JPWO2002060824A1 - Method of treating metal and / or metal-containing solution - Google Patents

Abstract

Metals and / or similar metals contained in various industrial wastewaters and industrial wastewaters are efficiently captured by using chelating fibers into which functional groups having chelating ability have been introduced to purify treated water, Disclosed is a method capable of concentrating and recovering metal as valuable resources.

Description

（式中、Ｒ_１、Ｒ_２、Ｒ_３は低級アルキレン基、ｎは１〜４の整数を表わす。）

［式中、Ｇは糖アルコール残基または多価アルコール残基、Ｒは水素原子、（低級）アルキル基または−Ｇ（Ｇは上記と同じ意味を表わし、上記Ｇと同一もしくは異なる残基であってもよい）を表わす］

［式中、Ｘはモノカルボン酸またはジカルボン酸から１つのカルボキシル基を除いた残基、Ｖは水素またはカルボキシル基、Ｍは水素または

（Ｒ_４はアルキレン基における炭素鎖から１つの水素を除いた残基、Ｒ_５は直接結合もしくはアルキレン基、Ｙ_１、Ｙ_２は同一もしくは異なって水素、カルボキシル基、アミノ基、ヒドロキシル基、ホスホン基またはチオール基、ｎは１〜４の整数、Ｍ’は水素または

（Ｒ_６はアルキレン基における炭素鎖から１つの水素を除いた残基、Ｒ_７は直接結合もしくはアルキレン基、Ｙ_３、Ｙ_４は同一もしくは異なって水素、カルボキシル基、アミノ基、ヒドロキシル基またはチオール基）、Ｚは水素または前記Ｍと同じ意味を表わし、ただし前記Ｍと同一であってもよいし、異なってもよい］

［式中、Ｖ、Ｘ、Ｚ、Ｍ’は前記式［３］と同じ意味を表わす］。
これらのキレート形成性官能基のうち、一般式［１］、［３］、［４］で示される官能基は、その中に存在する窒素、硫黄、カルボン酸が銅、亜鉛、ニッケル、コバルト等の重金属イオンに対して優れたキレート捕捉能を示し、また一般式［２］で示される官能基は、その中に存在する窒素や水酸基がホウ素、ゲルマニウム、ヒ素、アンチモン、セレン、テルル等の類金属イオンに対して優れた選択捕捉能を示す他、クロム、モリブデン、タングステンに対しても優れた選択捕捉能を示す。
本発明で使用するキレート形成性繊維においては、上記キレート捕捉能を有する官能基が繊維素材を構成する分子の表面に露出しているので、優れた選択吸着活性を発揮する。
次に、繊維分子中への代表的なキレート形成性官能基の導入法について説明する。
第１の方法は、繊維素材に下記一般式［５］で示されるキレート形成性化合物を反応させる方法であり、この方法によって導入される前記一般式［１］で示されるアシル基は、その中に存在する窒素やカルボン酸が銅、亜鉛、ニッケル、コバルト等の重金属イオンに対して優れたキレート捕捉能を発揮する。

（式中、Ｒ_１、Ｒ_２、Ｒ_３およびｎは前記一般式［１］と同じ意味）
上記一般式［１］および［５］において、Ｒ_１〜Ｒ_３で示される低級アルキレン基としては、Ｃ_１〜Ｃ_６のアルキレン基が挙げられるが、中でも特に好ましいのはメチレン、エチレン、プロピレンである。また繰り返し数ｎとして特に好ましいのは１または２である。
一般式［５］で示されるポリカルボン酸の酸無水物の好ましい具体例としては、ニトリロ三酢酸・無水物（ＮＴＡ無水物）、エチレンジアミン四酢酸・二無水物（ＥＤＴＡ・二無水物）、エチレンジアミン四酢酸・一無水物（ＥＤＴＡ・一無水物）、ジエチレントリアミン五酢酸・二無水物（ＤＴＰＡ・二無水物）、ジエチレントリアミン五酢酸・一無水物（ＤＴＰＡ・一無水物）等が例示されるが、中でも特に好ましいのは、ＮＴＡ無水物、ＥＤＴＡ・二無水物、ＤＴＰＡ・二無水物である。
そして、これらの酸無水物をＮ，Ｎ’−ジメチルホルムアミドやジメチルスルホキシド等の極性溶媒に溶解し、例えば６０〜１００℃程度で繊維素材と３０分〜数時間程度反応させると、酸無水物基が繊維素材を構成する分子中の反応性官能基（例えば水酸基やアミノ基など）と反応して結合し、前記アシル基からなるキレート形成性官能基がペンダント状に導入され、キレート形成性繊維が得られる。
繊維分子中に反応性官能基が存在しない場合は、繊維素材に酸化、グラフト重合など任意の手段で先ず反応性官能基を導入してから、前記ポリカルボン酸の無水物を反応させればよく、また反応性官能基が存在する場合でも、上記ポリカルボン酸の無水物との反応性が低い場合は、反応性の高い反応性官能基を導入してから前記ポリカルボン酸無水物と反応させることも有効である。
上記アシル基の導入反応を、綿あるいは絹とエチレンジアミン四酢酸・二無水物との反応を例にとって模式的に示すと、下記の通りである。
（綿の場合）

（絹の場合）

尚上記では、繊維分子中の水酸基またはアミノ基に前記ポリカルボン酸無水物を反応させる場合を代表的に示したが、＝ＮＨ，−ＳＨその他の反応性官能基を利用して前記アシル基を導入する場合も、同様に考えればよい。
かくして、繊維分子中に前記一般式［１］で示されるアシル基を導入することによって、中性付近はもとより低ｐＨ域においても、また金属イオン濃度の低い被処理液に適用した場合でも、優れた金属イオン捕捉活性を示すキレート形成性繊維を得ることができる。
上記キレート形成性官能基を導入したキレート形成性繊維の捕捉対象となる金属としては、銅、ニッケル、コバルト、亜鉛、カルシウム、マグネシウム、鉄など、または希土類元素であるスカンジウム、イットリウム、およびランタノイド系に属するランタン、セリウム、プラセオジム、ネオジム、サマリウム、ユウロピウム、ガドリウム、ジスプロシウム、ホルミウム、エルビウム、イッテルビウムなど、更には放射性元素であるテクネチウム、プロメチウム、フランシウム、ラジウム、ウラン、プルトニウム、セシウムなどが例示される。
繊維分子中にキレート形成性官能基を導入する他の方法は、分子中に水酸基やアミノ基などの反応性官能基を有する繊維素材を、下記一般式［６］で示されるアミン化合物を含有する処理液に浸漬して加熱し、該分子中に前記式［２］で示されるキレート形成性官能基を導入する方法である。

［式中、Ｇ、Ｒは前記一般式［２］と同じ意味］
一般式［２］で示されるキレート形成性官能基の導入されたキレート形成性繊維は、類金属イオンに対して優れたキレート捕捉能を有しており、その一例をＮ−メチル−Ｄ−グルカミン残基が導入されたキレート形成性繊維によるホウ素イオンの捕捉を例にとって示すと、下記式の様になる。

即ちこのキレート形成性繊維は、分子中にアミノ基と２個以上のヒドロキシル基とを持った基、とりわけ隣接する炭素に結合した少なくとも２個のヒドロキシル基とを持った基が導入されており、ホウ素やゲルマニウムなどの類金属に対して優れたキレート形成能を示し、それにより類金属を効果的に捕捉する。
また、上記一般式［２］で示されるキレート形成性官能基、とりわけＤ−グルカミン基が導入されたキレート形成性繊維は、クロム、モリブデン、タングステンに対しても優れたキレート捕捉能を発揮する。これは、上記金属元素が水中などでオキソ酸アニオン（例えば、タングステン酸やモリブデン酸など）として存在する場合に、これらがＤ−グルカミンの窒素にアニオン吸着し、或いは更に、ホウ素の場合と同様に水酸基に対してエステル様のキレートを形成するためと思われる。
この様な要件を満たす好ましい基は、前記式［２］として示した通りであり、該式［２］中、Ｇは糖アルコール残基または多価アルコール残基を示し、Ｒは水素原子、（低級）アルキル基または−Ｇ（Ｇは上記と同じ意味を表わし、前記−Ｇと同一もしくは異なるものであってもよい）を表わし、Ｒの中でも実用性の高いのは水素または（低級）アルキル基である。上記において（低級）アルキル基としてはＣ_１〜Ｃ_６のアルキル基が挙げられるが、中でも特に好ましいのはメチル基またはエチル基である。
前記一般式［２］で示される基の中でも特に好ましいのは、Ｇが鎖状の糖アルコール残基または多価アルコール残基、Ｒが水素原子または（低級）アルキル基である基であり、具体例としては、Ｄ−グルカミン、Ｄ−ガラクタミン、Ｄ−マンノサミン、Ｄ−アラビチルアミン、Ｎ−メチル−Ｄ−グルカミン、Ｎ−エチル−Ｄ−グルカミン、Ｎ−メチル−Ｄ−ガラクタミン、Ｎ−エチル−Ｄ−ガラクタミン、Ｎ−メチル−Ｄ−マンノサミン、Ｎ−エチル−Ｄ−アラビチルアミンなどからアミノ基を除いた糖アルコール残基、あるいはジヒドロキシアルキル基が例示されるが、繊維分子内への導入の容易性や原料の入手容易性等を考慮して最も好ましいのは、Ｄ−グルカミンやＮ−メチル−Ｄ−グルカミンのアミノ基を除いた残基あるいはジヒドロキシプロピル基である。
これらのキレート形成性官能基は、繊維分子中の反応性官能基（例えば、ヒドロキシル基、アミノ基、イミノ基、カルボキシル基、アルデヒド基、チオール基など）等に直接結合していてもよく、あるいは後述する様な架橋結合を介して間接的に結合していても構わない。
そして上記キレート形成性官能基を繊維分子内に導入する方法としては、繊維分子が元々有している前述の様な反応性官能基もしくは変性によって導入した反応性官能基に、前記一般式［６］で示されるアミン化合物を直接反応させ、あるいは、該反応性官能基に、分子中にエポキシ基、反応性二重結合、ハロゲン基、アルデヒド基、カルボキシル基、イソシアネート基の如き官能基を２個以上有する化合物を反応させた後、前記式［６］で示されるアミン化合物を反応させる方法が採用される。
即ち、繊維素材が分子中に水酸基やカルボキシル基等を有している場合は、これらの基に前記一般式［６］で示されるアミン化合物を直接反応させ、これを繊維分子にペンダント状に導入することができ、この場合の代表的な反応を例示すると下記の通りである。

（式中、Ｇ，Ｒは前記と同じ意味を表す）
また繊維分子中の反応性官能基とアミン化合物との反応性が乏しい場合は、繊維素材に先ず架橋剤を反応させることによって、前記アミン化合物との反応性の高い官能基をペンダント状に導入し、次いでこの官能基に前記アミン化合物を反応させることによって、キレート形成性官能基を繊維分子中にペンダント状に導入することができる。特に後者の方法を採用すれば、繊維分子に対する架橋剤やアミン化合物の使用量を調整することによって、使用目的に応じたキレート形成能（即ち、キレート形成性官能基の導入量）を任意に制御することができるので好ましい。
ここで用いられる好ましい架橋剤としては、エポキシ基、反応性二重結合、ハロゲン基、アルデヒド基、カルボキシル基、イソシアネート基などを２個以上、好ましくは２個有する化合物が挙げられ、好ましい架橋剤の具体例としては、グリシジルメタクリレート、グリシジルアクリレート、アリルグリシジルエーテル、グリシジルソルベート、エピクロルヒドリン、エピブロモヒドリン、エチレングリコールジグリシジルエーテル、ネオペンチルグリコールジグリシジルエーテル、グリセリンジグリシジルエーテル、ポリプロピレングリコールジグリシジルエーテル、マレイン酸、こはく酸、アジピン酸、グリオキザール、グリオキシル酸、トリレンジイソシアネート、ヘキサメチレンジイソシアネートなどが例示され、中でも特に好ましいのはグリシジルメタクリレート、エピクロルヒドリン、エチレングリコールジグリシジルエーテル等である。
上記の様な架橋剤を用いてアミン化合物を導入する際の具体的な反応を例示すると、次の通りである。

これらの架橋剤を用いて、繊維分子中にキレート形成性官能基を導入する際の反応は特に制限されないが、好ましい方法を挙げると、繊維素材に、前記架橋剤を水あるいはＮ，Ｎ’−ジメチルホルムアミドやジメチルスルホキシド等の極性溶媒に溶解し、必要により反応触媒や乳化剤等を併用し、６０〜１００℃程度で３０分〜数十時間程度接触させて反応させる方法であり、この反応により、架橋剤が、繊維分子中の反応性官能基（例えば、ヒドロキシル基やアミノ基など）と反応して繊維と結合し、前記式［６］で示した様なアミン化合物と容易に反応する官能基が繊維分子中に導入される。次いで、該官能基を導入した繊維素材と前記アミン化合物を水やＮ，Ｎ’−ジメチルホルムアミド、ジメチルスルホキシド等の極性溶媒に溶かした溶液を、必要により反応触媒を添加して６０〜１００℃×３０分〜数十時間程度接触させて反応させると、上記アミン化合物のアミノ基が架橋剤の反応性官能基（例えばエポキシ基やハロゲン基など）と反応し、前記式［２］で示されるキレート形成性官能基が繊維分子中にペンダント状に導入されたキレート形成性繊維が得られる。
この反応は、上記の様に通常は逐次的に行なわれるが、反応系によっては架橋剤とアミン化合物を同時に繊維素材と接触させ、該繊維分子に対して同時並行的に反応させることも可能である。
これらキレート形成性官能基を導入したキレート形成性繊維は、特に類金属に対して優れた選択捕捉性を示し、類金属としては、ホウ素、ゲルマニウム、砒素、アンチモン、セレン、テルル、珪素等が例示される。また、該キレート形成性官能基がＤ−グルカミンタイプのものである時は、クロム、モリブデン、タングステンに対しても優れた選択捕捉性を示すので、これらも有効な被捕捉金属に含まれる。
キレート形成性繊維を得るための更に他の方法は、繊維分子中に酸無水物との反応性官能基を有する繊維素材を使用し、該繊維分子に、架橋剤として反応性二重結合を有する酸無水物を反応させた後、キレート形成性化合物を反応させる方法である。
この方法によれば、前述の如く反応性二重結合を有する酸無水物を、繊維分子内の反応性官能基と反応させることによって、繊維分子中に反応性二重結合を導入し、該反応性二重結合に金属キレート形成性化合物を反応させることによって、繊維分子に優れたキレート捕捉性能が与えられる。
ここで用いられる反応性二重結合を有する酸無水物としては、分子中に酸無水物基と反応性二重結合を共に有する化合物であればその種類の如何は問わないが、好ましい具体例としては、無水マレイン酸、無水イタコン酸、無水アコニット酸、無水シトラコン酸、マレイン化メチルシクロヘキセン四塩基酸無水物、無水エンドメチレンテトラヒドロフタル酸、無水クロレンド酸、無水クロトン酸、無水アクリル酸、無水メタクリル酸などが挙げられる。これらの中でも特に好ましいのは二塩基酸の分子内無水物であり、上記分子内へ導入する際の反応効率やコスト等を考慮して特に好ましいのは無水マレイン酸と無水イタコン酸である。
これらの反応性二重結合を有する酸無水物と繊維素材とを、例えばＮ，Ｎ’−ジメチルホルムアミドやジメチルスルホキシド等の極性溶媒中で、必要により反応触媒を用いて例えば６０〜１００℃程度で３０分〜数時間接触させると、繊維分子中の反応性官能基が酸無水物基と反応して結合し、反応性二重結合を有する基が繊維分子に導入される。
そして、該反応性二重結合の導入された繊維にキレート形成性化合物を反応させると、該キレート形成性化合物が繊維分子中にペンダント状に導入され、キレート形成性繊維を得ることができる。
キレート形成性化合物としては、分子中に反応性二重結合との反応性を有する官能基を有する化合物が用いられる。反応性二重結合との反応性を有する官能基として特に好ましいのは、アミノ基、イミノ基、チオール基であり、これらの基は、上記反応性二重結合と容易に反応すると共に、それら基の中のＮやＳが、共存するカルボキシル基と共に金属キレート形成能を発揮する。
なお上記二重結合を有する酸無水物が繊維分子中に導入される際に、開環により１つのカルボキシル基が生成し、これがＮやＳと共にキレート形成能を発揮するので、上記キレート形成性化合物自身にカルボキシル基の存在を必須とするものではないが、キレート形成能は同一分子内に共存するＮやＳとカルボキシル基との相互作用によってより効果的に発揮されるので、好ましくは、分子中にアミノ基、イミノ基、チオール基の１種以上とカルボキシル基を共に有する化合物を、キレート形成性化合物として使用することが望ましい。
ここで用いられる分子中にアミノ基、イミノ基、チオール基の１種以上とカルボキシル基を有するキレート形成性化合物の具体例としては、グリシン、アラニン、アスパラギン酸、グルタミン酸などのアミノ酸、イミノ二酢酸、イミノ二こはく酸、エチレンジアミン二酢酸、エチレンジアミン三酢酸、エチレンジアミン二こはく酸、チオグリコール酸、チオりんご酸、チオサリチル酸、メルカプトプロピオン酸などが例示されるが、これらの中でも特に好ましいのはイミノ二酢酸、チオりんご酸である。
上記キレート形成性化合物を、二重結合を有する酸無水物が導入された前記繊維素材に反応させる方法は特に制限されないが、通常は、繊維素材と、金属キレート形成性化合物を水あるいはＮ，Ｎ’−ジメチルホルムアミドやジメチルスルホキシド等の極性溶媒に溶解し、必要により反応触媒を加えた処理液とを例えば１０〜１００℃程度で３０分〜数十時間接触させて反応させる方法であり、この反応により、繊維分子中に導入された反応性二重結合に上記アミノ基、イミノ基またはチオール基が反応し、前記一般式［３］，［４］に示したキレート形成性官能基が繊維分子内にペンダント状に導入される。
こうした反応の代表例を、繊維として綿、酸無水物として無水マレイン酸、キレート形成性化合物としてイミノ二酢酸、エチレンジアミン二酢酸、エチレンジアミン二こはく酸、イミノ二こはく酸、チオグリコール酸またはチオリんご酸を用いた場合について具体的に示すと、下記式に示す通りである。

なお上記式では、繊維分子中のヒドロキシル基に酸無水物を反応させる場合を代表的に示したが、アミノ基、イミノ基、グリシジル基、イソシアネート基、アリジニル基、チオール基などの他の反応性官能基を利用する場合も同様に考えればよい。
即ち、上記方法によって繊維分子内に導入される前記一般式［３］，［４］で示されるアシル基の種類は、該アシル基の導入に使用される前記酸無水物と金属キレート形成性化合物との組み合わせによって様々に変えることができる。従って該アシル基には、前記式に示したもの以外にも、次に示す様な種々のアシル基が挙げられる。

上記の様にして酸無水物基を介してキレート形成性官能基が導入されたキレート形成性繊維は、特に銅、ニッケル、コバルト、亜鉛、カルシウム、マグネシウム、鉄など、または希土類元素であるスカンジウム、イットリウム、およびランタノイド系に属するランタン、セリウム、プラセオジム、ネオジム、サマリウム、ユウロピウム、ガドリウム、ジスプロシウム、ホルミウム、エルビウム、イッテルビウムなど、更には放射性元素であるテクネチウム、プロメチウム、フランシウム、ラジウム、ウラン、プルトニウム、セシウムなどに対して優れたキレート捕捉能を発揮する。
本発明で使用されるキレート形成性繊維の更に他の好ましい製法としては、繊維分子、好ましくは天然繊維又は再生繊維の繊維分子に、反応性二重結合とグリシジル基を分子中に有する架橋反応性化合物を介して、エポキシ基との反応性を有するアミノジカルボン酸、チオカルボン酸およびリン酸よりなる群から選択される少なくとも１種の金属キレート形成性化合物を導入する方法が挙げられる。
即ち、分子中に反応性二重結合とグリシジル基を有する化合物を、例えばレドックス触媒の存在下で繊維と接触反応させると、反応性二重結合が繊維分子と反応し、反応性官能基としてグリシジル基を有する基が繊維分子中にペンダント状にグラフト付加する。そして、このグラフト付加物に、グリシジル基との反応性官能基を有する金属キレート形成性化合物を反応させると、該反応性官能基がグラフト付加した前記架橋反応性化合物のグリシジル基と反応し、繊維分子に金属キレート形成性官能基が導入されることになる。
ここで使用される架橋反応性化合物としては、繊維分子へのグラフト付加反応と、金属キレート形成性化合物との反応を実現するため、分子中に反応性二重結合とグリシジル基の双方を有する化合物であれば全て有効に使用できるが、繊維基材に効率よくグラフト付加すると共に、その後の金属キレート形成性化合物の導入反応も効率よく遂行し得るものとして特に好ましいのは、メタクリル酸グリシジル、アクリル酸グリシジル、アリルグリシジルエーテルであり、中でも、繊維分子への導入の容易性や原料の入手容易性等を考慮して最も好ましいのはメタクリル酸グリシジルである。
また金属キレート形成性化合物としては、グリシジル基との反応性を有するアミノジカルボン酸、チオカルボン酸およびリン酸が選択される。これらの化合物は、グリシジル基に対して高い反応性を有しており、繊維分子中に導入された架橋反応性化合物のグリシジル基に対してほぼ等モル量反応する。しかも、それらは金属イオンに対して高いキレート形成能を有しているので、これらの化合物を使用することによって、繊維分子中に金属キレート形成性官能基を高い反応率で効率よく導入することができる。
上記金属キレート形成性化合物の中でも、反応効率やキレート捕捉能、原料の入手容易性、コスト等を総合的に考慮して特に好ましいのはイミノジ酢酸、エチレンジアミン二酢酸、エチレンジアミン三酢酸、チオグリコール酸、チオリンゴ酸、リン酸であり、中でも特に好ましいのはイミノジ酢酸、エチレンジアミン三酢酸、チオグリコール酸である。
本発明において繊維分子中に導入される前記キレート形成性官能基の導入量は、ベースとなる繊維分子中の反応性官能基の量やキレート形成性化合物の使用量、架橋剤や架橋反応性化合物の使用量、更にはそれらの導入反応条件などによって任意に調整できるが、繊維分子に十分なキレート捕捉能を与えるには、下記式によって計算される導入量が５質量％程度以上、より好ましくは１０質量％程度以上となる様に調整することが望ましい。
導入量（質量％）＝［（キレート形成性官能基導入後の繊維質量−キレート形成性官能基導入前の繊維質量）／キレート形成性官能基導入前の繊維質量］×１００
（但し導入量とは、キレート形成性官能基の導入量を表わす）
キレート捕捉能を高めるうえでは、上記導入量は高い程好ましく、従って導入量の上限は特に規定されないが、導入量が多過ぎるとキレート形成性官能基導入繊維の結晶性が高くなってキレート形成性繊維が脆弱になり、繰り返し使用する際の寿命短縮を招く恐れがあるので、キレート捕捉材としての寿命や経済性などを総合的に考慮すると、導入量は１３０質量％程度以下、より好ましくは８０質量％程度以下に抑えることが望ましい。ただし、要求される清浄度の程度や処理速度（通液速度）等によっては、１５０〜２００質量％といった高レベルの導入量とすることにより、キレート捕捉能を高めることも可能である。
尚、キレート形成性官能基が導入される繊維素材の種類は特に制限されず、例えば綿、麻などを始めとする種々の植物繊維；絹、羊毛などを始めとする種々の動物性繊維；ビスコースレーヨンなどを始めとする種々の再生繊維；ポリアミド、アクリル、ポリエステルなどを始めとする様々の合成繊維を使用することができ、これらの繊維は必要に応じて各種の変性を加えたものであっても構わないが、キレート形成性官能基の導入のし易さ、被処理水に対する濡れ性、強度、安定性を考慮して最も好ましいのは、分子内に多数の反応性官能基を有している天然繊維、中でも植物性のセルロース系繊維である。
上記ベース繊維の性状にも格別の制限はなく、短繊維状の粉末、長繊維のモノフィラメント、マルチフィラメント、短繊維の紡績糸あるいはこれらを織物状もしくは編物状に製織もしくは製編した布帛、更には不織布のいずれであってもよく、必要によっては、それら性状の異なる複数の繊維を２種以上組み合わせることによって、処理時のキレート捕捉効率や通液抵抗を調整することも有効である。
上記の様にして得られるキレート形成性繊維は、細径の繊維分子表面にペンダント状に導入された前記キレート形成性官能基の実質的に全てが、金属や類金属に対して捕捉性能を有効に発揮するので、例えばビーズ状や粒状などの市販キレート形成性樹脂を充填して水処理を行なう方法に比べると非常に優れた捕捉性能を発揮する。
従って、このキレート形成繊維が充填された充填容器に被処理液を流して金属および／または類金属を捕捉することで、被処理液を効率よく清浄化できると共に、溶離液からは金属および／または類金属を有価元素として濃縮回収することができ、しかも、キレート形成性繊維によるキレート捕捉と溶離・再生の繰り返しにより、最小限の繊維使用量で効率のよい連続処理法を確立できる。
実施例
以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に含まれる。尚、下記において「％」とあるのは「質量％」を意味する。
実施例１
長さ０．５ｍｍにカットした約３デシテックスのレーヨン糸に、イミノ二酢酸を固定化したキレート形成性繊維（キレート形成性官能基の導入量：０．８２２ミリモル／ｇ）７００ｍｌ（２７０ｇ）を、吸着剤充填用カートリッジ容器（室町化学工業社製商品名「ムロマックカートリッジ」、容量７００ｍｌ）に充填し、このカートリッジを処理装置のハウジングに装着した。これに、ｐＨ５に調整した被処理水（２ミリモルの酢酸銅含有水溶液）をＳＶ（空間速度）：２０ｈｒ^−１で３０時間流して破過曲線を求め、図２に示す結果を得た。次に、破過状態に達した充填部に１モル濃度の塩酸をＳＶ：２０ｈｒ^−１で３０分間流して溶離処理を行ない、この時の溶離曲線を図３に示した。なお図２の横軸に示す通液率とは、充填されたキレート形成性繊維の飽和吸着容量（モル）に対する通液負荷量（モル）の割合である。
次に比較のため、上記キレート形成性繊維に代えて市販のイミノ二酢酸型キレート樹脂（三菱化学社製商品名「ダイヤイオンＣＲ１１」）５４０ｇを使用した以外は同様にして処理を行ない、得られた破過曲線と溶離曲線を図４，５に示した。
これらの破過曲線を比較すれば明らかな様に、市販キレート樹脂では、通液率約２０％で銅捕捉量が破過しているのに対し、キレート形成性繊維を用いた場合は、通液率約５０％まで銅を完全にキレート捕捉しており、本発明処理法の効率が極めて高いことを確認できる。
また各溶離曲線を比較すれば明らかなように、キレート形成性繊維を用いた場合は約７分で銅がほぼ完全に溶離しているのに対し、市販のキレート樹脂では銅の溶離に約２０分間を要しており、本発明は溶離効率においても非常に優れた処理法であることが分かる。
実施例２
長さ０．５ｍｍにカットした約１デシテックスのレーヨン糸にイミノ二酢酸を固定化したキレート形成性繊維（キレート形成性官能基の導入量：０．７９７ミリモル／ｇ）１ｇを、直径７ｍｍのガラスカラム内に充填し、これに、銅、ニッケル、コバルト、亜鉛を夫々１ミリモル／リットル含有する混合水溶液（ｐＨ５）を、ＳＶ：５０ｈｒ^−１で５時間流して破過曲線を求め、図６に示す結果を得た。次に、破過状態に達した充填部に１モル濃度の塩酸をＳＶ：５０ｈｒ^−１で３０分間流して溶離処理を行ない、この時の溶離曲線を図７に示した。
また比較のため、上記キレート形成性繊維に代えて市販のイミノ二酢酸型キレート樹脂（三菱化学社製商品名「ダイヤイオンＣＲ１１」）１ｇを使用した以外は同様にして処理を行ない、得られた破過曲線と溶離曲線を図８，９に示した。
これら破過曲線と溶離曲線を比較しても明確な様に、本発明の処理法は、市販キレート樹脂を用いた方法に比べて優れた処理効率を有していることが分かる。
実施例３
長さ１ｍｍにカットした約１デシテックスのレーヨン糸にＮ−メチル−Ｄ−グルカミンを固定化したキレート形成性繊維（キレート形成性官能基の導入量：０．８９４ミリモル／ｇ）０．４ｇを、直径７ｍｍのガラスカラム内に充填し、これに、ｐＨ８に調整したホウ素濃度１３ｐｐｍのホウ酸水溶液を、ＳＶ：１００ｈｒ^−１で３時間流して破過曲線を求め、図１０に示す結果を得た。次に、破過状態に達した充填部に１モル濃度の塩酸をＳＶ：１００ｈｒ^−１で３０分間流して溶離処理を行ない、この時の溶離曲線を図１１に示した。
また比較のため、上記キレート形成性繊維に代えて市販のグルカミン型キレート樹脂（三菱化学社製商品名「ダイヤイオンＣＲＢ０２」）０．４ｇを使用した以外は同様にして処理を行ない、得られた破過曲線と溶離曲線を図１２，１３に示した。
実施例４
上記実施例３のレーヨン糸に代えて、１ｍｍ角にカットした綿布（未晒しの綿ニット）に、Ｎ−メチル−Ｄ−グルカミンを固定化したキレート形成性繊維（キレート形成性官能基の導入量：０．８２１ミリモル／ｇ）を用いて同様の試験を行ない、得られた破過曲線を図１４、溶離曲線を図１５に示した。
実施例５
長さ０．５ｍｍにカットした約３デシテックスのレーヨン糸に、Ｎ−メチル−Ｄ−グルカミンを固定化したキレート繊維（キレート形成性官能基の導入量：０．７９５ミリモル／ｇ）１．０ｇを、直径７ｍｍのガラスカラム内に充填し、これに、タングステンを３０ｐｐｍ含有するｐＨ２．８の水溶液を、ＳＶ：２０ｈｒ^−１で１５時間流して破過曲線を求め、図１６に示す結果を得た。
実施例６
長さ０．５ｍｍにカットした約３デシテックスのレーヨン糸に、Ｎ−メチル−Ｄ−グルカミンを固定化したキレート繊維（キレート形成性官能基の導入量：０．７６４ミリモル／ｇ）５．０ｇを、直径１５ｍｍのガラスカラム内に充填し、これに、砒素を１ｐｐｍ含有するｐＨ３．８の水溶液を、ＳＶ：５ｈｒ^−１で７日間流して破過曲線を求め、図１７に示す結果を得た。
実施例７
長さ０．５ｍｍにカットした約３デシテックスのレーヨン糸に、Ｎ−メチル−Ｄ−グルカミンを固定化したキレート繊維（キレート形成性官能基の導入量：０．７６４ミリモル／ｇ）７．９ｇを、直径２５ｍｍのガラスカラム内に充填し、これに、砒素を１０ｐｐｍ含有するｐＨ３．９の水溶液を、ＳＶ：５ｈｒ^−１で１６時間流して砒素を吸着させた後、イオン交換水を１時間流して洗浄した。次いで、０．１モル濃度の水酸化ナトリウム水溶液（ｐＨ１３）をＳＶ：５ｈｒ^−１で３時間流して溶離処理を行ない、この時の溶離曲線を図１８に示した。
産業上の利用可能性
本発明は以上の様に構成されており、本発明の処理法を採用すれば、金属や類金属を高い捕捉率で除去できるばかりでなく、捕捉速度も格段に優れており、従来のイオン交換樹脂やキレート樹脂に較べて被処理液中の金属や類金属を極めて効率よく捕捉・除去することができ、それらを極めて効率よく清浄化することができる。しかも、金属や類金属を捕捉したキレート形成性繊維を酸あるいはアルカリ水溶液で処理すると、捕捉された金属や類金属は簡単に溶離するので、該繊維のキレート捕捉能を簡単に回復させることができ、繰り返し使用することによってキレート形成性繊維の消費量を大幅に低減することができる。更には、捕捉された金属や類金属は、溶離液から有価成分として効率よく濃縮採取することができるので、一石二鳥の効果を享受できる。
【図面の簡単な説明】
図１は、本発明にかかる処理法を実施する際の代表例を示すフロー図、図２，３は、実施例１の方法で得た破過曲線および溶離曲線、図４，５は、実施例１の比較法として示した市販キレート樹脂を用いたときの破過曲線および溶離曲線、図６，７は、実施例２の方法で得た破過曲線および溶離曲線、図８，９は、実施例２の比較法として示した市販キレート樹脂を用いたときの破過曲線および溶離曲線、図１０，１１は、実施例３の方法で得た破過曲線および溶離曲線、図１２，１３は、実施例３の比較法として示した市販キレート樹脂を用いたときの破過曲線および溶離曲線、図１４，１５は、実施例４の方法で得た破過曲線および溶離曲線、図１６，１７は、実施例５，６の方法で得た破過曲線、図１８は、実施例７の方法で得た溶離曲線である。
Ａ，Ｂ；キレート形成性繊維充填容器、２；被処理水槽、３；溶離水槽、４，６；調整槽、５；溶離液槽、Ｌ_１〜Ｌ_１３；ライン、Ｖ_１〜Ｖ_１３；バルブ。Technical field
The present invention uses a chelate-forming fiber having a chelate-forming functional group introduced into a fiber molecule, for example, an industrial effluent, drinking water, an aqueous liquid such as food processing water, or an organic solvent for cleaning, a metal processing oil, Metals contained in oily liquids such as edible oils (hereinafter sometimes collectively referred to as liquids to be treated), for example, heavy metals such as copper, zinc, nickel, cobalt, chromium, molybdenum, and tungsten, or similar metals, for example Regarding a treatment method capable of efficiently trapping similar metals such as boron, germanium, arsenic, antimony, selenium, and tellurium, if this treatment method is adopted, metals and similar metals present in trace amounts in the liquid to be treated can be efficiently removed. It can be captured, for example, purification of various industrial effluents discharged from glass factories, plating factories, power plants, etc., desalination of seawater, purification of hot spring water, and furthermore, It can be widely utilized for such recovery as valuable resources of the metal component.
Background art
Various harmful metals may be contained in the above-mentioned various industrial effluents and the like, and from the viewpoint of preventing environmental pollution, these harmful metals need to be sufficiently removed by effluent treatment. In addition, heavy metal components contained in rivers and groundwater adversely affect the human body. Therefore, when these are used as drinking water, sufficient care must be taken.
In addition, many metal-like substances have an adverse effect on the human body, and their environmental standards have been set in recent years. More specifically, boron and boron compounds, which are a kind of metal, are widely used in fields such as the glass industry, the plating industry, rust preventive agents, cosmetics, and the like. The liquid contains boron. In addition, wastewater from various power plants, flue gas desulfurization wastewater, and seawater also contain boron. It has been pointed out that boron may cause health problems such as a decline in reproductive function. In 1999, a standard value of 1 ppm was set as an environmental reference substance, and a standard value for wastewater is being set. It is also an important issue in the field of draining wastewater containing water and in the field of seawater desalination.
Examples of the method for treating the water containing boron include a coagulation precipitation method using aluminum sulfate and slaked lime (Japanese Patent Application Laid-Open No. 7-323292), a solvent extraction method using alcohols (Japanese Patent Application Laid-Open No. 11-652), and ion exchange. An adsorption method using a resin or the like (JP-A-57-197040) is known. Among these conventional methods, in the coagulation sedimentation method, it is pointed out that a large amount of coagulation sedimentation agent must be used to increase the efficiency of removing boron, and a large amount of sludge is generated accordingly. In the solvent extraction method, a large amount of solvent must be used because the extraction rate of boron is low, which causes an increase in COD of wastewater. In the adsorption method, the treatment efficiency is poor because the adsorption rate of boron to the ion exchange resin is low and the adsorption amount is small, and large-scale treatment requires large-scale treatment equipment.
In addition, selenium and selenium compounds are widely used as industrial raw materials in various industrial fields such as coloring and decoloring agents for glass, semiconductor materials, and additives to metals. May contain high concentrations of selenium. Wastewater discharged from thermal power plants also contains a considerable amount of selenium, and these selenium and its compounds are generally highly toxic, and even under the Water Pollution Control Law, the selenium effluent standard is 0.1 mg / s. 1 or less.
Therefore, in order to remove selenium from the wastewater, JP-A-5-78105 and JP-A-6-79286 adjust the pH of the wastewater and add a precipitant such as an iron salt to the wastewater. A method of precipitating dissolved selenium together with iron hydroxide or the like, JP-A-7-2502 discloses a method of adding an iron-based metal to a waste liquid containing selenium to precipitate selenium on the surface of the iron-based metal, Further, a method has been proposed in which an anion exchange resin is used and adsorbed as selenic acid (hexavalent selenium) or selenous acid (tetravalent selenium).
However, of the above-mentioned conventional methods, the method of precipitating selenium together with iron hydroxide or the like hardly removes hexavalent selenium ions, and the method of precipitating selenium on the surface of iron-based metal requires a large amount. It takes a long time to lower the effluent to a low reference concentration, and the treatment of a large amount of the generated iron-based metal is complicated and troublesome, and thus lacks versatility. Furthermore, in the method of adsorbing on an anion exchange resin, since there is no selective adsorption to other coexisting ions, a satisfactory removal efficiency cannot be obtained for a liquid to be treated in which various types of ions coexist.
In addition, it has been confirmed that arsenic is contained in effluents of pharmaceuticals, agricultural chemicals, pigments, petroleum plant industries, etc., in addition to the non-ferrous metal smelting industry, and also in heat drainage from geothermal power plants. The toxicity of arsenic, especially trivalent arsenic, has been known for a long time. However, as the carcinogenicity of arsenic has been confirmed in recent years, the allowable amount is 0.5 ppm or less for wastewater standards and 0.05 ppm or less for environmental standards. Is regulated at a low level.
As a method for treating such arsenic-containing wastewater, several methods are already known, and among them, the coagulation sedimentation method using a metal hydroxide such as calcium, magnesium, barium, iron, and aluminum is compared. It is widely used because the residual arsenic concentration can be reduced below the effluent standard by a simple operation. However, in this method, a large amount of chemical must be used to treat a large amount of arsenic-containing wastewater, such as wastewater from a geothermal power plant, and a large amount of arsenic-containing sludge generated by the treatment is treated. A heavy burden.
Therefore, other methods for removing arsenic include an adsorption method using activated carbon, activated alumina, and silica gel, a ligand ion exchange method using a cation exchange resin carrying iron or zirconium, and an ion exchange method using an anion exchange resin. Is being considered. However, the method using these adsorbents and ion exchange resins has a low adsorption capacity for arsenic, particularly harmful trivalent arsenic, has poor selective adsorption properties, and furthermore, the regeneration of the adsorbents and ion exchange resins is complicated. There was a problem.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object the purpose of metal and / or metal contained in a liquid to be treated such as wastewater, waste oil, processing oil, food oil and the like. It is an object of the present invention to provide a method capable of efficiently capturing metal by a simple method.
Disclosure of the invention
The treatment method of the present invention is a method for treating a solution containing a metal and / or a similar metal, and has the gist of repeating the following steps (1) to (3).
(1) A solution containing a metal and / or a similar metal is passed through a filling container filled with chelate-forming fibers in which a functional group capable of forming a chelate with a metal and / or a similar metal is introduced into a fiber molecule. Capturing a metal and / or a similar metal to the chelating fiber by chelating;
(2) After the capturing step (1), an acid or alkali aqueous solution is passed through the filling container to elute the chelate-trapped metal and / or similar metal from the chelate-forming fiber,
(3) After the elution step (2), a step of passing a liquid to be treated containing a metal and / or a similar metal through the filling container to cause the chelate-forming fibers to capture the metal and / or the similar metal again.
As the chelate-forming fiber used when performing this method, a non-woven fabric, a woven or knitted fabric or the like, or a thread, a powder, a granule, or any other shape can be used. These can be used alone, or two or more of them can be used in an appropriate combination in consideration of the efficiency of trapping a metal or a similar metal by passing the liquid or pressure loss.
Further, the metal and / or the similar metal to be treated when carrying out this method are iron, copper, nickel, aluminum, cobalt, cadmium, mercury, lead, zinc, calcium, magnesium, barium, manganese, chromium, molybdenum, When at least one selected from the group consisting of tungsten, the capturing step (1) is performed in a range of pH 1 to 11, more preferably 2 to 8, and the elution step (2) is performed in a pH range of 2 or less, more preferably 1 to 2. Less than,
When the capture target is boron and / or germanium, the capture step (1) is in the range of pH 3 to 12, and the elution step (2) is in the range of pH 0.5 to 2.5,
When it is arsenic and / or selenium, the capturing step (1) is in the range of pH 1 to 8, and the elution step (2) is in the range of pH 10 to 14.
It is preferable to perform each of the steps, since the object to be processed can be captured more efficiently.
Further, if the filling container filled with the chelate forming fiber is a cartridge type, and if it can be easily attached to and detached from the processing equipment, the chelate capturing ability of the chelate forming fiber deteriorates due to repeated use many times. It is preferable because the exchange of the simplicity can be easily performed. The present invention is applicable to all aqueous liquids and oily liquids (including organic solvent solutions).
BEST MODE FOR CARRYING OUT THE INVENTION
The method for treating a metal- and / or metal-containing solution according to the present invention comprises, as described above, a chelate-forming fiber in which a functional group having chelate-forming properties for a metal and / or a metal is introduced into a fiber molecule. To effectively utilize the chelate-capturing ability of the fiber and efficiently treat the metal- and / or metal-containing solution by minimizing the amount of the fiber used (removal from the processing solution or valuable The method provides a method for performing (recovery as a resource), and a series of steps will be described in detail below.
In the present invention, in the first capturing step (1), a metal- and / or metal-containing solution is passed through a filling container filled with the chelate-forming fibers, and the metal and / or metal-like contained in the solution is contained. Is chelate-trapped on the chelate-forming fiber. As a result, metals and similar metals in the liquid to be treated that have passed through the packed layer are removed as much as possible, and the problem of environmental pollution as described above does not occur. However, in consideration of direct discharge to the outside, it is desirable to adjust the pH to 5.8 to 8.6 in a public water area and to adjust the pH to 5 to 9 in a sea area before discharging.
In this trapping step (1), a preferable pH range for efficiently performing chelate trapping varies depending on the type of a metal and / or a class of metals to be trapped. For example, iron, copper, nickel, aluminum, cobalt, cadmium, When mercury, lead, zinc, calcium, magnesium, barium, manganese, chromium, molybdenum, and tungsten are to be captured, the preferred pH range is 1 to 11, and the preferred pH range varies slightly depending on the type of these metals. But more preferably in the range of pH 2-8. A preferred pH range when the target substance to be captured is boron and / or germanium, which is a class of metals, is 3 to 12, and a preferable pH range when the target element is arsenic or selenium is more than 0 to 8 or less. .
Next, in a second elution step (2), an acid or alkali aqueous solution is passed through the packed vessel that has undergone the above-described capturing step (1), and the metal and / or the like metal trapped by the chelate-forming fibers in the filled vessel. Is eluted from the fiber. As a result, the chelating fiber in the filled container recovers the chelate-trapping activity by eluting the metal and / or the like metal, and the eluent removes the metal and / or the like metal eluted from the chelating fiber. It can be recovered in concentration.
The preferred pH range in the elution step (2) also depends on the type of the captured metal and / or similar metal, and is, for example, iron, copper, nickel, aluminum, cobalt, cadmium, mercury, lead, zinc, calcium, magnesium, barium. , Manganese, chromium, molybdenum, and tungsten are preferably pH 2 or less, more preferably pH 1 or less, boron and / or germanium are preferably pH 0.5 to 2.5, and arsenic or selenium are preferably pH 10 to 14. As the acid used for pH adjustment, a mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid or an organic acid such as acetic acid or formic acid is preferable, and as the alkali, a hydroxide or carbonate of an alkali metal or an alkaline earth metal, such as a specific salt, is preferable. Typically, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, etc. are used. However, considering the effects on equipment and costs, sulfuric acid, alkali, etc. Sodium hydroxide is most suitable.
In the elution step (2), the metal and / or similar metal trapped in the chelating fiber elutes from the chelating fiber and elutes in an acid or alkali aqueous solution. By the method described above, metals and / or similar metals can be recovered in good yield.
In the third step (3), the metal and / or similar metal-containing solution is passed again through the chelate-forming fiber-filled container having recovered the chelate trapping ability in the elution step (2), so that the metal in the liquid to be treated is removed. Since the fibers are chelate-trapped by the fibers, by repeating the steps (1) to (3), the drainage treatment using the same chelate-forming fibers can be performed efficiently, and the eluent can be removed. Metal and / or similar metals can be concentrated and recovered.
Metals and similar metals are eluted from the chelate-forming fibers in the filled container after the elution step (2). However, since the acid or alkali used as the eluent is attached, the step (3) It is desirable to consider the pH at the time of reuse and to perform washing and pH adjustment as necessary before ()). Since the initial washing solution generated at that time contains a considerable amount of the eluted high-concentration metal and / or similar metal, it is collected, combined with the above eluent and treated, and the metal and / or similar metal is treated. It is preferable that the subsequent washing liquid having a low concentration is returned to the trapping step (1) for reprocessing.
FIG. 1 is a flow chart illustrating the processing method of the present invention. In the figure, A and B are filled containers filled with chelating fibers, 2 is a liquid tank to be treated, 3 is an eluent storage tank, and 4 is an eluent storage tank. An adjusting tank, 5 is an eluent tank, and 6 is an adjusting tank. By arranging and switching two filling vessels A and B in parallel so that chelate capture and elution processing can be performed continuously. An example is shown.
That is, the metal- and / or metal-containing liquid to be treated (the liquid to be treated) is first supplied to the valve V ₁ , V ₂ , V ₄ Open, valve V ₃ , V ₅ Is closed and the line L ₁ To L ₂ To the filling container A through the above-described process, and chelate-trapping the metal and / or the like metal in the liquid to be treated, and then the line L ₄ The water is then sent to the adjustment tank 4 where it is detoxified by pH adjustment and then discharged.
During this time, in the other filling container B, elution and regeneration of the metal and / or the like metal from the chelate forming fibers filled therein are performed. That is, in the elution step, the valve V ₇ , V ₈ , V ₁₀ , V ₁₂ Open, valve V ₉ , V ₁₁ Is closed, and an acid or alkali aqueous solution is supplied from the eluent storage tank 3 to the line L. ₇ , L ₈ To the filling container B, and the metal and / or the like metal is eluted from the chelate-forming fiber filled in the filling container B and capturing the metal and / or the like metal in the preceding step. And the eluent is line L ₁₀ , L ₁₂ After that, the mixture is sent to the eluent tank 5 to concentrate and recover metals and / or similar metals by an arbitrary method. Then, after the elution of the metal and / or the like metal is almost completed, the acid or alkali aqueous solution supplied to the filling container B is switched to the cleaning liquid and flows through the same line. _Thirteen From valve V _Thirteen Is sent to the adjusting tank 6 through which the pH is adjusted and then discharged. Since the initial cleaning liquid contains a small amount of metal and / or a similar metal, the cleaning liquid at the initial stage of cleaning is applied to the line L. ₁₄ It is desirable to return to the liquid tank 2 to be processed and completely remove metals and / or similar metals.
As described above, by using an automatic control system in which two packed containers A and B arranged in parallel are used, and when chelate capture is performed on the one hand, elution processing is performed on the other hand, these packed containers can be used. By performing the switching operation between A and B, purification of the liquid to be treated (capture of metal and / or similar metal) and regeneration of chelate-forming fibers (elution of metal and / or similar metal) can be performed continuously. This is preferable because the processing efficiency can be increased. At this time, it is preferable that the chelate-forming fibers to be filled in the filling container be of a cartridge type because the chelate-forming fibers can be easily replaced when the chelate-capturing ability of the chelate-forming fibers is reduced by a large number of repeated treatments. .
It should be noted that the flow charts shown are merely the most basic examples of practicing the present invention, and the present invention is not limited by the drawings, and is not limited to the specific design of the processing equipment. Various design changes or additions of preferable configurations are possible. For example, the structures and shapes of the filling containers A and B filled with the chelate-forming fibers, the treated water tank 2, the eluent storage tank 3, the adjustment tanks 4, 6, and the eluent tank 5 can be arbitrarily changed. In addition, the arrangement and structure of the lines and valves connecting them, the timing of switching operation, etc. can be automatically performed by an automatic control device, and the processing capacity can be increased by installing three or more filling containers. It is, of course, possible to increase them, all of which are included in the technical scope of the present invention.
Thus, according to the treatment method of the present invention, metals and / or similar metals contained in the liquid to be treated are efficiently captured and purified with a minimum of chelating fibers, and the metals and / or similar metals are removed from the eluate. The metal can be recovered at a high concentration as a valuable component, and the chelating fiber is regenerated and used repeatedly each time, so that the amount of the chelating fiber used can be minimized and the efficiency is extremely high. Good economic way.
The type of the chelate-forming fiber used in the present invention, in particular, the type of the chelate-forming functional group introduced into the fiber varies depending on the type of the metal and / or the like metal to be captured. Although it cannot be determined uniformly, preferred functional groups include, for example, functional groups represented by the following general formulas [1] to [4].

(Where R ₁ , R ₂ , R ₃ Represents a lower alkylene group, and n represents an integer of 1 to 4. )

[In the formula, G is a sugar alcohol residue or a polyhydric alcohol residue, R is a hydrogen atom, a (lower) alkyl group or -G (G has the same meaning as described above, and is the same as or different from G above. May be shown)]

[Wherein, X is a residue obtained by removing one carboxyl group from a monocarboxylic acid or dicarboxylic acid, V is hydrogen or a carboxyl group, M is hydrogen or

(R ₄ Is a residue obtained by removing one hydrogen from the carbon chain in the alkylene group; ₅ Is a direct bond or an alkylene group, Y ₁ , Y ₂ Are the same or different and are hydrogen, carboxyl group, amino group, hydroxyl group, phosphone group or thiol group, n is an integer of 1-4, M ′ is hydrogen or

(R ₆ Is a residue obtained by removing one hydrogen from the carbon chain in the alkylene group; ₇ Is a direct bond or an alkylene group, Y ₃ , Y ₄ Is the same or different and is hydrogen, a carboxyl group, an amino group, a hydroxyl group or a thiol group), and Z represents the same meaning as hydrogen or the above-mentioned M, but may be the same as or different from the above-mentioned M]

[Wherein, V, X, Z and M 'have the same meaning as in the above formula [3]].
Of these chelate-forming functional groups, the functional groups represented by the general formulas [1], [3] and [4] are those in which nitrogen, sulfur and carboxylic acid present therein are copper, zinc, nickel and cobalt. The functional group represented by the general formula [2] has a nitrogen or hydroxyl group in which boron, germanium, arsenic, antimony, selenium, tellurium and the like are present. In addition to showing excellent selective capturing ability for metal ions, it also shows excellent selective capturing ability for chromium, molybdenum, and tungsten.
The chelate-forming fiber used in the present invention exhibits excellent selective adsorption activity because the functional group having the chelate-capturing ability is exposed on the surface of the molecule constituting the fiber material.
Next, a method for introducing a typical chelate-forming functional group into a fiber molecule will be described.
The first method is a method in which a chelate-forming compound represented by the following general formula [5] is reacted with a fiber material, and the acyl group represented by the above general formula [1] introduced by this method contains, Nitrogen and carboxylic acid present in the steel exhibit excellent chelate trapping ability for heavy metal ions such as copper, zinc, nickel and cobalt.

(Where R ₁ , R ₂ , R ₃ And n have the same meaning as in the above formula [1])
In the above general formulas [1] and [5], R ₁ ~ R ₃ As the lower alkylene group represented by ₁ ~ C ₆ Of these, methylene, ethylene and propylene are particularly preferred. Further, 1 or 2 is particularly preferable as the number of repetitions n.
Preferred specific examples of the acid anhydride of the polycarboxylic acid represented by the general formula [5] include nitrilotriacetic acid anhydride (NTA anhydride), ethylenediaminetetraacetic acid dianhydride (EDTA dianhydride), ethylenediamine Examples include tetraacetic acid / monoanhydride (EDTA / monoanhydride), diethylenetriaminepentaacetic acid / dianhydride (DTPA / dianhydride), and diethylenetriaminepentaacetic acid / monoanhydride (DTPA / monoanhydride). Among them, particularly preferred are NTA anhydride, EDTA dianhydride and DTPA dianhydride.
Then, these acid anhydrides are dissolved in a polar solvent such as N, N'-dimethylformamide or dimethylsulfoxide, and reacted with a fiber material at about 60 to 100 ° C. for about 30 minutes to several hours to obtain an acid anhydride group. Reacts with and reacts with a reactive functional group (for example, a hydroxyl group or an amino group) in a molecule constituting the fiber material, and the chelate-forming functional group composed of the acyl group is introduced in a pendant form. can get.
When there is no reactive functional group in the fiber molecule, the reactive functional group may be first introduced into the fiber material by any means such as oxidation or graft polymerization, and then the anhydride of the polycarboxylic acid may be reacted. In addition, even when a reactive functional group is present, when the reactivity with the anhydride of the polycarboxylic acid is low, a reactive functional group having high reactivity is introduced and then reacted with the polycarboxylic anhydride. It is also effective.
The above introduction reaction of an acyl group is schematically shown below, taking the reaction of cotton or silk with ethylenediaminetetraacetic acid / dianhydride as an example.
(For cotton)

(For silk)

In the above description, the case where the polycarboxylic anhydride is reacted with the hydroxyl group or the amino group in the fiber molecule is typically shown. However, the acyl group is converted by using = NH, -SH or another reactive functional group. In the case of introduction, the same can be considered.
Thus, by introducing the acyl group represented by the general formula [1] into the fiber molecule, excellent properties can be obtained not only in the vicinity of neutrality but also in a low pH range, and even when applied to a liquid to be treated having a low metal ion concentration. Thus, a chelate-forming fiber exhibiting improved metal ion capturing activity can be obtained.
Examples of the metal to be captured by the chelate-forming fiber into which the chelate-forming functional group is introduced include copper, nickel, cobalt, zinc, calcium, magnesium, iron, and the like, or rare earth elements such as scandium, yttrium, and lanthanoid. Examples thereof include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium and the like, and also radioactive elements such as technetium, promethium, francium, radium, uranium, plutonium and cesium.
Another method of introducing a chelate-forming functional group into a fiber molecule involves using a fiber material having a reactive functional group such as a hydroxyl group or an amino group in a molecule, and containing an amine compound represented by the following general formula [6]. This is a method of immersing in a treatment liquid and heating to introduce a chelate-forming functional group represented by the formula [2] into the molecule.

[Wherein, G and R have the same meanings as in the general formula [2]]
The chelate-forming fiber into which the chelate-forming functional group represented by the general formula [2] is introduced has an excellent chelate-capturing ability for metal-like ions, and one example is N-methyl-D-glucamine. Taking boron ion capture by a chelating fiber into which a residue has been introduced as an example, the following formula is obtained.

That is, in the chelate-forming fiber, a group having an amino group and two or more hydroxyl groups in the molecule, particularly a group having at least two hydroxyl groups bonded to adjacent carbons is introduced, Shows excellent chelate-forming ability with respect to similar metals such as boron and germanium, and thereby effectively captures similar metals.
In addition, the chelate-forming fiber into which the chelate-formable functional group represented by the general formula [2], in particular, the D-glucamine group has been introduced, exhibits excellent chelate-capturing ability even for chromium, molybdenum, and tungsten. This is because when the metal element is present as an oxo acid anion (for example, tungstate or molybdate) in water or the like, these are anion-adsorbed to nitrogen of D-glucamine, or further, similarly to the case of boron. This is probably due to the formation of an ester-like chelate for the hydroxyl group.
Preferred groups satisfying such requirements are as shown in the above formula [2], wherein G represents a sugar alcohol residue or a polyhydric alcohol residue, R is a hydrogen atom, ( Represents a lower) alkyl group or -G (G has the same meaning as described above, and may be the same or different from the above -G), and among R, the most practical is hydrogen or a (lower) alkyl group. It is. In the above, the (lower) alkyl group is C ₁ ~ C ₆ Of these, a methyl group or an ethyl group is particularly preferred.
Among the groups represented by the general formula [2], particularly preferred are groups in which G is a chain sugar alcohol residue or a polyhydric alcohol residue, and R is a hydrogen atom or a (lower) alkyl group. Examples include D-glucamine, D-galactamine, D-mannosamine, D-arabitylamine, N-methyl-D-glucamine, N-ethyl-D-glucamine, N-methyl-D-galactamine, N- A sugar alcohol residue obtained by removing an amino group from ethyl-D-galactamine, N-methyl-D-mannosamine, N-ethyl-D-arabitylamine, or the like, or a dihydroxyalkyl group is exemplified. The most preferable in consideration of the ease of introduction of the compound and the availability of the raw material, etc., are residues or dihydric residues other than the amino group of D-glucamine or N-methyl-D-glucamine. Is a Kishipuropiru group.
These chelate-forming functional groups may be directly bonded to reactive functional groups (for example, hydroxyl group, amino group, imino group, carboxyl group, aldehyde group, thiol group, etc.) in the fiber molecule, or They may be indirectly linked via a cross-linking bond as described below.
As a method for introducing the chelate-forming functional group into the fiber molecule, the above-mentioned general formula [6] is added to the reactive functional group originally possessed by the fiber molecule or the reactive functional group introduced by modification. Or two reactive groups such as an epoxy group, a reactive double bond, a halogen group, an aldehyde group, a carboxyl group, and an isocyanate group in the molecule. After reacting the compound having the above, a method of reacting the amine compound represented by the formula [6] is employed.
That is, when the fiber material has a hydroxyl group, a carboxyl group, or the like in the molecule, the amine compound represented by the general formula [6] is directly reacted with these groups, and this is introduced into the fiber molecule in a pendant manner. A typical reaction in this case is as follows.

(Wherein, G and R represent the same meaning as described above)
When the reactivity between the reactive functional group in the fiber molecule and the amine compound is poor, a functional group having high reactivity with the amine compound is introduced in a pendant form by first reacting a crosslinking agent with the fiber material. Then, by reacting the amine compound with this functional group, the chelate-forming functional group can be introduced into the fiber molecule in a pendant manner. In particular, if the latter method is employed, the chelating ability (that is, the amount of the chelating functional group introduced) can be arbitrarily controlled according to the purpose of use by adjusting the amount of the crosslinking agent or amine compound used for the fiber molecule. Is preferred.
Preferred crosslinking agents used herein include compounds having two or more, preferably two, epoxy groups, reactive double bonds, halogen groups, aldehyde groups, carboxyl groups, isocyanate groups, and the like. Specific examples include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, glycidyl sorbate, epichlorohydrin, epibromohydrin, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin diglycidyl ether, polypropylene glycol diglycidyl ether, Maleic acid, succinic acid, adipic acid, glyoxal, glyoxylic acid, tolylene diisocyanate, hexamethylene diisocyanate, etc. are exemplified, and among them, particularly preferred. It is given to glycidyl methacrylate, epichlorohydrin, ethylene glycol diglycidyl ether.
The following is a specific reaction when introducing an amine compound using the above-mentioned crosslinking agent.

The reaction at the time of introducing a chelate-forming functional group into a fiber molecule using these cross-linking agents is not particularly limited. However, in a preferred method, the cross-linking agent is added to the fiber material with water or N, N′-. This is a method of dissolving in a polar solvent such as dimethylformamide or dimethylsulfoxide, and optionally using a reaction catalyst or an emulsifier, etc., and contacting at about 60 to 100 ° C. for about 30 minutes to several tens of hours to cause a reaction. A cross-linking agent reacts with a reactive functional group (for example, a hydroxyl group or an amino group) in the fiber molecule to bond with the fiber, and easily reacts with the amine compound represented by the above formula [6]. Is introduced into the fiber molecule. Next, a solution obtained by dissolving the functional group-introduced fiber material and the amine compound in a polar solvent such as water or N, N'-dimethylformamide or dimethyl sulfoxide is added to a reaction catalyst, if necessary, at 60 to 100 ° C. When the contact is carried out for about 30 minutes to several tens of hours, the amino group of the amine compound reacts with the reactive functional group (for example, an epoxy group or a halogen group) of the crosslinking agent, and the chelate represented by the above formula [2] A chelate-forming fiber in which a forming functional group is pendantly introduced into a fiber molecule is obtained.
This reaction is usually performed sequentially as described above. However, depending on the reaction system, the crosslinking agent and the amine compound can be simultaneously brought into contact with the fiber material, and the fiber molecules can be reacted simultaneously and in parallel. is there.
The chelate-forming fibers into which these chelate-forming functional groups have been introduced exhibit excellent selective trapping properties, particularly with respect to similar metals, and examples of such metals include boron, germanium, arsenic, antimony, selenium, tellurium, and silicon. Is done. Further, when the chelate-forming functional group is of the D-glucamine type, it exhibits excellent selective trapping properties even for chromium, molybdenum and tungsten, and these are also included in the effective trapped metals.
Yet another method for obtaining a chelate forming fiber uses a fiber material having a reactive functional group with an acid anhydride in the fiber molecule, and the fiber molecule has a reactive double bond as a crosslinking agent. This is a method of reacting an acid anhydride and then reacting a chelate-forming compound.
According to this method, an acid anhydride having a reactive double bond as described above is reacted with a reactive functional group in the fiber molecule to introduce a reactive double bond into the fiber molecule, By reacting a metal chelating compound with the reactive double bond, the fiber molecule has excellent chelate trapping performance.
The acid anhydride having a reactive double bond used herein is not particularly limited as long as it is a compound having both an acid anhydride group and a reactive double bond in a molecule. Are maleic anhydride, itaconic anhydride, aconitic anhydride, citraconic anhydride, maleated methylcyclohexene tetrabasic anhydride, endmethylene tetrahydrophthalic anhydride, chlorendic anhydride, crotonic anhydride, acrylic acid anhydride, methacrylic anhydride And the like. Among these, particularly preferred are intramolecular anhydrides of dibasic acids, and maleic anhydride and itaconic anhydride are particularly preferred in consideration of the reaction efficiency and cost when introduced into the molecule.
The acid anhydride having a reactive double bond and the fiber material are mixed, for example, in a polar solvent such as N, N'-dimethylformamide or dimethylsulfoxide by using a reaction catalyst, if necessary, for example, at about 60 to 100 ° C. When the contact is carried out for 30 minutes to several hours, the reactive functional group in the fiber molecule reacts with the acid anhydride group to bond, and a group having a reactive double bond is introduced into the fiber molecule.
Then, when the chelate-forming compound is caused to react with the fiber into which the reactive double bond has been introduced, the chelate-forming compound is introduced into the fiber molecule in a pendant manner, whereby a chelate-forming fiber can be obtained.
As the chelate-forming compound, a compound having a functional group having a reactivity with a reactive double bond in a molecule is used. Particularly preferred as the functional group having reactivity with the reactive double bond are an amino group, an imino group, and a thiol group. These groups react easily with the reactive double bond, and N and S in the compound exhibit a metal chelate forming ability together with a coexisting carboxyl group.
When the acid anhydride having a double bond is introduced into a fiber molecule, one carboxyl group is generated by ring opening, which exerts a chelate-forming ability together with N and S. Although the presence of a carboxyl group is not essential, the chelating ability is more effectively exerted by the interaction of N and S coexisting in the same molecule with the carboxyl group. It is preferable to use a compound having at least one of an amino group, an imino group and a thiol group and a carboxyl group as the chelate-forming compound.
Specific examples of the chelating compound having at least one of an amino group, an imino group and a thiol group and a carboxyl group in the molecule used herein include amino acids such as glycine, alanine, aspartic acid and glutamic acid, iminodiacetic acid, Examples include iminodisuccinic acid, ethylenediamine diacetate, ethylenediamine triacetic acid, ethylenediamine disuccinic acid, thioglycolic acid, thiomalic acid, thiosalicylic acid, mercaptopropionic acid, and among them, particularly preferred are iminodiacetic acid, Thiomalic acid.
The method of causing the chelate-forming compound to react with the fiber material into which the acid anhydride having a double bond has been introduced is not particularly limited. However, usually, the fiber material and the metal chelate-forming compound are reacted with water or N, N This is a method of dissolving in a polar solvent such as' -dimethylformamide or dimethylsulfoxide, and contacting with a treatment solution to which a reaction catalyst has been added as necessary, for example, at about 10 to 100 ° C. for about 30 minutes to several tens of hours. As a result, the amino group, imino group or thiol group reacts with the reactive double bond introduced into the fiber molecule, and the chelate-forming functional group shown in the general formulas [3] and [4] is converted into the fiber molecule. Pendant.
Typical examples of such a reaction are cotton as a fiber, maleic anhydride as an acid anhydride, iminodiacetic acid, ethylenediaminediacetic acid, ethylenediaminedisuccinic acid, iminodisuccinic acid, thioglycolic acid or thioliglic acid as chelating compounds. Specifically, the case where is used is as shown in the following formula.

In the above formula, a case where an acid anhydride is reacted with a hydroxyl group in a fiber molecule is typically shown, but other reactive groups such as an amino group, an imino group, a glycidyl group, an isocyanate group, an aridinyl group, and a thiol group are used. The same applies to the case where a functional group is used.
That is, the type of the acyl group represented by the general formulas [3] and [4] introduced into the fiber molecule by the above-mentioned method depends on the acid anhydride and the metal chelate-forming compound used for introducing the acyl group. It can be changed variously by the combination with. Accordingly, the acyl group includes various acyl groups as shown below in addition to those shown in the above formula.

Chelate-forming fibers in which a chelate-forming functional group has been introduced via an acid anhydride group as described above, especially copper, nickel, cobalt, zinc, calcium, magnesium, iron or the like, or scandium which is a rare earth element, Yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium, etc. belonging to the lanthanoid series, and also the radioactive elements technetium, promethium, francium, radium, uranium, uranium, plutonium, cesium, etc. Demonstrates excellent chelate trapping ability.
Still another preferred method for producing the chelating fiber used in the present invention is to provide a fiber molecule, preferably a fiber molecule of a natural fiber or a regenerated fiber, with a cross-linking reaction having a reactive double bond and a glycidyl group in the molecule. A method of introducing, via a compound, at least one metal chelate-forming compound selected from the group consisting of aminodicarboxylic acid, thiocarboxylic acid, and phosphoric acid having reactivity with an epoxy group.
That is, when a compound having a reactive double bond and a glycidyl group in a molecule is contacted with a fiber, for example, in the presence of a redox catalyst, the reactive double bond reacts with the fiber molecule and glycidyl as a reactive functional group. The group having the group is pendantly grafted into the fiber molecule. Then, when a metal chelate-forming compound having a reactive functional group with a glycidyl group is reacted with the graft adduct, the reactive functional group reacts with the glycidyl group of the cross-linked reactive compound to which the graft is added, and the fiber A metal chelating functional group will be introduced into the molecule.
The cross-linking reactive compound used here is a compound having both a reactive double bond and a glycidyl group in the molecule in order to realize a graft addition reaction to fiber molecules and a reaction with a metal chelate forming compound. Any of these can be effectively used, but it is particularly preferable that glycidyl methacrylate, acrylic acid and the like can be efficiently graft-attached to the fiber base material and can also efficiently carry out the subsequent introduction reaction of the metal chelate-forming compound. Glycidyl and allyl glycidyl ether are preferred. Among them, glycidyl methacrylate is most preferred in consideration of easy introduction into fiber molecules and availability of raw materials.
Further, as the metal chelate-forming compound, aminodicarboxylic acid, thiocarboxylic acid and phosphoric acid having reactivity with a glycidyl group are selected. These compounds have high reactivity with glycidyl groups and react with the glycidyl groups of the cross-linking reactive compound introduced into the fiber molecules in substantially equimolar amounts. Moreover, since they have a high chelate forming ability for metal ions, the use of these compounds makes it possible to efficiently introduce a metal chelate-forming functional group into a fiber molecule at a high reaction rate. it can.
Among the above metal chelate-forming compounds, particularly preferred in consideration of reaction efficiency and chelate capturing ability, availability of raw materials, cost, and the like are particularly preferred iminodiacetic acid, ethylenediamine diacetate, ethylenediamine triacetic acid, thioglycolic acid, Among these, thiomalic acid and phosphoric acid are preferable, and particularly preferable are iminodiacetic acid, ethylenediaminetriacetic acid, and thioglycolic acid.
In the present invention, the amount of the chelate-forming functional group introduced into the fiber molecule is the amount of the reactive functional group in the base fiber molecule, the amount of the chelate-forming compound used, the crosslinking agent and the crosslinking reactive compound. Can be arbitrarily adjusted depending on the amount used, furthermore, their introduction reaction conditions and the like. However, in order to impart sufficient chelate capturing ability to the fiber molecule, the introduction amount calculated by the following formula is about 5% by mass or more, more preferably It is desirable to adjust so as to be about 10% by mass or more.
Introduced amount (% by mass) = [(fiber mass after chelate-forming functional group introduction−fiber mass before chelate-forming functional group introduction) / fiber mass before chelate-forming functional group introduction] × 100
(However, the introduction amount indicates the introduction amount of the chelating functional group)
In order to enhance the chelate trapping ability, the higher the amount of introduction, the more preferable. Therefore, the upper limit of the amount of introduction is not particularly limited. Since the fibers become brittle and may shorten the life when used repeatedly, the amount of introduction is about 130% by mass or less, more preferably 80% or less, when the life and economy as a chelate trapping material are comprehensively considered. It is desirable that the content be suppressed to about mass% or less. However, depending on the required degree of cleanliness, the processing speed (liquid passing speed), and the like, it is possible to increase the chelate capturing ability by using a high-level introduction amount of 150 to 200% by mass.
The type of the fiber material into which the chelate-forming functional group is introduced is not particularly limited. For example, various plant fibers including cotton and hemp; various animal fibers including silk and wool; Various recycled fibers such as coarse rayon; various synthetic fibers such as polyamide, acrylic, and polyester can be used, and these fibers are variously modified as necessary. Although it does not matter, it is most preferable in consideration of the ease of introduction of the chelate-forming functional group, wettability to the water to be treated, strength, and stability, because it has a large number of reactive functional groups in the molecule. Natural fibers, especially vegetable cellulosic fibers.
There is also no particular limitation on the properties of the base fiber, short fiber powder, long fiber monofilament, multifilament, short fiber spun yarn or woven or knitted woven or knitted fabric, and furthermore Any of nonwoven fabrics may be used. If necessary, it is also effective to adjust the chelate trapping efficiency and the liquid permeation resistance during the treatment by combining two or more kinds of fibers having different properties.
In the chelate-forming fiber obtained as described above, substantially all of the chelate-forming functional groups introduced in a pendant manner on the surface of the small-diameter fiber molecule have an effective trapping performance with respect to a metal or a similar metal. Therefore, it exhibits extremely excellent trapping performance as compared with a method in which a commercially available chelate-forming resin such as beads or granules is filled and subjected to water treatment.
Therefore, the liquid to be treated can be efficiently cleaned by flowing the liquid to be treated into the filling container filled with the chelate forming fibers to capture the metal and / or the like metal, and the metal and / or the metal can be removed from the eluent. A similar metal can be concentrated and recovered as a valuable element, and an efficient continuous treatment method with a minimum amount of fiber can be established by repeating chelate capture and elution / regeneration with the chelate-forming fiber.
Example
Hereinafter, the present invention will be described more specifically with reference to Examples. However, the present invention is not limited to the following Examples, and may be appropriately modified within a range that can be adapted to the purpose of the preceding and the following. The present invention can be implemented, and all of them are included in the technical scope of the present invention. In the following, “%” means “% by mass”.
Example 1
700 ml (270 g) of a chelate-forming fiber (introduced amount of chelate-forming functional group: 0.822 mmol / g) in which iminodiacetic acid was immobilized was applied to about 3 dtex rayon yarn cut to a length of 0.5 mm. The cartridge was filled into a cartridge container for adsorbent filling (trade name “Muromac cartridge”, manufactured by Muromachi Chemical Co., Ltd., capacity: 700 ml), and this cartridge was mounted on the housing of the processing apparatus. To this, treated water (aqueous solution containing 2 mmol of copper acetate) adjusted to pH 5 was added with SV (space velocity): 20 hr. ^-1 For 30 hours to obtain a breakthrough curve, and the results shown in FIG. 2 were obtained. Next, 1 mol hydrochloric acid was added to the filled portion that reached the breakthrough state by SV: 20 hr. ^-1 For 30 minutes to perform an elution treatment. The elution curve at this time is shown in FIG. The liquid passage rate shown on the horizontal axis in FIG. 2 is the ratio of the liquid flow load (mol) to the saturated adsorption capacity (mol) of the filled chelate-forming fibers.
Next, for comparison, the same treatment was carried out except that 540 g of a commercially available iminodiacetic acid type chelate resin (trade name “Diaion CR11” manufactured by Mitsubishi Chemical Corporation) was used in place of the chelate-forming fiber. The breakthrough and elution curves are shown in FIGS.
As is clear from the comparison of these breakthrough curves, in the case of a commercially available chelate resin, the amount of trapped copper broke through at a liquid passage rate of about 20%. Copper is completely chelated and trapped to a liquid ratio of about 50%, confirming that the efficiency of the treatment method of the present invention is extremely high.
As is clear from comparison of the elution curves, when the chelating fiber was used, copper was almost completely eluted in about 7 minutes, whereas in the case of a commercially available chelate resin, about 20 minutes were eluted with copper. Minutes, which indicates that the present invention is a very excellent treatment method in terms of elution efficiency.
Example 2
1 g of chelate-forming fiber (implantation amount of chelate-forming functional group: 0.797 mmol / g) in which iminodiacetic acid is immobilized on rayon yarn of about 1 dtex cut to a length of 0.5 mm, and glass having a diameter of 7 mm A column was filled with a mixed aqueous solution (pH 5) containing 1 mmol / L of copper, nickel, cobalt, and zinc, respectively, and SV: 50 hr. ^-1 For 5 hours to obtain a breakthrough curve, and the results shown in FIG. 6 were obtained. Next, 1 mol hydrochloric acid was added to the filled portion that reached the breakthrough state by SV: 50 hr. ^-1 For 30 minutes to perform an elution treatment, and the elution curve at this time is shown in FIG.
For comparison, the same treatment was carried out except that 1 g of a commercially available iminodiacetic acid-type chelate resin (trade name “Diaion CR11” manufactured by Mitsubishi Chemical Corporation) was used in place of the chelate-forming fiber. The breakthrough curve and elution curve are shown in FIGS.
As is clear from comparison between the breakthrough curve and the elution curve, it can be seen that the treatment method of the present invention has a superior treatment efficiency as compared with a method using a commercially available chelate resin.
Example 3
0.4 g of chelate-forming fiber (introduced amount of chelate-forming functional group: 0.894 mmol / g) in which N-methyl-D-glucamine is immobilized on rayon yarn of about 1 dtex, cut to a length of 1 mm, A glass column having a diameter of 7 mm was filled, and a boric acid aqueous solution having a boron concentration of 13 ppm adjusted to pH 8 was added thereto with an SV of 100 hr. ^-1 For 3 hours to obtain a breakthrough curve, and the results shown in FIG. 10 were obtained. Next, 1 mol hydrochloric acid was added to the filled portion that reached the breakthrough state by SV: 100 hr. ^-1 For 30 minutes to perform an elution treatment. The elution curve at this time is shown in FIG.
For comparison, the same treatment was performed except that 0.4 g of a commercially available glucamine-type chelate resin (trade name “Diaion CRB02” manufactured by Mitsubishi Chemical Corporation) was used in place of the chelate-forming fiber. The breakthrough and elution curves are shown in FIGS.
Example 4
Instead of the rayon yarn of Example 3, chelate-forming fibers (introduced amount of chelate-forming functional groups) in which N-methyl-D-glucamine is immobilized on a cotton cloth (unbleached cotton knit) cut into 1 mm square. : 0.821 mmol / g), and the obtained breakthrough curve is shown in FIG. 14 and the elution curve is shown in FIG.
Example 5
1.0 g of a chelate fiber (introduced amount of chelate-forming functional group: 0.795 mmol / g) having N-methyl-D-glucamine immobilized thereon is applied to about 3 dtex rayon yarn cut to a length of 0.5 mm. , A glass column having a diameter of 7 mm, and an aqueous solution having a pH of 2.8 containing 30 ppm of tungsten and having an SV of 20 hr. ^-1 For 15 hours to obtain a breakthrough curve, and the result shown in FIG. 16 was obtained.
Example 6
5.0 g of chelating fiber (introduced amount of chelating functional group: 0.764 mmol / g) having N-methyl-D-glucamine immobilized on rayon yarn of about 3 decitex cut to a length of 0.5 mm. Into a glass column having a diameter of 15 mm, and an aqueous solution having a pH of 3.8 containing 1 ppm of arsenic was added thereto with an SV of 5 hr. ^-1 For 7 days to obtain a breakthrough curve, and the results shown in FIG. 17 were obtained.
Example 7
7.9 g of a chelate fiber (introduced amount of chelate-forming functional group: 0.764 mmol / g) having N-methyl-D-glucamine immobilized thereon was applied to about 3 dtex rayon yarn cut to a length of 0.5 mm. Into a glass column having a diameter of 25 mm, and an aqueous solution containing 10 ppm of arsenic and having a pH of 3.9 was added thereto with an SV of 5 hr. ^-1 For 16 hours to adsorb arsenic, and then washed by flowing ion-exchanged water for 1 hour. Next, an aqueous solution of sodium hydroxide (pH 13) having a concentration of 0.1 mol was added with an SV of 5 hr. ^-1 For 3 hours to perform an elution treatment. The elution curve at this time is shown in FIG.
Industrial applicability
The present invention is configured as described above.If the treatment method of the present invention is employed, not only can a metal or a similar metal be removed at a high trapping rate, but also the trapping speed is remarkably excellent. Metals and similar metals in the liquid to be treated can be captured and removed very efficiently as compared with resins and chelate resins, and can be cleaned very efficiently. Moreover, when the chelate-forming fiber capturing the metal or the like metal is treated with an acid or alkali aqueous solution, the captured metal or the like metal is easily eluted, so that the chelate capturing ability of the fiber can be easily recovered. By repeating the use, the consumption of the chelating fiber can be greatly reduced. Furthermore, the trapped metal or similar metal can be efficiently concentrated and collected as a valuable component from the eluate, so that the effect of two birds per stone can be enjoyed.
[Brief description of the drawings]
FIG. 1 is a flow chart showing a typical example when the processing method according to the present invention is carried out, FIGS. 2 and 3 are breakthrough curves and elution curves obtained by the method of Example 1, and FIGS. Breakthrough curves and elution curves obtained by using the commercially available chelate resin shown as a comparative method of Example 1, FIGS. 6 and 7 are breakthrough curves and elution curves obtained by the method of Example 2, and FIGS. Breakthrough curves and elution curves when using a commercially available chelating resin shown as a comparative method of Example 2, FIGS. 10 and 11 are breakthrough curves and elution curves obtained by the method of Example 3, and FIGS. 14 and 15 show breakthrough curves and elution curves obtained by using the method of Example 4, and breakthrough curves and elution curves obtained when a commercially available chelate resin was used as a comparative method of Example 3. Shows breakthrough curves obtained by the methods of Examples 5 and 6, and FIG. 18 shows elution obtained by the method of Example 7. Is a line.
A, B: Chelate-forming fiber-filled container, 2: water tank to be treated, 3: eluent water tank, 4, 6; adjustment tank, 5: eluent tank, L ₁ ~ L _Thirteen ; Line, V ₁ ~ V _Thirteen ;valve.

Claims (8)

A method for treating a solution containing a metal and / or a similar metal, wherein the method comprises the steps of repeating the following steps (1) to (3).
(1) A solution containing a metal and / or a similar metal is passed through a filling container filled with chelate-forming fibers in which a functional group capable of forming a chelate with a metal and / or a similar metal is introduced into a fiber molecule. Capturing a metal and / or a similar metal to the chelating fiber by chelating;
(2) After the capturing step (1), an acid or alkali aqueous solution is passed through the filling container to elute the chelate-trapped metal and / or similar metal from the chelate-forming fiber,
(3) After the elution step (2), a step of passing a solution containing a metal and / or a similar metal through the filling container to cause the chelate-forming fibers to capture the metal and / or the similar metal again. The treatment method according to claim 1, wherein the chelate-forming fibers are at least one selected from the group consisting of cloth, thread, powder, and granules. The metal and / or the like are at least one selected from the group consisting of iron, copper, nickel, aluminum, cobalt, cadmium, mercury, lead, zinc, calcium, magnesium, barium, manganese, chromium, molybdenum, and tungsten. 3. The method according to claim 1, wherein the capturing step (1) is performed at a pH of 1 to 11, and the eluting step (2) is performed at a pH of 2 or less. The metal and / or similar metal is boron and / or germanium, the capturing step (1) is performed at a pH of 3 to 12, and the eluting step (2) is performed at a pH of 0.5 to 2.5. 3. The processing method according to 1 or 2. 3. The method according to claim 1, wherein the metal and / or similar metal is arsenic and / or selenium, wherein the capturing step (1) is performed in a pH range of 1 to 8, and the elution step (2) is performed in a pH range of 10 to 14. 4. The processing method described. The processing method according to claim 1, wherein the filling container is of a cartridge type. The treatment method according to any one of claims 1 to 6, wherein the metal and / or metal-containing solution is an aqueous liquid. The treatment method according to any one of claims 1 to 6, wherein the metal and / or metal-containing solution is an oily liquid.

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