JP2004050009A - Method of removing bromate ion - Google Patents

Method of removing bromate ion Download PDF

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JP2004050009A
JP2004050009A JP2002209591A JP2002209591A JP2004050009A JP 2004050009 A JP2004050009 A JP 2004050009A JP 2002209591 A JP2002209591 A JP 2002209591A JP 2002209591 A JP2002209591 A JP 2002209591A JP 2004050009 A JP2004050009 A JP 2004050009A
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Prior art keywords
hydrogen
water
bromate
treatment
bromate ions
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Japanese (ja)
Inventor
Nobuhiro Oda
織田 信博
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Kurita Water Industries Ltd
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Kurita Water Industries Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To efficiently remove a bromate ion included in drinking water and food industry water in a short period of time by reducing the bromate ion to bromide ion. <P>SOLUTION: A water including the bromate ion is brought into contact with a hydrogen reducing catalyst and is subjected to reduction treatment in the presence of hydrogen. That is, after dissolving hydrogen or hydrogen donor into the water containing the bromate ion, the water is brought into contact with the hydrogen reducing catalyst and is subjected to reduction treatment. Thereby, the bromate ion is effectively degraded and removed. Further, by performing deoxygenation treatment and reduction treatment, the consumption of hydrogen can be reduced. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、臭素酸イオンの除去方法に関する。さらに詳しくは、本発明は、飲用水や食品工業用水中に含まれる臭素酸イオンを臭化物イオンに還元して、短時間で効率的に除去することができる臭素酸イオンの除去方法に関する。
【0002】
【従来の技術】
天然水中には臭素酸イオンはほとんど存在しないために、従来は飲用水などに含まれる臭素酸イオンが問題となることはなかった。しかし、水処理にオゾンが用いられるようになり、水中の臭化物イオンがオゾンにより酸化されて臭素酸イオン(BrO )が発生し、その発癌性が指摘されている。世界保健機関(WHO)では、飲用水中の臭素酸イオン濃度の規制値を20μg/Lとし、米国の環境保護局(EPA)では、飲用水中の臭素酸イオン濃度の規制値を10μg/Lとしている。日本でも、原水中の臭化物イオン濃度が高く、臭素酸イオンの生成が問題となる浄水場については、対策が義務付けられている。
臭素酸イオンの除去には、活性炭を充填したカラムを通水することが考えられるが、臭素酸イオンは活性炭によってはほとんど除去できないと言われている。このために、臭素酸イオンの発生を防止し、あるいは、臭素酸イオンを除去する方法がさまざまに検討されている。
例えば、特開2001−225086号公報には、臭素酸イオンの生成を抑制する方法として、被処理水中の親水性有機物濃度を監視し、その値に応じてオゾン注入量を制御する方法が提案されている。しかし、経時的に変動する原水の水質を分析し、オゾン注入量を制御するためには、複雑な管理が必要であり、臭素酸イオンの生成を完全に抑制することは容易ではない。特開2000−317470号公報には、被処理水中の臭素酸イオンを分解除去する方法として、還元作用を有する金属を表面に吸着させた活性炭と被処理水を接触させる方法が提案されている。しかし、臭素酸イオンと金属との反応速度は遅く、処理に長時間を要する。特開2001−145877号公報には、光触媒を用いる臭素酸イオンの分解方法として、光触媒が添加された反応槽に被処理水を注入したのち、撹拌しながら光触媒にバンドギャップ以上のエネルギーを有する光線を照射する方法が提案されている。しかし、懸濁系における光反応は、相界面で光の散乱が起こるので、大型の装置を用いる大量の水処理には適していない。
このために、水中に含まれる臭素酸イオンを、短時間で効率的に除去し得る臭素酸イオンの除去方法が求められていた。
【0003】
【発明が解決しようとする課題】
本発明は、飲用水や食品工業用水中に含まれる臭素酸イオンを臭化物イオンに還元して、短時間で効率的に除去することができる臭素酸イオンの除去方法を提供することを目的としてなされたものである。
【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、臭素酸イオンを含む水に水素又は水素供与体を溶解したのち、水素還元触媒に接触させて還元処理することにより、臭素酸イオンを効率的に分解除去することができ、さらに、脱酸素処理及び還元処理を行うことにより、水素の使用量を低減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)臭素酸イオンを含む水を、水素の存在下に水素還元触媒に接触させて還元処理することを特徴とする臭素酸イオンの除去方法、
(2)水素還元触媒が、Pd、Pt、Ni及びCuから選ばれた1種又は2種以上を担体に担持させた触媒である第1項記載の臭素酸イオンの除去方法、
(3)担体が、活性炭、イオン交換樹脂、ゼオライト、シリカ又はチタニアである第2項記載の臭素酸イオンの除去方法、
(4)水素が、ヒドラジン、テトラヒドロホウ酸ナトリウム及びヒドロキシルアミンから選ばれた1種又は2種以上の水素供与体により供給される第1項記載の臭素酸イオンの除去方法、及び、
(5)脱酸素処理及び還元処理を行う第1項記載の臭素酸イオンの除去方法、
を提供するものである。
【0005】
【発明の実施の形態】
本発明方法においては、臭素酸イオンを含む水を水素の存在下に水素還元触媒に接触させて還元処理し、臭素酸イオンを臭化物イオンに還元して除去する。
本発明方法を適用する臭素酸イオンを含む水に特に制限はなく、例えば、オゾン酸化処理により臭化物イオンが酸化されて生成した臭素酸イオンを含む飲用水、染毛剤、パーマ液などの一成分である臭素酸イオンを含む美容院の排水などを挙げることができる。
本発明方法において、水素還元触媒に特に制限はなく、例えば、パラジウム、白金、ロジウム、ニッケル、銅などの遷移金属触媒、酸化亜鉛、酸化マグネシウムなどの金属酸化物触媒などを挙げることができる。これらの中で、パラジウム、白金、ニッケル及び銅を特に好適に用いることができる。これらの水素還元触媒は、1種を単独で用いることができ、あるいは、2種以上を組み合わせて用いることもできる。
本発明方法において、水素還元触媒は、担体に担持させることが好ましい。水素還元触媒を担持させる担体としては、例えば、活性炭、イオン交換樹脂、ゼオライト、シリカ、チタニア、アルミナ、ケイソウ土などを挙げることができる。このような多孔性物質を担体とすることにより、水素還元触媒を安定に担持し、触媒機能物質の有効表面積が大きくなり、触媒活性を高め、選択性を増加し、被毒作用に対する抵抗を高めることができる。
【0006】
本発明方法において、水素の形態に特に制限はなく、例えば、ガス状の水素(H)を用いることができ、あるいは、分解して水素を供与するヒドラジン(HNNH)、テトラヒドロホウ酸ナトリウム(NaBH)、ヒドロキシルアミン(HNOH)などの水素供与体などを用いることもできる。ガス状の水素を供給する場合に比べて、これらの水素供与体は、水溶液として添加することができるので、取り扱いやすく、供給を容易に自動化することができる。ヒドラジンとしては、ヒドラジン一水和物(HNNH・HO)、硫酸ヒドラジニウム(1+)((NSO)、硫酸ヒドラジニウム(2+)(NSO)、塩化ヒドラジニウム(1+)(NCl)、塩化ヒドラジニウム(2+)(NCl)などを用いることができる。ヒドロキシルアミンとしては、硫酸ヒドロキシルアンモニウム((HNOH)SO)、塩化ヒドロキシルアンモニウム(HNOHCl)などを用いることができる。これらの水素供与体は、1種を単独で用いることができ、あるいは、2種以上を組み合わせて用いることもできる。これらの中で、ヒドラジン一水和物は、臭素酸イオンを還元したのちは、水と窒素になり、水中に他の物質を残さないので、特に好適に用いることができる。
本発明方法においては、臭素酸イオンを含む水の脱酸素処理及び還元処理を行うことが好ましい。脱酸素処理及び還元処理を行うことにより、水素又は水素供与体の使用量を節減することができる。脱酸素処理の方法に特に制限はなく、例えば、真空脱気塔を用いる脱酸素処理、窒素により酸素を置換する窒素脱気、気体透過膜を用いて酸素を除去する膜脱気、亜硫酸塩、コハク酸などを用いて酸素を除去する薬剤処理などを挙げることができる。したがって、脱酸素処理の後還元処理を行っても、同時でもよい。
【0007】
図1は、本発明の臭素酸イオンの除去方法の実施の一態様の工程系統図である。臭素酸イオン含有水がポンプ1により送られ、水素発生器2から水素が臭素酸イオン含有水に供給されたのち、触媒還元塔3において水素還元触媒4に接触し、臭素酸イオンが臭化物イオンに還元されて除去され、処理水が得られる。
図2は、本発明方法の実施の他の態様の工程系統図である。臭素酸イオン含有水がポンプ1により脱気膜装置5に送られ、真空ポンプ6により減圧に保たれた気相部に酸素が移動して除去され、脱酸素処理が施される。脱酸素された臭素酸イオン含有水に、次いで水素発生器2から水素が供給されたのち、触媒還元塔3において水素還元触媒4に接触し、臭素酸イオンが臭化物イオンに還元されて除去され、処理水が得られる。
図3は、本発明方法の実施の他の態様の工程系統図である。臭素酸イオン含有水がポンプ1により脱気膜装置5に送られ、真空ポンプ6により減圧に保たれた気相部に酸素が移動して除去され、脱酸素処理が施される。脱酸素された臭素酸イオン含有水に、次いで薬液タンク7から薬注ポンプ8により水素供与体の水溶液が供給されたのち、触媒還元塔3において水素還元触媒4に接触し、臭素酸イオンが臭化物イオンに還元されて除去され、処理水が得られる。
本発明方法によれば、飲用水や食品工業用水中に含まれる発癌性のおそれがある臭素酸イオンを、短時間で効率的に臭化物イオンに還元して除去することができる。
【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。
なお、実施例においては、赤嶺永正らにより日本オゾン協会第10回年次研究講演会において発表された「オゾン処理副生成物の低減化対策と生成因子の検討」(予稿集27〜30頁、2000年)から推定し、オゾン処理した沖縄県北谷の海水淡水化水を模擬したBrO 0.02mg/Lを含むオゾン処理模擬水を合成して用いた。
海水、淡水化水及びオゾン処理模擬水の水質を、第1表に示す。
【0009】
【表1】

Figure 2004050009
【0010】
実施例1
オゾン処理模擬水について、図1に示す装置を用いて臭素酸イオンの除去を行った。触媒還元塔は、内径250mm、高さ1,500mmであり、この中へ粒径2.5mmのチタニアにパラジウム0.5重量%を担持した触媒[田中貴金属(株)]25Lを充填した。触媒充填高さは、約510mmであった。
オゾン処理模擬水に水素1.2mg/Lを添加し、触媒還元塔に500L/h(SV20h)で通水した。通水開始30分後には処理水質は安定し、以降100時間まで同じ水質の処理水が得られた。触媒還元塔入口の溶存酸素濃度は6.2mg/Lであり、処理水の溶存酸濃度は0.01mg/L以下であり、処理水の臭素酸イオン濃度は0.005mg/L以下であった。
実施例2
オゾン処理模擬水への水素の添加量を0.5mg/Lとした以外は、実施例1と同様にして、臭素酸イオンの除去を行った。
触媒還元塔入口の溶存酸素濃度は6.2mg/Lであり、処理水の溶存酸濃度は2.1mg/Lであり、処理水の臭素酸イオン濃度は0.015mg/Lであった。
実施例3
図2に示す装置を用いて、オゾン処理模擬水の臭素酸イオンの除去を行った。この装置は、図1に示す装置に脱気膜装置[NOK(株)、DWA50]を付設した装置であり、触媒還元塔は図1に示す装置と同じである。
オゾン処理模擬水500L/hを脱気膜装置に送って脱気したのち、水素0.1mg/Lを添加し、触媒還元塔に通水した。触媒還元塔入口の溶存酸素濃度は0.5mg/Lであり、処理水の溶存酸濃度は0.01mg/L以下であり、処理水の臭素酸イオン濃度は0.005mg/L以下であった。
実施例1〜3の結果を、第2表に示す。
【0011】
【表2】
Figure 2004050009
【0012】
第2表に見られるように、臭素酸イオン0.02mg/Lを含むオゾン処理模擬水に水素1.2mg/Lを添加して還元処理した実施例1では、処理水の臭素酸イオン濃度は0.005mg/L以下となる。水素の添加量を0.5mg/Lまで減らして同様に処理した実施例2では、処理水の臭素酸イオン濃度は0.015mg/Lとなる。しかし、脱気膜装置を用いて脱酸素処理した実施例3では、水素添加量を0.1mg/Lに減らしても、処理水の臭素酸イオン濃度は0.005mg/L以下であり、オゾン処理模擬水を脱酸素処理することにより、消費する水素の量を節減して、効率的に臭素酸イオンを除去し得ることが分かる。
実施例4
図3に示す装置を用いて、オゾン処理模擬水の臭素酸イオンの除去を行った。この装置は、図2に示す装置の水素発生器3を取り外して、薬液タンク6と薬注ポンプ7を付設した装置であり、触媒還元塔は図1に示す装置と同じであり、脱気膜装置は図2に示す装置と同じである。
オゾン処理模擬水500L/hを脱気膜装置に送って脱気したのち、ヒドラジン濃度が0.8mg/Lになるようにヒドラジン一水和物(HNNH・HO)の10重量%水溶液を添加し、触媒還元塔に通水した。触媒還元塔入口の溶存酸素濃度は0.5mg/Lであり、処理水の溶存酸濃度は0.01mg/L以下であり、処理水の臭素酸イオン濃度は0.005mg/L以下であった。
実施例5
ヒドラジン一水和物の10重量%水溶液の代わりに、テトラヒドロホウ酸ナトリウムの濃度が0.5mg/Lになるように、テトラヒドロホウ酸ナトリウム(NaBH)の10重量%水溶液を添加した以外は、実施例4と同様にして、オゾン処理模擬水の処理を行った。
触媒還元塔入口の溶存酸素濃度は0.5mg/Lであり、処理水の溶存酸濃度は0.01mg/L以下であり、処理水の臭素酸イオン濃度は0.005mg/L以下であった。
実施例6
ヒドラジン一水和物の10重量%水溶液の代わりに、塩化ヒドロキシルアンモニウムの濃度が7mg/Lになるように、塩化ヒドロキシルアンモニウム(HNOHCl)の10重量%水溶液を添加した以外は、実施例4と同様にして、オゾン処理模擬水の処理を行った。
触媒還元塔入口の溶存酸素濃度は0.5mg/Lであり、処理水の溶存酸濃度は0.01mg/L以下であり、処理水の臭素酸イオン濃度は0.005mg/L以下であった。
実施例4〜6の結果を、第3表に示す。
【0013】
【表3】
Figure 2004050009
【0014】
第3表に見られるように、水素供与体として、ヒドラジン一水和物、テトラヒドロホウ酸ナトリウム又は塩化ヒドロキシルアンモニウムを用いた実施例4〜6においても、水素を用いた実施例3と同様に、水中の臭素酸イオンが分解除去されている。
【0015】
【発明の効果】
本発明方法によれば、飲用水や食品工業用水中に含まれる腎臓腫瘍の発生を引き起こす疑いのある臭素酸イオンを、短時間で効率的に臭化物イオンに還元して除去することができる。
【図面の簡単な説明】
【図1】図1は、本発明方法の実施の一態様の工程系統図である。
【図2】図2は、本発明方法の実施の他の態様の工程系統図である。
【図3】図3は、本発明方法の実施の他の態様の工程系統図である。
【符号の説明】
1 ポンプ
2 水素発生器
3 触媒還元塔
4 水素還元触媒
5 脱気膜装置
6 真空ポンプ
7 薬液タンク
8 薬注ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for removing bromate ions. More specifically, the present invention relates to a method for removing bromate ions, which is capable of reducing bromate ions contained in drinking water or food industry water to bromide ions and efficiently removing the bromate ions in a short time.
[0002]
[Prior art]
Since there is almost no bromate ion in natural water, conventionally, bromate ion contained in drinking water and the like has not been a problem. However, ozone is used for water treatment, and bromide ions in water are oxidized by ozone to generate bromate ions (BrO 3 ), and its carcinogenicity has been pointed out. The World Health Organization (WHO) regulates the bromate ion concentration in drinking water to 20 μg / L, and the US Environmental Protection Agency (EPA) regulates the bromate ion concentration in drinking water to 10 μg / L. And In Japan as well, countermeasures are obligatory for water purification plants where the concentration of bromide ions in raw water is high and the production of bromate ions is a problem.
To remove bromate ions, it is conceivable to pass water through a column filled with activated carbon, but it is said that bromate ions can hardly be removed by activated carbon. For this reason, various methods for preventing the generation of bromate ions or removing bromate ions have been studied.
For example, Japanese Patent Application Laid-Open No. 2001-225086 proposes a method of monitoring the concentration of a hydrophilic organic substance in the water to be treated and controlling the ozone injection amount according to the value as a method of suppressing the production of bromate ions. ing. However, in order to analyze the quality of raw water that fluctuates with time and control the amount of ozone injected, complicated management is required, and it is not easy to completely suppress the production of bromate ions. Japanese Patent Application Laid-Open No. 2000-317470 proposes, as a method for decomposing and removing bromate ions in water to be treated, a method in which activated carbon having a metal having a reducing action adsorbed on its surface is brought into contact with the water to be treated. However, the reaction rate between bromate ion and metal is slow, and the treatment requires a long time. Japanese Patent Application Laid-Open No. 2001-145877 discloses a method for decomposing bromate ions using a photocatalyst, injecting water to be treated into a reaction tank to which a photocatalyst is added, and then stirring the photocatalyst with a light beam having energy equal to or greater than the band gap. Has been proposed. However, photoreactions in suspension systems are not suitable for large volume water treatment using large equipment because light scattering occurs at the phase interface.
For this reason, there has been a demand for a bromate ion removal method capable of efficiently removing bromate ions contained in water in a short time.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for removing bromate ions, which can reduce bromate ions contained in drinking water and food industry water to bromide ions, and can be efficiently removed in a short time. It is a thing.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, after dissolving hydrogen or a hydrogen donor in water containing bromate ions, by contacting with a hydrogen reduction catalyst and performing a reduction treatment, bromine is obtained. It has been found that acid ions can be efficiently decomposed and removed, and that the amount of hydrogen used can be reduced by performing deoxygenation treatment and reduction treatment. Based on this finding, the present invention has been completed. Was.
That is, the present invention
(1) a method for removing bromate ions, comprising contacting water containing bromate ions with a hydrogen reduction catalyst in the presence of hydrogen to perform a reduction treatment;
(2) The method for removing bromate ions according to (1), wherein the hydrogen reduction catalyst is a catalyst in which one or more selected from Pd, Pt, Ni, and Cu are supported on a carrier.
(3) The method for removing bromate ions according to (2), wherein the carrier is activated carbon, an ion exchange resin, zeolite, silica or titania;
(4) The method for removing bromate ions according to (1), wherein the hydrogen is supplied by one or more hydrogen donors selected from hydrazine, sodium tetrahydroborate and hydroxylamine, and
(5) The method for removing bromate ions according to (1), wherein deoxidation treatment and reduction treatment are performed.
Is provided.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
In the method of the present invention, water containing bromate ions is brought into contact with a hydrogen reduction catalyst in the presence of hydrogen to perform a reduction treatment, and bromate ions are reduced to bromide ions and removed.
There is no particular limitation on water containing bromate ions to which the method of the present invention is applied. For example, one component such as drinking water, hair dye, and perm solution containing bromate ions generated by oxidation of bromide ions by ozone oxidation treatment. And beauty salon wastewater containing bromate ions.
In the method of the present invention, the hydrogen reduction catalyst is not particularly limited, and examples thereof include transition metal catalysts such as palladium, platinum, rhodium, nickel, and copper, and metal oxide catalysts such as zinc oxide and magnesium oxide. Among them, palladium, platinum, nickel and copper can be particularly preferably used. One of these hydrogen reduction catalysts can be used alone, or two or more can be used in combination.
In the method of the present invention, the hydrogen reduction catalyst is preferably supported on a carrier. Examples of the carrier for supporting the hydrogen reduction catalyst include activated carbon, ion exchange resin, zeolite, silica, titania, alumina, and diatomaceous earth. By using such a porous substance as a carrier, the hydrogen reduction catalyst is stably supported, the effective surface area of the catalytic functional substance is increased, the catalytic activity is increased, the selectivity is increased, and the resistance to poisoning is increased. be able to.
[0006]
In the method of the present invention, the form of hydrogen is not particularly limited. For example, gaseous hydrogen (H 2 ) can be used, or hydrazine (H 2 NNH 2 ), which decomposes to provide hydrogen, tetrahydroboric acid A hydrogen donor such as sodium (NaBH 4 ) or hydroxylamine (H 2 NOH) can also be used. Compared to the case of supplying gaseous hydrogen, these hydrogen donors can be added as an aqueous solution, so that they can be easily handled and the supply can be easily automated. The hydrazine, hydrazine monohydrate (H 2 NNH 2 · H 2 O), hydrazinium sulfate (1 +) ((N 2 H 5) 2 SO 4), hydrazine sulfate (2 +) (N 2 H 6 SO 4) , Hydrazinium chloride (1+) (N 2 H 5 Cl), hydrazinium chloride (2+) (N 2 H 6 Cl 2 ), or the like can be used. The hydroxylamine, hydroxylammonium sulfate ((H 3 NOH) 2 SO 4), and the like can be used hydroxylammonium chloride (H 3 NOHCl). One of these hydrogen donors can be used alone, or two or more can be used in combination. Among them, hydrazine monohydrate is particularly preferably used because it becomes water and nitrogen after reducing bromate ions and does not leave other substances in water.
In the method of the present invention, it is preferable to perform a deoxygenation treatment and a reduction treatment of water containing bromate ions. By performing the deoxygenation treatment and the reduction treatment, the amount of hydrogen or the hydrogen donor used can be reduced. There is no particular limitation on the method of deoxygenation treatment, for example, deoxygenation treatment using a vacuum deaeration tower, nitrogen deaeration to replace oxygen with nitrogen, membrane deaeration to remove oxygen using a gas permeable membrane, sulfite, A chemical treatment for removing oxygen using succinic acid or the like can be given. Therefore, the reduction treatment may be performed after the deoxygenation treatment or may be performed simultaneously.
[0007]
FIG. 1 is a process flow chart of one embodiment of the method for removing bromate ions of the present invention. After the bromate ion-containing water is sent by the pump 1 and hydrogen is supplied from the hydrogen generator 2 to the bromate ion-containing water, it contacts the hydrogen reduction catalyst 4 in the catalyst reduction tower 3, and the bromate ions are converted into bromide ions. It is reduced and removed to obtain treated water.
FIG. 2 is a flow chart of another embodiment of the method of the present invention. The bromate ion-containing water is sent to the degassing membrane device 5 by the pump 1, and the oxygen is moved to and removed by the vacuum pump 6 to the gaseous phase section kept at a reduced pressure, and subjected to deoxygenation treatment. After hydrogen is supplied to the deoxygenated bromate ion-containing water and then from the hydrogen generator 2, it contacts the hydrogen reduction catalyst 4 in the catalyst reduction tower 3, and the bromate ions are reduced to bromide ions and removed, The treated water is obtained.
FIG. 3 is a process flow chart of another embodiment of the method of the present invention. The bromate ion-containing water is sent to the degassing membrane device 5 by the pump 1, and the oxygen is moved to and removed by the vacuum pump 6 to the gaseous phase section kept at a reduced pressure, and subjected to deoxygenation treatment. An aqueous solution of a hydrogen donor is supplied to the deoxygenated bromate ion-containing water and then from a chemical solution tank 7 by a chemical injection pump 8, and then comes into contact with a hydrogen reduction catalyst 4 in a catalytic reduction tower 3, where bromate ions are converted to bromide. It is reduced to ions and removed to obtain treated water.
ADVANTAGE OF THE INVENTION According to the method of this invention, the bromate ion contained in drinking water or food industry water which has a risk of carcinogenicity can be efficiently reduced to bromide ion in a short time and removed.
[0008]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the examples, “Measures for reduction of ozone treatment by-products and examination of generation factors” announced at the 10th Annual Research Lecture by the Ozone Association of Japan by Nagamasa Akamine et al. (Preprints 27 to 30) , estimated from 2000), BrO simulating the ozone-treated Okinawa Chatan of seawater desalination water 3 - 0.02mg / ozone treatment simulated water containing L was used in synthesis.
Table 1 shows the quality of seawater, desalinated water and ozone-treated simulated water.
[0009]
[Table 1]
Figure 2004050009
[0010]
Example 1
Bromate ions were removed from the simulated ozone water using the apparatus shown in FIG. The catalyst reduction tower had an inner diameter of 250 mm and a height of 1,500 mm, and 25 L of a catalyst (Tanaka Kikinzoku Co., Ltd.) supporting 0.5% by weight of palladium on titania having a particle size of 2.5 mm was filled therein. The catalyst loading height was about 510 mm.
Hydrogen (1.2 mg / L) was added to the ozone treatment simulated water, and the water was passed through the catalyst reduction tower at 500 L / h (SV 20 h ). The treated water quality was stabilized 30 minutes after the start of water passage, and the treated water of the same quality was obtained up to 100 hours thereafter. The dissolved oxygen concentration at the inlet of the catalyst reduction tower was 6.2 mg / L, the dissolved acid concentration in the treated water was 0.01 mg / L or less, and the bromate ion concentration in the treated water was 0.005 mg / L or less. .
Example 2
Bromate ions were removed in the same manner as in Example 1 except that the amount of hydrogen added to the ozone-treated simulated water was 0.5 mg / L.
The dissolved oxygen concentration at the inlet of the catalyst reduction tower was 6.2 mg / L, the dissolved acid concentration in the treated water was 2.1 mg / L, and the bromate ion concentration in the treated water was 0.015 mg / L.
Example 3
Using the apparatus shown in FIG. 2, the bromate ions in the simulated ozone-treated water were removed. This device is a device in which a degassing membrane device [NOK Corporation, DWA50] is added to the device shown in FIG. 1, and the catalytic reduction tower is the same as the device shown in FIG.
After 500 L / h of ozone-treated simulated water was sent to a degassing membrane device and degassed, 0.1 mg / L of hydrogen was added and passed through a catalyst reduction tower. The dissolved oxygen concentration at the catalyst reduction tower inlet was 0.5 mg / L, the dissolved acid concentration in the treated water was 0.01 mg / L or less, and the bromate ion concentration in the treated water was 0.005 mg / L or less. .
Table 2 shows the results of Examples 1 to 3.
[0011]
[Table 2]
Figure 2004050009
[0012]
As can be seen from Table 2, in Example 1 in which 1.2 mg / L of hydrogen was added to simulated ozone-treated water containing 0.02 mg / L of bromate ion for reduction treatment, the bromate ion concentration of the treated water was It becomes 0.005 mg / L or less. In Example 2 in which the amount of hydrogen added was reduced to 0.5 mg / L and the same treatment was performed, the bromate ion concentration of the treated water was 0.015 mg / L. However, in Example 3 in which deoxidation treatment was performed using a degassing membrane device, even if the hydrogenation amount was reduced to 0.1 mg / L, the bromate ion concentration of the treated water was 0.005 mg / L or less, and ozone It can be understood that the amount of hydrogen consumed can be reduced and the bromate ions can be efficiently removed by deoxidizing the simulated water.
Example 4
Using the apparatus shown in FIG. 3, bromate ions in the simulated ozone-treated water were removed. This device is a device in which the hydrogen generator 3 of the device shown in FIG. 2 is removed, and a chemical solution tank 6 and a chemical injection pump 7 are attached. The catalytic reduction tower is the same as the device shown in FIG. The device is the same as the device shown in FIG.
After 500 L / h of ozone-treated simulated water is sent to a degassing membrane device to degas, 10 weight of hydrazine monohydrate (H 2 NNH 2 .H 2 O) is adjusted to a hydrazine concentration of 0.8 mg / L. % Aqueous solution was added, and the mixture was passed through a catalytic reduction tower. The dissolved oxygen concentration at the catalyst reduction tower inlet was 0.5 mg / L, the dissolved acid concentration in the treated water was 0.01 mg / L or less, and the bromate ion concentration in the treated water was 0.005 mg / L or less. .
Example 5
Instead of a 10% by weight aqueous solution of hydrazine monohydrate, a 10% by weight aqueous solution of sodium tetrahydroborate (NaBH 4 ) was added so that the concentration of sodium tetrahydroborate was 0.5 mg / L. In the same manner as in Example 4, the ozone treatment simulated water was treated.
The dissolved oxygen concentration at the catalyst reduction tower inlet was 0.5 mg / L, the dissolved acid concentration in the treated water was 0.01 mg / L or less, and the bromate ion concentration in the treated water was 0.005 mg / L or less. .
Example 6
Example 4 except that a 10% by weight aqueous solution of hydroxylammonium chloride (H 3 NOHCl) was added so that the concentration of hydroxylammonium chloride became 7 mg / L instead of the 10% by weight aqueous solution of hydrazine monohydrate. The ozone treatment simulated water was treated in the same manner as described above.
The dissolved oxygen concentration at the catalyst reduction tower inlet was 0.5 mg / L, the dissolved acid concentration in the treated water was 0.01 mg / L or less, and the bromate ion concentration in the treated water was 0.005 mg / L or less. .
Table 3 shows the results of Examples 4 to 6.
[0013]
[Table 3]
Figure 2004050009
[0014]
As seen in Table 3, in Examples 4 to 6 using hydrazine monohydrate, sodium tetrahydroborate or hydroxylammonium chloride as the hydrogen donor, as in Example 3 using hydrogen, Bromate ions in water are decomposed and removed.
[0015]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the method of this invention, the bromate ion contained in drinking water and water for food industry which is supposed to cause kidney tumors can be efficiently reduced and removed in a short time.
[Brief description of the drawings]
FIG. 1 is a process flow diagram of one embodiment of the method of the present invention.
FIG. 2 is a process flow chart of another embodiment of the method of the present invention.
FIG. 3 is a process flow chart of another embodiment of the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pump 2 Hydrogen generator 3 Catalytic reduction tower 4 Hydrogen reduction catalyst 5 Degassing membrane device 6 Vacuum pump 7 Chemical tank 8 Chemical injection pump

Claims (5)

臭素酸イオンを含む水を、水素の存在下に水素還元触媒に接触させて還元処理することを特徴とする臭素酸イオンの除去方法。A method for removing bromate ions, comprising contacting water containing bromate ions with a hydrogen reduction catalyst in the presence of hydrogen to perform a reduction treatment. 水素還元触媒が、Pd、Pt、Ni及びCuから選ばれた1種又は2種以上を担体に担持させた触媒である請求項1記載の臭素酸イオンの除去方法。The method for removing bromate ions according to claim 1, wherein the hydrogen reduction catalyst is a catalyst in which one or more selected from Pd, Pt, Ni and Cu are supported on a carrier. 担体が、活性炭、イオン交換樹脂、ゼオライト、シリカ又はチタニアである請求項2記載の臭素酸イオンの除去方法。The method for removing bromate ions according to claim 2, wherein the carrier is activated carbon, an ion exchange resin, zeolite, silica or titania. 水素が、ヒドラジン、テトラヒドロホウ酸ナトリウム及びヒドロキシルアミンから選ばれた1種又は2種以上の水素供与体により供給される請求項1記載の臭素酸イオンの除去方法。The method for removing bromate ions according to claim 1, wherein the hydrogen is supplied by one or more hydrogen donors selected from hydrazine, sodium tetrahydroborate and hydroxylamine. 脱酸素処理及び還元処理を行う請求項1記載の臭素酸イオンの除去方法。2. The method for removing bromate ions according to claim 1, wherein deoxidation treatment and reduction treatment are performed.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6427690A (en) * 1987-07-20 1989-01-30 Agency Ind Science Techn Treatment of water containing organic compounds having difficulty in decomposition
JPH01254293A (en) * 1988-04-01 1989-10-11 Jgc Corp Corrosion-resistant treatment of metal
JPH0647384A (en) * 1992-07-31 1994-02-22 Naoetsu Denshi Kogyo Kk Production of pure water
JPH10504999A (en) * 1994-09-08 1998-05-19 ゾルファイ ウムヴェルトヒエミー ゲゼルシャフト ミット ベシュレンクテル ハフツング Method for removing chlorate and bromate compounds from water by catalytic reduction
JP2001225086A (en) * 2000-02-18 2001-08-21 Fuji Electric Co Ltd Method and apparatus for treating ozone water
JP2001293486A (en) * 2000-04-13 2001-10-23 Kurita Water Ind Ltd Method for treating hexavalent chromium-containing waste water

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6427690A (en) * 1987-07-20 1989-01-30 Agency Ind Science Techn Treatment of water containing organic compounds having difficulty in decomposition
JPH01254293A (en) * 1988-04-01 1989-10-11 Jgc Corp Corrosion-resistant treatment of metal
JPH0647384A (en) * 1992-07-31 1994-02-22 Naoetsu Denshi Kogyo Kk Production of pure water
JPH10504999A (en) * 1994-09-08 1998-05-19 ゾルファイ ウムヴェルトヒエミー ゲゼルシャフト ミット ベシュレンクテル ハフツング Method for removing chlorate and bromate compounds from water by catalytic reduction
JP2001225086A (en) * 2000-02-18 2001-08-21 Fuji Electric Co Ltd Method and apparatus for treating ozone water
JP2001293486A (en) * 2000-04-13 2001-10-23 Kurita Water Ind Ltd Method for treating hexavalent chromium-containing waste water

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