JPH11188359A - Pure water producing apparatus - Google Patents
Pure water producing apparatusInfo
- Publication number
- JPH11188359A JPH11188359A JP36011797A JP36011797A JPH11188359A JP H11188359 A JPH11188359 A JP H11188359A JP 36011797 A JP36011797 A JP 36011797A JP 36011797 A JP36011797 A JP 36011797A JP H11188359 A JPH11188359 A JP H11188359A
- Authority
- JP
- Japan
- Prior art keywords
- water
- reverse osmosis
- alkali
- osmosis membrane
- boron
- 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)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、純水製造装置に関
する。さらに詳しくは、本発明は、半導体製造などの電
子産業分野、あるいはその関連分野などで用いられる、
ホウ素濃度を大幅に低減した純水又は超純水の製造に適
した純水製造装置に関する。[0001] The present invention relates to a pure water producing apparatus. More specifically, the present invention is used in the electronic industry field such as semiconductor manufacturing, or related fields,
The present invention relates to a pure water producing apparatus suitable for producing pure water or ultrapure water in which the boron concentration is significantly reduced.
【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装置として、アルカリ添加によりpH
を１０以上にしたのち、耐アルカリ性逆浸透膜装置に通
水する純水製造装置が知られている。また、第４７回全
国水道研究会発表会（平成８年５月、発表番号４−９
８）では、逆浸透膜装置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
除率が高くなることが報告されている。しかし、アルカ
リ性のホウ素含有水を逆浸透膜装置に通水すると、カル
シウムなどの硬度成分が析出して膜閉塞を生じ、造水量
が低下するという問題がある。ホウ素を含有する原水の
処理に、電気脱イオン装置の利用が検討されている。電
気脱イオン装置は、２つの側面がそれぞれ陽イオン交換
膜と陰イオン交換膜からなり、その間にイオン交換樹脂
又はイオン交換繊維を充填した希釈室に、電位差を与え
て、通水することにより、陽イオンを陽イオン交換膜を
通過させ、陰イオンを陰イオン交換膜を通過させて除去
するものであり、従来の混床式脱イオン装置と同等以上
の水質の処理水を得ることができる。電気脱イオン装置
は、薬品再生が不要であり、コンパクトである点に特徴
があり、近年大容量の電気脱イオン装置が開発されてい
る。しかし、ホウ素含有水の処理に電気脱イオン装置を
用いると、ホウ素の除去率は７０％程度にしか達せず、
ホウ素の除去を目的とする純水製造装置においては、水
質的に不十分であった。このため、電気脱イオン装置で
処理した水を、さらに非再生型イオン交換装置などを用
いて後処理する必要があったが、水中に残存するホウ素
のために非再生型イオン交換装置の寿命が著しく短くな
り、その交換頻度が非常に大きくなるために、著しく不
経済となってしまうという問題があった。2. Description of the Related Art As an apparatus for producing pure water or ultrapure water by treating raw water containing boron, pH is adjusted by adding alkali.
A pure water production apparatus is known in which water is passed through an alkali-resistant reverse osmosis membrane device after the water content is increased to 10 or more. In addition, the 47th National Waterworks Research Institute Presentation (May 1996, Publication No. 4-9
8) reports that in a boron reduction system using a reverse osmosis membrane device, increasing the pH of water to 10 or more increases the boron rejection rate. However, when alkaline boron-containing water is passed through the reverse osmosis membrane device, there is a problem that hardness components such as calcium are precipitated and the membrane is clogged, and the amount of fresh water is reduced. The use of an electrodeionization apparatus for the treatment of raw water containing boron is being studied. The electrodeionization apparatus has two side surfaces each composed of a cation exchange membrane and an anion exchange membrane, between which a potential difference is applied to a dilution chamber filled with an ion exchange resin or an ion exchange fiber, and water is passed through. It removes cations by passing through a cation exchange membrane and anions by passing through an anion exchange membrane, and can obtain treated water having water quality equal to or higher than that of a conventional mixed-bed deionization apparatus. The electrodeionization apparatus is characterized in that it does not require chemical regeneration and is compact, and a large-capacity electrodeionization apparatus has recently been developed. However, when an electrodeionization apparatus is used for the treatment of boron-containing water, the removal rate of boron reaches only about 70%,
In a pure water production apparatus for removing boron, water quality was insufficient. For this reason, it was necessary to further post-process the water treated by the electrodeionization apparatus using a non-regenerative ion exchanger, but the life of the non-regenerative ion exchanger was reduced due to boron remaining in the water. There is a problem that the length of the replacement becomes extremely short and the frequency of replacement becomes extremely large, which is extremely uneconomical.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、半導体製造
などの電子産業分野、あるいはその関連分野などで用い
られる、ホウ素濃度を低減した純水の製造において、電
気脱イオン装置におけるホウ素除去率を飛躍的に高める
ことができる純水製造装置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 reducing the boron removal rate in an electrodeionization apparatus in the production of pure water with a reduced boron concentration, which is used in the field of the electronics industry such as semiconductor manufacturing or related fields. The purpose of the present invention is to provide a pure water production apparatus that can be dramatically improved.
【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、逆浸透膜装置と電
気脱イオン装置を有する純水製造装置にpH調整用のアル
カリ添加装置を設け、逆浸透膜装置への供給水又は電気
脱イオン装置への供給水のpHを９.２以上に調整するこ
とにより、電気脱イオン装置におけるホウ素の除去率を
飛躍的に高め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）（Ａ）ホウ素含有水にアルカリを添加してpHを
９.２以上に調整するアルカリ添加装置、（Ｂ）pHの調
整されたホウ素含有水が通水される耐アルカリ性逆浸透
膜装置及び（Ｃ）耐アルカリ性逆浸透膜装置の透過水が
通水される電気脱イオン装置を有することを特徴とする
純水製造装置、及び、（２）（Ｄ）ホウ素含有水が通水
される逆浸透膜装置、（Ｅ）逆浸透膜装置の透過水にア
ルカリを添加してpHを９.２以上に調整するアルカリ添
加装置、（Ｆ）pHの調整された逆浸透膜装置の透過水が
通水される電気脱イオン装置を有することを特徴とする
純水製造装置、を提供するものである。Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that the addition of alkali for pH adjustment to a pure water production apparatus having a reverse osmosis membrane device and an electrodeionization device. By installing a device and adjusting the pH of the water supplied to the reverse osmosis membrane device or the water supplied to the electrodeionization device to 9.2 or more, the removal rate of boron in the electrodeionization device can be dramatically increased. And completed the present invention on the basis of this finding. That is, the present invention
(1) (A) an alkali addition device for adjusting the pH to 9.2 or more by adding an alkali to boron-containing water, and (B) an alkali-resistant reverse osmosis membrane device through which the pH-adjusted boron-containing water flows. And (C) a pure water production apparatus having an electrodeionization apparatus through which permeated water of an alkali resistant reverse osmosis membrane apparatus is passed, and (2) (D) boron-containing water is passed through A reverse osmosis membrane apparatus, (E) an alkali addition apparatus for adjusting the pH to 9.2 or more by adding alkali to the permeated water of the reverse osmosis membrane apparatus, and (F) a permeated water of the reverse osmosis membrane apparatus whose pH is adjusted. It is intended to provide a pure water production apparatus having an electrodeionization apparatus through which water is passed.
【０００５】[0005]
【発明の実施の形態】図１(ａ)は、本発明の純水製造装
置の一態様の工程系統図である。本態様の純水製造装置
は、(Ａ)ホウ素含有水にアルカリを添加してpHを９.２
以上に調整するアルカリ添加装置１、(Ｂ)pHの調整され
たホウ素含有水が通水される耐アルカリ性逆浸透膜装置
２及び(Ｃ)耐アルカリ性逆浸透膜装置の透過水が通水さ
れる電気脱イオン装置３を有する。本態様の純水製造装
置の場合は、耐アルカリ性逆浸透膜装置の前後で高pHと
するためカルシウムスケールなどが生じ易いので、アル
カリ添加装置の前段に、強酸性イオン交換樹脂を含むイ
オン交換装置４と膜脱気装置５を設けて、原水中のカル
シウムイオンと炭酸を十分に除去し、逆浸透膜面におけ
る炭酸カルシウムスケールの発生を防止することが好ま
しい。また、電気脱イオン装置の後段に非再生型イオン
交換装置６を設けて、電気脱イオン装置で除去しきれな
かった微量の不純物を除去することができる。 本態様の純水製造装置における(Ａ)アルカリ添加装置に
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装置や、強塩基性イオン交換樹
脂を含むイオン交換装置、あるいはその両方を設置する
ことができる。アルカリ水溶液を添加する装置として
は、例えば、撹拌機つきのpH調整槽を設けたり、通水ラ
インにアルカリ水溶液注入口を設け、その下流側にスタ
チックミキサーなどを設置することなどができる。アル
カリ添加装置は、ホウ素含有水にアルカリを添加して、
pHをホウ酸のｐＫa９.２（２５℃）以上、より好ましく
はpHを１０以上に調整し得るものである。図１(ａ)に示
す態様の装置においては、耐アルカリ性逆浸透膜装置の
入口にpHセンサー７を設け、制御器８を通じて信号を薬
注ポンプ９に送り、アルカリ貯槽１０からのアルカリ注
入量を制御する。ホウ酸の酸解離指数ｐＫaは２５℃に
おいて９.２であるので、ホウ素含有水にアルカリを添
加してpHを９.２以上、好ましくは１０以上にすると、
水中のホウ酸は下式のようにイオン化され、逆浸透膜装
置及び電気脱イオン装置におけるホウ素の除去率が著し
く高くなるものと考えられる。 Ｈ3ＢＯ3 ＋ Ｈ2Ｏ → Ｂ(ＯＨ)4 - ＋ Ｈ+ DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a) is a process flow diagram of one embodiment of the pure water production apparatus of the present invention. In the pure water production apparatus of this embodiment, the alkali is added to (A) boron-containing water to adjust the pH to 9.2.
The permeated water of the alkali addition apparatus 1 adjusted as described above, (B) the alkali resistant reverse osmosis membrane apparatus 2 through which the pH-adjusted boron-containing water is passed, and (C) the permeated water of the alkali resistant reverse osmosis membrane apparatus are passed through. It has an electrodeionization device 3. In the case of the pure water production apparatus of this embodiment, calcium scale and the like are likely to occur due to a high pH before and after the alkali-resistant reverse osmosis membrane apparatus, and therefore, an ion exchange apparatus containing a strongly acidic ion exchange resin before the alkali addition apparatus. 4 and a membrane deaerator 5 are preferably provided to sufficiently remove calcium ions and carbonic acid in the raw water to prevent the generation of calcium carbonate scale on the reverse osmosis membrane surface. In addition, a non-regenerative ion exchange device 6 is provided at a stage subsequent to the electrodeionization device, so that a trace amount of impurities that could not be removed by the electrodeionization device can be removed. There is no particular limitation on the (A) alkali addition apparatus in the pure water production apparatus of the present embodiment, for example, an apparatus for adding an alkali aqueous solution such as sodium hydroxide, an ion exchange apparatus containing a strongly basic ion exchange resin, or an apparatus therefor. Both can be installed. As a device for adding the alkaline aqueous solution, for example, a pH adjusting tank with a stirrer may be provided, or 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. The alkali addition device adds an alkali to the boron-containing water,
The pH can be adjusted to a pKa of boric acid of 9.2 (25 ° C.) or more, and more preferably to a pH of 10 or more. In the apparatus of the embodiment shown in FIG. 1 (a), a pH sensor 7 is provided at the entrance of the alkali-resistant reverse osmosis membrane device, a signal is sent to a chemical injection pump 9 through a controller 8, and an alkali injection amount from an alkali storage tank 10 is measured. Control. Since the acid dissociation index pKa of boric acid is 9.2 at 25 ° C., if an alkali is added to boron-containing water to adjust the pH to 9.2 or more, preferably 10 or more,
It is considered that boric acid in water is ionized as in the following formula, and the removal rate of boron in the reverse osmosis membrane device and the electrodeionization device is significantly increased. H 3 BO 3 + H 2 O → B (OH) 4 − + H +
【０００６】本態様の純水製造装置における(Ｂ)耐アル
カリ性逆浸透膜装置は、長期的にpH１０以上、より好ま
しくはpH１１以上の水と接しても劣化を生じないもので
あることが好ましい。この場合、通水される水のpHより
も、逆浸透膜装置の濃縮水の方がさらに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まで長期耐久性があるものと
して市販されているＦＩＬＭＴＥＣ ｔｙｐｅＦＴ３０
などや、pH１０まで長期耐久性があるものとして市販さ
れている日東電工(株)製のＥＳ２０、ＥＳ１０、ＮＴＲ
７５９や、東レ(株)製のＳＵ７００などのポリアミド系
の逆浸透膜などを挙げることができる。本態様の純水製
造装置における(Ｃ)電気脱イオン装置には特に制限はな
く、公知の電気脱イオン装置を使用することができる。
電気脱イオン装置は、薬品再生が不要であり、小型で大
容量を有するために、経済的にホウ素含有水を処理して
純水を製造することができる。本態様の純水製造装置に
おいては、逆浸透膜装置への供給水に水酸化ナトリウム
などを添加してアルカリ性とすることにより、逆浸透膜
装置の透過水すなわち電気脱イオン装置への供給水も、
水酸化ナトリウムなどを主成分として含有してアルカリ
性となるので、水酸化ナトリウムなどのアルカリを有効
に利用することができる。電気脱イオン装置に、通常の
通水条件である中性のホウ素含有水を通水した場合に
は、ホウ素の除去率は７０％程度であるが、本発明者
は、電気脱イオン装置への供給水のpHをアルカリ条件に
することにより、ホウ素除去率を高めることができるこ
とを見いだしたものである。本態様の純水製造装置によ
れば、耐アルカリ性逆浸透膜装置において、原水である
ホウ素含有水中のホウ素の９５％以上を除去し、さら
に、逆浸透膜装置の透過水を電気脱イオン装置に通水す
ることにより、原水であるホウ素含有水中のホウ素の９
９％以上を除去することができる。It is preferable that the alkali-resistant reverse osmosis membrane device (B) in the pure water production device of the present embodiment does not deteriorate even if it is brought into contact with water having a pH of 10 or more, more preferably pH 11 or more, for a long term. In this case, since the concentrated water of the reverse osmosis membrane device has a higher pH than the pH of the water to be passed, it is preferable to select the alkali-resistant reverse osmosis membrane in consideration of the pH of the concentrated water. As such an alkali-resistant reverse osmosis membrane, for example, FILMTEC type FT30 commercially available as having long-term durability up to pH 11
And Nitto Denko Corporation's ES20, ES10, and NTR, which are commercially available as having long-term durability up to pH 10.
759 and polyamide reverse osmosis membranes such as SU700 manufactured by Toray Industries, Inc. The (C) electrodeionization apparatus in the pure water production apparatus of this embodiment is not particularly limited, and a known electrodeionization apparatus can be used.
Since the electrodeionization apparatus does not require chemical regeneration, is small and has a large capacity, it can economically treat boron-containing water to produce pure water. In the pure water production apparatus of this embodiment, by adding sodium hydroxide or the like to the supply water to the reverse osmosis membrane apparatus to make it alkaline, the permeate of the reverse osmosis membrane apparatus, that is, the supply water to the electrodeionization apparatus is also reduced. ,
Since sodium hydroxide or the like is contained as a main component and becomes alkaline, an alkali such as sodium hydroxide can be effectively used. When neutral boron-containing water, which is a normal water flow condition, is passed through the electrodeionization apparatus, the removal rate of boron is about 70%. It has been found that by setting the pH of the feed water to an alkaline condition, the boron removal rate can be increased. According to the pure water production apparatus of this embodiment, in the alkali-resistant reverse osmosis membrane device, 95% or more of boron in the boron-containing water as raw water is removed, and the permeated water of the reverse osmosis membrane device is used for the electrodeionization device. By passing water, 9 of boron in the boron-containing water which is raw water
9% or more can be removed.
【０００７】図１(ｂ)は、本発明の純水製造装置の他の
態様の工程系統図である。本態様の純水製造装置は、
(Ｄ)ホウ素含有水が通水される逆浸透膜装置１１、(Ｅ)
逆浸透膜装置の透過水にアルカリを添加してpHを９.２
以上に調整するアルカリ添加装置１２、(Ｆ)pHの調整さ
れた逆浸透膜装置の透過水が通水される電気脱イオン装
置１３を有する。本態様の純水製造装置によれば、電気
脱イオン装置の前段に逆浸透膜装置が設けられているの
で、カルシウムイオンなどが除去される。従って、その
透過水を高pHとしても、電気脱イオン装置でのスケール
生成が防止できる。また、逆浸透膜装置の前段に、強酸
性イオン交換樹脂を含むイオン交換装置１４と膜脱気装
置１５を設けて、原水中のカルシウムイオンと炭酸を除
去し、逆浸透膜装置における炭酸カルシウムスケールの
発生を防止することが好ましいが、逆浸透膜装置の前段
で高pHとしないので、カルシウムスケールによる膜の障
害は生じにくい。従って、イオン交換装置と膜脱気装置
による前処理は省略してもよい。また、電気脱イオン装
置の後段に非再生型イオン交換装置１６を設けて、電気
脱イオン装置で除去しきれなかった微量の不純物を除去
することができる。本態様の純水製造装置における(Ｄ)
逆浸透膜には特に制限はなく、例えば、酢酸セルロース
系逆浸透膜、ポリアミド系逆浸透膜、ポリエチレンイミ
ン系逆浸透膜、ポリエチレンオキシド系逆浸透膜などを
挙げることができる。本態様の純水製造装置において
は、逆浸透膜装置へ通水する水のpHを中性に近い７.５
程度とするので、逆浸透膜装置におけるホウ素の除去率
は高くないが、耐アルカリ性逆浸透膜でなく通常の逆浸
透膜を使用することができる。本態様の純水製造装置に
おける(Ｅ)アルカリ添加装置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
装置や、強塩基性イオン交換樹脂を含むイオン交換装
置、あるいはその両方を設置することができる。アルカ
リ水溶液を添加する装置としては、例えば、撹拌機つき
のpH調整槽を設けたり、通水ラインにアルカリ水溶液注
入口を設け、その下流側にスタチックミキサーなどを設
置することなどができる。アルカリ添加装置は、ホウ素
含有水にアルカリを添加して、pHをホウ酸のｐＫa９.２
（２５℃）以上、より好ましくはpHを１０以上に調整し
得るものである。図１(ｂ)に示す態様の装置において
は、耐アルカリ性逆浸透膜装置の入口にpHセンサー１７
を設け、制御器１８を通じて信号を薬注ポンプ１９に送
り、アルカリ貯槽２０からのアルカリ注入量を制御す
る。本態様の純水製造装置における(Ｆ)電気脱イオン装
置には特に制限はなく、公知の電気脱イオン装置を使用
することができる。電気脱イオン装置は、薬品再生が不
要であり、小型で大容量を有するために、経済的にホウ
素含有水を処理して純水を製造することができる。本態
様の純水製造装置によれば、逆浸透膜装置におけるホウ
素の除去率は４０％程度であるが、逆浸透膜装置の透過
水のpHを９.２以上に調整して、さらに電気脱イオン装
置に通水することにより、原水であるホウ素含有水中の
ホウ素の９５％以上を除去することができる。本発明の
純水製造装置によれば、電気脱イオン装置において、水
中のホウ素を低濃度まで除去し、後段の非再生型イオン
交換装置の負荷を軽減して、その寿命を延長することが
できる。また、耐アルカリ性逆浸透膜装置を用い、その
前段にpHを調整するためのアルカリ添加装置を設ける態
様においては、逆浸透膜装置への供給水をアルカリ性に
することにより、逆浸透膜装置の透過水すなわち電気脱
イオン装置への供給水も同時にアルカリ性とすることが
でき、アルカリを有効に利用するとともに、高いホウ素
除去率を達成することができる。FIG. 1B is a process flow diagram of another embodiment of the pure water producing apparatus of the present invention. The pure water production apparatus of the present embodiment includes:
(D) Reverse osmosis membrane device 11 through which boron-containing water flows, (E)
The alkali is added to the permeated water of the reverse osmosis membrane device to adjust the pH to 9.2
It has an alkali addition device 12 adjusted as described above, and (F) an electrodeionization device 13 through which permeated water of the reverse osmosis membrane device whose pH is adjusted is passed. According to the pure water production apparatus of this aspect, since the reverse osmosis membrane device is provided in the preceding stage of the electrodeionization device, calcium ions and the like are removed. Therefore, even if the permeated water is set to a high pH, scale formation in the electrodeionization apparatus can be prevented. In addition, an ion exchange device 14 containing a strongly acidic ion exchange resin and a membrane deaerator 15 are provided in front of the reverse osmosis membrane device to remove calcium ions and carbonic acid in raw water, and a calcium carbonate scale in the reverse osmosis membrane device is provided. Although it is preferable to prevent the occurrence of water, the pH is not set high in the preceding stage of the reverse osmosis membrane device, so that damage to the membrane due to calcium scale hardly occurs. Therefore, the pretreatment by the ion exchange device and the membrane deaerator may be omitted. In addition, a non-regenerative ion exchange device 16 is provided at the subsequent stage of the electrodeionization device, so that a trace amount of impurities that cannot be completely removed by the electrodeionization device can be removed. (D) in the pure water production apparatus of this embodiment
The reverse osmosis membrane is not particularly limited, and examples thereof include a cellulose acetate-based reverse osmosis membrane, a polyamide-based reverse osmosis membrane, a polyethyleneimine-based reverse osmosis membrane, and a polyethylene oxide-based reverse osmosis membrane. In the pure water production apparatus of this embodiment, the pH of the water passing through the reverse osmosis membrane apparatus is set to a value close to neutral pH of 7.5.
Therefore, the removal rate of boron in the reverse osmosis membrane device is not high, but a normal reverse osmosis membrane can be used instead of the alkali-resistant reverse osmosis membrane. There is no particular limitation on the (E) alkali addition apparatus in the pure water production apparatus of the present embodiment, for example, an apparatus for adding an aqueous alkali solution such as sodium hydroxide, an ion exchange apparatus containing a strongly basic ion exchange resin, or an ion exchange apparatus containing the same. Both can be installed. As a device for adding the alkaline aqueous solution, for example, a pH adjusting tank with a stirrer may be provided, or 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. The alkali addition apparatus adds an alkali to the boron-containing water to adjust the pH to a pKa of boric acid of 9.2.
(25 ° C.) or more, more preferably, the pH can be adjusted to 10 or more. In the apparatus of the embodiment shown in FIG. 1 (b), a pH sensor 17 is provided at the entrance of the alkali-resistant reverse osmosis membrane device.
And sends a signal to the chemical injection pump 19 through the controller 18 to control the amount of alkali injected from the alkali storage tank 20. The (F) electrodeionization apparatus in the pure water production apparatus of this embodiment is not particularly limited, and a known electrodeionization apparatus can be used. Since the electrodeionization apparatus does not require chemical regeneration, is small and has a large capacity, it can economically treat boron-containing water to produce pure water. According to the pure water production apparatus of this embodiment, the removal rate of boron in the reverse osmosis membrane device is about 40%, but the pH of the permeated water of the reverse osmosis membrane device is adjusted to 9.2 or more, and By passing the water through the ion device, it is possible to remove 95% or more of the boron in the boron-containing water that is the raw water. ADVANTAGE OF THE INVENTION According to the pure water production apparatus of this invention, in an electrodeionization apparatus, the boron in water can be removed to a low concentration, the load of the non-regeneration type ion exchange apparatus of a latter stage can be reduced, and the life can be extended. . Further, in an embodiment in which an alkali-resistant reverse osmosis membrane device is used and an alkali addition device for adjusting the pH is provided at the preceding stage, the water supplied to the reverse osmosis membrane device is made alkaline, so that the permeation of the reverse osmosis membrane device is reduced. The water, that is, the water supplied to the electrodeionization apparatus, can be made alkaline at the same time, so that the alkali can be effectively used and a high boron removal rate can be achieved.
【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(ａ)に示す純水製造装置を用いて、純水の製造を行
った。水道水を２トン／hrの速度でＨ型強酸性イオン交
換樹脂塔に通水したのち、気相側を減圧にした膜脱気装
置に通水して、水中の炭酸を除去した。次に、炭酸を除
去した水に水酸化ナトリウム水溶液を添加してpHを１
０.０に調整し、耐アルカリ性逆浸透膜［ＦＩＬＭＴＥ
Ｃ ｔｙｐｅ ＦＴ３０］装置に通水した。耐アルカリ性
逆浸透膜装置入口の水のホウ素濃度は３０ppbであり、
耐アルカリ性逆浸透膜装置出口の水のホウ素濃度は１pp
bであった。耐アルカリ性逆浸透膜装置の透過水は、次
いで電気脱イオン装置に通水した。電気脱イオン装置入
口の水のpHは９.５であり、電気脱イオン装置出口の水
のホウ素濃度は０.１ppbであった。電気脱イオン装置か
ら流出する水は、さらに非再生型イオン交換装置に通水
して純水１.８トン／hrを得た。 実施例２ 図１(ｂ)に示す純水製造装置を用いて、純水の製造を行
った。水道水を２トン／hrの速度でＨ型強酸性イオン交
換樹脂塔に通水したのち、気相側を減圧にした膜脱気装
置に通水して、水中の炭酸を除去した。次に、炭酸を除
去した水に水酸化ナトリウム水溶液を添加してpHを７.
５に調整し、逆浸透膜［日東電工(株)、ＥＳ２０］装置
に通水した。逆浸透膜装置入口の水のホウ素濃度は３０
ppbであり、逆浸透膜装置出口の水のホウ素濃度は１８p
pbであった。さらに、逆浸透膜装置の透過水に水酸化ナ
トリウム水溶液を添加してpHを１０.０に調整し、電気
脱イオン装置に通水した。電気脱イオン装置出口の水の
ホウ素濃度は、０.９ppbであった。電気脱イオン装置か
ら流出する水は、さらに非再生型イオン交換装置に通水
して純水１.８トン／hrを得た。 比較例１ 逆浸透膜装置の透過水への水酸化ナトリウム水溶液の添
加によるpH調整を行わないこと以外は、実施例２と同じ
操作を繰り返した。電気脱イオン装置入口の水のホウ素
濃度は１８ppbであり、pHは７.２であった。また、電気
脱イオン装置出口の水のホウ素濃度は５.８ppbであっ
た。実施例１〜２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 Pure water was produced using the pure water producing apparatus shown in FIG. Tap water was passed through the H-type strongly acidic ion exchange resin tower at a rate of 2 tons / hr, and then passed through a membrane deaerator in which the gas phase was reduced in pressure to remove carbonic acid in the water. Next, an aqueous solution of sodium hydroxide was added to the water from which carbon dioxide had been removed to adjust the pH to 1.
Adjusted to 0.0, alkali-resistant reverse osmosis membrane [FILMTE
[C type FT30] apparatus. The boron concentration of water at the entrance of the alkali resistant reverse osmosis membrane device is 30 ppb,
The concentration of boron at the outlet of the alkali-resistant reverse osmosis membrane device is 1 pp
b. The permeated water of the alkali-resistant reverse osmosis membrane device was then passed through an electrodeionization device. The pH of the water at the inlet of the electrodeionization device was 9.5, and the boron concentration of the water at the outlet of the electrodeionization device was 0.1 ppb. The water flowing out of the electrodeionization apparatus was further passed through a non-regenerative ion exchange apparatus to obtain 1.8 tons / hr of pure water. Example 2 Pure water was produced using the pure water producing apparatus shown in FIG. Tap water was passed through the H-type strongly acidic ion exchange resin tower at a rate of 2 tons / hr, and then passed through a membrane deaerator in which the gas phase was reduced in pressure to remove carbonic acid in the water. Next, an aqueous solution of sodium hydroxide was added to the water from which carbonic acid had been removed to adjust the pH to 7.
5 and water was passed through a reverse osmosis membrane [Nitto Denko Corporation, ES20] apparatus. The boron concentration of the water at the inlet of the reverse osmosis membrane device is 30.
ppb, and the boron concentration of water at the outlet of the reverse osmosis membrane device is 18p
pb. Further, an aqueous sodium hydroxide solution was added to the permeated water of the reverse osmosis membrane device to adjust the pH to 10.0, and the solution was passed through an electrodeionization device. The boron concentration of the water at the outlet of the electrodeionization apparatus was 0.9 ppb. The water flowing out of the electrodeionization apparatus was further passed through a non-regenerative ion exchange apparatus to obtain 1.8 tons / hr of pure water. Comparative Example 1 The same operation as in Example 2 was repeated except that the pH was not adjusted by adding an aqueous solution of sodium hydroxide to the permeated water of the reverse osmosis membrane device. The boron concentration of the water at the inlet of the electrodeionizer was 18 ppb and the pH was 7.2. The boron concentration of the water at the outlet of the electrodeionization apparatus was 5.8 ppb. Table 1 shows the results of Examples 1 and 2 and Comparative Example 1.
【０００９】[0009]
【表１】 [Table 1]
【００１０】第１表に見られるように、逆浸透膜装置入
口の水に対する電気脱イオン装置出口の水のホウ素除去
率は、耐アルカリ性逆浸透膜装置入口で水のpHを１０.
０に調整した実施例１では９９.７％、電気脱イオン装
置入口で水のpHを１０.０に調整した実施例２では９７.
０％であるのに対して、水のpHを１０.０に調整しなか
った比較例１では８０.７％にとどまっている。この結
果から、水にアルカリを添加してpHを９.２以上に調整
するアルカリ添加装置を備えた本発明の純水製造装置に
より、ホウ素除去率の高い純水が得られることが分か
る。特に、耐アルカリ性逆浸透膜装置を用い、アルカリ
添加装置を逆浸透膜装置の前段に設けた純水製造装置に
おいて、非常に高いホウ素除去率が達成されている。As can be seen from Table 1, the boron removal rate of the water at the outlet of the electrodeionization apparatus with respect to the water at the inlet of the reverse osmosis membrane apparatus is determined by setting the pH of the water at the inlet of the alkali-resistant reverse osmosis membrane apparatus to 10.
Example 1 in which the pH was adjusted to 0 was 99.7%, and Example 2 in which the pH of water was adjusted to 10.0 at the inlet of the electrodeionization apparatus was 99.7%.
Compared to 0%, in Comparative Example 1 in which the pH of water was not adjusted to 10.0, it remained at 80.7%. From this result, it can be seen that pure water having a high boron removal rate can be obtained by the pure water production apparatus of the present invention including the alkali addition apparatus for adjusting the pH to 9.2 or more by adding an alkali to water. In particular, a very high boron removal rate has been achieved in a pure water production apparatus using an alkali-resistant reverse osmosis membrane apparatus and an alkali addition apparatus provided in a stage preceding the reverse osmosis membrane apparatus.
【００１１】[0011]
【発明の効果】本発明の純水製造装置によれば、電気脱
イオン装置において、水中のホウ素を低濃度まで除去
し、後段の非再生型イオン交換装置の負荷を軽減し、そ
の寿命を延ばすことができる。また、耐アルカリ性逆浸
透膜装置を用い、その前段にpHを調整するためのアルカ
リ添加装置を設けて、逆浸透膜装置への供給水をアルカ
リ性にすることにより、逆浸透膜装置の透過水すなわち
電気脱イオン装置への供給水も同時にアルカリ性とする
ことができ、アルカリを有効に利用するとともに、高い
ホウ素除去率を達成することができる。According to the pure water production apparatus of the present invention, in an electrodeionization apparatus, boron in water is removed to a low concentration to reduce the load on a subsequent non-regeneration type ion exchange apparatus and extend its life. be able to. Further, by using an alkali-resistant reverse osmosis membrane device, an alkali addition device for adjusting the pH is provided at the preceding stage, and the supply water to the reverse osmosis membrane device is made alkaline, so that the permeated water of the reverse osmosis membrane device, The water supplied to the electrodeionization apparatus can be made alkaline at the same time, so that the alkali can be effectively used and a high boron removal rate can be achieved.
【図１】図１は、本発明の純水製造装置の工程系統図で
ある。FIG. 1 is a process flow diagram of a pure water production apparatus of the present invention.
１ アルカリ添加装置 ２ 耐アルカリ性逆浸透膜装置 ３ 電気脱イオン装置 ４ 強酸性イオン交換樹脂を含むイオン交換装置 ５ 膜脱気装置 ６ 非再生型イオン交換装置 ７ pHセンサー ８ 制御器 ９ 薬注ポンプ １０ アルカリ貯槽 １１ 逆浸透膜装置 １２ アルカリ添加装置 １３ 電気脱イオン装置 １４ 強酸性イオン交換樹脂を含むイオン交換装置 １５ 膜脱気装置 １６ 非再生型イオン交換装置 １７ pHセンサー １８ 制御器 １９ 薬注ポンプ ２０ アルカリ貯槽 DESCRIPTION OF SYMBOLS 1 Alkali addition apparatus 2 Alkali-resistant reverse osmosis membrane apparatus 3 Electrodeionization apparatus 4 Ion exchange apparatus containing a strongly acidic ion exchange resin 5 Membrane deaerator 6 Non-regenerative ion exchange apparatus 7 pH sensor 8 Controller 9 Chemical injection pump 10 Alkaline storage tank 11 Reverse osmosis membrane device 12 Alkali addition device 13 Electrodeionization device 14 Ion exchange device containing strongly acidic ion exchange resin 15 Membrane deaerator 16 Non-regenerative ion exchange device 17 pH sensor 18 Controller 19 Chemical pump 20 Alkaline storage tank
Claims (2)
pHを９.２以上に調整するアルカリ添加装置、（Ｂ）pH
の調整されたホウ素含有水が通水される耐アルカリ性逆
浸透膜装置及び（Ｃ）耐アルカリ性逆浸透膜装置の透過
水が通水される電気脱イオン装置を有することを特徴と
する純水製造装置。1. An alkali is added to (A) boron-containing water.
Alkali addition device for adjusting pH to 9.2 or more, (B) pH
Pure water production, comprising: an alkali-resistant reverse osmosis membrane device through which the adjusted boron-containing water is passed; and (C) an electrodeionization device through which permeated water from the alkali-resistant reverse osmosis membrane device is passed. apparatus.
装置、（Ｅ）逆浸透膜装置の透過水にアルカリを添加し
てpHを９.２以上に調整するアルカリ添加装置、（Ｆ）p
Hの調整された逆浸透膜装置の透過水が通水される電気
脱イオン装置を有することを特徴とする純水製造装置。(D) a reverse osmosis membrane device through which boron-containing water is passed; (E) an alkali addition device for adjusting the pH to 9.2 or more by adding an alkali to permeated water of the reverse osmosis membrane device; (F) p
An apparatus for producing pure water, comprising: an electrodeionization device through which permeated water from a reverse osmosis membrane device with adjusted H is passed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36011797A JP3575260B2 (en) | 1997-12-26 | 1997-12-26 | Pure water production equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36011797A JP3575260B2 (en) | 1997-12-26 | 1997-12-26 | Pure water production equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11188359A true JPH11188359A (en) | 1999-07-13 |
| JP3575260B2 JP3575260B2 (en) | 2004-10-13 |
Family
ID=18467980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP36011797A Expired - Fee Related JP3575260B2 (en) | 1997-12-26 | 1997-12-26 | Pure water production equipment |
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| Country | Link |
|---|---|
| JP (1) | JP3575260B2 (en) |
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| JP2002320971A (en) * | 2001-04-26 | 2002-11-05 | Nippon Rensui Co Ltd | Method and equipment for producing pure water by electric regeneration |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002028660A (en) * | 2000-07-13 | 2002-01-29 | Nomura Micro Sci Co Ltd | Desalting device |
| JP4531213B2 (en) * | 2000-07-13 | 2010-08-25 | 野村マイクロ・サイエンス株式会社 | Desalination equipment |
| JP2002320971A (en) * | 2001-04-26 | 2002-11-05 | Nippon Rensui Co Ltd | Method and equipment for producing pure water by electric regeneration |
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| JP4599803B2 (en) * | 2002-04-05 | 2010-12-15 | 栗田工業株式会社 | Demineralized water production equipment |
| EP1598318A4 (en) * | 2003-02-14 | 2010-02-03 | Kurita Water Ind Ltd | Electric deionization apparatus and method of operating the same |
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| KR20160033119A (en) | 2013-07-22 | 2016-03-25 | 쿠리타 고교 가부시키가이샤 | Method and device for treating boron-containing water |
| JP2014000575A (en) * | 2013-10-10 | 2014-01-09 | Kurita Water Ind Ltd | Apparatus and method for producing purified water |
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