１）、エチルアミン（分子量４５）、オクチルアミン（分子量１２９）、１，９−ジアミノノナン（Ｃ_９Ｈ_１８（ＮＨ_２）_２）（分子量１５８）等の炭素数１〜２０程度の直鎖炭化水素基と１個又は複数のアミノ基を有するもの、及び、１−アミノペンタン（ＮＨ_２（ＣＨ_２）_４ＣＨ_３）（分子量８７）、２−メチル−１，８−オクタンジアミン（ＮＨ_２ＣＨ_２ＣＨ（ＣＨ_３）（ＣＨ_２）_６ＮＨ_２）（分子量１５８）等の炭素数１〜２０程度の分岐炭化水素基と１個又は複数のアミノ基を有するもの。 Aliphatic amino compounds: For example, carbon such as methylamine (molecular weight 31), ethylamine (molecular weight 45), octylamine (molecular weight 129), 1,9-diaminononane (C ₉ H ₁₈ (NH ₂ ) ₂ ) (molecular weight 158) Those having a linear hydrocarbon group of about 1 to 20 and one or more amino groups, 1-aminopentane (NH ₂ (CH ₂ ) ₄ CH ₃ ) (molecular weight 87), 2-methyl-1 , 8-octanediamine (NH ₂ CH ₂ CH (CH ₃ ) (CH ₂ ) ₆ NH ₂ ) (molecular weight 158) and the like having a branched hydrocarbon group having about 1 to 20 carbon atoms and one or more amino groups thing.

脂肪族アミノアルコール：例えば、４−アミノ−２−メチル−１−ブタノール（ＮＨ_２（ＣＨ_２）_２ＣＨ（ＣＨ_３）ＣＨ_２ＯＨ）（分子量１０３）等の直鎖又は分岐の炭素数１〜２０の炭化水素基にアミノ基と水酸基を有するもの。
複素環アミノ化合物：例えば、テトラヒドロフルフリルアミン（下記構造式）（分子量１０１）、ピリミジン−２，４，５，６−テトラアミン（分子量２３２）などの複素環とアミノ基を有するもの。 Aliphatic amino alcohol: for example, 4-amino-2-methyl-1-butanol (NH ₂ (CH ₂ ) ₂ CH (CH ₃ ) CH ₂ OH) (molecular weight 103) Those having an amino group and a hydroxyl group in 20 hydrocarbon groups.
Heterocyclic amino compound: For example, a compound having a heterocyclic ring and an amino group such as tetrahydrofurfurylamine (the following structural formula) (molecular weight 101), pyrimidine-2,4,5,6-tetraamine (molecular weight 232).

アミノ酸化合物：例えば、アルギニン（分子量１７４）、リシン（分子量１４６）やオルニチン（分子量１３２）等の塩基性アミノ酸化合物、アスパラギン（分子量１３２）やグルタミン（分子量１４６）等のアミド基を有するアミノ酸化合物、グリシン（分子量７５）やフェニルアラニン（分子量１６５）等のその他のアミノ酸化合物。
エチレンジアミン類：テトラエチレンペンタミン（分子量１８９）、トリエチレンテトラミン（分子量１４６）、ペンタエチレンヘキサミン（分子量２３２）等の一般式Ｈ_２Ｎ（ＣＨ_２ＣＨ_２ＮＨ）_ｎＨで表される化合物。
また、アスパルテーム（分子量：２９４）、カルノシン（分子量：２２６）、Ｎα−（Ｌ−チロシル）−Ｌ−アルギニン（分子量：３３６）などを用いることもできる。 Amino acid compounds: for example, basic amino acid compounds such as arginine (molecular weight 174), lysine (molecular weight 146) and ornithine (molecular weight 132), amino acid compounds having an amide group such as asparagine (molecular weight 132) and glutamine (molecular weight 146), glycine Other amino acid compounds such as (molecular weight 75) and phenylalanine (molecular weight 165).
Ethylenediamines: Compounds represented by the general formula H ₂ N (CH ₂ CH ₂ NH) _n H such as tetraethylenepentamine (molecular weight 189), triethylenetetramine (molecular weight 146), pentaethylenehexamine (molecular weight 232) and the like.
Further, aspartame (molecular weight: 294), carnosine (molecular weight: 226), Nα- (L-tyrosyl) -L-arginine (molecular weight: 336), or the like can also be used.

これらの低分子量アミノ化合物のうち、アミノ基を２個以上、例えば２〜４個有するものが安定性の点で好ましく、このような低分子量アミノ化合物としてアルギニン、オルニチン、リシン、テトラエチレンペンタミン、トリエチレンテトラミン、ペンタエチレンヘキサミンやピリミジン−２，４，５，６−テトラアミンなどが挙げられる。 Among these low molecular weight amino compounds, those having two or more amino groups, for example, 2 to 4 are preferable in terms of stability. Examples of such low molecular weight amino compounds include arginine, ornithine, lysine, tetraethylenepentamine, Examples include triethylenetetramine, pentaethylenehexamine, and pyrimidine-2,4,5,6-tetraamine.

これらの低分子量アミノ化合物は、水に対する溶解性が高く、安定な水溶液としてＲＯ膜に通水することができ、前述の如く、ＲＯ膜のカルボキシル基と反応してＲＯ膜に結合し、不溶性の塩を形成して、膜の劣化により生じた穴を塞ぐことができる。 These low molecular weight amino compounds are highly soluble in water and can be passed through the RO membrane as a stable aqueous solution. As described above, they react with the carboxyl group of the RO membrane and bind to the RO membrane, making it insoluble. Salts can be formed to plug holes created by membrane degradation.

これらの低分子量アミノ化合物は、１種を単独で用いても良く、２種以上を混合して用いても良い。 These low molecular weight amino compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them.

分子量や骨格構造の異なる２種以上の低分子量アミノ化合物を含む第一の水溶液をＲＯ膜に通水すると、各々の化合物が膜を透過する際に互いに障害となり、膜内の劣化箇所に滞留する時間が長くなることにより、膜のカルボキシル基と低分子量アミノ化合物のアミノ基との接触確率が高くなり、膜の修復効果が高められる。この場合、これらの低分子量アミノ化合物のうち、分子量２００未満の第１の低分子量アミノ化合物と、分子量２００以上５００未満の第２の低分子量アミノ化合物とを併用することが好ましく、第１の低分子量アミノ化合物としては、アミノ酸又はアミノ酸化合物が好適であり、例えば、塩基性アミノ酸である、アルギニン（分子量１７４）、リシン（分子量１４６）、又はヒスチジン（分子量１５５）や分子量がより小さいグリシン（分子量７５）が好適である。また、第２の低分子量アミノ化合物としては、ペプチドあるいはその誘導体として、例えば、フェニルアラニンとアスパラギン酸のジペプチドのメチルエステルであるアスパルテーム（分子量２９４）が好適である。 When the first aqueous solution containing two or more kinds of low molecular weight amino compounds having different molecular weights or skeletal structures is passed through the RO membrane, each compound becomes an obstacle to permeate the membrane and stays at the degradation site in the membrane. By increasing the time, the contact probability between the carboxyl group of the film and the amino group of the low molecular weight amino compound is increased, and the effect of repairing the film is enhanced. In this case, among these low molecular weight amino compounds, it is preferable to use a first low molecular weight amino compound having a molecular weight of less than 200 and a second low molecular weight amino compound having a molecular weight of 200 or more and less than 500 in combination. As the molecular weight amino compound, an amino acid or an amino acid compound is preferable. For example, arginine (molecular weight 174), lysine (molecular weight 146), histidine (molecular weight 155) or glycine having a lower molecular weight (molecular weight 75) which is a basic amino acid. ) Is preferred. As the second low molecular weight amino compound, for example, aspartame (molecular weight 294) which is a methyl ester of a dipeptide of phenylalanine and aspartic acid is suitable as a peptide or a derivative thereof.

第一の水溶液中の低分子量アミノ化合物の濃度は１．０〜５００ｍｇ／Ｌ、特に５〜１００ｍｇ／Ｌが好ましい。第一の水溶液中の低分子量アミノ化合物の濃度が低過ぎると、後述の有機化合物接触量を満たすためには長時間の処理が必要となり非効率であり、また、低分子量アミノ化合物の濃度が高過ぎるとＲＯ膜の表面で低分子量アミノ化合物が多層化して吸着し、劣化部位に到達しない低分子量アミノ化合物が増え、補修効率が悪くなる。なお、第一の水溶液に低分子量アミノ化合物を２種以上含む場合は、各々の低分子量アミノ化合物の濃度が１．０ｍｇ／Ｌ以上であることが好ましいが、第一の水溶液中の低分子量アミノ化合物の合計濃度としては５００ｍｇ／Ｌ以下であることが好ましい。また、水溶液中の最も濃度の低い低分子量アミノ化合物と最も濃度の高い低分子量アミノ化合物との濃度比は、０．１〜１．０の範囲であることが各化合物の接触比率の偏りを防止して均一な処理を行う上で好ましい。 The concentration of the low molecular weight amino compound in the first aqueous solution is preferably 1.0 to 500 mg / L, particularly 5 to 100 mg / L. If the concentration of the low molecular weight amino compound in the first aqueous solution is too low, a long treatment is required to satisfy the contact amount of the organic compound described later, which is inefficient, and the concentration of the low molecular weight amino compound is high. If it is too much, low molecular weight amino compounds are adsorbed in a multilayered manner on the surface of the RO membrane, and low molecular weight amino compounds that do not reach the degradation site increase, resulting in poor repair efficiency. In addition, when the first aqueous solution contains two or more kinds of low molecular weight amino compounds, the concentration of each low molecular weight amino compound is preferably 1.0 mg / L or more. The total concentration of the compounds is preferably 500 mg / L or less. Further, the concentration ratio of the lowest concentration low molecular weight amino compound to the highest concentration low molecular weight amino compound in the aqueous solution is in the range of 0.1 to 1.0 to prevent uneven contact ratio of each compound. Therefore, it is preferable for uniform processing.

＜第二の水溶液＞
本発明において、第二の水溶液に溶解させる分子量５００以上のポリフェノール化合物としては、例えば、タンニン酸、リグニン、リグニン誘導体などを挙げることができる。タンニン酸としては、五倍子、没食子、ケプラチョ、ミモザなどのタンニン酸を挙げることができる。
これらのポリフェノール化合物についても、１種を単独で用いても良く、２種以上を混合して用いても良い。 <Second aqueous solution>
In the present invention, examples of the polyphenol compound having a molecular weight of 500 or more dissolved in the second aqueous solution include tannic acid, lignin, and lignin derivatives. Examples of tannic acid include tannic acid such as pentaploid, gallic, kepracho and mimosa.
These polyphenol compounds may be used alone or in combination of two or more.

第二の水溶液中のポリフェノール化合物の濃度は１．０〜５００ｍｇ／Ｌ、特に５〜１００ｍｇ／Ｌが好ましい。第二の水溶液中のポリフェノール化合物の濃度が低過ぎると、後述の有機化合物接触量を満たすためには長時間の処理が必要となり非効率であり、また、ポリフェノール化合物の濃度が高過ぎるとＲＯ膜の表面でポリフェノール化合物が多層化して吸着し、劣化部位に到達しないポリフェノール化合物が増え、補修効率が悪くなる。なお、第二の水溶液にポリフェノール化合物を２種以上含む場合は、各々のポリフェノール化合物の濃度が１．０ｍｇ／Ｌ以上であることが好ましいが、第二の水溶液中のポリフェノール化合物の合計濃度としては５００ｍｇ／Ｌ以下であることが好ましい。また、水溶液中の最も濃度の低いポリフェノール化合物と最も濃度の高いポリフェノール化合物との濃度比は、０．１〜１．０の範囲であることが各化合物の接触比率の偏りを防止して均一な処理を行う上で好ましい。 The concentration of the polyphenol compound in the second aqueous solution is preferably 1.0 to 500 mg / L, particularly 5 to 100 mg / L. If the concentration of the polyphenol compound in the second aqueous solution is too low, a long-time treatment is required to satisfy the contact amount of the organic compound described later, which is inefficient. If the concentration of the polyphenol compound is too high, the RO membrane The polyphenol compound is multilayered and adsorbed on the surface, and the amount of polyphenol compound that does not reach the deteriorated portion increases, resulting in poor repair efficiency. In addition, when the second aqueous solution contains two or more polyphenol compounds, the concentration of each polyphenol compound is preferably 1.0 mg / L or more, but the total concentration of polyphenol compounds in the second aqueous solution is as follows. It is preferable that it is 500 mg / L or less. In addition, the concentration ratio of the polyphenol compound having the lowest concentration to the polyphenol compound having the highest concentration in the aqueous solution is in the range of 0.1 to 1.0 to prevent uneven contact ratio of each compound and to be uniform. It is preferable when processing is performed.

＜有機化合物接触量＞
本発明では、第一の水溶液及び第二の水溶液による処理において、下記式で算出される膜単位面積当りの有機化合物接触量が、低分子量アミノ化合物及びポリフェノール化合物のそれぞれについて、２，５００ｍｇ／ｍ^２以上、好ましくは５，０００〜１００，０００ｍｇ／ｍ^２、低分子量アミノ化合物とポリフェノール化合物の合計について５，０００ｍｇ／ｍ^２以上、好ましくは１０，０００〜２００，０００ｍｇ／ｍ^２となるように第一の水溶液及び第二の水溶液をそれぞれＲＯ膜に通水、すなわち透過させることが好ましい。
有機化合物接触量（ｍｇ／ｍ^２）＝［水溶液中の有機化合物濃度（ｍｇ／Ｌ）×処理時間（ｈｒ）×処理時透過水量（ｍ^３／ｈｒ）／膜面積（ｍ^２）］×１０００
（ここで、水溶液中の有機化合物濃度は、前記第一の水溶液中における分子量５００未満のアミノ基を有する有機化合物の濃度、又は前記第二の水溶液中における分子量５００以上のポリフェノール化合物の濃度である。） <Contact amount of organic compound>
In the present invention, in the treatment with the first aqueous solution and the second aqueous solution, the contact amount of the organic compound per unit membrane area calculated by the following formula is 2,500 mg / m for each of the low molecular weight amino compound and the polyphenol compound. ² or more, preferably 5,000~100,000mg / ^{m 2,} for a total of low molecular weight amino compound and the polyphenol compound 5,000 mg / ^{m 2} or more, so preferably a 10,000~200,000mg / ^{m 2} The first aqueous solution and the second aqueous solution are preferably passed through the RO membrane, that is, permeated.
Contact amount of organic compound (mg / m ² ) = [concentration of organic compound in aqueous solution (mg / L) × treatment time (hr) × permeated water amount during treatment (m ³ / hr) / membrane area (m ² )] × 1000
(Here, the concentration of the organic compound in the aqueous solution is the concentration of the organic compound having an amino group having a molecular weight of less than 500 in the first aqueous solution, or the concentration of the polyphenol compound having a molecular weight of 500 or more in the second aqueous solution. .)

有機化合物接触量が上記下限よりも少ないと、膜の劣化箇所への低分子量アミノ化合物及びポリフェノール化合物の吸着量が少ないために、十分な補修効果で良好な阻止率向上効果を得ることができず、上記上限を超えると膜の劣化していない箇所にも低分子量アミノ化合物及びポリフェノール化合物の吸着が進行してフラックスが低下するおそれがある。なお、上記の有機化合物接触量は、第一の水溶液中に２種以上の低分子量アミノ化合物が含まれる場合は、これらの低分子量アミノ化合物の合計の有機化合物接触量に該当し、同様に第二の水溶液中に２種以上のポリフェノール化合物が含まれる場合は、これらのポリフェノール化合物の合計の有機化合物接触量に該当する。この場合、各低分子量アミノ化合物又はポリフェノール化合物についての有機化合物接触量は、２，５００ｍｇ／ｍ^２以上、特に５，０００〜１００，０００ｍｇ／ｍ^２であることが好ましい。 If the contact amount of the organic compound is less than the above lower limit, the adsorption amount of the low molecular weight amino compound and the polyphenol compound to the deteriorated portion of the film is small, so that it is not possible to obtain a good rejection improvement effect with a sufficient repair effect. If the above upper limit is exceeded, the adsorption of the low molecular weight amino compound and the polyphenol compound may proceed even in a portion where the film is not deteriorated, and the flux may decrease. The above-mentioned contact amount of organic compound corresponds to the total contact amount of organic compounds of these low molecular weight amino compounds when two or more kinds of low molecular weight amino compounds are contained in the first aqueous solution. When two or more types of polyphenol compounds are contained in the second aqueous solution, this corresponds to the total contact amount of organic compounds of these polyphenol compounds. In this case, the organic compound contact amount for each low molecular weight amino compounds or polyphenols compounds, 2,500 mg / ^{m 2} or more, and particularly preferably 5,000~100,000mg / ^{m 2.}

＜処理条件＞
第一の水溶液又は第二の水溶液をＲＯ膜に接触させる際の圧力（通水圧力）は、過度に高いと劣化していない箇所への吸着が進むという問題があり、過度に低いと劣化箇所への接触効率が悪化する。このため、超低圧膜の場合、入口圧力として０．１〜１．０ＭＰａであることが好ましく、低圧膜の場合、入口圧力として０．１〜１．５ＭＰａであることが好ましい。また、海水淡水化膜の場合は、入口圧力が０．３〜２．５ＭＰａであることが好ましい。 <Processing conditions>
When the pressure of the first aqueous solution or the second aqueous solution in contact with the RO membrane (water passage pressure) is excessively high, there is a problem that adsorption to a non-degraded portion proceeds. Contact efficiency deteriorates. For this reason, in the case of an ultra-low pressure membrane, the inlet pressure is preferably 0.1 to 1.0 MPa, and in the case of a low-pressure membrane, the inlet pressure is preferably 0.1 to 1.5 MPa. In the case of a seawater desalination membrane, the inlet pressure is preferably 0.3 to 2.5 MPa.

第一の水溶液又は第二の水溶液通水時の透過水量は、圧力、水温、膜の形状等に関わってくるが、０．１〜１．０ｍ／ｄａｙであることが好ましい。その理由は上記と同様、過度に高いと膜の劣化していない箇所への吸着が進むという問題があり、過度に低いと劣化箇所への接触効率が悪化するためである。 The amount of permeated water when the first aqueous solution or the second aqueous solution is passed is related to pressure, water temperature, membrane shape, and the like, but is preferably 0.1 to 1.0 m / day. The reason is that, as described above, if it is excessively high, there is a problem that the adsorption to a portion where the film is not deteriorated proceeds.

処理順序（通水順序）としては、第一の水溶液から通水処理を行い、続いて第二の水溶液の通水処理を行う。その後、再度、第一の水溶液、第二の水溶液による交互通水処理を繰り返す。繰り返し回数としては第一の水溶液による通水、第二の水溶液による通水を１セットとして、１〜９回実施（即ち、合計で２〜１０回）することが好ましい。このように繰り返し処理を実施することで補修層が緻密化し、高い除去率を得ることができるが、過度に繰り返し回数を多くすると、処理時間が長くなるため好ましくない。 As a treatment order (water flow order), water flow treatment is performed from the first aqueous solution, and then water flow treatment of the second aqueous solution is performed. Then, the alternate water flow treatment with the first aqueous solution and the second aqueous solution is repeated again. The number of repetitions is preferably 1 to 9 times (that is, 2 to 10 times in total), with water passing through the first aqueous solution and water passing through the second aqueous solution as one set. By carrying out the repetition treatment in this way, the repair layer can be densified and a high removal rate can be obtained. However, if the number of repetitions is excessively increased, the treatment time becomes longer, which is not preferable.

処理時間としては、第一の水溶液及び第二の水溶液のそれぞれの水溶液について、１回の通水時間が１〜２４時間、合計の通水時間として、それぞれ３時間以上５００時間以下であることが好ましい。この通水時間が短過ぎると、有機化合物の定着性が十分得られないまま処理を終了させることになり、付着した有機化合物が剥離してしまうことがあり、好ましくない。 As the treatment time, for each of the first aqueous solution and the second aqueous solution, one water passage time is 1 to 24 hours, and the total water passage time is 3 hours or more and 500 hours or less, respectively. preferable. If the water passing time is too short, the treatment is terminated without sufficient fixing of the organic compound, and the attached organic compound may be peeled off, which is not preferable.

また、第一の水溶液又は第二の水溶液の通水時の水温は、常温、例えば１０〜３５℃程度が好ましい。水温が低すぎると透過水量が低下し、接触効率が悪化する。一方、水温が高すぎると膜素材の変性等の問題が起こる場合がある。 Moreover, the water temperature at the time of water flow of 1st aqueous solution or 2nd aqueous solution has normal temperature, for example, about 10-35 degreeC is preferable. If the water temperature is too low, the amount of permeated water is lowered and the contact efficiency is deteriorated. On the other hand, if the water temperature is too high, problems such as membrane material denaturation may occur.

第一の水溶液及び第二の水溶液による阻止率向上処理はＲＯ膜装置の定常運転時に行ってもよいし、非定常運転時に行ってもよい。 The rejection improvement process using the first aqueous solution and the second aqueous solution may be performed during the steady operation of the RO membrane device, or may be performed during the unsteady operation.

ＲＯ膜装置を長時間運転することにより、膜汚染が生じて透過流束が低下している場合は、膜洗浄を行った後に阻止率向上処理を行ってもよい。 When the RO membrane device is operated for a long time and the membrane contamination occurs and the permeation flux is reduced, the rejection rate improving process may be performed after the membrane cleaning.

この場合に用いる膜洗浄の薬剤としては、酸洗浄では、塩酸、硝酸、硫酸などの鉱酸、クエン酸、シュウ酸といった有機酸を挙げることができる。アルカリ洗浄では、水酸化ナトリウム、水酸化カリウムなどを挙げることができる。一般的に、酸洗浄ではｐＨ２付近とし、アルカリ洗浄ではｐＨ１２付近とする。 Examples of the membrane cleaning agent used in this case include mineral acids such as hydrochloric acid, nitric acid and sulfuric acid, and organic acids such as citric acid and oxalic acid. Examples of the alkali cleaning include sodium hydroxide and potassium hydroxide. In general, the pH is about 2 for acid cleaning and about 12 for alkali cleaning.

なお、第一の水溶液又は第二の水溶液には、トレーサーとして、食塩（ＮａＣｌ）等の無機電解質やイソプロピルアルコール（ＩＰＡ）やグルコース等の中性有機物、ポリマレイン酸などの低分子ポリマーなどを添加してもよく、これにより、ＲＯ膜の透過水への食塩やグルコースなどのトレーサーの透過の程度を分析して、膜の修復の程度を確認することができる。 In addition, an inorganic electrolyte such as sodium chloride (NaCl), a neutral organic substance such as isopropyl alcohol (IPA) and glucose, and a low molecular polymer such as polymaleic acid are added to the first aqueous solution or the second aqueous solution as a tracer. Thus, the degree of membrane repair can be confirmed by analyzing the degree of penetration of tracers such as salt and glucose into the permeated water of the RO membrane.

＜ＲＯ膜＞
本発明において阻止率向上処理の処理対象となるＲＯ膜の膜構造としては、非対称膜、複合膜などの高分子膜などを挙げることができる。ＲＯ膜の素材としては、例えば、芳香族系ポリアミド、脂肪族系ポリアミド、これらの複合材などのポリアミド系素材、酢酸セルロースなどのセルロース系素材などを挙げることができる。これらの中で、芳香族系ポリアミド素材のＲＯ膜であって、劣化することによりＣ−Ｎ結合の分断でカルボキシル基を多く有するＲＯ膜に、本発明の阻止率向上方法を特に好適に適用することができ、特に阻止率向上処理前のＲＯ膜の脱塩率が９５％以下、特に９０％以下である場合、本発明方法を適用するのに好適である。 <RO membrane>
In the present invention, examples of the membrane structure of the RO membrane to be subjected to the rejection improvement processing include polymer membranes such as asymmetric membranes and composite membranes. Examples of the RO membrane material include aromatic polyamides, aliphatic polyamides, polyamide materials such as composite materials thereof, and cellulose materials such as cellulose acetate. Among these, the method for improving the rejection rate of the present invention is particularly suitably applied to RO membranes made of aromatic polyamide materials, which have a large number of carboxyl groups due to degradation of CN bonds due to degradation. In particular, when the desalination rate of the RO membrane before the treatment for improving the rejection rate is 95% or less, particularly 90% or less, it is suitable for applying the method of the present invention.

ＲＯ膜モジュールの形式に特に制限はなく、例えば、管状膜モジュール、平面膜モジュール、スパイラル膜モジュール、中空糸膜モジュールなどを挙げることができる。 There is no restriction | limiting in particular in the form of RO membrane module, For example, a tubular membrane module, a plane membrane module, a spiral membrane module, a hollow fiber membrane module etc. can be mentioned.

本発明の阻止率向上方法により阻止率向上処理されたＲＯ膜は、電子デバイス製造分野、半導体製造分野、その他の各種産業分野で排出される高濃度ないし低濃度ＴＯＣ含有排水の回収・再利用のための水処理、あるいは工業用水や市水からの超純水製造、その他の分野の水処理に有効に適用される。
本発明に係るＲＯ膜装置で処理される被処理水は特に限定されるものではないが、電解質含有水が好適であり、例えば電気伝導度２〜１００００ｍＳ／ｍ、好ましくは１０〜７０００ｍＳ／ｍ程度の有機物含有水が好適である。このような有機物含有水としては電子デバイス製造工場排水、輸送機械製造工場排水、有機合成工場排水又は印刷製版・塗装工場排水など、あるいはそれらの一次処理水など挙げることができるが、これらに限定されない。 The RO membrane that has been processed to improve the rejection rate by the method for improving the rejection rate of the present invention can be used to collect and reuse wastewater containing high or low concentration TOC discharged in the electronic device manufacturing field, semiconductor manufacturing field, and other various industrial fields. Therefore, it is effectively applied to water treatment for industrial use, ultrapure water production from industrial water and city water, and water treatment in other fields.
Water to be treated to be treated by the RO membrane device according to the present invention is not particularly limited, but electrolyte-containing water is suitable, for example, electrical conductivity of 2 to 10000 mS / m, preferably about 10 to 7000 mS / m. The organic substance-containing water is preferable. Examples of such organic substance-containing water include, but are not limited to, wastewater from electronic device manufacturing factories, transportation machinery manufacturing factories, organic synthesis factories, printing plate making / painting factories, or the primary treatment water thereof. .

以下に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.

［試験装置］
以下の実施例及び比較例では図２に示す平膜試験装置を用いた。
この平膜試験装置は、有底有蓋の円筒状容器１の高さ方向の中間位置に平膜セル２を設けて容器内を原水室１Ａと透過水室１Ｂとに仕切り、この容器１をスターラー３上に設置し、ポンプ４で被処理水を配管１１を介して原水室１Ａに給水すると共に、容器１内の攪拌子５を回転させて原水室１Ａ内を攪拌し、透過水を透過水室１Ｂより配管１２を介して取り出すと共に、濃縮水を原水室１Ａより配管１３を介して取り出すものである。濃縮水取り出し配管１３には圧力計６と開閉バルブ７が設けられている。 [Test equipment]
In the following examples and comparative examples, the flat membrane test apparatus shown in FIG. 2 was used.
This flat membrane test apparatus is provided with a flat membrane cell 2 at an intermediate position in the height direction of a cylindrical container 1 having a bottom and a lid, and the inside of the container is divided into a raw water chamber 1A and a permeated water chamber 1B, and the container 1 is divided into a stirrer. 3, water to be treated is supplied to the raw water chamber 1 </ b> A via the pipe 11 by the pump 4, and the stirrer 5 in the container 1 is rotated to stir the raw water chamber 1 </ b> A so that the permeated water passes through the permeated water. While taking out from the chamber 1B through the pipe 12, the concentrated water is taken out from the raw water chamber 1A through the pipe 13. The concentrated water outlet pipe 13 is provided with a pressure gauge 6 and an opening / closing valve 7.

［劣化膜の作製］
以下の実施例及び比較例では、阻止率向上処理に供する劣化膜として、ハイドロノーティクス製超低圧ＲＯ膜「ＥＳＰＡ２−４０４０」（膜面積７．９ｍ^２）を、次亜塩素酸ナトリウムを１００ｍｇ／Ｌ濃度で超純水に溶解させた水溶液を、以下の劣化条件で通水して加速劣化させたものを用いた。
劣化条件：入口圧力０．７５ＭＰａ、濃縮水量１ｍ^３／ｈｒ、水温２５℃、
ｐＨ７．０、通水時間１０００時間
なお、ＲＯ膜の加速劣化処理は、各例毎に行ったため、劣化膜の性能（阻止率向上処理前の性能）は、各例毎に若干異なるものとなった。 [Production of deteriorated film]
In the following Examples and Comparative Examples, as a deteriorated film subjected to the rejection improvement process, an ultra-low pressure RO membrane “ESPA2-4040” (membrane area 7.9 m ² ) manufactured by Hydronautics is used, and sodium hypochlorite 100 mg / An aqueous solution dissolved in ultrapure water at an L concentration was subjected to accelerated deterioration by passing water under the following deterioration conditions.
Deterioration conditions: Inlet pressure 0.75 MPa, concentrated water volume 1 m ³ / hr, water temperature 25 ° C.,
pH 7.0, water flow time 1000 hours Since the RO membrane accelerated deterioration process was performed for each example, the performance of the deteriorated film (performance before the blocking rate improvement process) was slightly different for each example. It was.

［ＲＯ膜の性能評価］
以下の実施例及び比較例における阻止率向上処理前後のＲＯ膜の性能評価は、超純水にＮａＣｌを５００ｍｇ／Ｌの濃度で溶解させた水溶液を評価用給水として用い、以下の性能評価条件でＲＯ膜に通水して透過水量を調べると共に、下記式でＮａＣｌ除去率（脱塩率）を算出することにより行った。
性能評価条件：入口圧力０．７５ＭＰａ、濃縮水量１ｍ^３／ｈｒ、水温２５℃、
ｐＨ７．０
ＮａＣｌ除去率［％］＝
（１−透過水の導電率［ｍＳ／ｍ］／濃縮水の導電率［ｍＳ／ｍ］）×１００ [RO membrane performance evaluation]
In the following examples and comparative examples, the performance evaluation of the RO membrane before and after the rejection rate improvement treatment was performed using an aqueous solution in which NaCl was dissolved in ultrapure water at a concentration of 500 mg / L as evaluation water supply, and under the following performance evaluation conditions. The amount of permeated water was examined by passing water through the RO membrane, and the NaCl removal rate (desalting rate) was calculated by the following formula.
Performance evaluation conditions: Inlet pressure 0.75 MPa, concentrated water volume 1 m ³ / hr, water temperature 25 ° C.,
pH 7.0
NaCl removal rate [%] =
(1-permeated water conductivity [mS / m] / concentrated water conductivity [mS / m]) × 100

［実施例１］
第一の水溶液及び第二の水溶液として以下のものを用い、表１に示す処理前性能の劣化膜に、第一の水溶液→第二の水溶液→第一の水溶液→第二の水溶液→第一の水溶液→第二の水溶液の順で２時間毎に液を切り替えて以下の通水条件で通水し、各水溶液による処理を３回ずつ、合計の通水時間がそれぞれ６時間となるように行った。
水溶液１：超純水に、アルギニン（味の素製、分子量１７４）とアスパルテーム
（味の素製、分子量２９４）をそれぞれ１００ｍｇ／Ｌ溶解させた水溶液
水溶液２：タンニン酸ＡＬ（富士化学工業製、分子量５００以上）を１００ｍｇ／
Ｌ溶解させた水溶液
通水条件：入口圧力０．２ＭＰａ、濃縮水圧力０．１７ＭＰａ、透過水量０．１
ｍ^３／ｈｒ（０．３ｍ／ｄａｙ）、濃縮水量１ｍ^３／ｈｒ、水温２５℃、
ｐＨ７．０
上記阻止率向上処理における、アルギニン、アスパルテーム及びタンニン酸ＡＬのそれぞれの有機化合物接触量は次の通りであった。
有機化合物接触量（ｍｇ／ｍ^２）＝
［１００（ｍｇ／Ｌ）×６（ｈｒ）×０．１（ｍ^３／ｈｒ）／７．９（ｍ^２）］
×１０００＝７５９５（ｍｇ／ｍ^２） [Example 1]
The following are used as the first aqueous solution and the second aqueous solution, and the first treatment solution → second solution → first solution → second solution → first is used as the pre-treatment performance degradation film shown in Table 1. The solution is switched every 2 hours in the order of aqueous solution → second aqueous solution, and water is passed under the following water flow conditions. The treatment with each aqueous solution is performed 3 times, so that the total water flow time is 6 hours each. went.
Aqueous solution 1: Arginine (Ajinomoto, molecular weight 174) and aspartame in ultrapure water
An aqueous solution in which 100 mg / L each (manufactured by Ajinomoto Co., Inc., molecular weight 294) was dissolved. Aqueous solution 2: Tannic acid AL (manufactured by Fuji Chemical Industry, molecular weight 500 or more) was 100 mg / L.
L-dissolved aqueous solution water flow conditions: inlet pressure 0.2 MPa, concentrated water pressure 0.17 MPa, permeated water amount 0.1
m ³ / hr (0.3 m / day), amount of concentrated water 1 m ³ / hr, water temperature 25 ° C.,
pH 7.0
The organic compound contact amounts of arginine, aspartame, and tannic acid AL in the above-described inhibition rate improvement treatment were as follows.
Contact amount of organic compound (mg / m ² ) =
[100 (mg / L) × 6 (hr) × 0.1 (m ³ /hr)/7.9 (m ² )]
× 1000 = 7595 (mg / m ² )

阻止率向上処理後のＲＯ膜について、性能評価を行い、結果を表１に示した。 The performance of the RO membrane after the rejection improvement process was evaluated, and the results are shown in Table 1.

［実施例２］
実施例１において、第一の水溶液として、アルギニンのみを１００ｍｇ／Ｌ含む水溶液を用いたこと以外は同様にして阻止率向上処理を行った。阻止率向上処理前後のＲＯ膜の性能評価結果を表１に示す。 [Example 2]
In Example 1, the blocking rate improving treatment was performed in the same manner except that an aqueous solution containing only 100 mg / L of arginine was used as the first aqueous solution. Table 1 shows the performance evaluation results of the RO membrane before and after the rejection improvement process.

［比較例１］
実施例１において、第一の水溶液及び第二の水溶液の代りに、アルギニン（味の素製、分子量１７４）とアスパルテーム（味の素製、分子量２９４）及びタンニン酸ＡＬ（富士化学工業製、分子量５００以上）をそれぞれ１００ｍｇ／Ｌの濃度に溶解させた水溶液のみを用い、この水溶液を１２時間連続通水したこと以外は同様にして阻止率向上処理を行った。阻止率向上処理前後のＲＯ膜の性能評価結果を表１に示す。
なお、このときの各有機化合物接触量は以下の通りであり、合計で約４５６０ｍｇ／ｍ^２であった。
有機化合物接触量（ｍｇ／ｍ^２）＝
［１００（ｍｇ／Ｌ）×１２（ｈｒ）×０．１（ｍ^３／ｈｒ）／７．９（ｍ^２）］
×１０００＝１５１９０（ｍｇ／ｍ^２） [Comparative Example 1]
In Example 1, instead of the first aqueous solution and the second aqueous solution, arginine (manufactured by Ajinomoto, molecular weight 174), aspartame (manufactured by Ajinomoto, molecular weight 294) and tannic acid AL (manufactured by Fuji Chemical Industry, molecular weight of 500 or more) The inhibition rate improvement treatment was performed in the same manner except that only an aqueous solution dissolved at a concentration of 100 mg / L was used and this aqueous solution was continuously passed for 12 hours. Table 1 shows the performance evaluation results of the RO membrane before and after the rejection improvement process.
In addition, the contact amount of each organic compound at this time was as follows, and was about 4560 mg / m ² in total.
Contact amount of organic compound (mg / m ² ) =
[100 (mg / L) × 12 (hr) × 0.1 (m ³ /hr)/7.9 (m ² )]
× 1000 = 15190 (mg / m ² )

表１より、本発明によれば、低分子量アミノ化合物とポリフェノール化合物とを交互に用いる繰り返し処理を行うことにより、膜性能を効果的に回復させることができる。
これに対して、同一の化合物を用いても、これを一つの水溶液として処理した比較例１では、処理後の膜性能の回復効果が低い。 From Table 1, according to the present invention, the membrane performance can be effectively recovered by carrying out the repeated treatment using the low molecular weight amino compound and the polyphenol compound alternately.
On the other hand, even if the same compound is used, in Comparative Example 1 in which the same compound is treated as one aqueous solution, the effect of recovering the film performance after the treatment is low.

１容器
１Ａ原水室
１Ｂ透過水室
２平膜セル
３スターラー 1 container 1A raw water chamber 1B permeate water chamber 2 flat membrane cell 3 stirrer

Claims

A reverse osmosis membrane blocking rate improving method in which a first aqueous solution containing an organic compound having an amino group having a molecular weight of less than 500 and a second aqueous solution containing a polyphenol compound having a molecular weight of 500 or more are brought into contact with the reverse osmosis membrane. ,
A process in which the first aqueous solution is brought into contact with the reverse osmosis membrane, the second aqueous solution is brought into contact with the reverse osmosis membrane, and the first aqueous solution and the second aqueous solution are alternately brought into contact with the reverse osmosis membrane. The method of improving the rejection rate of the reverse osmosis membrane, wherein the method is performed at least once.

The method for improving the rejection of a reverse osmosis membrane according to claim 1, wherein the organic compound having an amino group having a molecular weight of less than 500 is a compound having two or more amino groups.

3. The polyphenol compound according to claim 1, wherein the concentration of the organic compound having an amino group having a molecular weight of less than 500 in the first aqueous solution is 1.0 to 500 mg / L, and the molecular weight is 500 or more in the second aqueous solution. The method of improving the rejection rate of a reverse osmosis membrane, wherein the concentration of the solution is 1.0 to 500 mg / L.

The organic compound contact amount per unit film area defined by the following formula according to any one of claims 1 to 3 for each of an organic compound having an amino group with a molecular weight of less than 500 and a polyphenol compound with a molecular weight of 500 or more. A method for improving the rejection rate of a reverse osmosis membrane, wherein the first aqueous solution and the second aqueous solution are each passed through the reverse osmosis membrane so as to be 2,500 mg / m ² or more.
Contact amount of organic compound (mg / m ² ) = [concentration of organic compound in aqueous solution (mg / L) × treatment time (hr) × permeated water amount during treatment (m ³ / hr) / membrane area (m ² )] × 1000
(Here, the concentration of the organic compound in the aqueous solution is the concentration of the organic compound having an amino group having a molecular weight of less than 500 in the first aqueous solution, or the concentration of the polyphenol compound having a molecular weight of 500 or more in the second aqueous solution. .)

A reverse osmosis membrane, which has been subjected to a rejection improvement process by the method for improving the rejection of a reverse osmosis membrane according to any one of claims 1 to 4.