JPH11138165A - Treatment of boron-containing water - Google Patents
Treatment of boron-containing waterInfo
- Publication number
- JPH11138165A JPH11138165A JP9308878A JP30887897A JPH11138165A JP H11138165 A JPH11138165 A JP H11138165A JP 9308878 A JP9308878 A JP 9308878A JP 30887897 A JP30887897 A JP 30887897A JP H11138165 A JPH11138165 A JP H11138165A
- Authority
- JP
- Japan
- Prior art keywords
- water
- boron
- osmosis membrane
- reverse osmosis
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Removal Of Specific Substances (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ホウ素含有水の処
理方法に関する。さらに詳しくは、本発明は、ホウ素含
有水のpHを９.２以上に調整し、逆浸透膜に通水してホ
ウ素を除去するホウ素含有水の処理方法において、逆浸
透膜の透過速度の低下を生ずることなく、長時間にわた
って高い透過水量を維持することができるホウ素含有水
の処理方法に関する。[0001] The present invention relates to a method for treating boron-containing water. More specifically, the present invention relates to a method for treating boron-containing water in which the pH of boron-containing water is adjusted to 9.2 or more and water is passed through a reverse osmosis membrane to remove boron. The present invention relates to a method for treating boron-containing water, which can maintain a high permeated water amount for a long period of time without producing the water.
【０００２】[0002]
【従来の技術】ホウ素を含有する原水を処理して純水又
は超純水を製造する方法として、アルカリ添加によりpH
を１０以上にしたのち、逆浸透膜に通水する純水製造方
法が知られている。また、このような逆浸透膜処理にお
いては、カルシウムスケールが発生しやすいため、前処
理として弱酸性イオン交換装置及び脱気装置を用いてカ
ルシウムと炭酸を除去し、カルシウムスケールの発生を
防止する方法が知られている。第４７回全国水道研究会
発表会（平成８年５月、発表番号４−９８）では、逆浸
透膜を利用したホウ素低減システムにおいて、水のpHを
１０以上とすることによりホウ素排除率が高くなるが、
微量のカルシウムなどの硬度成分が析出して膜閉塞を生
じ、短時間で造水量が低下することが報告されている。
カルシウムの除去に弱酸性イオン交換装置を用いると、
原水中のカルシウムイオンの形態がＣａ(ＨＣＯ3)2の場
合はカルシウムは効果的に除去されるが、ＣａＣｌ2の
ような形態であると除去は困難であり、カルシウムが残
存する。このような場合、原水にアルカリを添加して、
通水しながらイオン交換樹脂の一部をＮａ型に変えるこ
とにより、ＣａＣｌ2のような形態のカルシウムを除去
することも考えられるが、再生後の通水初期でのカルシ
ウム除去性の低下や、原水のカルシウム濃度の変動に対
してアルカリ添加量の調整が必要になるなど、装置の運
転が難しいという問題がある。原水中のカルシウムイオ
ンの形態がＣａ(ＨＣＯ3)2である場合、弱酸性イオン交
換装置によりカルシウムを除去したのち、脱気膜装置に
より脱炭酸を行う方法が提案されている。カルシウムを
除去するとともに、脱炭酸を行うことにより、高pHで特
に析出しやすい炭酸カルシウムスケールの発生を防止す
ることができる。しかし、カルシウム又は全無機炭酸濃
度のいずれか一方を必要濃度以下にすれば、炭酸カルシ
ウムスケールは発生しないので、弱酸性イオン交換樹脂
装置と脱気膜装置の両方を設けることは、無駄でもあり
不経済でもある。また、従来のホウ素含有水の処理方法
においては、アルカリを添加してpH１０以上とした被処
理水を、耐アルカリ性逆浸透膜に通水することにより、
ホウ素の除去率を高めているが、pHを高くするために水
酸化ナトリウムなどのアルカリの添加量が著しく多くな
り、耐アルカリ性逆浸透膜透過水中のアルカリ濃度が高
くなり、後段へのアルカリ負荷が大きくなるという問題
がある。2. Description of the Related Art As a method for producing pure water or ultrapure water by treating raw water containing boron, pH is adjusted by adding an alkali.
Is adjusted to 10 or more, and then a method for producing pure water in which water is passed through a reverse osmosis membrane is known. Further, in such a reverse osmosis membrane treatment, since calcium scale is easily generated, a method of removing calcium and carbonic acid using a weakly acidic ion exchange device and a deaerator as a pretreatment to prevent the generation of calcium scale. It has been known. At the 47th National Water Works Research Conference (May 1996, Announcement No. 4-98), in a boron reduction system using a reverse osmosis membrane, by setting the pH of water to 10 or more, the boron rejection rate was high. But
It has been reported that a minute amount of a hard component such as calcium precipitates to cause film blockage, and the amount of fresh water is reduced in a short time.
Using a weakly acidic ion exchange device to remove calcium,
When the form of calcium ions in the raw water is Ca (HCO 3 ) 2 , calcium is effectively removed. However, when the form is CaCl 2 , it is difficult to remove calcium, and calcium remains. In such a case, add alkali to raw water,
It is also conceivable to remove calcium in a form such as CaCl 2 by changing a part of the ion exchange resin to the Na type while passing water. There is a problem that the operation of the apparatus is difficult, for example, it is necessary to adjust the amount of alkali added to the fluctuation of the calcium concentration of the raw water. When the form of calcium ions in raw water is Ca (HCO 3 ) 2 , a method has been proposed in which calcium is removed by a weakly acidic ion exchange device and then decarbonation is performed by a degassing membrane device. By removing calcium and performing decarboxylation, it is possible to prevent the formation of calcium carbonate scale, which easily precipitates at a high pH. However, if either calcium or the total inorganic carbonic acid concentration is reduced to a required concentration or less, calcium carbonate scale will not be generated, so providing both a weakly acidic ion exchange resin apparatus and a degassing membrane apparatus is wasteful and impractical. It is also an economy. Further, in the conventional method of treating boron-containing water, the water to be treated having a pH of 10 or more by adding an alkali is passed through an alkali-resistant reverse osmosis membrane,
Although the removal rate of boron is increased, the amount of alkali added such as sodium hydroxide is significantly increased in order to raise the pH, the alkali concentration in the permeated water of the alkali-resistant reverse osmosis membrane is increased, and the alkali load on the subsequent stage is reduced. There is a problem that it becomes larger.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、ホウ素含有
水のpHを９.２以上に調整し、逆浸透膜に通水してホウ
素を除去するホウ素含有水の処理方法において、弱酸性
イオン交換樹脂装置などによる前処理を行うことなく逆
浸透膜に通水しても、カルシウムスケールの発生による
透過速度の低下がなく、長時間にわたって高い透過水量
を維持することができるホウ素含有水の処理方法を提供
することを目的としてなされたものである。SUMMARY OF THE INVENTION The present invention relates to a method for treating boron-containing water in which the pH of boron-containing water is adjusted to 9.2 or higher and the water is passed through a reverse osmosis membrane to remove boron. Even if water is passed through the reverse osmosis membrane without performing pre-treatment with an exchange resin device etc., there is no decrease in the permeation rate due to the generation of calcium scale, and the treatment of boron-containing water that can maintain a high permeate water amount for a long time It is intended to provide a method.
【０００４】[0004]
【課題を解決するための手段】本発明者は、上記の課題
を解決すべく鋭意研究を重ねた結果、逆浸透膜に通水す
るホウ素含有水にスケール防止剤を添加することによ
り、逆浸透膜へのカルシウムスケールの付着を防止し、
長時間にわたって高い透過水量を維持し得ることを見い
だし、この知見に基づいて本発明を完成するに至った。
すなわち、本発明は、（１）ホウ素含有水のpHを９.２
以上に調整し、逆浸透膜に通水してホウ素を除去するホ
ウ素含有水の処理方法において、逆浸透膜に通水するホ
ウ素含有水にスケール防止剤を添加することを特徴とす
るホウ素含有水の処理方法、を提供するものである。さ
らに、本発明の好ましい態様として、（２）ホウ素含有
水のpHを１０以上に調整する第(１)項記載のホウ素含有
水の処理方法、（３）逆浸透膜が、耐アルカリ性逆浸透
膜である第(１)項記載のホウ素含有水の処理方法、
（４）ホウ素含有水に脱炭酸処理を行ったのち、逆浸透
膜に通水する第(１)項記載のホウ素含有水の処理方法、
（５）酸性に調整したホウ素含有水を、脱気膜装置に通
水することにより脱炭酸処理を行う第(４)項記載のホウ
素含有水の処理方法、及び、（６）スケール防止剤が、
カルボキシル基を有する低分子量ポリマー又はキレート
化剤である第(１)項記載のホウ素含有水の処理方法、を
挙げることができる。Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that by adding a scale inhibitor to boron-containing water passing through a reverse osmosis membrane, reverse osmosis is achieved. Prevents calcium scale from adhering to the membrane,
It has been found that a high permeate volume can be maintained for a long time, and the present invention has been completed based on this finding.
That is, the present invention provides (1) a method of adjusting the pH of boron-containing water to 9.2.
Adjusted above, the boron-containing water treatment method for removing boron by passing through a reverse osmosis membrane, wherein a boron-containing water is added to the boron-containing water that passes through the reverse osmosis membrane, wherein a scale inhibitor is added. Processing method. Further, as a preferred embodiment of the present invention, (2) the method for treating boron-containing water according to (1), wherein the pH of the boron-containing water is adjusted to 10 or more, and (3) the reverse osmosis membrane is an alkali-resistant reverse osmosis membrane. The method for treating boron-containing water according to item (1),
(4) The method for treating boron-containing water according to (1), wherein after the decarbonation treatment is performed on the boron-containing water, the water is passed through a reverse osmosis membrane.
(5) The method for treating boron-containing water according to item (4), wherein the acid-adjusted boron-containing water is subjected to a decarboxylation treatment by passing the water through a degassing membrane device, and (6) a scale inhibitor. ,
The method for treating boron-containing water according to item (1), which is a low-molecular-weight polymer having a carboxyl group or a chelating agent, may be used.
【０００５】[0005]
【発明の実施の形態】本発明のホウ素含有水の処理方法
は、ホウ素含有水のpHを９.２以上に調整し、逆浸透膜
に通水してホウ素を除去するホウ素含有水の処理に適用
することができる。本発明方法においては、逆浸透膜に
通水するホウ素含有水にスケール防止剤を添加する。本
発明方法において、ホウ素含有水のpHを９.２以上に調
整する方法には特に制限はなく、例えば、水酸化ナトリ
ウムなどのアルカリ水溶液を添加する方法や、強塩基性
イオン交換樹脂塔に通水する方法などを挙げることがで
きる。アルカリ水溶液を添加する方法としては、例え
ば、撹拌機つきのpH調整槽を設けてアルカリを添加し、
あるいは、通水ラインにアルカリ水溶液注入口、その下
流側にスタチックミキサーなどを設けて、注入口よりア
ルカリ水溶液を添加することができる。ホウ素含有水に
アルカリを添加することにより、pHをホウ酸のｐＫa９.
２（２５℃）以上、より好ましくはpHを１０以上に調整
する。本発明方法に用いる逆浸透膜は、耐アルカリ性逆
浸透膜であることが好ましく、pH１０以上の水と長期的
に接しても劣化を受けないものであることが好ましい。
この場合、供給されるアルカリ性のホウ素含有水のpHよ
りも、濃縮水の方がpHが高くなるので、濃縮水のpHを考
慮して耐アルカリ性逆浸透膜を選択することが好まし
い。このような耐アルカリ性逆浸透膜としては、例え
ば、pH１１まで長期耐久性のあるものとして市販されて
いる ＦＩＬＭＴＥＣ ｔｙｐｅ ＦＴ３０などや、pH１
０まで長期耐久性のあるものとして市販されている日東
電工(株)製ＥＳ２０、ＥＳ１０、ＮＴＲ７５９や、東レ
(株)製ＳＵ７００などのポリアミド系の膜などを挙げる
ことができる。BEST MODE FOR CARRYING OUT THE INVENTION The method for treating boron-containing water according to the present invention adjusts the pH of boron-containing water to 9.2 or more and passes the water through a reverse osmosis membrane to remove boron. Can be applied. In the method of the present invention, a scale inhibitor is added to the boron-containing water passing through the reverse osmosis membrane. In the method of the present invention, there is no particular limitation on the method of adjusting the pH of the boron-containing water to 9.2 or higher, and for example, a method of adding an aqueous alkali solution such as sodium hydroxide or a method of passing through a strongly basic ion exchange resin tower. Examples of the method include watering. As a method of adding an alkali aqueous solution, for example, providing a pH adjustment tank with a stirrer, adding an alkali,
Alternatively, an alkaline aqueous solution inlet may be provided in the water flow line, and a static mixer or the like may be provided downstream of the inlet, and the alkaline aqueous solution can be added from the inlet. By adding an alkali to the boron-containing water, the pH is raised to the pKa of boric acid 9.
The pH is adjusted to 2 (25 ° C.) or more, more preferably to 10 or more. The reverse osmosis membrane used in the method of the present invention is preferably an alkali-resistant reverse osmosis membrane, and preferably does not deteriorate even if it is in contact with water having a pH of 10 or more for a long time.
In this case, since the concentrated water has a higher pH than the supplied alkaline boron-containing water, it is preferable to select an alkali-resistant reverse osmosis membrane in consideration of the pH of the concentrated water. Examples of such an alkali-resistant reverse osmosis membrane include FILMTEC type FT30, which is commercially available as a material having long-term durability up to pH 11, and pH 1
Nitto Denko Corporation's ES20, ES10, NTR759, and Toray that are commercially available as long-lasting
Polyamide-based films such as SU700 manufactured by K.K.
【０００６】本発明方法においては、逆浸透膜に通水す
るホウ素含有水の脱炭酸処理を行うことが好ましい。脱
炭酸処理の方法には特に制限はなく、例えば、脱気膜、
真空脱気、脱炭酸塔などを用いて脱炭酸処理を行うこと
ができる。脱気膜を用いる場合は、例えば、ホウ素含有
水に酸を添加して酸性としたのち、脱気膜に通水するこ
とにより脱炭酸することができる。ホウ素含有水中の炭
酸を除去することにより、スケール防止剤の添加量を減
少するとともに、逆浸透膜に通水する前のpH調整に必要
なアルカリ添加量も減少することができる。炭酸が存在
すると必要なアルカリ添加量が多くなるのは、水中の全
炭酸濃度が多いほど、pHの緩衝作用が大きいためである
と考えられる。脱炭酸処理を行ってpH調整のためのアル
カリ添加量を減少することにより、逆浸透膜からのアル
カリリーク量、例えば、アルカリとして水酸化ナトリウ
ムを使用した場合には、ナトリウムのリーク量を減少す
ることができる。本発明に用いるスケール防止剤には特
に制限はなく、例えば、アクリル酸、メタクリル酸、マ
レイン酸などを重合して得られるカルボキシル基を有す
る低分子量ポリマー、イミノ二酢酸、エチレンジアミン
四酢酸などのキレート化剤、ニトリロトリメチレンホス
ホン酸などのホスホン酸、ヘキサメタリン酸ナトリウム
などのポリリン酸塩などを挙げることができる。これら
の中で、カルボキシル基を有する低分子量ポリマー及び
キレート化剤はカルシウムスケールを防止する効果が大
きく、特に好適に使用することができる。本発明方法に
おいて、逆浸透膜に通水するホウ素含有水にスケール防
止剤を添加する場所には特に制限はなく、例えば、ホウ
素を含有する原水に直接スケール防止剤を添加すること
ができ、脱炭酸処理の前に酸性としたホウ素含有水にス
ケール防止剤を添加することもでき、脱炭酸処理を終え
た直後のホウ素含有水にスケール防止剤を添加すること
もでき、あるいは、脱炭酸とpH調整を行った後のpH９.
２以上のホウ素含有水にスケール防止剤を添加すること
もできる。In the method of the present invention, it is preferable to carry out a decarboxylation treatment of the water containing boron passing through the reverse osmosis membrane. There is no particular limitation on the method of the decarboxylation treatment, for example, a degassing membrane,
The decarboxylation treatment can be performed using a vacuum deaeration, a decarbonation tower, or the like. When using a degassing membrane, for example, after adding acid to boron-containing water to make it acidic, decarbonation can be performed by passing water through the degassing membrane. By removing the carbonic acid in the boron-containing water, the amount of the scale inhibitor to be added can be reduced, and the amount of the alkali added for adjusting the pH before the water is passed through the reverse osmosis membrane can also be reduced. It is considered that the reason why the required amount of added alkali increases when carbonic acid is present is that the higher the total carbonic acid concentration in water, the greater the pH buffering action. The amount of alkali leak from the reverse osmosis membrane, for example, when sodium hydroxide is used as the alkali, reduces the amount of sodium leak by reducing the amount of alkali added for pH adjustment by performing decarboxylation treatment. be able to. There is no particular limitation on the scale inhibitor used in the present invention, for example, acrylic acid, methacrylic acid, low molecular weight polymer having a carboxyl group obtained by polymerizing maleic acid, iminodiacetic acid, chelation of ethylenediaminetetraacetic acid and the like Agents, phosphonic acids such as nitrilotrimethylenephosphonic acid, and polyphosphates such as sodium hexametaphosphate. Among these, a low molecular weight polymer having a carboxyl group and a chelating agent have a large effect of preventing calcium scale and can be used particularly preferably. In the method of the present invention, the place where the scale inhibitor is added to the boron-containing water passing through the reverse osmosis membrane is not particularly limited. For example, the scale inhibitor can be directly added to the raw water containing boron, and A scale inhibitor can be added to the boron-containing water that has been acidified before the carbonation treatment, and a scale inhibitor can be added to the boron-containing water immediately after the decarboxylation treatment, or decarboxylation and pH PH after adjustment 9.
A scale inhibitor can be added to two or more boron-containing waters.
【０００７】図１(ａ)は、本発明のホウ素含有水の処理
方法の一態様の工程系統図である。本態様においては、
ホウ素を含有する原水にアルカリを添加してpHを９.２
以上に調整したのち、スケール防止剤を添加し、逆浸透
膜１に通水してホウ素を除去する。図１(ｂ)は、本発明
方法の他の態様の工程系統図である。本態様において
は、ホウ素を含有する原水に酸を添加していったん酸性
とし、脱気膜２において炭酸を除去し、脱炭酸されたホ
ウ素含有水にアルカリを添加してpHを９.２以上に調整
したのち、スケール防止剤を添加し、逆浸透膜１に通水
してホウ素を除去する。図１(ｃ)は、本発明方法の他の
態様の工程系統図である。本態様においては、ホウ素を
含有する原水に先ずスケール防止剤を添加し、さらに酸
を添加していったん酸性として、脱気膜２において炭酸
を除去し、脱炭酸されたホウ素含有水にアルカリを添加
してpHを９.２以上に調整したのち、逆浸透膜１に通水
してホウ素を除去する。これらの態様の中で、脱気膜に
通水するホウ素含有水にスケール防止剤を添加する態様
は、脱気膜と逆浸透膜の両方において膜面のスケールを
防止することができるので好ましい。本発明方法におい
ては、複数の逆浸透膜を多段に設け、前段の逆浸透膜の
透過水を後段の逆浸透膜の供給水とすることができる。
図２(ａ)は、本発明方法の他の態様の工程系統図であ
る。本態様においては、逆浸透膜を２段に設け、ホウ素
を含有する原水に酸を添加して酸性とし、さらにスケー
ル防止剤を添加したのち、脱気膜２において炭酸を除去
し、脱炭酸されたホウ素含有水にアルカリを添加してpH
を９.２以上に調整し、前段の逆浸透膜１及び後段の逆
浸透膜１に通水してホウ素を除去する。図２(ｂ)は、本
発明方法の他の態様の工程系統図である。本態様におい
ては、逆浸透膜を３段に設け、ホウ素を含有する原水に
先ずスケール防止剤を添加し、さらに酸を添加していっ
たん酸性として、脱気膜２において炭酸を除去し、脱炭
酸されたホウ素含有水にアルカリを添加してpHを９.２
以上に調整したのち、１段目、２段目及び３段目の逆浸
透膜１に逐次通水してホウ素を除去する。複数の逆浸透
膜を多段に設けることにより、ホウ素の除去率を高め、
処理水中のホウ素濃度を低下させることができる。本発
明のホウ素含有水の処理方法によれば、高いpH条件下で
逆浸透膜によるホウ素除去処理を行うに際して、弱酸性
イオン交換装置を設置してカルシウムを除去するなどの
前処理を行うことなく、逆浸透膜面へのカルシウムスケ
ールの付着を防止することができる。そのために、弱酸
性イオン交換装置などを省いて設備を簡略化するととも
に、処理工程を短縮することができる。本発明方法によ
り膜面へのカルシウムスケールの付着を防止し得る機構
は、ホウ素含有水中に含まれるカルシウムなどのイオン
が、キレート化剤によって封鎖され、pH９.２以上のア
ルカリ条件となっても炭酸カルシウムなどの塩を生成し
なくなるためと考えられる。FIG. 1A is a flow chart of one embodiment of the method for treating boron-containing water of the present invention. In this embodiment,
PH was adjusted to 9.2 by adding alkali to raw water containing boron.
After the above adjustment, a scale inhibitor is added, and water is passed through the reverse osmosis membrane 1 to remove boron. FIG. 1 (b) is a process flow diagram of another embodiment of the method of the present invention. In this embodiment, the raw water containing boron is acidified once by adding an acid, carbonic acid is removed in the degassing membrane 2, and the alkali is added to the decarbonated boron-containing water to adjust the pH to 9.2 or more. After the adjustment, a scale inhibitor is added, and water is passed through the reverse osmosis membrane 1 to remove boron. FIG. 1 (c) is a process flow diagram of another embodiment of the method of the present invention. In this embodiment, a scale inhibitor is first added to the raw water containing boron, and then an acid is added to make the mixture once acidic, carbon dioxide is removed in the degassing membrane 2, and an alkali is added to the decarbonated boron-containing water. After adjusting the pH to 9.2 or more, water is passed through the reverse osmosis membrane 1 to remove boron. Among these embodiments, an embodiment in which a scale inhibitor is added to the boron-containing water passing through the degassing membrane is preferable because scale on the membrane surface can be prevented in both the degassing membrane and the reverse osmosis membrane. In the method of the present invention, a plurality of reverse osmosis membranes can be provided in multiple stages, and the permeated water of the preceding stage reverse osmosis membrane can be used as the supply water for the subsequent stage of reverse osmosis membrane.
FIG. 2A is a process flow diagram of another embodiment of the method of the present invention. In this embodiment, the reverse osmosis membrane is provided in two stages, the acid is added to the raw water containing boron to make it acidic, and after the scale inhibitor is added, the carbon dioxide is removed in the degassing membrane 2 and the carbon dioxide is removed. PH was adjusted by adding alkali to the boron-containing water
Is adjusted to 9.2 or more, and water is passed through the reverse osmosis membrane 1 in the first stage and the reverse osmosis membrane 1 in the second stage to remove boron. FIG. 2 (b) is a process flow diagram of another embodiment of the method of the present invention. In the present embodiment, a reverse osmosis membrane is provided in three stages, a scale inhibitor is first added to the raw water containing boron, and then an acid is added to make the water once acidic. PH was adjusted to 9.2 by adding alkali to the boron-containing water.
After the above adjustment, water is sequentially passed through the first, second, and third reverse osmosis membranes 1 to remove boron. By providing multiple reverse osmosis membranes in multiple stages, the removal rate of boron is increased,
The boron concentration in the treated water can be reduced. According to the method for treating boron-containing water of the present invention, when performing a boron removal treatment by a reverse osmosis membrane under high pH conditions, without performing a pretreatment such as installing a weakly acidic ion exchange device to remove calcium. Further, it is possible to prevent calcium scale from adhering to the reverse osmosis membrane surface. Therefore, the equipment can be simplified by omitting the weakly acidic ion exchange device and the like, and the processing steps can be shortened. The mechanism that can prevent the adhesion of calcium scale to the membrane surface by the method of the present invention is that ions such as calcium contained in the boron-containing water are blocked by a chelating agent and carbonated even under alkaline conditions of pH 9.2 or more. It is considered that salts such as calcium are not generated.
【０００８】[0008]
【実施例】以下に、実施例を挙げて本発明をさらに詳細
に説明するが、本発明はこれらの実施例によりなんら限
定されるものではない。 実施例１ 図１(ｂ)に示す酸添加、脱気膜による脱炭酸、アルカリ
添加、スケール防止剤添加及び逆浸透膜への通水をこの
順に行う工程により、ホウ素含有水の処理を行った。脱
炭酸装置は、脱気膜［大日本インキ化学工業(株)、ＳＥ
ＰＡＲＥＬ ＥＦ−０４０Ｐ］を備えたものであり、逆
浸透膜装置は、耐アルカリ性逆浸透膜［ＦＩＬＭＴＥ
Ｃ、ｔｙｐｅ ＥＴ３０］を備えたものである。また、
ホウ素３０ppbを含有する半導体製造工場の回収水を、
厚木市水で倍量に希釈した水を原水として用いた。原水
を初期水量３００リットル／時で送水し、原水に塩酸を
添加してpHを４.５に調整したのち、脱気膜に通水して
脱炭酸処理を行った。次いで、脱炭酸水に水酸化ナトリ
ウムを添加してpHを１０.０に調整したのち、スケール
防止剤としてエチレンジアミン四酢酸四ナトリウム塩
（ＥＤＴＡ・４Ｎａ）を２０mg／リットルになるように
添加して、逆浸透膜に通水した。試験開始当初の逆浸透
膜の透過水量は２４０リットル／時であったものが、７
２０時間経過後は１５０リットル／時となった。 実施例２ ＥＤＴＡ・４Ｎａの添加量を５０mg／リットルとした以
外は、実施例１と同じ操作を繰り返した。７２０時間経
過後の逆浸透膜の透過水量は、２００リットル／時であ
った。 実施例３ ＥＤＴＡ・４Ｎａの添加量を１００mg／リットルとした
以外は、実施例１と同じ操作を繰り返した。７２０時間
経過後の逆浸透膜の透過水量は、２３０リットル／時で
あった。 実施例４ 図１(ｃ)に示すスケール防止剤添加、酸添加、脱気膜に
よる脱炭酸、アルカリ添加及び逆浸透膜への通水をこの
順に行う工程により、ホウ素含有水の処理を行った。脱
炭酸装置は、脱気膜［大日本インキ化学工業(株)、ＳＥ
ＰＡＲＥＬ ＥＦ−０４０Ｐ］を備えたものであり、逆
浸透膜装置は、耐アルカリ性逆浸透膜［ＦＩＬＭＴＥ
Ｃ、ｔｙｐｅ ＥＴ３０］を備えたものである。また、
ホウ素３０ppbを含有する半導体製造工場の回収水を、
厚木市水で倍量に希釈した水を原水として用いた。原水
を初期水量３００リットル／時で送水し、原水にスケー
ル防止剤としてエチレンジアミン四酢酸四ナトリウム塩
（ＥＤＴＡ・４Ｎａ）を２０mg／リットルになるように
添加し、さらに塩酸を添加してpHを４.５に調整したの
ち、脱気膜に通水して脱炭酸処理を行った。次いで、脱
炭酸水に水酸化ナトリウムを添加してpHを１０.０に調
整したのち、逆浸透膜に通水した。試験開始当初の逆浸
透膜の透過水量は２４０リットル／時であったものが、
７２０時間経過後は２３０リットル／時となった。 実施例５ ＥＤＴＡ・４Ｎａの添加量を５０mg／リットルとした以
外は、実施例４と同じ操作を繰り返した。７２０時間経
過後の逆浸透膜の透過水量は、２４０リットル／時で、
試験開始当初と同じであった。 実施例６ ＥＤＴＡ・４Ｎａの添加量を１００mg／リットルとした
以外は、実施例４と同じ操作を繰り返した。７２０時間
経過後の逆浸透膜の透過水量は、２４０リットル／時
で、試験開始当初と同じであった。 比較例１ ＥＤＴＡ・４Ｎａを添加しないこと以外は、実施例１と
同じ操作を繰り返した。７２０時間経過後の逆浸透膜の
透過水量は、１２０リットル／時であった。実施例１〜
６及び比較例１の結果を、第１表に示す。EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 Boron-containing water was treated by the steps shown in FIG. 1 (b) in which acid addition, decarboxylation using a degassing membrane, alkali addition, scale inhibitor addition, and water passing through a reverse osmosis membrane were performed in this order. . The decarbonation unit is a degassing membrane [Dainippon Ink and Chemicals, Inc., SE
PAREL EF-040P], and the reverse osmosis membrane device is an alkali-resistant reverse osmosis membrane [FILMTE
C, type ET30]. Also,
Recovered water from a semiconductor manufacturing plant containing 30 ppb boron
Water diluted twice in Atsugi City water was used as raw water. Raw water was supplied at an initial water volume of 300 liters / hour, hydrochloric acid was added to the raw water to adjust the pH to 4.5, and then water was passed through a degassing membrane to perform a decarbonation treatment. Next, sodium hydroxide was added to the decarbonated water to adjust the pH to 10.0, and then ethylenediaminetetraacetic acid tetrasodium salt (EDTA.4Na) was added as a scale inhibitor to a concentration of 20 mg / liter. Water was passed through the reverse osmosis membrane. At the beginning of the test, the reverse osmosis membrane had a permeated water volume of 240 liters / hour.
After 20 hours, it was 150 liters / hour. Example 2 The same operation as in Example 1 was repeated, except that the amount of EDTA / 4Na added was 50 mg / liter. After 720 hours, the amount of water permeated through the reverse osmosis membrane was 200 liters / hour. Example 3 The same operation as in Example 1 was repeated except that the amount of EDTA / 4Na added was 100 mg / liter. After 720 hours, the amount of water permeated through the reverse osmosis membrane was 230 liters / hour. Example 4 The treatment with boron-containing water was carried out by the steps shown in FIG. 1 (c), in which a scale inhibitor was added, an acid was added, decarboxylation by a degassing membrane, an alkali was added, and water passed through the reverse osmosis membrane in this order. . The decarbonation unit is a degassing membrane [Dainippon Ink and Chemicals, Inc., SE
PAREL EF-040P], and the reverse osmosis membrane device is an alkali-resistant reverse osmosis membrane [FILMTE
C, type ET30]. Also,
Recovered water from a semiconductor manufacturing plant containing 30 ppb boron
Water diluted twice in Atsugi City water was used as raw water. Raw water is supplied at an initial water volume of 300 liters / hour, and ethylenediaminetetraacetic acid tetrasodium salt (EDTA.4Na) is added to the raw water as a scale inhibitor so as to have a concentration of 20 mg / liter. After adjusting to 5, water was passed through a degassing membrane to perform a decarbonation treatment. Next, sodium hydroxide was added to the decarbonated water to adjust the pH to 10.0, and the solution was passed through a reverse osmosis membrane. The amount of water permeated through the reverse osmosis membrane at the beginning of the test was 240 liters / hour,
After 720 hours, it was 230 liters / hour. Example 5 The same operation as in Example 4 was repeated except that the amount of EDTA-4Na added was 50 mg / liter. After 720 hours, the amount of water permeated through the reverse osmosis membrane is 240 liters / hour.
It was the same as at the beginning of the test. Example 6 The same operation as in Example 4 was repeated except that the amount of EDTA-4Na added was 100 mg / liter. After 720 hours, the amount of water permeated through the reverse osmosis membrane was 240 liters / hour, which was the same as at the beginning of the test. Comparative Example 1 The same operation as in Example 1 was repeated except that EDTA / 4Na was not added. After 720 hours, the amount of water permeated through the reverse osmosis membrane was 120 liters / hour. Example 1
Table 1 shows the results of Comparative Example 6 and Comparative Example 1.
【０００９】[0009]
【表１】 [Table 1]
【００１０】第１表の結果から、スケール防止剤を添加
しない比較例１においては、７２０時間通水後には、逆
浸透膜透過水の水量は、試験開始当初に比べて半減する
のに対して、脱炭酸水にＥＤＴＡ・４Ｎａを添加した実
施例１〜３と、原水にＥＤＴＡ・４Ｎａを添加した実施
例４〜６では、逆浸透膜透過水の水量の減少の程度が少
ない。また、同じ場所でＥＤＴＡ・４Ｎａを添加した場
合は、その添加量が多いほど逆浸透膜透過水の水量が多
くなっていることから、逆浸透膜に通水するホウ素含有
水にスケール防止剤を添加する本発明方法により、逆浸
透膜の透過速度の低下を防いで、長時間にわたって高い
透過水量を維持し得ることが分かる。特に、原水にＥＤ
ＴＡ・４Ｎａを５０mg／リットル以上添加した実施例５
と実施例６においては、７２０時間経過後も逆浸透膜透
過水量は全く減少していない。なお、実施例１〜６及び
比較例１において、逆浸透膜透過水のホウ素濃度は、す
べて０.９ppbであった。[0010] From the results in Table 1, in Comparative Example 1 in which no scale inhibitor was added, the amount of water permeated through the reverse osmosis membrane was reduced by half after passing for 720 hours, compared to the amount at the beginning of the test. In Examples 1 to 3 in which EDTA / 4Na was added to decarbonated water and Examples 4 to 6 in which EDTA / 4Na was added to raw water, the amount of water permeated through the reverse osmosis membrane was less reduced. When EDTA / 4Na is added at the same place, the larger the amount of EDTA / 4Na, the larger the amount of water permeated through the reverse osmosis membrane. Therefore, a scale inhibitor is added to the boron-containing water passing through the reverse osmosis membrane. It can be seen that the method of the present invention to be added can prevent a decrease in the permeation rate of the reverse osmosis membrane and maintain a high permeated water amount for a long time. In particular, ED
Example 5 in which TA-4Na was added at 50 mg / liter or more
In Example 6, the amount of water permeated through the reverse osmosis membrane did not decrease at all even after elapse of 720 hours. In Examples 1 to 6 and Comparative Example 1, the boron concentration in the reverse osmosis membrane permeated water was 0.9 ppb.
【００１１】[0011]
【発明の効果】本発明方法によれば、弱酸性イオン交換
樹脂塔を設けてカルシウムを除去するなどの前処理なし
でも、逆浸透膜面にカルシウムスケールが発生して膜透
過水量が低下することがなく、ホウ素含有水の高pH条件
下での逆浸透膜処理が可能となり、設備を簡略化し、処
理工程を短縮することができる。According to the method of the present invention, calcium scale is generated on the reverse osmosis membrane surface and the amount of permeated water decreases even without a pretreatment such as removing calcium by providing a weakly acidic ion exchange resin tower. Therefore, reverse osmosis membrane treatment under high pH conditions of boron-containing water becomes possible, equipment can be simplified, and the treatment process can be shortened.
【図１】図１は、本発明のホウ素含有水の処理方法の工
程系統図である。FIG. 1 is a process flow chart of a method for treating boron-containing water of the present invention.
【図２】図２は、本発明のホウ素含有水の処理方法の工
程系統図である。FIG. 2 is a process flow diagram of the method for treating boron-containing water of the present invention.
１ 逆浸透膜 ２ 脱気膜 1 reverse osmosis membrane 2 degassing membrane
Claims (1)
逆浸透膜に通水してホウ素を除去するホウ素含有水の処
理方法において、逆浸透膜に通水するホウ素含有水にス
ケール防止剤を添加することを特徴とするホウ素含有水
の処理方法。(1) adjusting the pH of the boron-containing water to 9.2 or more,
A method for treating boron-containing water, which removes boron by passing through a reverse osmosis membrane, comprising adding a scale inhibitor to the boron-containing water passing through a reverse osmosis membrane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30887897A JP3890708B2 (en) | 1997-11-11 | 1997-11-11 | Method for treating boron-containing water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30887897A JP3890708B2 (en) | 1997-11-11 | 1997-11-11 | Method for treating boron-containing water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11138165A true JPH11138165A (en) | 1999-05-25 |
| JP3890708B2 JP3890708B2 (en) | 2007-03-07 |
Family
ID=17986358
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30887897A Expired - Fee Related JP3890708B2 (en) | 1997-11-11 | 1997-11-11 | Method for treating boron-containing water |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3890708B2 (en) |
Cited By (11)
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|---|---|---|---|---|
| JP2002186835A (en) * | 2000-12-20 | 2002-07-02 | Japan Organo Co Ltd | Operation method for reverse osmosis membrane device |
| JP2002320979A (en) * | 2001-04-27 | 2002-11-05 | Sharp Corp | Method and system for treating metal-containing drainage |
| WO2002068338A3 (en) * | 2001-02-26 | 2002-12-27 | Ide Technologies Ltd | Method of boron removal in presence of magnesium ions |
| JPWO2003062151A1 (en) * | 2002-01-22 | 2005-05-19 | 東レ株式会社 | Fresh water generation method and fresh water generator |
| WO2008020444A1 (en) * | 2006-08-15 | 2008-02-21 | Mekorot Israel National Water Company, Ltd. | Multiple stage reverse osmosis method for removing boron from a salinated fluid |
| US7442309B2 (en) * | 2002-06-13 | 2008-10-28 | Hydranautics | Methods for reducing boron concentration in high salinity liquid |
| US7618538B2 (en) * | 2006-08-10 | 2009-11-17 | Acciona Agua, S.A.U. | Procedure for elimination of boron from sea-water by reverse osmosis membranes |
| CN102107996A (en) * | 2004-12-14 | 2011-06-29 | 栗田工业株式会社 | Apparatus and method for treating waste water |
| US8357300B2 (en) | 2010-08-16 | 2013-01-22 | Hydranautics | Methods and materials for selective boron adsorption from aqueous solution |
| US8702978B2 (en) | 2010-09-16 | 2014-04-22 | Kabushiki Kaisha Toshiba | Seawater desalination apparatus and chemical injection apparatus |
| WO2015102272A1 (en) * | 2013-12-30 | 2015-07-09 | 부경대학교산학협력단 | Method for removing boron present in seawater |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002186835A (en) * | 2000-12-20 | 2002-07-02 | Japan Organo Co Ltd | Operation method for reverse osmosis membrane device |
| WO2002068338A3 (en) * | 2001-02-26 | 2002-12-27 | Ide Technologies Ltd | Method of boron removal in presence of magnesium ions |
| US7097769B2 (en) | 2001-02-26 | 2006-08-29 | I.D.E. Technologies Ltd. | Method of boron removal in presence of magnesium ions |
| JP2002320979A (en) * | 2001-04-27 | 2002-11-05 | Sharp Corp | Method and system for treating metal-containing drainage |
| JPWO2003062151A1 (en) * | 2002-01-22 | 2005-05-19 | 東レ株式会社 | Fresh water generation method and fresh water generator |
| US7442309B2 (en) * | 2002-06-13 | 2008-10-28 | Hydranautics | Methods for reducing boron concentration in high salinity liquid |
| CN102107996A (en) * | 2004-12-14 | 2011-06-29 | 栗田工业株式会社 | Apparatus and method for treating waste water |
| US7618538B2 (en) * | 2006-08-10 | 2009-11-17 | Acciona Agua, S.A.U. | Procedure for elimination of boron from sea-water by reverse osmosis membranes |
| WO2008020444A1 (en) * | 2006-08-15 | 2008-02-21 | Mekorot Israel National Water Company, Ltd. | Multiple stage reverse osmosis method for removing boron from a salinated fluid |
| US8357300B2 (en) | 2010-08-16 | 2013-01-22 | Hydranautics | Methods and materials for selective boron adsorption from aqueous solution |
| US8702978B2 (en) | 2010-09-16 | 2014-04-22 | Kabushiki Kaisha Toshiba | Seawater desalination apparatus and chemical injection apparatus |
| WO2015102272A1 (en) * | 2013-12-30 | 2015-07-09 | 부경대학교산학협력단 | Method for removing boron present in seawater |
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|---|---|
| JP3890708B2 (en) | 2007-03-07 |
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