JP2004073923A - Electric deionization apparatus and water purifying apparatus - Google Patents

Electric deionization apparatus and water purifying apparatus Download PDF

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JP2004073923A
JP2004073923A JP2002234560A JP2002234560A JP2004073923A JP 2004073923 A JP2004073923 A JP 2004073923A JP 2002234560 A JP2002234560 A JP 2002234560A JP 2002234560 A JP2002234560 A JP 2002234560A JP 2004073923 A JP2004073923 A JP 2004073923A
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anion
ratio
exchange resin
electrodeionization
water
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JP4345272B2 (en
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Kiminobu Osawa
大澤　公伸
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Kurita Water Industries Ltd
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Kurita Water Industries Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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    • Y02A20/124—Water desalination

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Abstract

<P>PROBLEM TO BE SOLVED: To obtain a treated water of a pH higher than the pH of raw water by adequately selecting ion exchangers to be packed into desalting chambers of an electric deionization apparatus. <P>SOLUTION: The electric deionization apparatus is alternately laminated and provided with desalting chambers which are alternately arrayed with a plurality of anion exchange membranes and cation exchange membranes between anodes and cathodes and are packed with the ion exchangers between two sheets of the anion exchange membranes and cation exchange membranes adjacent to each other and thickening chambers. The thickness of the desalting chambers is ≥7 mm. The ion exchangers to be packed into the desalting chambers comprise the mixtures composed of the anion exchange resins and cation exchange resins and the mixing ratio of the anion exchange resins and the cation exchange resins is specified to 7.2: 2.8 (anion ratio 72%) to 7.8:2.2 (anion ratio 78%) by volumetric ratio of a regeneration rate. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、半導体、液晶、製薬、食品、電力等の各種分野の産業や研究設備で利用される脱イオン水を製造する電気脱イオン装置、及び複数の電気脱イオン装置を直列に接続して純水を製造する純水製造装置に関する。
【０００２】
【従来の技術】
本特許出願人は、ｐＨ８．５以下の原水をアルカリ薬剤を添加することなく処理したときに、上記原水のｐＨよりもｐＨが１．０以上、高い処理水を得るために、陰極と陽極との間に複数のアニオン交換膜とカチオン交換膜とを交互に配列し、上記隣接した２枚のアニオン交換膜とカチオン交換膜との間に、セル（枠体）を配置し、イオン交換体を充填した脱塩室と、濃縮室とを交互に積層して設け、脱塩室の厚さを７ｍｍ以上の電気脱イオン装置と、複数の電気脱イオン装置を直列に接続し、原水を上記直列に接続された複数の電気脱イオン装置に順次通水して処理する純水製造装置を、特開２００１−１１３２８１号公報で提案した。
【０００３】
【発明が解決しようとする課題】
しかし、その後、鋭意研究を進めていった結果、電気脱イオン装置でｐＨ８．５以下の原水をアルカリ薬剤を添加することなく処理したときに、上記原水のｐＨよりもｐＨが１．０以上、高い処理水を得るには、脱塩室にイオン交換体として充填するアニオン、カチオン両交換樹脂の混合比に最適値が存在し、アニオン交換樹脂の比率が７２％未満であると、原水中のナトリウムイオンが除去されてしまい、処理水のｐＨの上昇が起きにくくなり、脱塩室内がアルカリにならず、且つシリカがイオン化しないために、シリカの除去率も低下し、逆にアニオン交換樹脂の比率が７８％より大きくなると必要な電流を確保するための電圧値が上昇し、セル間の電気抵抗が上昇して好ましくないことを見出した。
【０００４】
更に、複数の電気脱イオン装置を直列に接続し、被処理水をこの直列に接続した複数の電気脱イオン装置に順次通水して処理する純水製造装置においても、２段目以降の電気脱イオン装置の脱塩室内に充填するアニオン、カチオン両イオン交換樹脂の混合比にも最適値があり、アニオン交換樹脂の比率が５５％未満であるとシリカの除去率が低下し、逆に６５％より大きくなると、被処理水中のナトリウムイオンを除去できず、処理水の比抵抗値が極端に低下することを見出した。
【０００５】
このように脱塩室に充填するアニオン、カチオン両イオン交換樹脂の混合比を最適化することにより、ｐＨ８．５以下の原水をアルカリ薬剤を添加することなく処理したときに、上記原水のｐＨよりもｐＨが１．０以上高い処理水が得られるのは、原水中のナトリウムイオンを選択的に残留させ、シリカのイオン化のために利用するからであって、このことは前述した特開２００１−１１３２８１号の従来装置と大きく異なる点である。
【０００６】
【課題を解決するための手段】
そこで本発明の電気脱イオン装置は、陰極と陽極との間に複数のアニオン交換膜とカチオン交換膜とを交互に配列し、前記隣接した２枚のアニオン交換膜とカチオン交換膜との間にイオン交換体を充填した脱塩室と、濃縮室とを交互に積層して設け、脱塩室の厚さが７ｍｍ以上である電気脱イオン装置において、前記脱塩室に充填するイオン交換体をアニオン交換樹脂とカチオン交換樹脂との混合物にし、アニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で７．２：２．８（アニオン比率７２％）〜７．８：２．２（アニオン比率７８％）にしたことを特徴とする。この場合、電気脱イオン装置に供給する被処理水の供給管の上流側に被処理水にナトリウム塩を添加する添加装置を設け、上記添加装置で被処理水にナトリウム塩を添加して電気脱イオン装置から排出される処理水のｐＨを制御するようにすることが好ましい。また、本発明の純水製造装置は複数の電気脱イオン装置を直列に接続し、被処理水を前記直列に接続した複数の電気脱イオン装置に順次通水して処理する純水製造装置において、前記各電気脱イオン装置の脱塩室に充填するイオン交換体をアニオン交換樹脂とカチオン交換樹脂との混合物にし、第１段目の電気脱イオン装置のアニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で７．２：２．８（アニオン比率７２％）〜７．８：２．２（アニオン比率７８％）にし、第２段以降の電気脱イオン装置のアニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で５．５：４．５（アニオン比率５５％）〜６．５：３．５（アニオン比率６５％）にしたことを特徴とする。この場合も、第１段目の電気脱イオン装置に供給する被処理水の供給管の上流側に被処理水にナトリウム塩を添加する添加装置を設け、該添加装置で被処理水にナトリウム塩を添加し、最終段の電気脱イオン装置から排出される処理水の比抵抗値が向上するように制御することが好ましい。なお、第１段目の電気脱イオン装置の脱塩室の厚さは７ｍｍ以上、特に８〜３０ｍｍが好ましい。第２段目以降の電気脱イオン装置における脱塩室の厚さは、第１段目の電気脱イオン装置の脱塩室の厚さよりも薄い方が好ましく、特に２．０〜６．０ｍｍがより好ましい。これにより、第１段目の電気脱イオン装置でシリカ、ホウ素等の弱電解物質及び硬度成分が除去され、第２段目以降でシリカ及びホウ素がさらに除去される。
【０００７】
【発明の実施の形態】
以下に実施例を挙げて本発明の効果を具体的に説明する。実験には直列に接続可能な前段、後段の２基の電気脱イオン装置を使用した。
１．前後各段におけるイオン交換樹脂を充填するセル（枠体）の有効寸法、使用枚数、イオン交換樹脂、イオン交換膜は次の通りである。
▲１▼前段の電気脱イオン装置
脱塩室の厚さ＝１５ｍｍ、樹脂層高＝６００ｍｍ
脱塩室のセルの枚数＝３枚
▲２▼後段の電気脱イオン装置
脱塩室の厚さ＝５ｍｍ、樹脂層高＝６００ｍｍ
脱塩室のセルの枚数＝６枚
▲３▼前後両電気脱イオン装置の脱塩室に充填された混合物を構成するイオン交換樹脂
アニオン交換樹脂：ダウケミカル社製　商品名　５５０Ａ
カチオン交換樹脂：ダウケミカル社製　商品名　６５０Ｃ
▲４▼前後両脱イオン装置に使用したイオン交換膜
アニオン交換樹脂：（株）トクヤマ製　商品名　ネオセプタＡＨＡ
カチオン交換樹脂：（株）トクヤマ製　商品名　ネオセプタＣＭＢ
【０００８】
［実施例１］
前段の電気脱イオン装置を使用し、セル当たりの操作電圧を６Ｖ／セル、ＳＶ８５／時で原水を通水して厚さを７ｍｍ以上の１５ｍｍの脱塩室に充填すベきアニオン交換樹脂の、カチオン交換樹脂に対する混合比率を再生型体積比で５０〜１００％の間で変え、その時々のシリカ除去率、ナトリウム除去率、セルの電気抵抗を測定した。試験結果を図１に示す。
アニオン交換樹脂の比率が７２％未満なると、被処理水ナトリウムイオンが除去されてしまい、シリカの除去率も低下した。これは脱塩室内がアルカリにならないため、シリカがイオン化しないからである。又、アニオン交換樹脂の比率が７８％より大きくなると、必要な電流を確保する電圧値が上昇し、これに伴いセル間の電気抵抗が上昇した。この結果、陰極と陽極との間に複数のアニオン交換膜とカチオン交換膜とを交互に配列し、この隣接した２枚のアニオン交換膜とカチオン交換膜との間にイオン交換体を充填した脱塩室と、濃縮室とを交互に積層して設け、脱塩室の厚さを７ｍｍ以上、且つセル当たりの操作電圧が１〜５０Ｖ／セル、ＳＶ３０〜１５０／時である電気脱イオン装置において、上記脱塩室に充填するイオン交換体をアニオン交換樹脂とカチオン交換樹脂との混合物にし、アニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で７．２：２．８（アニオン比率７２％）〜７．８：２．２（アニオン比率７８％）にすることにより最適の結果が得られることを見出した。
【０００９】
［実施例２］
実施例１で使用した電気脱イオン装置に供給する被処理水にナトリウム塩（塩化ナトリウム）を添加し、被処理水の導電率を任意に変化させた。その時の電気脱イオン装置からの処理水のｐＨを測定した結果を図２に示した。この図からも明らかなように、供給する被処理水の導電率の上昇に伴い処理水のｐＨは上昇した。
【００１０】
［実施例３］
前段の電気脱イオン装置と後段の電気脱イオン装置とを直列に接続し、純水製造装置としての評価試験を行った。尚、前段の電気脱イオン装置の脱塩室に充填したアニオン交換樹脂の、カチオン交換樹脂に対する比率は７５％にした。
後段の電気脱イオン装置の脱塩室に充填すべきアニオン交換樹脂の、カチオン交換樹脂に対する混合比率を再生型体積比で５０〜７０％の間で変え、その時々のシリカ除去率、電気比抵抗値を測定した結果を図３に示す。５５％未満になるとシリカの除去率が低下した。又、６５％より大きくなると、被処理水中のナトリウムイオンを除去することができず、処理水の比抵抗値は極端に低下した。この結果、複数の電気脱イオン装置を直列に接続し、被処理水を順次通水して処理する純水製造装置において、上記各電気脱イオン装置の脱塩室に充填するイオン交換体をアニオン交換樹脂とカチオン交換樹脂との混合物にし、第１段の電気脱イオン装置のアニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で７．２：２．８（アニオン比率７２％）〜７．８：２．２（アニオン比率７８％）にし、第２段以降の電気脱イオン装置のアニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で５．５：４．５（アニオン比率５５％）〜６．５：３．５（アニオン比率６５％）にすることにより最適の結果が得られることを見出した。
【００１１】
［実施例４］
実施例３で使用した純水製造装置の前段の電気脱イオン装置に供給する被処理水にナトリウム塩（塩化ナトリウム）を添加して、被処理水の導電率を任意に変化させ、後段の電気脱イオン装置から排出される処理水のシリカ濃度を測定し、それから算出されるシリカ除去率を図４に示した。なお、この時の被処理水中のシリカ濃度は２００〜３００ｐｐｂであった。この図からも明らかなように、供給する被処理水の導電率の上昇に伴い処理水のシリカ除去率は向上した。
【００１２】
請求項２で被処理水に添加するナトリウム塩としては価格面からＮａＣｌが好ましい。そして、ナトリウム塩を添加して被処理水の導電率を３〜２０μｓ／ｃｍ、好ましくは５〜１５μｓ／ｃｍに調整すると、前段の電気脱イオン装置の処理水のｐＨは９．５前後になり、後段の電気脱イオン装置においてシリカが効率よく除去できる。
【００１３】
【発明の効果】
請求項１の発明のように、脱塩室に充填するアニオン、カチオン両イオン交換樹脂の、カチオン交換樹脂に対するアニオン交換樹脂の混合比を、再生型体積比を最適に選択することで脱イオン装置のナトリウムイオンのリークを増進し、処理水のｐＨが上昇する。又、請求項３により、第１段目の電気脱イオン装置においては被処理水のナトリウムイオンを選択的に残留させ、第２段目以降の電気脱イオン装置におけるシリカのイオン化のために利用してシリカを効率よく除去できる。
【図面の簡単な説明】
【図１】実施例１のカチオン交換樹脂に対するアニオン交換樹脂の混合比率を再生型体積比で５０〜１００％の間で変えたときのシリカ除去率、ナトリウム除去率、セルの電気抵抗の変化を示す図。
【図２】実施例２の電気脱イオン装置に供給する被処理水にナトリウム塩を添加して導電率を変化させた場合の処理水のｐＨの変化を示す図。
【図３】実施例３の脱塩室に充填するアニオン交換樹脂の、カチオン交換樹脂に対する混合比率を、再生型体積比で５０〜７０％の間で変化させた場合のシリカ除去率、電気比抵抗値の変化を示す図。
【図４】実施例４の前段の電気脱イオン装置に供給する被処理水にナトリウム塩を添加して導電率を変化させた場合の、後段の電気脱イオンから排出される処理水のシリカ除去率を示す図。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric deionization device for producing deionized water used in industries and research facilities in various fields such as semiconductors, liquid crystals, pharmaceuticals, foods, and electric power, and a plurality of electric deionization devices connected in series. The present invention relates to a pure water producing apparatus for producing pure water.
[0002]
[Prior art]
The applicant of the present invention has proposed that, when raw water having a pH of 8.5 or less is treated without adding an alkaline agent, a cathode and an anode are provided to obtain a treated water having a pH of 1.0 or more higher than the pH of the raw water. A plurality of anion exchange membranes and cation exchange membranes are alternately arranged between the two, and a cell (frame) is arranged between the two adjacent anion exchange membranes and the cation exchange membrane to form an ion exchanger. A filled deionization chamber and a concentration chamber are alternately stacked and provided. An electrodeionization apparatus having a thickness of the demineralization chamber of 7 mm or more and a plurality of electrodeionization apparatuses are connected in series, and raw water is connected in series. No. 2001-113281 has proposed a pure water production apparatus for treating water by sequentially passing water through a plurality of electrodeionization apparatuses connected to the apparatus.
[0003]
[Problems to be solved by the invention]
However, since then, as a result of intensive research, when the raw water having a pH of 8.5 or less was treated with an electrodeionization apparatus without adding an alkaline agent, the pH was 1.0 or more higher than the pH of the raw water, In order to obtain high treated water, there is an optimum value for the mixing ratio of the anion and cation exchange resins to be filled as an ion exchanger in the desalting chamber. If the ratio of the anion exchange resin is less than 72%, the raw water Sodium ions are removed, the pH of the treated water is less likely to rise, the desalting chamber is not alkalinized, and the silica is not ionized. When the ratio is larger than 78%, it has been found that a voltage value for securing a necessary current increases and an electric resistance between cells increases, which is not preferable.
[0004]
Further, in a pure water producing apparatus in which a plurality of electrodeionization devices are connected in series and water to be treated is sequentially passed through the plurality of electrodeionization devices connected in series to treat the same, the second and subsequent electric The mixing ratio of the anion and cation ion exchange resins charged into the deionization chamber of the deionization apparatus also has an optimum value. If the ratio of the anion exchange resin is less than 55%, the silica removal rate decreases, and conversely 65%. %, It was found that sodium ions in the water to be treated could not be removed, and the resistivity of the treated water was extremely reduced.
[0005]
By optimizing the mixing ratio of the anion and cation amphoteric ion exchange resin charged in the desalting chamber in this way, when the raw water having a pH of 8.5 or less is treated without adding an alkaline agent, the pH of the raw water is reduced. The reason why treated water having a high pH of 1.0 or more is obtained is that sodium ions in raw water are selectively left and used for ionizing silica. This is significantly different from the conventional apparatus of No. 113281.
[0006]
[Means for Solving the Problems]
Therefore, the electrodeionization apparatus of the present invention is configured such that a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between a cathode and an anode, and between the two adjacent anion exchange membranes and the cation exchange membrane. In an electric deionization apparatus in which a desalination chamber filled with an ion exchanger and a concentration chamber are alternately provided and the thickness of the desalination chamber is 7 mm or more, the ion exchanger charged into the desalination chamber is A mixture of an anion exchange resin and a cation exchange resin is used, and the mixing ratio of the anion exchange resin and the cation exchange resin is 7.2: 2.8 (anion ratio 72%) to 7.8: 2.2 in a regenerating type volume ratio. (Anion ratio: 78%). In this case, an addition device for adding a sodium salt to the water to be treated is provided on the upstream side of the supply pipe of the water to be supplied to the electrodeionization device. It is preferable to control the pH of the treated water discharged from the ion device. Further, the pure water production apparatus of the present invention is a pure water production apparatus in which a plurality of electrodeionization devices are connected in series, and the water to be treated is sequentially passed through the plurality of electrodeionization devices connected in series for treatment. The ion exchanger to be filled in the desalting chamber of each of the above electrodeionization devices is made into a mixture of an anion exchange resin and a cation exchange resin, and the mixture of the anion exchange resin and the cation exchange resin in the first-stage electrodeionization device is mixed. The ratio is set to 7.2: 2.8 (anion ratio 72%) to 7.8: 2.2 (anion ratio 78%) in a regenerating type volume ratio, and the anion exchange resin of the second and subsequent stages of the electrodeionization apparatus. It is characterized in that the mixing ratio with the cation exchange resin is 5.5: 4.5 (anion ratio 55%) to 6.5: 3.5 (anion ratio 65%) in a regeneration type volume ratio. Also in this case, an addition device for adding a sodium salt to the water to be treated is provided upstream of the supply pipe of the water to be supplied to the first-stage electrodeionization device, and the sodium salt is added to the water to be treated by the addition device. Is preferably controlled so that the specific resistance value of the treated water discharged from the electrodeionization device at the final stage is improved. The thickness of the desalting chamber of the first-stage electrodeionization apparatus is preferably 7 mm or more, particularly preferably 8 to 30 mm. The thickness of the desalination chamber in the second and subsequent electrodeionization apparatuses is preferably smaller than the thickness of the desalination chamber of the first-stage electrodeionization apparatus, and particularly preferably 2.0 to 6.0 mm. More preferred. Thereby, the weak electrolytic substances such as silica and boron and the hardness component are removed by the first-stage electrodeionization apparatus, and the silica and boron are further removed in the second and subsequent stages.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the effects of the present invention will be specifically described with reference to examples. In the experiment, two front and rear electrodeionization devices that can be connected in series were used.
1. The effective dimensions, the number of used cells, the number of cells used, the ion exchange resin, and the ion exchange membrane in each of the preceding and succeeding stages are as follows.
{Circle around (1)} The thickness of the deionization chamber of the preceding electrodeionization apparatus = 15 mm, the height of the resin layer = 600 mm
Number of cells in the desalination chamber = 3 (2) Thickness of the subsequent electrodeionization apparatus desalination chamber = 5 mm, height of resin layer = 600 mm
Number of cells in the desalting chamber = 6 (3) Ion-exchange resin constituting the mixture filled in the desalting chambers of the front and rear electric deionizers Anion-exchange resin: trade name 550A manufactured by Dow Chemical Company
Cation exchange resin: 650C, manufactured by Dow Chemical Company
(4) Ion-exchange membrane used in both front and rear deionizers Anion-exchange resin: trade name Neosepta AHA manufactured by Tokuyama Corporation
Cation exchange resin: trade name Neosepta CMB manufactured by Tokuyama Corporation
[0008]
[Example 1]
Using an anion exchange resin of the preceding stage, the operation voltage per cell is 6 V / cell, and the raw water is passed at SV 85 / hour, and the anion exchange resin to be filled into a 15 mm desalting chamber having a thickness of 7 mm or more is charged. The mixing ratio with respect to the cation exchange resin was changed in the range of 50 to 100% by volume of the regeneration type, and the silica removal rate, sodium removal rate, and electric resistance of the cell at each time were measured. The test results are shown in FIG.
When the ratio of the anion exchange resin was less than 72%, sodium ions to be treated were removed, and the silica removal rate also decreased. This is because silica is not ionized because the interior of the desalting chamber does not become alkali. Further, when the ratio of the anion exchange resin was larger than 78%, the voltage value for securing the required current increased, and the electric resistance between cells increased accordingly. As a result, a plurality of anion-exchange membranes and cation-exchange membranes are alternately arranged between the cathode and the anode, and the ion-exchanger is filled between the adjacent two anion-exchange membranes and the cation-exchange membrane. In an electrodeionization apparatus in which a salt room and a concentration room are alternately stacked, the thickness of the desalination room is 7 mm or more, and the operating voltage per cell is 1 to 50 V / cell, SV 30 to 150 / hour. The ion exchanger filled in the desalting chamber is made into a mixture of an anion exchange resin and a cation exchange resin, and the mixture ratio of the anion exchange resin and the cation exchange resin is 7.2: 2.8 (anion exchange ratio). It has been found that an optimum result can be obtained by setting the ratio to 7.8: 2.2 (anion ratio 78%).
[0009]
[Example 2]
Sodium salt (sodium chloride) was added to the water to be treated supplied to the electrodeionization apparatus used in Example 1 to arbitrarily change the conductivity of the water to be treated. FIG. 2 shows the result of measuring the pH of the treated water from the electrodeionization apparatus at that time. As is clear from this figure, the pH of the treated water increased as the conductivity of the supplied treated water increased.
[0010]
[Example 3]
The first-stage electrodeionization apparatus and the second-stage electrodeionization apparatus were connected in series, and an evaluation test as a pure water production apparatus was performed. The ratio of the anion exchange resin charged in the desalting chamber of the previous electrodeionization apparatus to the cation exchange resin was set to 75%.
The mixing ratio of the anion exchange resin to be filled in the desalting chamber of the subsequent electrodeionization apparatus to the cation exchange resin was changed in the range of 50 to 70% by regeneration type volume ratio, and the silica removal rate and electrical resistivity at that time were changed. FIG. 3 shows the measurement results of the values. If it is less than 55%, the removal rate of silica decreases. On the other hand, when it was more than 65%, sodium ions in the water to be treated could not be removed, and the resistivity of the treated water was extremely reduced. As a result, in a pure water production apparatus in which a plurality of electrodeionization apparatuses are connected in series and water to be treated is sequentially passed and treated, an ion exchanger filled in a desalination chamber of each of the above electrodeionization apparatuses is anion-exchanged. A mixture of an exchange resin and a cation exchange resin, and the mixture ratio of the anion exchange resin and the cation exchange resin in the first-stage electrodeionization apparatus is 7.2: 2.8 in regenerating volume ratio (anion ratio 72%). To 7.8: 2.2 (anion ratio: 78%), and the mixing ratio of the anion exchange resin and the cation exchange resin in the second and subsequent electrodeionization apparatuses is 5.5: 4.5 by the regeneration type volume ratio. It has been found that an optimum result can be obtained by setting (anion ratio: 55%) to 6.5: 3.5 (anion ratio: 65%).
[0011]
[Example 4]
Sodium salt (sodium chloride) is added to the water to be treated, which is supplied to the electrodeionization apparatus at the preceding stage of the pure water producing apparatus used in Example 3, to arbitrarily change the conductivity of the water to be treated, and The silica concentration of the treated water discharged from the deionizer was measured, and the silica removal ratio calculated from the measured silica concentration is shown in FIG. At this time, the concentration of silica in the water to be treated was 200 to 300 ppb. As is clear from this figure, the silica removal rate of the treated water increased with an increase in the conductivity of the supplied treated water.
[0012]
In the second aspect, the sodium salt to be added to the water to be treated is preferably NaCl from the viewpoint of cost. When the conductivity of the water to be treated is adjusted to 3 to 20 μs / cm, preferably 5 to 15 μs / cm by adding a sodium salt, the pH of the treated water of the preceding electrodeionization apparatus becomes about 9.5. The silica can be efficiently removed in the subsequent electrodeionization apparatus.
[0013]
【The invention's effect】
As in the first aspect of the present invention, a deionization apparatus is provided by optimally selecting a mixture ratio of an anion exchange resin to a cation exchange resin of an anion / cation amphoteric ion exchange resin to be filled in a desalination chamber and a regeneration type volume ratio. And increases the pH of the treated water. According to the third aspect, in the first-stage electrodeionization apparatus, sodium ions in the water to be treated are selectively left and used for ionization of silica in the second-stage and subsequent electrodeionization apparatuses. Silica can be removed efficiently.
[Brief description of the drawings]
FIG. 1 shows changes in silica removal rate, sodium removal rate, and electric resistance of a cell when the mixing ratio of an anion exchange resin to a cation exchange resin in Example 1 is changed between 50% and 100% in a regenerating type volume ratio. FIG.
FIG. 2 is a diagram showing a change in pH of treated water when a conductivity is changed by adding a sodium salt to treated water supplied to the electrodeionization apparatus of Example 2.
FIG. 3 shows the silica removal ratio and the electrical ratio when the mixing ratio of the anion exchange resin to the cation exchange resin charged in the desalting chamber of Example 3 is changed between 50 and 70% by volume of the regeneration type. The figure which shows the change of a resistance value.
FIG. 4 shows the removal of silica from the treated water discharged from the subsequent electrodeionization in the case where the conductivity is changed by adding a sodium salt to the water to be treated supplied to the preceding electrodeionization apparatus of Example 4. The figure which shows a rate.

Claims (3)

陰極と陽極との間に複数のアニオン交換膜とカチオン交換膜とを交互に配列し、前記隣接した２枚のアニオン交換膜とカチオン交換膜との間にイオン交換体を充填した脱塩室と、濃縮室とを交互に積層して設け、脱塩室の厚さが７ｍｍ以上である電気脱イオン装置において、前記脱塩室に充填するイオン交換体をアニオン交換樹脂とカチオン交換樹脂との混合物にし、アニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で７．２：２．８（アニオン比率７２％）〜７．８：２．２（アニオン比率７８％）にしたことを特徴とする電気脱イオン装置。A desalination chamber in which a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between the cathode and the anode, and an ion exchanger is filled between the two adjacent anion exchange membranes and the cation exchange membrane; And an enrichment chamber are alternately stacked, and the ion exchanger filled in the desalination chamber is a mixture of an anion exchange resin and a cation exchange resin. And that the mixing ratio of the anion exchange resin and the cation exchange resin was from 7.2: 2.8 (anion ratio 72%) to 7.8: 2.2 (anion ratio 78%) in regenerating volume ratio. Characteristic electrodeionization device. 請求項１に記載の電気脱イオン装置において、該電気脱イオン装置に供給する被処理水の供給管の上流側に被処理水にナトリウム塩を添加する添加装置を設け、上記添加装置で被処理水にナトリウム塩を添加して電気脱イオン装置から排出される処理水のｐＨを制御するようにしたことを特徴とする電気脱イオン装置。2. The electrodeionization apparatus according to claim 1, further comprising an addition device for adding a sodium salt to the water to be treated, provided upstream of a supply pipe of the water to be supplied to the electrodeionization device. An electrodeionization apparatus characterized in that the pH of treated water discharged from the electrodeionization apparatus is controlled by adding a sodium salt to water. 被処理水を直列に接続した複数の電気脱イオン装置に順次通水して処理する純水製造装置において、第１段目の電気脱イオン装置が、請求項１又は２に記載の電気脱イオン装置であって、第２段以降の電気脱イオン装置のアニオン交換樹脂とカチオン交換樹脂との混合比率を再生型体積比率で５．５：４．５（アニオン比率５５％）〜６．５：３．５（アニオン比率６５％）にしたことを特徴とする純水製造装置。In the pure water producing apparatus for sequentially treating and passing water to be treated through a plurality of electrodeionization apparatuses connected in series, the first-stage electrodeionization apparatus according to claim 1 or 2, wherein: In the apparatus, the mixing ratio of the anion exchange resin and the cation exchange resin in the second and subsequent electrodeionization apparatuses is from 5.5: 4.5 (anion ratio 55%) to 6.5: A pure water production apparatus characterized in that 3.5 (anion ratio: 65%).
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WO2005066079A1 (en) * 2004-01-09 2005-07-21 Kurita Water Industries Ltd. Electric deionization device and electric deionization method
JP2006110438A (en) * 2004-10-14 2006-04-27 Japan Organo Co Ltd Method of operating electric type deionized water manufacturing apparatus, and electric type deionized water manufacturing apparatus
JP2006116086A (en) * 2004-10-21 2006-05-11 Tokuyama Corp Action pole structure for iontophoresis apparatus and iontophoresis apparatus
JP2011056376A (en) * 2009-09-09 2011-03-24 Nippon Rensui Co Ltd Filling method for ion exchange resin, and electric regeneration-type pure water making apparatus
KR101558188B1 (en) * 2014-03-13 2015-10-08 주식회사 제이에스티 Deionized water supply apparatus

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JP2001113281A (en) * 1999-08-11 2001-04-24 Kurita Water Ind Ltd Electro-deionizing apparatus and pure water making apparatus
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WO2005066079A1 (en) * 2004-01-09 2005-07-21 Kurita Water Industries Ltd. Electric deionization device and electric deionization method
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JP2006110438A (en) * 2004-10-14 2006-04-27 Japan Organo Co Ltd Method of operating electric type deionized water manufacturing apparatus, and electric type deionized water manufacturing apparatus
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JP2006116086A (en) * 2004-10-21 2006-05-11 Tokuyama Corp Action pole structure for iontophoresis apparatus and iontophoresis apparatus
JP2011056376A (en) * 2009-09-09 2011-03-24 Nippon Rensui Co Ltd Filling method for ion exchange resin, and electric regeneration-type pure water making apparatus
KR101558188B1 (en) * 2014-03-13 2015-10-08 주식회사 제이에스티 Deionized water supply apparatus

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