JP2004057881A

JP2004057881A - Agent for making material polluted with organic halogen compound harmless, method of producing the agent, and method of making harmless using the agent

Info

Publication number: JP2004057881A
Application number: JP2002217227A
Authority: JP
Inventors: Toshiki Shimizu; 清水　要樹; Yasuyuki Nagai; 長井　康行
Original assignee: Tosoh Corp
Current assignee: Tosoh Corp
Priority date: 2002-07-25
Filing date: 2002-07-25
Publication date: 2004-02-26
Anticipated expiration: 2022-07-25
Also published as: JP4009739B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agent for making a material polluted with organic halogen compounds harmless capable of decomposing and making harmless organic halogen compounds (trichloroethylene etc.) in polluted soil, sludge, or aqueous solutions which cause environmental problems, in a short time without producing harmful by-products, and provide a method for producing the same, and a method of making harmless using the agent. <P>SOLUTION: An Fe-Ni alloy obtained by alloying a mixture comprising 100 pts.wt. of Fe powder and 0.01-2 pts.wt. of Ni powder by a mechanical alloying method is used as the agent for making the material polluted with the organic halogen compounds harmless. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、有機ハロゲン化合物で汚染された土壌、産業廃棄物、汚泥、スラッジ、排水、地下水等の被処理物に対する無害化処理剤、その製造方法及びそれを用いた無害化処理方法に関するものである。
【０００２】
【従来の技術】
近年、世界各地でＴＣＥ（トリクロロエチレン）、ＰＣＥ（テトラクロロエチレン）、ジクロロメタン、ＰＣＢ（ポリ塩化ビフェニル）及びダイオキシン類等の有機ハロゲン化合物による環境汚染問題が顕在化し大きな問題となっている。
【０００３】
これらの問題に対し、特に有機ハロゲン化合物により汚染された土壌、排水、地下水等に対する無害化用処理剤およびその処理方法が検討され、いくつかの技術報告や特許出願がされている。
【０００４】
１）汚染排水、地下水の場合、真空抽出法や揚水曝気法等が知られているが、地上への引き上げ装置、さらに引き上げた前記汚染物質の吸着設備、活性炭吸着剤の再生処理や発生廃棄物の処理が必要となり、全体としては高コストな処理方法となる。また、無害化には数年を要し、完全除去は難しい技術である。近年、金属系処理剤を混合または散布するだけで汚染物質を還元脱ハロゲン化する無害化処理法が報告され、従来法に比べ低コスト化が図れるとしている。鉄系処理剤により無害化する方法として、例えば特許第２６３６１７１号公報、特公平２−４９１５８号公報、特公平２−４９７９８号公報があるが，汚染排水、地下水のｐＨ調整、水素ガスや還元剤等を供給する脱酸素処理が必要であり、実工法としては困難でありコスト高となる。また、先崎ら［工業用水、ＶＯＬ３９１，（１９９１），２９．］によるとＴＣＥで汚染された排水、用水をＦｅ粉末や、ＮｉまたはＣｕ化学メッキＦｅ粉末により還元脱塩素処理する技術が報告されている。しかし、これら処理剤自体の経時的性能劣化を抑制するためには汚染排水、用水中の溶存酸素を除去することが必要であり、さらに活性を示すニッケルメッキ量の範囲が限られており、再現性が問題として残る。特表平１０−５１３１０３号公報はジクロロメタンをＦｅ−Ｐｄ触媒により分解する技術であるが，比較例として塩化ニッケル溶液でメッキ処理したＦｅ粉末はその分解速度が遅く無害化には長時間を要し、完全に分解できない。特表平６−５０６６３１号公報は活性炭とＦｅ粉末を混合したものであり、高価な活性炭を多量に使用するためコスト高となり実用化は困難である。
【０００５】
２）汚染土壌、スラッジ、汚泥等の処理法としては掘削土壌または直接土壌中に加熱用電極を挿入し加熱処理する熱脱着法および熱分解法が知られている。この方法は大掛かりな加熱装置が必要である。また電極近傍は熱分解されるが、その他は揮発性の有機塩素化合物を中心に地上に揮散するだけで根本的な処理法では無く、処理後の土壌は熱により固化し、微生物はほとんど死滅するため再利用の点でも採用は難しい。微生物を経由した還元物質により無害化処理するバイオレメデイエ−ション法があるが、無害化には長時間必要であり、しかも全種類の土壌に対応できず完全な無害化は不可能である。化学的処理として、汚染土壌に鉄系処理剤を添加した特開平１１−２３５５７７号公報、Ｆｅ系を含む卑金属系処理剤と微生物を併用した特開平１１−２５３９２６号公報があるが、短時間に分解されないため、より高性能化が必要である。また、特開２００２−２０８０６号公報は鉄系廃棄物を加熱処理した処理剤の製造方法であり、低コスト化は図れるが、適正な組成、金属組織を調整することが困難であり、処理時間がかかるため高活性化が必要である。
【０００６】
【発明が解決しようとする課題】
以上述べたように有機ハロゲン化合物で汚染された土壌、産業廃棄物、汚泥、スラッジ、排水、地下水等に対する従来の処理法は処理時間が長い、高コスト、処理法が複雑で実用性に乏しいといった課題を抱えている。特に、卑金属系処理剤を添加し、無害化する技術としては、汚染排水、地下水に対するｐＨ調整、脱溶存酸素処理が必要であり、汚染土壌、産業廃棄物、汚泥、スラッジに対しては短時間に分解されないため、高活性化が必要である。
【０００７】
【課題を解決するための手段】
発明者等は、これらの課題を解決するために鋭意検討した結果、本発明を完成するに至った。即ち、Ｆｅ粉末１００重量部とＮｉ粉末０．０１〜２重量部からなる混合物をメカニカルアロイング法により合金化したＦｅ−Ｎｉ合金からなる有機ハロゲン化合物で汚染された被処理物用無害化処理剤、その製造方法およびそれを用いた処理方法を提供するもので、本発明の処理剤によれば短期間において汚染有機ハロゲン化合物濃度を法的規制値以下にすることができる。更に、難分解性と言われるＣｉｓ−ＤＣＥ（ｃｉｓ−１，２−ジクロロエチレン）、ＭＣ（メチルクロロホルム、１，１，１−トリクロロエタン）、ＰＣＥをも分解することができる。
【０００８】
以下、本発明についてさらに詳細に説明する。
【０００９】
本発明の無害化処理剤が処理する被処理物は、有機ハロゲン化合物で汚染されたものである。有機ハロゲン化合物の例としては、ジクロロメタン、四塩化炭素、クロロホルム、１，２−ジクロロエタン、１，１−ジクロロエチレン、Ｃｉｓ−ＤＣＥ、Ｔｒａｎｓ−ＤＣＥ（ｔｒａｎｓ−１，２−ジクロロエチレン）、ＭＣ、１，１，２−トリクロロエタン、ＴＣＥ、ＰＣＥ、１，３−ジクロロプロペン等の有機塩素系化合物、またはこれらの有機臭素系化合物等が挙げられる。
【００１０】
本発明で使用するＦｅ粉末としては純鉄の他に、鋼（例えば還元鉄粉）、鋳鉄、銑鉄等を用いることが出来る。粉末の形状は特に限定するものではなく、球形状、樹枝状、片状、針状、角状、積層状、ロッド状、板状，海綿状等が使用できる。Ｆｅ粉末の製法には制限はなく、溶湯から直接粒末を製造する粒状化法、アトマイズ法、還元法、粉砕法、旋盤等で削り出したダライ粉等を用いることができる。Ｆｅ粉末の粒径は、特に限定されないが、一般に上記した調製法により５０〜５００μｍ程度の粒径を有しており、この範囲においては好適に使用できる。
【００１１】
本発明で使用するＮｉ粉末は純Ｎｉ粉末、工業用Ｎｉ粉末の他にフェロニッケル粉末等が含まれる。一般的に入手可能な工業用Ｎｉ紛末は１０〜１００μｍの粒径を有しており、更には、１〜１０μｍ程度の微粒Ｎｉ紛末も好適に使用可能である。
【００１２】
本発明においては、前記のＦｅ粉末とＮｉ粉末の混合物を、機械的合金化法とも呼ばれているメカニカルアロイング法（以下ＭＡ法という）により合金化または部分合金化して調製する。ＭＡ法とはＢｅｎｊａｍｉｎ，Ｊ．ｓ：Ｍｅｔ．Ｔｒａｎｓ．，１，１０（１９７０）、２９４３及び　渡辺龍三：日本金属学会会報、２７、１０（１９８８）、７９９によると、金属や合金粉末に機械的エネルギ−を加えることにより合金を得る、一種のメカノケミカル方法である。一般的には、原料粉末と粉砕ボ−ルを密閉容器に入れ、攪拌または振動を連続して加えることにより、粉末に塑性変形、粉砕、凝着が繰り返され特有の組織を持つ合金粉末が得られる。攪拌または振動する際に発生する熱は、水冷または空冷により除熱され、合金材に主として機械的エネルギーが与えられる。攪拌時間等の条件によっては微視的な結晶構造変化により，微細結晶粒、過飽和固溶体、準安定結晶相あるいはアモルファス相などを得ることもできる。
【００１３】
通常、ＦｅとＮｉの合金調製法として、溶融法や熱拡散法等の熱的合金化法が採用されているが、Ｆｅ原子にＮｉ原子が固溶した合金材が得られるため、有機ハロゲン化合物の分解能は低く、また分解反応時にはＦｅ溶出と同時にＮｉが溶出してしまう。これに対して、ＭＡ法による合金化及び部分合金化処理剤は有機ハロゲン化合物の分解能に極めて優れ、分解反応時のＮｉの溶出も大幅に抑制される。特にＦｅ成分に対するＮｉ成分の混合量及び混合状態、すなわち最適な合金化、部分合金化状態とすることが必要である。Ｆｅ粉末１００重量部に対しＮｉ粉末を０．０１〜２重量部、好ましくは０．１〜０．５重量部、更に好ましくは０．１〜０．３重量部混合させる。この範囲において驚くべきことに被処理物の還元分解能は著しく向上する。また、一方反応に伴う被処理物へのＮｉの溶出も極めて低く、重金属汚染の問題もない。Ｎｉ粉末が０．０１重量部未満では有機ハロゲン化合物の分解能は低下し、Ｎｉ粉末無添加であるＦｅ粉末のみと同様に分解能が不十分である。Ｎｉ粉末２重量部を超えても分解能はこれ以上高くはならず、コストの面で相当不利となるともに、Ｎｉ溶出が顕著に認められるようになり環境負荷が問題となる。
【００１４】
以下に、本発明のＭＡ法による製造方法について説明する。
前記のＦｅ粉末およびＮｉ粉末を所定の組成に調整し、一般的なボ−ルミル，Ｖミキサ−等により混合し均質化する。また、場合によっては、ＭＡ法装置に定量供給機等を採用して、混合工程を省くことも可能である。
【００１５】
ＭＡ法に使用する装置としては、アトライタ−ミル（攪拌ボ−ルミル、アトリッションミルとも呼ばれる）、振動ミル、回転ミル（メカノフユ−ジョン含む）のバッチ式または連続式粉砕機を使用する。加工条件は、使用する装置により異なり一義的に定められないが、通常各装置の仕様条件の範囲内で採用できる。これらの装置の中で加工時間を最小とすることができるアトライターミルが特に好ましい。以下に装置毎の加工条件を説明する。
【００１６】
アトライタ−ミルを用いたときは、Ｆｅ粉末とＮｉ粉末の混合物１重量部に対して、鋼球等の粉砕メディアを７〜１５倍仕込む。原料が加工中に空気酸化する恐れがある場合は窒素ガス等の不活性ガスを流すことができる。ミル回転数は２００〜８００ｒｐｍが好適である。加工時間は、特に制限されないが、０．５〜５０時間とした場合、Ｎｉ溶出がなく、かつ高い分解活性を発現できるため好ましい。更に、加工時間を０．５〜６時間とした場合には、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金となり、高い活性を得ることができ特に好ましい。
【００１７】
振動ミルを用いた場合は、Ｆｅ粉末とＮｉ粉末の混合物１重量部に対して、鋼球等の粉砕メディアを２〜１０倍の仕込割合、振動数６００〜２０００ｖｐｍが好適である。さらに加工時間は５〜５０時間が分解能を発現できる。特に、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金を得るには、好ましくは５〜１０時間が適当である。
【００１８】
回転ミルを用いた場合は、Ｆｅ粉末とＮｉ粉末の混合物１重量部に対して、鋼球等の粉砕メディアを５〜１５倍の仕込割合、回転数６００〜１４００ｒｐｍが好適である。さらに加工時間は１０〜６０時間が分解能を発現できる。特に、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金を得るには、好ましくは１０〜２０時間が適当である。
【００１９】
以上の製法で得られた処理剤の粉末形状は特に限定するものではなく、球形状、樹枝状、片状、針状、角状、積層状、ロッド状、板状、海綿状等が含まれる。また処理剤の比表面積は０．０５ｍ^２／ｇ以上、好ましくは０．２〜１０ｍ^２／ｇ、また２００μｍのふるいを通過する粒径、望ましくは３０〜１００μｍを用いることにより、分解反応速度や接触確率を向上させることができる。特に比表面積が０．２ｍ^２／ｇ以上、粒径７５μｍ以下の処理剤を使用すれば難分解性と言われているＣｉｓ−ＤＣＥ、ＭＣ、ＰＣＥをも、より短時間に分解することができるのでより好ましい。これ以下の細かい粒径を用いると地下水汚染下で使用する場合、処理剤充填部分で目つまりを起こし地下水の流れを止めてしまう可能性があり，土壌中に分散する際も飛散等が起こりハンドリングに問題がある。一方、粒径が大きすぎると汚染地下水，土壌に使用する際、被処理物との接触確率が悪くなり分解能が著しく低下する。
【００２０】
本発明の無害化処理剤以外に、その効果を損なわない程度に添加剤を含んでいてもよい。添加剤としては特に限定するものではなく、例えば、酸化防止剤、反応促進剤、分散剤、ｐＨ調整剤、脱酸素処理剤等があげられる。酸化防止剤としては亜硫酸ナトリウム、硫酸第一鉄、硫化鉄、アスコルビン酸等、反応促進剤としては塩化ナトリウム、硫酸ナトリウム等、分散剤としては、活性炭素、アルミナ、ゼオライト、シリカゲル、シリカ−アルミナ等があげられる。
【００２１】
また、本発明の無害化処理剤は還元的脱ハロゲンにより無害化するものであるが、従来技術であるフェントン酸化法の無害化処理剤としても使用することができる。
【００２２】
無害化処理方法としては、１）掘削した土壌をパイル状に積み上げ本発明の無害化処理剤を添加し、ドラム型スクラバ−、改質ミキサ−、ニ−ダ−等による連続均一混合処理する方法やバックホウ等による回分混合処理後埋め戻す方法、またはパイル状に積み上げ養生する方法、２）汚染土壌中に縦または横井戸を堀り、無害化処理剤を高圧空気または高圧水で注入する原位置処理法、３）無害化処理剤、分散剤、反応促進剤等をスラリ−状にして土壌に注入する方法、４）揚水した汚染地下水等に対しては無害化処理剤を充填した処理塔を通す連続処理法、５）汚染地下水の周辺を掘削する際に発生した砂利、石、岩等をジョ−クラッシャ−等で粉砕し、無害化処理剤と混合し、直接または地下水の流れる穴を空けた容器に仕込み、井戸に埋め戻す方法、６）汚染地下水位置より低い部分に無害化処理剤層を設けた浄化ピット法等ができる。
【００２３】
無害化処理剤の添加量は、浄化対象である被処理物の汚染濃度等により変動するが、本発明の処理剤では非常に高活性であることから、従来剤に比較し、少ない添加量で環境基準値以下への浄化が達成できる。本発明の処理剤を用いる場合に、その分解活性及び経済性を考慮すると、粉末状では湿体土壌や地下水等の被処理物に対して０．１〜１０重量％、特に１〜３重量％であることが好ましい。
【００２４】
【実施例】
次に、本発明を実施例にさらに具体的に説明するが、本発明はこれらによって限定されるものではない。
【００２５】
実施例では、原料鉄粉として、還元鉄粉（川崎製鉄（株）製、商品名ＫＩＰ１００Ｔ）、鋳鉄粉（日本アトマイズ（株）製、商品名ＦＳ）、原料Ｎｉ粉として、添川理化学社製、（純度９９％、粒径１５０μｍグレ−ド）を用いた。
【００２６】
実施例１〜１５および比較例１〜８
ＴＣＥ含有汚染水溶液に対する本発明の無害化処理剤の評価試験を行った。１２５ｍｌバイアル瓶に１００ｐｐｍのＴＣＥ水溶液を１００ｍｌ、メタノ−ルに溶解した内標ベンゼン、そして処理剤１ｇ（対水溶液１重量％）を添加後、密封した。反応条件として３０℃、２００ｒｐｍ振とうを維持した。尚、この水溶液は脱溶存酸素処理、ｐＨ調整は行っていない。
【００２７】
次に、無害化処理剤のＭＡ加工条件として、実施例１〜４，７〜１３は原料１ｋｇをボ−ルミルで１０分間混合後，５Ｌポットを有するアトライターミル（三井鉱山（株）製、商品名ＤＹＮＡＭＩＣＭＩＬＬ、ＭＡ１Ｄ型）内に鋼球（ＳＵＪ２）７．５ｋｇと一緒に仕込み、ＭＡ加工した。この際の窒素ガス流量は４０ｍｌ／分とした。実施例１〜４，７，８はＭＡ加工３時間、回転数４００ｒｐｍ、実施例９〜１３、１５はＭＡ加工２２時間、回転数６００ｒｐｍ、実施例１４はＭＡ加工７２時間、回転数６００ｒｐｍである。また、実施例５は振動ミル（中央化工機（株）製、商品名Ｖ−ＭＩＬＬ，ＢＭ−３、１２００ｖｐｍ，６．６Ｌポット、硬球２０ｋｇ、原料１０ｋｇ）を用い、ＭＡ加工１５時間の処理剤である。実施例６は回転ミル（（株）入江商会製、ボールミル回転架台、８００ｒｐｍ，２Ｌポット、硬球５ｋｇ、原料１ｋｇ）を用い、ＭＡ加工１０時間の処理剤である。処理剤の組成は表１に示すようにＦｅ粉末１００重量部に対しＮｉ粉末量は０．０１〜１．８７重量部に調整した。
【００２８】
比較例１はＮｉを含まない還元Ｆｅ粉末（同和鉱業（以下Ｄ社と略記）製、製品名Ｅ２００）である。比較例２，４，５は実施例１，４，７の処理剤を９００℃、４時間、窒素ガス雰囲気中で熱処理した剤である。比較例３は実施例４と同じ原料、組成を用い、ＭＡ加工０時間、つまり混合のみの粉末である。比較例６は所定の成分調整後、高周波加熱炉において溶解後、窒素ガス雰囲気中で噴霧し粉末を形成したＦｅ−１．０４重量％Ｎｉ−４．３６重量％Ｃに調整した窒素ガス−アトマイズ品である。比較例７はＦｅ−Ｎｉ焼結粉末（川崎製鉄（株）（以下Ｋ社と略記）製、商品名シグマ２０１０合金）である。比較例８はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部、ＭＡ加工時間３時間、回転数６００ｒｐｍの剤である。
【００２９】
今回用いた処理剤の比表面積は０．２〜０．３ｍ^２／ｇ、７５μｍのふるいを通過した粉末を用いた。
【００３０】
ＴＣＥ濃度の分析方法としては、ＪＩＳ　Ｋ　０１２５（用水、排水中の揮発性有機化合物試験方法）に基づいたヘッドスペース法を用い、ＴＣＥ濃度を経時的に定量分析し、指数関数的にＴＣＥ濃度が減少する期間より求めた反応速度定数を算出し、ＴＣＥ濃度が環境基準値未満になった分解日数を求めた。さらに、ＴＣＥ濃度が環境基準以下になった時点で、ＴＣＥ水溶液を０．４５μｍ−メンブランフィルタ−を用いてろ過後、ろ液中のＮｉ濃度をＪＩＳ　Ｋ　０１０２に基づき測定し、これらの結果を表１に示した。
【００３１】
【表１】

実施例１〜４，７，８は反応定数が９．６×１０^−３〜９．７×１０^−２（ｈ^−１）であり，ＴＣＥ濃度が１０日以内に環境基準値０．０３ｐｐｍ未満になることが分かった。実施例９〜１３，１５は反応定数が８．７×１０^−３〜８．７×１０^−２（ｈ^−１）であり、ＴＣＥ濃度が１４日以内に環境基準値０．０３ｐｐｍ未満になることが分かった。実施例５，６はＮｉ量が０．３重量部、粉砕機として振動ミル、回転ミルを用いたＭＡ加工１５〜２０時間行った処理剤であるが、６〜８日で無害化することが分った。実施例１４はアトライタ−ミルを用いたＭＡ加工時間を長くした処理剤であるが、１５日で無害化することが分った。
【００３２】
表１には示していないが，分解生成物はエチレンが主成分であり、環境基準項目の有機塩素系化合物は生成していないことを確認している。またＴＣＥ水溶液中のＮｉ濃度を誘導結合プラズマ発光分光分析方法（パーキンエルマー製、商品名ＯＰＴＩＭＡ３０００）により測定したところ、ほとんどの処理剤が０．０１ｍｇ／Ｌ未満であり環境負荷の面からも本発明処理剤は優れていることが分かった。
【００３３】
これに対し、比較例１はＮｉを含有しないＦｅ粉末であり，反応定数が１．１×１０^−３（ｈ^−１）と小さく、１ヶ月経過しても環境基準０．０３ｐｐｍ未満になることはなかった。また分解生成物はエチレンの他に環境基準項目に挙げられているｃｉｓ−ＤＣＥが検出された。比較例２，４，５は実施例１，４，７を加熱したものであり、反応速度として半減、分解日数としては２〜４倍となる。比較例３はＦｅ粉末とＮｉ粉末を混合した剤のため、実施例４に比べると１０倍の分解日数が必要であった。比較例６は溶解法の１種であるアトマイズ剤、比較例７はＦｅ−Ｎｉ系焼結剤であり、いずれも反応定数が１０^−３（ｈ^−１）オーダーとなり、分解能が低く、また、実施例では検出されなかったＮｉの溶出も認められた。このことから、熱処理剤または焼結剤は分解能が低く、また環境負荷も大きいことが分る。比較例８はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部含まれるＭＡ法処理剤であるが，反応定数は１．４×１０^−２と大きいが，反応終了後のＴＣＥ水溶液中のＮｉ溶出量が０．３６ｍｇ／Ｌ検出され環境負荷が問題となる。
【００３４】
従って、実施例１〜１５で用いた無害化処理剤を用いれば汚染地下水で多くの事例のあるＴＣＥを分解する能力は顕著であり、短期間に法的規制値をクリアすることができ、かつ環境負荷が小さいことが分った。
【００３５】
実施例１６〜２０および比較例９〜１２
揮発性有機ハロゲン化合物を含有する汚染土壌における無害化処理剤の評価試験を行った。１２５ｍｌバイアル瓶に１００ｐｐｍのＴＣＥ汚染土壌２７ｇ（含水率３３重量％）、メタノ−ルに溶解した内標ベンゼン、そして処理剤を０．２７ｇ（対土壌１重量％）を入れて均質混合後、密封した。反応条件として３０℃、静置状態とした。なお、土壌中の含水調整に用いた水は脱溶存酸素処理、ｐＨ調整は行っていない。
【００３６】
次に、今回用いた処理剤の製造条件を説明する。実施例１６，１７，１９ではＭＡ加工３時間、回転数４００ｒｐｍ、Ｎｉ添加量はＦｅ粉末１００重量部に対し０．１〜０．９９重量部に調整した。実施例１８はＭＡ加工２２時間、回転数６００ｒｐｍであり、Ｎｉ添加量は０．３重量部に調整した。実施例２０はＭＡ加工７２時間、回転数６００ｒｐｍであり、Ｎｉ添加量は０．９９重量部に調整した。
【００３７】
比較例９はＮｉを含まない還元Ｆｅ粉末（Ｄ社）である。比較例１０は実施例２０と同じ原料であるが、ＭＡ加工０時間、つまり混合のみの粉末である。比較例１２は実施例１９の処理剤を９００℃、４時間、窒素ガス雰囲気中で熱処理した剤である。比較例１２はＭＡ加工３時間、回転数４００ｒｐｍ、Ｎｉ添加量を５重量部に調整した処理剤である。
【００３８】
なお、今回用いた処理剤の比表面積は０．２〜０．３ｍ^２／ｇ、７５μｍのふるいを通過した粉末を用いた。
【００３９】
ＴＣＥ濃度変化、反応速度の算出および用いた処理剤のＮｉ含有量、溶出Ｎｉ濃度の測定方法は実施例１〜１５と同様であり、それらの結果を表２に示す。
【００４０】
【表２】

実施例１６〜２０はＭＡ法（アトライタ−ミル）による処理剤であり、ＴＣＥ汚染土壌中に処理剤１重量％添加・混合すれば１４〜３０日でＴＣＥ濃度が環境基準０．０３ｐｐｍ未満となった。また土壌中のＮｉ溶出量は環境省告示４６号試験に基づき検液を作製し、誘導結合プラズマ発光分光分析方法により測定するとほとんどの処理剤が０．０１ｍｇ／Ｌ未満であった。また、表２には示していないが，分解生成物はエチレンが主成分であり、環境基準項目の有機塩素系化合物は生成していないことを確認している。
【００４１】
一方、比較例９はＮｉを含有しておらず反応定数は１０^−５（ｈ^−１）オーダーであり、５ケ月経ても環境基準以下にはならなかった。比較例１０はＦｅ粉末とＮｉ粉末の混合剤であり、Ｎｉを０．９９重量部含有しているにもかかわらず、２ケ月以上の浄化期間が必要である。比較例１１は実施例１９の熱処理品であり、反応定数は１０^−４（ｈ^−１）オーダー、分解日数は約２ケ月であり、またＮｉ溶出も認められた。比較例１２はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部含まれるＭＡ法処理剤であり、反応定数も１０^−３（ｈ^−１）オーダー、分解日数は約１ケ月であり、高分解能を示唆しているが、Ｎｉ溶出量が０．４５ｍｇ／Ｌと大きく、環境負荷が問題となる。
【００４２】
従って、実施例１６〜２０で用いた無害化処理剤を用いれば、土壌中のＴＣＥを分解する能力は顕著であり、短期間に法的規制値をクリアすることができ、かつ環境負荷が小さいことが分った。
【００４３】
実施例２１〜２５および比較例１３〜１６
ＰＣＥ含有汚染水溶液に対する本発明の無害化処理剤の評価試験を行った。１２５ｍｌバイアル瓶に１００ｐｐｍのＰＣＥ水溶液を１００ｍｌ、メタノ−ルに溶解した内標ベンゼン、そして本発明の処理剤を１ｇ（対水溶液１重量％）添加後、素早く密封した。反応条件として３０℃、２００ｒｐｍ振とうを維持した。尚、この水溶液は脱溶存酸素処理、ｐＨ調整は行っていない。
【００４４】
なお、実施例および比較例で用いた処理剤の製法、およびそれらの評価方法は実施例１６〜２０、比較例１０〜１４と同様であり、測定結果を表３に示す。
【００４５】
【表３】

実施例２１〜２５は反応定数が１０^−２〜１０^−３（ｈ^−１）オーダーであり、ＴＣＥ水溶液のそれと比べると分解速度は同程度であり、ＰＣＥ濃度が環境基準をクリアできる日数は１０〜２８日と、短時間に分解できることが分る。また表３には示していないが，ＰＣＥが完全分解した時点で、分解生成物としてはエタンが主成分であり、環境基準項目のＴＣＥ等の有機塩素系化合物は生成していないことを確認している。またＰＣＥ水溶液中のＮｉ濃度もほとんどの処理剤が０．０１ｍｇ／Ｌ未満であり、環境負荷の面からも本発明処理剤は優れていることが分かった。
【００４６】
これに対し、比較例１３はＮｉを含有しないＦｅ粉末であるが，反応定数が１０^−４（ｈ^−１）オーダーと小さく１０ヶ月経過しても環境基準値０．０１ｐｐｍ未満になることはなかった。また分解生成物はエタンの他に環境基準項目に挙げられているＴＣＥ，ｃｉｓ−ＤＣＥが検出された。比較剤１４は実施例２５と同じ原料を用い、ＭＡ加工の無い、単なる混合粉末であり、分解能は著しく低いことが分る。比較例１５は実施例２４の熱処理品であり、反応定数が１０^−３（ｈ^−１）オーダーとなり、また、実施例では検出されなかったＮｉの溶出も認められた。このことから熱処理剤は分解能が低く、また環境負荷も大きいことが分る。比較例１６はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部含まれるＭＡ法処理剤であるが、還元脱塩素反応定数は本発明剤並みであるが、反応終了後のＰＣＥ水溶液中のＮｉ溶出量が０．９４ｍｇ／Ｌ検出され、環境負荷が問題となる。
【００４７】
従って、実施例２１〜２５で用いた無害化処理剤を用いれば難分解性といわれるＰＣＥを含む水溶液を分解する能力は顕著であり、短期間に法的規制値をクリアすることができ、かつ環境負荷は小さいことが分った。また、ＰＣＥにより汚染された土壌においても本発明剤を使用することにより無害化できることは言うまでもない。
【００４８】
実施例２６〜３０および比較例１７〜２０
ｃｉｓ−ＤＣＥ含有汚染水溶液に対する本発明の無害化処理剤の評価試験を行った。１２５ｍｌバイアル瓶に１０ｐｐｍのｃｉｓ−ＤＣＥ水溶液を１００ｍｌ、メタノ−ルに溶解した内標ベンゼン、そして処理剤を１ｇ（対水溶液１重量％）、素早く添加後密封した。反応条件として３０℃、２００ｒｐｍ振とうを維持した。尚、この水溶液は脱溶存酸素処理、ｐＨ調整は行っていない。
【００４９】
なお、実施例および比較例で用いた処理剤の製法およびそれらの評価方法は実施例１６〜２０、比較例１０〜１４と同様であり、これらの測定結果を表４に示す。
【００５０】
【表４】

実施例２６〜３０は反応定数が１０^−１〜１０^−３（ｈ^−１）オーダーであり，ＴＣＥ溶液のそれと比べると分解速度が大きく、１４日後には難分解有機ハロゲン化合物であるｃｉｓ−ＤＣＥが環境基準以下まで短時間に分解されることが確認できた。また表４には示していないが，分解生成物はエタンが主成分であり、環境基準項目の有機塩素系化合物は生成していないことを確認している。またｃｉｓ−ＤＣＥ水溶液中のＮｉ濃度もほとんどの処理剤が０．０１ｍｇ／Ｌ未満であり環境負荷の面からも本発明処理剤は優れていることが分かった。
【００５１】
これに対し、比較例１７はＮｉを含有しないＦｅ粉末であり，反応定数が１０^−３（ｈ^−１）オーダー、環境基準０．０４ｐｐｍ未満になる日数として１５日間必要であった。また分解生成物はエタンの他に環境基準項目に挙げられている１，２−ジクロロエタンが検出された。比較例１８は実施例３０と同じ原料を用いるが、ＭＡ加工無し、つまり単なる混合粉末であり、分解能は著しく低い。比較例１９は実施例２９の熱処理品であるが、反応定数が１０^−２（ｈ^−１）オーダーとなり、２週間以内には土壌環境基準０．０４ｐｐｍ未満にならなかった。また、実施例では検出されなかったＮｉの溶出も認められた。このことから熱処理剤または溶解処理剤は分解能が低く、また環境負荷も大きくなることが分る。比較例２０はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部含まれるＭＡ法処理剤であり、反応定数は１０^−２（ｈ^−１）オーダーと大きいが、反応終了後のｃｉｓ−ＤＣＥ溶液中のＮｉ溶出量が０．５９ｍｇ／Ｌ検出され、環境負荷が問題となる。
【００５２】
従って、実施例２６〜３０で用いた無害化処理剤を用いれば汚染地下水で多くの事例のあるＣｉｓ−ＤＣＥを分解する能力は顕著であり、短期間に法的規制値をクリアすることができ、かつ環境負荷が小さいことが分った。また、Ｃｉｓ−ＤＣＥにより汚染された土壌においても本発明処理剤を使用することにより無害化できることは言うまでもない。
【００５３】
実施例３１〜３５および比較例２１〜２４
ＭＣ含有汚染水溶液に対する本発明の無害化処理剤の評価試験を行った。１２５ｍｌバイアル瓶に１０ｐｐｍのＭＣ水溶液１００ｍｌ、メタノ−ルに溶解した内標ベンゼン、そして本発明の処理剤を１ｇ（対水溶液１重量％）、素早く添加後、密封した。反応条件として３０℃、２００ｒｐｍ振とうを維持した。尚、この水溶液は脱溶存酸素処理、ｐＨ調整は行っていない。
なお、実施例および比較例で用いた処理剤の製法およびそれらの評価方法は実施例１６〜２０、比較例１０〜１４と同様であり、それらの測定結果を表５に示す。
【００５４】
【表５】

実施例３１〜３５は反応定数が１０^−１〜１０^−３（ｈ^−１）オーダーであり，ＴＣＥ水溶液のそれと比べると分解速度が大きく、７日後にはＭＣが環境基準以下まで分解されることが確認できた。また表５には示していないが，分解生成物はエタンが主成分であり、環境基準項目の有機塩素系化合物は生成していないことを確認した。またＭＣ水溶液中のＮｉ濃度も０．０２ｍｇ／Ｌ未満であり環境負荷の面からも本発明処理剤は優れていることが分かった。
【００５５】
これに対し、比較例２１はＮｉを含有しないＦｅ粉末であり，反応定数が１０^−３（ｈ^−１）オーダーと小さく、土壌環境基準１ｐｐｍ未満になるためには約１ケ月必要であることが分った。また分解生成物はエタンの他に環境基準項目に挙げられている四塩化炭素が検出された。比較剤２２は実施例３５と同じ原料を用い、ＭＡ加工無し、つまり単なる混合粉末であり、活性は著しく低下した。比較例２３は実施例３４を加熱したものであるが、反応定数が１０^−３（ｈ^−１）オーダーとなり、土壌環境基準１ｐｐｍ未満になるためには１週間以上必要であることが分った。また、実施例では検出されなかったＮｉの溶出も認められた。このことから熱処理剤または溶解処理剤は分解能が低く、また環境負荷も大きくなることが分る。比較例２４はＦｅ粉末１００重量部に対してＮｉ粉末量が５重量部含まれるＭＡ法処理剤であり、反応定数は１０^−２（ｈ^−１）オーダーと大きいが，反応終了後のＭＣ水溶液中のＮｉ溶出量が０．２８ｍｇ／Ｌ検出され、環境負荷が問題となる。
【００５６】
従って、実施例３１〜３５で用いた無害化処理剤を用いれば汚染地下水で多くの事例のあるＭＣを分解する能力は顕著であり、短期間に法的規制値をクリアすることができ、かつ環境負荷が小さいことが分った。また、ＭＣにより汚染された土壌においても本発明剤を使用することにより無害化できることは言うまでもない。
【００５７】
【発明の効果】
以上の説明から明らかなように、本発明の無害化処理剤、その製造方法及びそれを用いた無害化処理方法によれば土壌、産業廃棄物、汚泥、スラッジ、排水、地下水中の有機ハロゲン化合物を少量の添加で短時間に分解し、有害な副生物を生成せず無害化処理できる効果を有するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a detoxifying agent for an object to be treated such as soil, industrial waste, sludge, sludge, wastewater, and groundwater contaminated with an organic halogen compound, a production method thereof, and a detoxification method using the same. is there.
[0002]
[Prior art]
In recent years, environmental pollution problems due to organic halogen compounds such as TCE (trichloroethylene), PCE (tetrachloroethylene), dichloromethane, PCB (polychlorinated biphenyl), and dioxins have become remarkable in various parts of the world and have become a serious problem.
[0003]
In order to solve these problems, in particular, treatment agents for detoxifying soil, drainage water, groundwater, and the like contaminated with an organic halogen compound and a treatment method thereof have been studied, and several technical reports and patent applications have been filed.
[0004]
1) In the case of contaminated wastewater and groundwater, vacuum extraction and pumping and aeration methods are known, but a lifting device to the ground, an adsorption facility for the contaminated material that has been raised, regeneration of activated carbon adsorbent, and waste generated Is required, and as a whole, it becomes a costly processing method. In addition, detoxification requires several years, and complete removal is a difficult technology. In recent years, a detoxification treatment method for reducing and dehalogenating contaminants by merely mixing or spraying a metal-based treatment agent has been reported, and it is said that the cost can be reduced as compared with the conventional method. As a method of detoxifying with an iron-based treating agent, there are, for example, Japanese Patent Publication No. 2636171, Japanese Patent Publication No. 2-49158, and Japanese Patent Publication No. 2-49798. It is necessary to perform a deoxygenation treatment for supplying the same and the like, which is difficult as an actual method and increases the cost. Also, Sakizaki et al. [Industrial Water, VOL391, (1991), 29. According to the report, a technology for reducing and dechlorinating waste water and water contaminated by TCE with Fe powder or Ni or Cu chemically plated Fe powder is reported. However, it is necessary to remove dissolved oxygen in contaminated wastewater and service water in order to suppress the performance deterioration of these treatment agents over time, and the range of the nickel plating amount that shows activity is limited. Sex remains a problem. Japanese Patent Publication No. Hei 10-513103 discloses a technique for decomposing dichloromethane with an Fe-Pd catalyst. As a comparative example, Fe powder plated with a nickel chloride solution has a low decomposition rate and requires a long time for detoxification. , Cannot be completely disassembled. Japanese Unexamined Patent Publication (Kokai) No. Hei 6-506631 discloses a mixture of activated carbon and Fe powder, and uses a large amount of expensive activated carbon.
[0005]
2) As a method for treating contaminated soil, sludge, sludge, and the like, a thermal desorption method and a thermal decomposition method in which a heating electrode is inserted into excavated soil or directly into soil to perform heat treatment are known. This method requires a large heating device. In addition, the vicinity of the electrode is thermally decomposed, but the others are volatilized mainly on volatile organochlorine compounds and are not a fundamental treatment method.The soil after treatment is solidified by heat and almost all microorganisms die. Therefore, it is difficult to adopt it in terms of reuse. Although there is a bioremediation method in which detoxification is performed by using a reducing substance via microorganisms, detoxification requires a long time, and cannot be applied to all kinds of soils, and complete detoxification is impossible. As the chemical treatment, there are JP-A-11-235577 in which an iron-based treating agent is added to contaminated soil, and JP-A-11-253926 in which a base metal-based treating agent containing Fe is used in combination with a microorganism. Since it is not decomposed, higher performance is required. Japanese Patent Application Laid-Open No. 2002-20806 is a method for producing a treating agent obtained by heat-treating iron-based waste, which can reduce the cost, but it is difficult to adjust a proper composition and metal structure, and the treating time is reduced. Therefore, high activation is required.
[0006]
[Problems to be solved by the invention]
As mentioned above, conventional treatment methods for soil, industrial waste, sludge, sludge, wastewater, groundwater, etc. contaminated with organic halogen compounds have long treatment times, high costs, complicated treatment methods and poor practicality. Have issues. In particular, as a technique for adding a base metal-based treatment agent to render it harmless, it is necessary to adjust the pH of contaminated wastewater and groundwater, and to dissolve dissolved oxygen, and to process contaminated soil, industrial waste, sludge, and sludge in a short time. Since it is not decomposed into water, high activation is required.
[0007]
[Means for Solving the Problems]
The inventors have conducted intensive studies to solve these problems, and as a result, completed the present invention. That is, a detoxifying agent for an object to be treated, which is contaminated with an organic halogen compound composed of an Fe-Ni alloy obtained by alloying a mixture of 100 parts by weight of Fe powder and 0.01 to 2 parts by weight of Ni powder by a mechanical alloying method. The present invention provides a method for producing the same and a treatment method using the same. According to the treatment agent of the present invention, the concentration of a contaminated organic halogen compound can be reduced to a legally regulated value or less in a short period of time. Furthermore, it can also decompose Cis-DCE (cis-1,2-dichloroethylene), MC (methyl chloroform, 1,1,1-trichloroethane) and PCE, which are said to be hardly decomposable.
[0008]
Hereinafter, the present invention will be described in more detail.
[0009]
An object to be treated by the detoxifying agent of the present invention is one that is contaminated with an organic halogen compound. Examples of the organic halogen compound include dichloromethane, carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethylene, Cis-DCE, Trans-DCE (trans-1,2-dichloroethylene), MC, 1,1 , 2-trichloroethane, TCE, PCE, 1,3-dichloropropene, and the like, or organic bromine-based compounds thereof.
[0010]
As the Fe powder used in the present invention, besides pure iron, steel (for example, reduced iron powder), cast iron, pig iron and the like can be used. The shape of the powder is not particularly limited, and spheres, dendrites, flakes, needles, squares, laminates, rods, plates, sponges, and the like can be used. There is no limitation on the method for producing the Fe powder, and a granulation method for producing granules directly from the molten metal, an atomizing method, a reduction method, a pulverizing method, a Dalai powder cut by a lathe, or the like can be used. The particle size of the Fe powder is not particularly limited, but generally has a particle size of about 50 to 500 μm by the above-mentioned preparation method, and can be suitably used in this range.
[0011]
The Ni powder used in the present invention includes pure Ni powder, industrial Ni powder, and ferronickel powder. Generally available industrial Ni powder has a particle size of 10 to 100 μm, and fine Ni powder of about 1 to 10 μm can also be suitably used.
[0012]
In the present invention, the mixture of the Fe powder and the Ni powder is prepared by alloying or partially alloying by a mechanical alloying method (hereinafter, referred to as an MA method) also called a mechanical alloying method. The MA method is described in Benjamin, J. et al. s: Met. Trans. , 1, 10 (1970), 2943 and Ryuzo Watanabe: According to the Japan Society of Metals, 27, 10 (1988), 799, a kind of mechanochemical for obtaining alloys by applying mechanical energy to metals and alloy powders. Is the way. In general, the raw material powder and the crushing ball are placed in a closed container and continuously stirred or vibrated to obtain an alloy powder having a unique structure by repeating plastic deformation, crushing and adhesion of the powder. Can be Heat generated when stirring or vibrating is removed by water cooling or air cooling, and mechanical energy is mainly given to the alloy material. Depending on conditions such as stirring time, fine crystal grains, a supersaturated solid solution, a metastable crystal phase, an amorphous phase, or the like can be obtained by microscopic crystal structure change.
[0013]
Usually, a thermal alloying method such as a melting method or a thermal diffusion method is adopted as a method for preparing an alloy of Fe and Ni. However, since an alloy material in which Ni atoms are dissolved in Fe atoms is obtained, an organic halogen compound is used. Is low in resolution, and Ni is eluted simultaneously with the elution of Fe during the decomposition reaction. On the other hand, the alloying and partial alloying treatment agents by the MA method are extremely excellent in resolving power of the organic halogen compound, and the elution of Ni during the decomposition reaction is largely suppressed. In particular, it is necessary to set the mixed amount and the mixed state of the Ni component to the Fe component, that is, the optimum alloying and partial alloying states. 0.01 to 2 parts by weight, preferably 0.1 to 0.5 parts by weight, more preferably 0.1 to 0.3 parts by weight of Ni powder is mixed with 100 parts by weight of Fe powder. Surprisingly, in this range, the reduction ability of the object to be treated is significantly improved. In addition, the elution of Ni into the object to be processed due to the one-way reaction is extremely low, and there is no problem of heavy metal contamination. When the amount of the Ni powder is less than 0.01 parts by weight, the resolution of the organic halogen compound is reduced, and the resolution is insufficient as in the case of the Fe powder without the Ni powder alone. Even if the content exceeds 2 parts by weight of Ni powder, the resolution does not increase any more, the cost is considerably disadvantageous, and the elution of Ni becomes remarkable, and the environmental load becomes a problem.
[0014]
Hereinafter, the production method by the MA method of the present invention will be described.
The above-mentioned Fe powder and Ni powder are adjusted to a predetermined composition, mixed and homogenized by a general ball mill, V mixer and the like. In some cases, the mixing process can be omitted by adopting a quantitative feeder or the like in the MA method apparatus.
[0015]
As an apparatus used in the MA method, a batch type or continuous type pulverizer such as an attritor mill (also called a stirring ball mill or an attrition mill), a vibration mill, and a rotary mill (including a mechanofusion) is used. The processing conditions vary depending on the equipment used and cannot be unambiguously determined, but can usually be adopted within the range of the specification conditions of each equipment. Among these devices, attritor mills that can minimize the processing time are particularly preferred. The processing conditions for each device will be described below.
[0016]
When an attritor mill is used, milling media such as steel balls are charged 7 to 15 times with respect to 1 part by weight of a mixture of Fe powder and Ni powder. In the case where the raw material may be oxidized by air during processing, an inert gas such as nitrogen gas can be flowed. The mill rotation speed is preferably from 200 to 800 rpm. The processing time is not particularly limited, but is preferably 0.5 to 50 hours, since Ni is not eluted and high decomposition activity can be exhibited. Further, when the processing time is set to 0.5 to 6 hours, a partial alloy in which the Ni component is segregated in and on the surface of the Fe powder is obtained, and high activity can be obtained, which is particularly preferable.
[0017]
When a vibrating mill is used, it is preferable that the mixing ratio of the grinding media such as steel balls is 2 to 10 times and the frequency is 600 to 2000 vpm with respect to 1 part by weight of the mixture of the Fe powder and the Ni powder. Further, the processing time can express a resolution of 5 to 50 hours. Particularly, in order to obtain a partial alloy in which the Ni component is segregated in and on the surface of the Fe powder, preferably 5 to 10 hours is appropriate.
[0018]
When a rotary mill is used, it is preferable that the mixing ratio of the grinding media such as steel balls is 5 to 15 times and the number of rotations is 600 to 1400 rpm with respect to 1 part by weight of the mixture of the Fe powder and the Ni powder. Further, the processing time can express a resolution of 10 to 60 hours. In particular, in order to obtain a partial alloy in which the Ni component is segregated in and on the surface of the Fe powder, it is preferably appropriate for 10 to 20 hours.
[0019]
The shape of the powder of the treating agent obtained by the above manufacturing method is not particularly limited, and includes a spherical shape, a dendritic shape, a flaky shape, a needle shape, a square shape, a laminated shape, a rod shape, a plate shape, a spongy shape and the like. . The specific surface area of the treating agent is 0.05 m ² / G or more, preferably 0.2 to 10 m ² / G, and a particle size passing through a 200 μm sieve, desirably 30 to 100 μm, can improve the decomposition reaction rate and the contact probability. Especially the specific surface area is 0.2m ² It is more preferable to use a treating agent having a particle size of not less than / g and a particle size of not more than 75 µm, because it is possible to decompose Cis-DCE, MC and PCE which are said to be hardly decomposable in a shorter time. When used under groundwater contamination, a fine particle size smaller than this may cause clogging at the treatment agent-filled part and stop the flow of groundwater, causing dispersion when dispersed in soil and handling. There is a problem. On the other hand, if the particle size is too large, when used for contaminated groundwater or soil, the probability of contact with the object to be treated is reduced, and the resolution is significantly reduced.
[0020]
In addition to the detoxifying agent of the present invention, an additive may be contained to such an extent that its effect is not impaired. The additive is not particularly limited, and examples thereof include an antioxidant, a reaction accelerator, a dispersant, a pH adjuster, a deoxidizing agent, and the like. Sodium sulfite, ferrous sulfate, iron sulfide, ascorbic acid, etc. as antioxidants, sodium chloride, sodium sulfate, etc. as reaction accelerators, activated carbon, alumina, zeolite, silica gel, silica-alumina, etc. as dispersants Is raised.
[0021]
Although the detoxifying agent of the present invention detoxifies by reductive dehalogenation, it can also be used as a detoxifying agent of the Fenton oxidation method which is a conventional technique.
[0022]
As the detoxification method, 1) a method in which excavated soil is piled up, a detoxification agent of the present invention is added, and a continuous and uniform mixing treatment is performed by a drum type scrubber, a modified mixer, a kneader or the like. Backfilling after batch mixing with a mortar or backhoe, or stacking and curing, 2) excavating a vertical or horizontal well in contaminated soil and injecting the detoxifying agent with high-pressure air or high-pressure water Treatment method, 3) a method of injecting detoxification agent, dispersant, reaction accelerator, etc. into the slurry in the form of slurry, and 4) treating a contaminated decontamination agent with pumped groundwater, etc. 5) Gravel, stones, rocks, etc. generated when excavating around contaminated groundwater are crushed with a jo crusher, etc., mixed with a detoxifying agent, and drilled holes directly or through groundwater. Into a well container How to return because, 6) detoxification agent layer purification can pit method is provided in the lower portion than the contaminated groundwater position.
[0023]
The addition amount of the detoxifying agent varies depending on the contamination concentration of the object to be purified and the like. However, since the agent of the present invention has a very high activity, the amount added is smaller than that of the conventional agent. Purification below the environmental standard value can be achieved. When the treating agent of the present invention is used, its decomposition activity and economy are taken into consideration. In powder form, 0.1 to 10% by weight, especially 1 to 3% by weight, based on the material to be treated such as wet soil or groundwater. It is preferable that
[0024]
【Example】
Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.
[0025]
In Examples, reduced iron powder (manufactured by Kawasaki Steel Co., Ltd., trade name: KIP100T), cast iron powder (manufactured by Nippon Atomize Co., Ltd., trade name: FS) as raw iron powder, and Ni powder as raw material Ni powder, (Purity: 99%, particle size: 150 μm grade).
[0026]
Examples 1 to 15 and Comparative Examples 1 to 8
An evaluation test of the detoxifying agent of the present invention for a TCE-containing contaminated aqueous solution was performed. A 125 ml vial was charged with 100 ml of a 100 ppm aqueous TCE solution, benzene (internal standard) dissolved in methanol, and 1 g of a treating agent (1% by weight with respect to the aqueous solution), followed by sealing. The reaction conditions were 30 ° C. and 200 rpm shaking. This aqueous solution was not subjected to a dissolved oxygen treatment or a pH adjustment.
[0027]
Next, as the MA processing conditions of the detoxifying agent, Examples 1 to 4 and 7 to 13 were prepared by mixing 1 kg of the raw material with a ball mill for 10 minutes and then using an attritor mill having a 5 L pot (manufactured by Mitsui Mining Co., Ltd.). A steel ball (SUJ2) was charged together with 7.5 kg in DYNAMICCMILL (MA1D type, trade name), and MA processing was performed. At this time, the nitrogen gas flow rate was 40 ml / min. Examples 1 to 4, 7, and 8 have a MA processing time of 3 hours and a rotation speed of 400 rpm, Examples 9 to 13 and 15 have a MA processing time of 22 hours and a rotation speed of 600 rpm, and Example 14 has a MA processing time of 72 hours and a rotation speed of 600 rpm. . Example 5 used a vibration mill (manufactured by Chuo Kakoki Co., Ltd., trade name: V-MILL, BM-3, 1200 vpm, 6.6 L pot, 20 kg of hard spheres, 10 kg of raw material), and a treatment agent for 15 hours of MA processing. It is. Example 6 is a treating agent for MA processing for 10 hours using a rotary mill (manufactured by Irie Shokai Co., Ltd., ball mill rotary mount, 800 rpm, 2 L pot, 5 kg of hard balls, 1 kg of raw material). As shown in Table 1, the composition of the treating agent was adjusted to 0.01 to 1.87 parts by weight of Ni powder per 100 parts by weight of Fe powder.
[0028]
Comparative Example 1 is a reduced Fe powder containing no Ni (manufactured by Dowa Mining (hereinafter abbreviated as Company D), product name E200). Comparative Examples 2, 4, and 5 are agents obtained by heat treating the treating agents of Examples 1, 4, and 7 at 900 ° C. for 4 hours in a nitrogen gas atmosphere. Comparative Example 3 uses the same raw materials and composition as in Example 4, and is a powder obtained by MA processing for 0 hour, that is, only mixing. Comparative Example 6 was prepared by adjusting a predetermined component, dissolving in a high-frequency heating furnace, and then spraying in a nitrogen gas atmosphere to form a powder. Nitrogen gas-atomized adjusted to 1.04% by weight Ni-4.36% by weight C. Goods. Comparative Example 7 is Fe-Ni sintered powder (trade name: Sigma 2010 alloy, manufactured by Kawasaki Steel Corp. (hereinafter abbreviated as K company)). Comparative Example 8 is an agent in which the amount of Ni powder is 5 parts by weight, the MA processing time is 3 hours, and the number of rotations is 600 rpm with respect to 100 parts by weight of Fe powder.
[0029]
The specific surface area of the treatment agent used this time is 0.2-0.3m ² / G, a powder passed through a 75 μm sieve was used.
[0030]
As a method of analyzing the TCE concentration, a headspace method based on JIS K 0125 (test method for volatile organic compounds in water and wastewater) was used, and the TCE concentration was quantitatively analyzed with time, and the TCE concentration was exponentially calculated. The reaction rate constant calculated from the decreasing period was calculated, and the number of decomposition days when the TCE concentration became lower than the environmental standard value was calculated. Further, when the TCE concentration became below the environmental standard, the TCE aqueous solution was filtered using a 0.45 μm-membrane filter, and the Ni concentration in the filtrate was measured based on JIS K0102. 1 is shown.
[0031]
[Table 1]

In Examples 1 to 4, 7, and 8, the reaction constant was 9.6 × 10 ^-3 ~ 9.7 × 10 ^-2 (H ^-1 ), And it was found that the TCE concentration became less than the environmental standard value of 0.03 ppm within 10 days. In Examples 9 to 13, 15, the reaction constant was 8.7 × 10 ^-3 ~ 8.7 × 10 ^-2 (H ^-1 ), And it was found that the TCE concentration became less than the environmental standard value of 0.03 ppm within 14 days. In Examples 5 and 6, the amount of Ni was 0.3 parts by weight, and the processing agent was subjected to MA processing for 15 to 20 hours using a vibrating mill or a rotary mill as a pulverizer, but could be rendered harmless in 6 to 8 days. I understand. Example 14 was a treatment agent using an attritor mill and having a longer processing time for MA, but was found to be harmless in 15 days.
[0032]
Although not shown in Table 1, it was confirmed that ethylene was the main component of the decomposition product, and that no organic chlorine-based compound, which is an environmental standard, was produced. Further, when the Ni concentration in the TCE aqueous solution was measured by inductively coupled plasma emission spectroscopy (trade name: OPTIMA3000, manufactured by PerkinElmer), most of the treating agents were less than 0.01 mg / L, and the present invention was also considered from the viewpoint of environmental load. The treating agent was found to be excellent.
[0033]
On the other hand, Comparative Example 1 was Fe powder containing no Ni and had a reaction constant of 1.1 × 10 ^-3 (H ^-1 ), And did not fall below the environmental standard of 0.03 ppm even after one month. In addition, in addition to ethylene, cis-DCE listed in the environmental standard items was detected as the decomposition product. Comparative Examples 2, 4, and 5 are obtained by heating Examples 1, 4, and 7, and the reaction rate is halved and the number of decomposition days is 2 to 4 times. Comparative Example 3 was an agent in which Fe powder and Ni powder were mixed, and thus required 10 times as many decomposition days as Example 4. Comparative Example 6 is an atomizing agent which is one of the dissolving methods, and Comparative Example 7 is an Fe-Ni-based sintering agent, all of which have a reaction constant of 10 ^-3 (H ^-1 ), The resolution was low, and the elution of Ni, which was not detected in Examples, was also observed. This indicates that the heat treatment agent or the sintering agent has a low resolution and a large environmental load. Comparative Example 8 is an MA method treating agent containing 5 parts by weight of Ni powder per 100 parts by weight of Fe powder, but the reaction constant is 1.4 × 10 ^-2 However, the amount of Ni eluted in the TCE aqueous solution after the completion of the reaction is detected as 0.36 mg / L, which poses a problem of environmental load.
[0034]
Therefore, if the detoxifying agent used in Examples 1 to 15 is used, the ability to decompose TCE, which has many cases in contaminated groundwater, is remarkable, and the legally regulated value can be cleared in a short time, and It turned out that the environmental load was small.
[0035]
Examples 16 to 20 and Comparative Examples 9 to 12
An evaluation test of a detoxifying treatment agent for contaminated soil containing a volatile organic halogen compound was performed. In a 125 ml vial, 27 g of 100 ppm TCE-contaminated soil (water content 33% by weight), benzene internal standard dissolved in methanol, and 0.27 g of a treating agent (1% by weight based on soil) are homogenized and sealed. did. The reaction conditions were 30 ° C. and a standing state. The water used for the adjustment of the water content in the soil was not subjected to the dissolved oxygen treatment and the pH adjustment.
[0036]
Next, the manufacturing conditions of the treatment agent used this time will be described. In Examples 16, 17, and 19, the MA processing was performed for 3 hours, the number of rotations was 400 rpm, and the amount of Ni added was adjusted to 0.1 to 0.99 parts by weight based on 100 parts by weight of Fe powder. In Example 18, the MA processing was performed for 22 hours, the number of revolutions was 600 rpm, and the amount of Ni added was adjusted to 0.3 parts by weight. In Example 20, the MA processing was performed for 72 hours, the number of revolutions was 600 rpm, and the amount of Ni added was adjusted to 0.99 parts by weight.
[0037]
Comparative Example 9 is a reduced Fe powder containing no Ni (Company D). Comparative Example 10 is the same raw material as that of Example 20, but is a powder of only MA mixing, that is, 0 hours of processing. Comparative Example 12 is an agent obtained by heat treating the treating agent of Example 19 at 900 ° C. for 4 hours in a nitrogen gas atmosphere. Comparative Example 12 is a processing agent in which MA processing was performed for 3 hours, the number of rotations was 400 rpm, and the amount of Ni added was adjusted to 5 parts by weight.
[0038]
The specific surface area of the treating agent used this time is 0.2 to 0.3 m. ² / G, a powder passed through a 75 μm sieve was used.
[0039]
The TCE concentration change, the calculation of the reaction rate, and the method of measuring the Ni content and the eluted Ni concentration of the treating agent used were the same as in Examples 1 to 15, and the results are shown in Table 2.
[0040]
[Table 2]

Examples 16 to 20 are treatment agents according to the MA method (attritor-mill). If 1% by weight of treatment agent is added to and mixed with TCE-contaminated soil, the TCE concentration becomes less than 0.03 ppm in 14 to 30 days. Was. In addition, the amount of Ni eluted in the soil was less than 0.01 mg / L for most of the treatment agents when a test solution was prepared based on the test conducted by the Ministry of the Environment, No. 46, and measured by inductively coupled plasma emission spectroscopy. In addition, although not shown in Table 2, it was confirmed that ethylene was the main component of the decomposition product, and that no organic chlorine-based compound as an environmental standard item was generated.
[0041]
On the other hand, Comparative Example 9 contained no Ni and had a reaction constant of 10 ^-5 (H ^-1 ) It was an order and did not fall below the environmental standard even after 5 months. Comparative Example 10 is a mixture of Fe powder and Ni powder, and requires a purification period of two months or more despite containing 0.99 parts by weight of Ni. Comparative Example 11 is a heat-treated product of Example 19, and the reaction constant is 10 ^-4 (H ^-1 ) The order and the number of decomposition days were about 2 months, and Ni elution was also observed. Comparative Example 12 is an MA treating agent containing 5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder, and has a reaction constant of 10 parts by weight. ^-3 (H ^-1 ) The order and the number of decomposition days are about one month, suggesting high resolution, but the Ni elution amount is as large as 0.45 mg / L, and the environmental load is a problem.
[0042]
Therefore, when the detoxifying agent used in Examples 16 to 20 is used, the ability to decompose TCE in soil is remarkable, the legal regulation value can be cleared in a short time, and the environmental load is small. I understood that.
[0043]
Examples 21 to 25 and Comparative Examples 13 to 16
An evaluation test of the detoxifying agent of the present invention for a PCE-containing contaminated aqueous solution was performed. 100 ml of a 100 ppm PCE aqueous solution, 100 g of an internal standard benzene dissolved in methanol, and 1 g of a treating agent of the present invention (1% by weight with respect to the aqueous solution) were added to a 125 ml vial, and then quickly sealed. The reaction conditions were 30 ° C. and 200 rpm shaking. This aqueous solution was not subjected to a dissolved oxygen treatment or a pH adjustment.
[0044]
In addition, the manufacturing method of the processing agent used in the Example and the comparative example, and those evaluation methods are the same as that of Examples 16-20 and Comparative Examples 10-14, and the measurement result is shown in Table 3.
[0045]
[Table 3]

In Examples 21 to 25, the reaction constant was 10 ^-2 -10 ^-3 (H ^-1 ) Order, the decomposition rate is almost the same as that of the TCE aqueous solution, and it can be seen that the number of days in which the PCE concentration can meet the environmental standard is 10 to 28 days, and it can be decomposed in a short time. Although not shown in Table 3, it was confirmed that when PCE was completely decomposed, ethane was the main component as a decomposition product, and no organic chlorine-based compound such as TCE, which is an environmental standard, was formed. ing. In addition, the Ni concentration in the PCE aqueous solution was less than 0.01 mg / L for most of the treating agents, and it was found that the treating agent of the present invention was excellent also from the viewpoint of environmental load.
[0046]
On the other hand, Comparative Example 13 is Fe powder containing no Ni, but has a reaction constant of 10%. ^-4 (H ^-1 ) Even after 10 months, it was not less than the environmental standard value of 0.01 ppm. As for the decomposition products, TCE and cis-DCE listed in the environmental standard items were detected in addition to ethane. The comparative agent 14 is the same raw material as in Example 25, is a simple mixed powder without MA processing, and has a remarkably low resolution. Comparative Example 15 is a heat-treated product of Example 24, and has a reaction constant of 10 ^-3 (H ^-1 ), And elution of Ni, which was not detected in Examples, was also observed. This indicates that the heat treatment agent has a low resolution and a large environmental load. Comparative Example 16 is a MA method treating agent containing 5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder. The reduction and dechlorination reaction constant is similar to that of the agent of the present invention. Is detected as 0.94 mg / L, which poses a problem of environmental load.
[0047]
Therefore, the ability to decompose the aqueous solution containing PCE, which is said to be hardly decomposable, is remarkable by using the detoxifying treatment agents used in Examples 21 to 25, and the legally regulated values can be cleared in a short time, and The environmental load was found to be small. Needless to say, the use of the agent of the present invention can render the soil contaminated with PCE harmless.
[0048]
Examples 26 to 30 and Comparative Examples 17 to 20
An evaluation test of the detoxifying agent of the present invention for a cis-DCE-containing contaminated aqueous solution was performed. In a 125 ml vial, 100 ml of a 10 ppm cis-DCE aqueous solution, benzene (internal standard) dissolved in methanol, and 1 g (1% by weight of the aqueous solution) of a treating agent were quickly added and sealed. The reaction conditions were 30 ° C. and 200 rpm shaking. This aqueous solution was not subjected to a dissolved oxygen treatment or a pH adjustment.
[0049]
In addition, the manufacturing method of the processing agent used in the Example and the comparative example, and the evaluation method thereof are the same as that of Examples 16-20 and Comparative Examples 10-14, and these measurement results are shown in Table 4.
[0050]
[Table 4]

In Examples 26 to 30, the reaction constant was 10 ^-1 -10 ^-3 (H ^-1 ) Order, and the decomposition rate was higher than that of the TCE solution. It was confirmed that cis-DCE, which is a hardly decomposable organic halogen compound, was decomposed in a short time to below environmental standards after 14 days. Further, although not shown in Table 4, it was confirmed that ethane was the main component of the decomposition product, and that no organic chlorine-based compound, which is an environmental standard, was formed. In addition, the Ni concentration in the cis-DCE aqueous solution was less than 0.01 mg / L for most of the treating agents, and it was found that the treating agent of the present invention was excellent also in terms of environmental load.
[0051]
On the other hand, Comparative Example 17 is Fe powder containing no Ni and has a reaction constant of 10%. ^-3 (H ^-1 15) 15 days were required as the number of days on which the order and the environmental standard were less than 0.04 ppm. As for the decomposition products, in addition to ethane, 1,2-dichloroethane listed in the environmental standard items was detected. Comparative Example 18 uses the same raw materials as in Example 30, but has no MA processing, that is, it is simply a mixed powder, and has a remarkably low resolution. Comparative Example 19 is the heat-treated product of Example 29, but with a reaction constant of 10 ^-2 (H ^-1 ) Order, and did not fall below the soil environmental standard of 0.04 ppm within two weeks. In addition, elution of Ni, which was not detected in the examples, was also observed. This shows that the heat treatment agent or the dissolution treatment agent has a low resolution and a large environmental load. Comparative Example 20 is an MA method treating agent containing 5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder. ^-2 (H ^-1 ) Although the order is large, the amount of Ni eluted in the cis-DCE solution after completion of the reaction is detected as 0.59 mg / L, which poses a problem of environmental load.
[0052]
Therefore, if the detoxifying agent used in Examples 26 to 30 is used, the ability to decompose Cis-DCE, which has many cases in contaminated groundwater, is remarkable, and the legally regulated value can be cleared in a short time. And the environmental load was small. Needless to say, even the soil contaminated by Cis-DCE can be rendered harmless by using the treating agent of the present invention.
[0053]
Examples 31 to 35 and Comparative Examples 21 to 24
An evaluation test of the detoxifying agent of the present invention with respect to the MC-containing contaminated aqueous solution was performed. 100 ml of a 10 ppm MC aqueous solution, 1 g of an internal standard benzene dissolved in methanol, and 1 g (1% by weight of the aqueous solution) of the treating agent of the present invention were quickly added to a 125 ml vial, and then sealed. The reaction conditions were 30 ° C. and 200 rpm shaking. This aqueous solution was not subjected to a dissolved oxygen treatment or a pH adjustment.
In addition, the manufacturing method of the processing agent used in the Example and the comparative example and the evaluation method thereof are the same as that of Examples 16-20 and Comparative Examples 10-14, and the measurement result is shown in Table 5.
[0054]
[Table 5]

In Examples 31 to 35, the reaction constant was 10 ^-1 -10 ^-3 (H ^-1 ) Order, the decomposition rate was higher than that of the TCE aqueous solution, and it was confirmed that MC was decomposed below the environmental standard after 7 days. Although not shown in Table 5, it was confirmed that ethane was the main component of the decomposition product, and that no organic chlorine-based compound as an environmental standard item was generated. Also, the Ni concentration in the MC aqueous solution was less than 0.02 mg / L, and it was found that the treating agent of the present invention was excellent also from the viewpoint of environmental load.
[0055]
On the other hand, Comparative Example 21 is Fe powder containing no Ni and has a reaction constant of 10%. ^-3 (H ^-1 ) It was found that it takes about one month to reach the soil environmental standard of less than 1 ppm, which is as small as an order. As for the decomposition products, carbon tetrachloride listed in the environmental standard items was detected in addition to ethane. The comparative agent 22 used the same raw material as in Example 35, was not subjected to MA processing, that is, was simply a mixed powder, and the activity was significantly reduced. Comparative Example 23 is obtained by heating Example 34, but has a reaction constant of 10 ^-3 (H ^-1 ) It was found that it takes more than one week for the order to be below the soil environmental standard of 1 ppm. In addition, elution of Ni, which was not detected in the examples, was also observed. This indicates that the heat treatment agent or the dissolution treatment agent has a low resolution and a large environmental load. Comparative Example 24 is an MA method treating agent containing 5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder, and the reaction constant was 10%. ^-2 (H ^-1 ) Although it is as large as the order, the amount of Ni eluted in the MC aqueous solution after the reaction is detected to be 0.28 mg / L, which poses a problem of environmental load.
[0056]
Therefore, if the detoxifying agent used in Examples 31 to 35 is used, the ability to decompose MC in many cases in contaminated groundwater is remarkable, and the legally regulated value can be cleared in a short time, and It turned out that the environmental load was small. Needless to say, even soil contaminated with MC can be rendered harmless by using the agent of the present invention.
[0057]
【The invention's effect】
As is clear from the above description, according to the detoxifying agent of the present invention, the method for producing the same, and the detoxifying method using the same, soil, industrial waste, sludge, sludge, wastewater, and organic halogen compounds in groundwater Is decomposed in a short time by addition of a small amount, and does not generate harmful by-products.

Claims

A detoxifying agent for an object to be treated, which is contaminated with an organic halogen compound comprising an Fe-Ni alloy obtained by alloying a mixture of 100 parts by weight of Fe powder and 0.01 to 2 parts by weight of Ni powder by a mechanical alloying method.

The detoxifying agent according to claim 1, wherein the Fe-Ni alloy is a partial alloy in which a Ni component is segregated in and on the surface of the Fe powder.

3. The detoxifying agent according to claim 1, wherein the Fe powder is pure iron, steel, cast iron or pig iron.

Using an attritor mill, a mixture of 100 parts by weight of Fe powder and 0.01 to 2 parts by weight of Ni powder was mixed with a pulverizing medium at a mixing ratio of 7 to 15 times with respect to 1 part by weight of the mixture at a rotation speed of 200 to 200 parts. The method for producing a detoxifying agent according to any one of claims 1 to 3, wherein the treatment is performed under a condition of 800 rpm.

Using a vibrating mill, a mixture of 100 parts by weight of Fe powder and 0.01 to 2 parts by weight of Ni powder was charged with a grinding medium at a ratio of 2 to 10 times the weight of 1 part by weight of the mixture, and a frequency of 600 to 2000 vpm. 4. The method for producing a detoxifying agent according to claim 1, wherein the treatment is performed under the following conditions.

Using a rotary mill, a mixture consisting of 100 parts by weight of Fe powder and 0.01 to 2 parts by weight of Ni powder was charged at a ratio of 5 to 15 times the amount of the pulverized media with respect to 1 part by weight of the mixture, and a rotation speed of 600 to 1400 rpm. 4. The method for producing a detoxifying agent according to claim 1, wherein the treatment is performed under the following conditions.

The method for producing a detoxifying agent according to claim 4, wherein the processing time is 0.5 to 50 hours.

The method for producing a detoxifying agent according to claim 4, wherein the processing time is 0.5 to 6 hours.

The method for producing a detoxifying agent according to claim 5, wherein the processing time is 5 to 50 hours.

The method for producing a detoxifying agent according to claim 5, wherein the processing time is 5 to 10 hours.

The method for producing a detoxifying agent according to claim 6, wherein the processing time is 10 to 60 hours.

The method for producing a detoxifying agent according to claim 6, wherein the processing time is 10 to 20 hours.

A method for detoxifying an object contaminated with an organic halogen compound, comprising treating the object contaminated with an organic halogen compound with the detoxifying agent according to claim 1.

The method for detoxifying an object to be treated contaminated with an organic halogen compound according to claim 13, wherein the amount of the detoxifying agent added is 0.1 to 10% by weight based on the object to be processed.