JP2004141752A - Humic material adsorbing agent and method of removing humic material - Google Patents
Humic material adsorbing agent and method of removing humic material Download PDFInfo
- Publication number
- JP2004141752A JP2004141752A JP2002308598A JP2002308598A JP2004141752A JP 2004141752 A JP2004141752 A JP 2004141752A JP 2002308598 A JP2002308598 A JP 2002308598A JP 2002308598 A JP2002308598 A JP 2002308598A JP 2004141752 A JP2004141752 A JP 2004141752A
- Authority
- JP
- Japan
- Prior art keywords
- humic
- silica gel
- humic substance
- aqueous solution
- metal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Water Treatment By Sorption (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、フミン物質吸着剤、およびフミン物質除去方法に関する。
【０００２】
【従来の技術】
フミン物質（腐植物質）は、河川、湖水、土壌、泥炭などの中に含まれている物質であり、主に土壌中等において分解、生成された動植物由来の有機成分である。このフミン物質は、単一の化合物からなるものではなく、構造を特定できない複数種の有機物を含んでいる混合物であるが、代表的な元素組成は、Ｃ：５０〜６５％、Ｈ：４〜６％、Ｏ：３０〜４１％、その他微量のＮ、Ｐ、Ｓなどを含み、その分子量は数百〜数十万程度である。また、フミン物質は、カルボキシル基、フェノール性水酸基、カルボニル基、水酸基などの官能基を有する高分子量の有機電解質である。フミン物質の中で、ｐＨ＜２の酸により沈殿する成分はフミン酸（Ｈｕｍｉｃ ａｃｉｄ）と呼ばれ、沈殿することなく濾液中に残る成分はフルボ酸（Ｆｕｌｖｉｃ ａｃｉｄ）と呼ばれている。
【０００３】
なお、出願人が調査した範囲内において、フミン物質の吸着・除去に関する先行技術文献は発見しなかった。
【０００４】
【発明が解決しようとする課題】
フミン物質には、植物に対する栄養分の供給に好影響を与えるなど有益な面も存在するが、以下に述べるとおり、有害な面も存在すると言われている。
例えば、フミン物質は、河川、湖水中の難分解性ＤＯＭ（ＤｉｓｓｏｌｖｅｄＯｒｇａｎｉｃ Ｍａｔｔｅｒ）のうち３０〜８０％を占めており、生活排水や下水施設排水にも多く含まれ、環境汚染の一因となっている。また、フミン物質は、上水道の塩素処理により生成するトリハロメタンの原因物質であるとされている。さらに、人体の赤血球に対する酸化的ストレス（変性、溶血）を起こす可能性や、カシンベック病などとの因果関係も指摘されている。
【０００５】
そのため、今後は、フミン物質の除去を求められる場面も増えてゆくものと考えられるが、フミン物質を効果的に除去する方法は、未だ開発されていないのが現状である。
本発明は、上記問題を解決するためになされたものであり、その目的は、フミン物質を効果的に除去することができる吸着剤、およびフミン物質の除去方法を提供することにある。
【０００６】
【課題を解決するための手段、および発明の効果】
以下、本発明の特徴について詳述する。
請求項１に記載のフミン物質吸着剤は、
２族金属元素および遷移金属元素の中から選ばれる一種または二種以上の金属をシリカゲルに担持してなる金属担持シリカゲルを主成分とすることを特徴とする。
【０００７】
請求項２に記載のフミン物質吸着剤は、請求項１に記載のフミン物質吸着剤において、
担体シリカゲルに対する重量パーセントで、前記金属が２〜４０％担持されていることを特徴とする。
【０００８】
請求項３に記載のフミン物質吸着剤は、請求項１または請求項２に記載のフミン物質吸着剤において、
前記金属担持シリカゲルの表面に対して、アミノ化処理が施されていることを特徴とする。
【０００９】
請求項４記載のフミン物質吸着剤は、請求項１または請求項２に記載のフミン物質吸着剤において、
前記金属担持シリカゲルの表面に対して、疎水化処理が施されていることを特徴とする。
【００１０】
請求項５に記載のフミン物質除去方法は、
請求項１〜請求項４のいずれかに記載したフミン物質吸着剤と、フミン物質を含有する水とを接触処理して、前記フミン物質吸着剤で前記フミン物質を吸着することにより、水中からフミン物質を除去することを特徴とする。
【００１１】
上記フミン物質吸着剤において、金属としては、Ｍｇ、Ｃａなどの２族金属元素、およびＦｅなどの遷移金属元素を利用することができる。これらの金属は、金属塩の水溶液としてシリカゲルに含浸させ、加熱、乾燥することによって担持させればよい。金属の担持量については、金属担持シリカゲル全体に対する重量比で金属が２〜４０％とすることが望ましい。この数値範囲より、金属の担持量が少ないと、金属を担持したことによる効果が弱まり、一方、金属の担持量が多すぎても、吸着に関与しない金属が増えるだけなので、コスト的に不利である。
【００１２】
シリカゲルとしては、種々の物性のものが知られており、どれでも任意に利用できるが、特に細孔容積が０．７ｍｌ／ｇ以上のものは、本発明において使用した場合に吸着能が高いので望ましい。
以上のように構成されたフミン物質吸着剤によれば、２族金属元素および遷移金属元素の中から選ばれる一種または二種以上の金属をシリカゲルに担持してなる金属担持シリカゲルを主成分としているので、フミン物質をよく吸着する。
【００１３】
ここで、吸着剤としては、シリカゲルを主成分とするものが公知であるが、シリカゲルのみを主成分とする吸着剤では、本発明の吸着剤ほどフミン物質を吸着することができない。また、Ｍｇ、Ｃａ、およびＦｅなどの２族金属元素および遷移金属元素の中から選ばれる一種または二種以上の金属の塩（塩化物）を、フミン物質を含む水溶液に添加した場合、フミン物質は金属と反応しても、微細なコロイド粒子になるか、あるいは水溶性の錯体を形成するため、本発明の吸着剤のようにフミン物質を大量に吸着して除去することはできない。すなわち、本発明においては、フミン物質に対する吸着能が比較的低いシリカゲルと金属塩とを組み合わせることにより、フミン物質に対する吸着能がきわめて高い新規な吸着剤を創製しているのである。
【００１４】
本発明でいう金属担持シリカゲルが、フミン物質に対するきわめて高い吸着能を示す理由は、今のところ明確に解明されてはいない。ただし、次のような現象によって、フミン物質が効果的にシリカゲルに吸着していると推察される。
まず、Ｍｇ、Ｃａ、およびＦｅなどの金属は、多孔性物質であるシリカゲルの細孔内表面に存在する酸素原子あるいは酸素イオンと、静電的結合またはイオン結合によって強く結合した状態で担持されていると考えられる。もともとＭｇ、Ｃａ、およびＦｅなどの金属には、フミン物質と化学的な結合を形成しやすい性質があり、具体的には、ＣａやＭｇなどの２族金属元素とフミン物質とは、水に難溶性の塩を形成したり、Ｆｅなどの遷移金属元素とフミン物質とは、錯体を形成したりする。
【００１５】
したがって、これらＭｇ、Ｃａ、およびＦｅなどの２族金属元素や遷移金属元素を担持した金属担持シリカゲルを、フミン物質を含む水溶液に加えると、第一に、フミン物質がインクボトル型の細孔を持ったシリカゲルの細孔内に毛細管現象によって取り込まれる。第二に、細孔内に取り込まれたフミン物質は細孔内表面に存在する金属と相互作用して塩や錯体を形成する。第三に、形成された塩は水に難溶性で、錯体は安定な結合状態を維持しており、結果的にフミン物質がシリカゲルの細孔内に固定化された状態になると考えられる。第四に、仮に、塩や錯体が水中に溶解したとしても、シリカゲルの細孔がインクボトル型であるため、フミン物質が効果的に細孔内に閉じこめられた状態にあると考えられる。以上のような作用によって、フミン物質は効果的に金属担持シリカゲルに吸着され、水中のフミン物質の濃度が大幅に減少しているものと推察される。また、金属担持シリカゲルに対してアミノ処理や疎水処理を施すと、上記に述べたような金属とフミン物質との相互作用に加えて、導入されたアミノ基とフミン物質の官能基（カルボキシル基等）との相互作用や、導入された疎水基とフミン物質の疎水基との相互作用が起こるため、さらにフミン物質と金属担持シリカゲルとの相互作用が向上すると考えられる。
【００１６】
これに対し、シリカゲル単独では、細孔内にフミン物質がとりこまれても、細孔内表面（酸素原子、酸素イオン、またはシラノール基）とフミン物質との相互作用が弱いために、吸着した時点で、ある程度吸着と脱着の平衡状態に達してしまい、これが原因でフミン物質を吸着しにくくなるものと推察される。また、Ｍｇ、Ｃａ、およびＦｅなどの２族金属元素および遷移金属元素の金属塩の水溶液を、フミン物質を含む水溶液に添加しても、水に難溶性の塩となって、これが濾過によって除去できないほど微細なコロイド粒子として水中に存在するか、または、錯体となって、これが水中に溶存しているため、フミン物質を水中から分離しにくいと考えられる。
【００１７】
以上説明したようなフミン物質吸着剤を用いれば、このフミン物質吸着剤と、フミン物質を含有する水とを接触処理して、フミン物質吸着剤でフミン物質を吸着すれば、水中からフミン物質を効率よく除去することができる。
したがって、河川、湖水中の難分解性ＤＯＭ、生活排水、下水施設排水から、フミン物質を除去することができるようになる、また、上水道の塩素処理前に、フミン物質を除去しておくことにより、トリハロメタンなどの有害塩素化合物の生成を抑制することができるようになる。
【００１８】
【発明の実施の形態】
次に、本発明の実施形態についていくつかの例を挙げて説明する。
［実施例１］
ＦｅＣｌ３・６Ｈ２Ｏ １２０ｇとイオン交換水８０ｇとを混合して、３６％ＦｅＣｌ３水溶液を調製した。この水溶液７５ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）７５ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＦｅの重量パーセントは１２％である。
【００１９】
このフミン物質吸着剤２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は９７％に達していた。
【００２０】
［実施例２］
ＦｅＣｌ３・６Ｈ２Ｏ ８０ｇとイオン交換水１２０ｇとを混合して、２４％ＦｅＣｌ３水溶液を調製した。この水溶液７５ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）７５ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＦｅの重量パーセントは８．３％である。
【００２１】
このフミン物質吸着剤２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は８８％に達していた。
【００２２】
［実施例３］
ＭｇＣｌ２・６Ｈ２Ｏ ２５２ｇとイオン交換水１４８ｇとを混合して、２９．５％ＭｇＣｌ２水溶液を調製した。この水溶液３５０ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）２５０ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＭｇの重量パーセントは１１％である。
【００２３】
このフミン物質吸着剤２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は１５分で８４％、２０時間で９６％に達していた。
【００２４】
［実施例４］
ＭｇＣｌ２・６Ｈ２Ｏ １２０ｇとイオン交換水８０ｇとを混合して、２８％ＭｇＣｌ２水溶液を調製した。この水溶液７５ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）７５ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＭｇの重量パーセントは７．２％である。
【００２５】
このフミン物質吸着剤２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は８７％に達していた。
【００２６】
［比較例１］
上記実施例１〜４で用いた球状シリカゲル２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は５１％しかなかった。
【００２７】
上記実施例１〜４と比較例１との対比から、上記実施例１〜４に記載したフミン物質吸着剤が、優れたフミン酸吸着能を備えていることがわかる。
［実施例５］
ＣａＣｌ２・２Ｈ２Ｏ １２０ｇとイオン交換水８０ｇとを混合して、４５％ＣａＣｌ２水溶液を調製した。この水溶液７５ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）７５ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＣａの重量パーセントは１６％である。
【００２８】
このフミン物質吸着剤２０ｍｇと、フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は１５分で５１％、２０時間で６０％に達していた。
【００２９】
［実施例６］
ＦｅＣｌ３・６Ｈ２Ｏ １２０ｇとイオン交換水８０ｇとを混合して、３６％ＦｅＣｌ３水溶液を調製した。この水溶液７５ｇと、微粉末シリカゲル（サイリシア４４０：富士シリシア化学株式会社製）７５ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＦｅの重量パーセントは１２％である。
【００３０】
このフミン物質吸着剤２０ｍｇと、フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、吸着率は１５分で４５％、２０時間で７６％に達していた。
【００３１】
［実施例７］
ＭｇＣｌ２・６Ｈ２Ｏ １５１ｇとイオン交換水７４ｇとを混合して、３１％ＭｇＣｌ２水溶液を調製した。この水溶液２２５ｇと、微粉末シリカゲル（サイリシア４４０：富士シリシア化学株式会社製）１５０ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＭｇの重量パーセントは１２％である。
【００３２】
このフミン物質吸着剤２０ｍｇと、フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、吸着率は１５分で９２％に達していた。
【００３３】
［実施例８］
ＭｇＣｌ２・６Ｈ２Ｏ ２５２ｇとイオン交換水１４８ｇとを混合して、２９．５％ＭｇＣｌ２水溶液を調製した。この水溶液３５０ｇと、球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）２５０ｇとを混合して、電熱器で１７０℃まで加熱して乾燥した。担体シリカゲルに対するＭｇの重量パーセントは１１％である。
【００３４】
この乾燥品１００ｇに、アミノシラン（信越シリコーン製）８ｇと市水１１２ｇとの混合物を混ぜて、所期のアミノ化フミン物質吸着剤を得た。
このアミノ化フミン物質吸着剤２０ｍｇと、スワニー川フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、１５分間後、２０時間後ともに、吸着率は９６％に達していた。
【００３５】
［実施例９］
ＭｇＣｌ２・６Ｈ２Ｏ ２５２ｇとイオン交換水１４８ｇとを混合して、２９．５％ＭｇＣｌ２水溶液を調製した。この水溶液３５０ｇと、微粉末シリカゲル（サイリシア４４０：富士シリシア化学株式会社製）２５０ｇとを混合して、電熱器で１７０℃まで加熱して乾燥し、所期のフミン物質吸着剤を得た。担体シリカゲルに対するＭｇの重量パーセントは１１％である。
【００３６】
この乾燥物にポリアルキルシロキサン（東芝シリコーン製）を使って乾燥物の表面を疎水化処理し、所期の疎水化フミン物質吸着剤を得た。
この疎水化フミン物質吸着剤２０ｍｇと、スワニー川フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、吸着率は１５分で３２％、２０時間で６２％に達していた。
【００３７】
［比較例２］
上記実施例８で用いた球状シリカゲル２０ｍｇと、スワニー川フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、１５分間後、２０時間後ともに、吸着率は１％以下であった。
【００３８】
上記実施例８と比較例２との対比から、上記実施例８に記載したフミン物質吸着剤が、優れたフルボ酸吸着能を備えていることがわかる。
［比較例３］
フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌ中に、ＭｇＣｌ２水溶液０．１ｍｌ（実施例４のＭｇ担持シリカゲル２０ｍｇ中のＭｇ含有量が同等）を褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は１５分で２３％しかなかった。これは、実施例４のおよそ１／４程度しか除去できていないことを示している。
【００３９】
［比較例４］
フミン酸水溶液（７．６ｍｇ／リットル）１０ｍｌ中に、ＣａＣｌ２水溶液０．１ｍｌ（実施例５のＣａ担持シリカゲル２０ｍｇ中のＣａ含有量が同等）を褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フミン酸の吸着率（％）を求めたところ、吸着率は１５分で４４％しかなかった。
【００４０】
［比較例５］
上記実施例８で用いた球状シリカゲル（キャリアクトＱ−５０：富士シリシア化学株式会社製）１００ｇに、アミノシラン（信越シリコーン製）８ｇと市水１１２ｇとの混合物を混ぜて、アミノ化シリカゲルを得た。
【００４１】
このアミノ化シリカゲル２０ｍｇと、スワニー川フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分間または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、１５分後で３２％、２０時間で８８％であった。
【００４２】
上記実施例８と比較例５との対比から、上記実施例８に記載したフミン物質吸着剤が、優れたフルボ酸吸着能を備えていることがわかる。
［比較例６］
上記実施例９で用いた微粉末シリカゲル（サイリシア４４０：富士シリシア化学株式会社製）にポリアルキルシロキサン（東芝シリコーン製）を使って微粉末シリカゲルの表面を疎水化処理し、疎水化微粉末シリカゲルを得た。
【００４３】
この疎水化微粉末シリカゲル２０ｍｇと、スワニー川フルボ酸水溶液（７．６ｍｇ／リットル）１０ｍｌとを褐色容器に入れて蓋をし、２５℃にした恒温振盪機で１５分または２０時間にわたって激しく振盪させた。０．４５μｍのフィルターで濾過した濾液をＵＶ−ＶＩＳスペクトル（２５０ｎｍ、３５０ｎｍ、４５０ｎｍ）で測定し、フルボ酸の吸着率（％）を求めたところ、１５分後、２０時間後ともに、吸着率は１％以下であった。
【００４４】
上記実施例９と比較例６との対比から、上記実施例９に記載したフミン物質吸着剤が、優れたフルボ酸吸着能を備えていることがわかる。
以上、本発明の実施形態について説明したが、本発明は上記の具体的な一実施形態に限定されず、この他にも種々の形態で実施することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a humic substance adsorbent and a humic substance removing method.
[0002]
[Prior art]
Humic substances (humic substances) are substances contained in rivers, lakes, soil, peat, and the like, and are organic components derived from animals and plants that are mainly decomposed and generated in soil and the like. This humic substance is not composed of a single compound but is a mixture containing a plurality of organic substances whose structure cannot be specified. The typical elemental composition is as follows: C: 50 to 65%, H: 4 to 6%, O: 30-41%, and other trace amounts of N, P, S, etc., and the molecular weight is about several hundred to several hundred thousand. The humic substance is a high molecular weight organic electrolyte having a functional group such as a carboxyl group, a phenolic hydroxyl group, a carbonyl group, and a hydroxyl group. Among the humic substances, a component precipitated by an acid having a pH <2 is called humic acid, and a component remaining in the filtrate without precipitation is called fulvic acid.
[0003]
No prior art document relating to adsorption and removal of humic substances was found within the scope examined by the applicant.
[0004]
[Problems to be solved by the invention]
Although humic substances have beneficial aspects such as positively affecting the supply of nutrients to plants, they are said to have harmful aspects as described below.
For example, humic substances occupy 30 to 80% of persistent DOM (Dissolved Organic Matter) in rivers and lake waters, and are contained in a large amount in household wastewater and sewage facility wastewater, and contribute to environmental pollution. I have. Further, humic substances are said to be the causative substances of trihalomethane generated by chlorination of waterworks. Furthermore, the possibility of causing oxidative stress (degeneration, hemolysis) on red blood cells of the human body and a causal relationship with Kasinbek's disease have been pointed out.
[0005]
For this reason, it is expected that the number of situations in which removal of humic substances is required will increase in the future, but a method for effectively removing humic substances has not yet been developed.
The present invention has been made to solve the above problems, and an object of the present invention is to provide an adsorbent capable of effectively removing humic substances and a method for removing humic substances.
[0006]
Means for Solving the Problems and Effects of the Invention
Hereinafter, features of the present invention will be described in detail.
The humic substance adsorbent according to claim 1,
The present invention is characterized in that a metal-supported silica gel in which one or more metals selected from a Group 2 metal element and a transition metal element are supported on silica gel is a main component.
[0007]
The humic substance adsorbent according to claim 2 is the humic substance adsorbent according to claim 1,
The metal is supported by 2 to 40% by weight based on the weight of the silica gel carrier.
[0008]
The humic substance adsorbent according to claim 3 is the humic substance adsorbent according to claim 1 or 2,
The surface of the metal-supported silica gel is subjected to an amination treatment.
[0009]
The humic substance adsorbent according to claim 4 is the humic substance adsorbent according to claim 1 or 2,
The surface of the metal-supported silica gel is subjected to a hydrophobic treatment.
[0010]
The humic substance removing method according to claim 5,
A humic substance adsorbent according to any one of claims 1 to 4, and a humic substance-containing water in a contact treatment, and the humic substance is adsorbed by the humic substance adsorbent. It is characterized by removing the substance.
[0011]
In the humic substance adsorbent, as the metal, a Group 2 metal element such as Mg and Ca, and a transition metal element such as Fe can be used. These metals may be supported by impregnating silica gel as an aqueous solution of a metal salt, heating and drying. Regarding the amount of metal supported, it is desirable that the metal be 2 to 40% by weight based on the whole metal-supported silica gel. From this numerical range, if the supported amount of metal is small, the effect of supporting the metal is weakened.On the other hand, if the supported amount of metal is too large, only the metal that does not participate in adsorption increases, which is disadvantageous in cost. is there.
[0012]
As silica gel, various physical properties are known and any of them can be used arbitrarily. Particularly, silica gel having a pore volume of 0.7 ml / g or more has a high adsorptivity when used in the present invention. desirable.
According to the humic substance adsorbent configured as described above, the main component is a metal-supported silica gel obtained by supporting one or more metals selected from Group 2 metal elements and transition metal elements on silica gel. So it adsorbs humic substances well.
[0013]
Here, as the adsorbent, those containing silica gel as a main component are known, but an adsorbent containing only silica gel as a main component cannot adsorb humic substances as much as the adsorbent of the present invention. Further, when a salt (chloride) of one or more metals selected from Group 2 metal elements and transition metal elements such as Mg, Ca and Fe is added to an aqueous solution containing a humic substance, Even if reacts with a metal, it forms fine colloidal particles or forms a water-soluble complex, so that it cannot adsorb and remove humic substances in a large amount unlike the adsorbent of the present invention. That is, in the present invention, a novel adsorbent having an extremely high adsorptivity for humic substances is created by combining silica gel and a metal salt having relatively low adsorptivity for humic substances.
[0014]
The reason why the metal-supported silica gel according to the present invention exhibits an extremely high adsorptivity for humic substances has not been clearly elucidated so far. However, it is inferred that the humic substances are effectively adsorbed on the silica gel due to the following phenomena.
First, metals such as Mg, Ca, and Fe are supported in a state where they are strongly bonded to oxygen atoms or oxygen ions existing on the inner surface of the pores of silica gel, which is a porous substance, by electrostatic bonding or ionic bonding. It is thought that there is. Originally, metals such as Mg, Ca, and Fe have a property of easily forming a chemical bond with a humic substance. Specifically, a Group 2 metal element such as Ca or Mg and a humic substance are combined with water. A sparingly soluble salt is formed, or a transition metal element such as Fe and a humic substance form a complex.
[0015]
Therefore, when a metal-supported silica gel supporting a Group 2 metal element or a transition metal element such as Mg, Ca, and Fe is added to an aqueous solution containing a humic substance, first, the humic substance causes an ink bottle-type pore to form. It is taken into the pores of the silica gel by capillary action. Second, the humic substance taken into the pore interacts with the metal present on the pore inner surface to form a salt or a complex. Third, it is considered that the formed salt is hardly soluble in water, and the complex maintains a stable binding state, resulting in a state in which the humic substance is immobilized in the pores of the silica gel. Fourth, even if the salt or complex is dissolved in water, it is considered that the humic substance is effectively trapped in the pores because the pores of the silica gel are ink bottle type. It is presumed that the humic substance is effectively adsorbed on the metal-supported silica gel due to the above-mentioned action, and the concentration of the humic substance in water is greatly reduced. Further, when amino treatment or hydrophobic treatment is performed on the metal-supported silica gel, in addition to the interaction between the metal and the humic substance as described above, the introduced amino group and the functional group of the humic substance (such as a carboxyl group) are added. ) And the interaction between the introduced hydrophobic group and the hydrophobic group of the humic substance, which is considered to further improve the interaction between the humic substance and the metal-supported silica gel.
[0016]
In contrast, silica gel alone adsorbs humic substances even when the humic substances are incorporated into the pores, because the interaction between the inner surface of the pores (oxygen atoms, oxygen ions, or silanol groups) and the humic substances is weak. Thus, it is speculated that the equilibrium state of adsorption and desorption is reached to some extent, which makes it difficult to adsorb humic substances. Further, even when an aqueous solution of a metal salt of a Group 2 metal element such as Mg, Ca, and Fe and a transition metal element is added to an aqueous solution containing a humic substance, it becomes a poorly water-soluble salt, which is removed by filtration. It is considered that humic substances are difficult to separate from water because they exist in water as colloidal particles that are too small or are dissolved in water as a complex.
[0017]
If the humic substance adsorbent described above is used, the humic substance adsorbent is contact-treated with water containing the humic substance, and the humic substance is adsorbed by the humic substance adsorbent. It can be removed efficiently.
Therefore, humic substances can be removed from hard-to-degrade DOM in rivers and lakes, domestic wastewater, and wastewater from sewage facilities. By removing humic substances before chlorination of waterworks, And the production of harmful chlorine compounds such as trihalomethane.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with some examples.
[Example 1]
120 g of FeCl 3 .6H 2 O and 80 g of ion-exchanged water were mixed to prepare a 36% aqueous solution of FeCl 3 . 75 g of this aqueous solution and 75 g of spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain a desired humic substance adsorbent. . The weight percentage of Fe on the support silica gel is 12%.
[0019]
20 mg of this humic substance adsorbent and 10 ml of an aqueous humic acid solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 20 hours using a constant temperature shaker at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. As a result, the adsorption rate reached 97%.
[0020]
[Example 2]
80 g of FeCl 3 .6H 2 O and 120 g of ion-exchanged water were mixed to prepare a 24% FeCl 3 aqueous solution. 75 g of this aqueous solution and 75 g of spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain a desired humic substance adsorbent. . The weight percentage of Fe on the support silica gel is 8.3%.
[0021]
20 mg of this humic substance adsorbent and 10 ml of an aqueous humic acid solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 20 hours using a constant temperature shaker at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. As a result, the adsorption rate reached 88%.
[0022]
[Example 3]
By mixing a MgCl 2 · 6H 2 O 252g of ion-exchanged water 148 g, to prepare a 29.5% MgCl 2 aqueous solution. 350 g of this aqueous solution and 250 g of spherical silica gel (Carrierct Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain an intended humic substance adsorbent. . The weight percentage of Mg relative to the supported silica gel is 11%.
[0023]
20 mg of this humic substance adsorbent and 10 ml of an aqueous solution of humic acid (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 15 minutes or 20 hours with a thermostat at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the humic acid adsorption rate (%). It had reached 96%.
[0024]
[Example 4]
By mixing a MgCl 2 · 6H 2 O 120g of ion-exchanged water 80 g, to prepare a 28% MgCl 2 aqueous solution. 75 g of this aqueous solution and 75 g of spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain a desired humic substance adsorbent. . The weight percentage of Mg relative to the supported silica gel is 7.2%.
[0025]
20 mg of this humic substance adsorbent and 10 ml of an aqueous humic acid solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 20 hours using a constant temperature shaker at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. As a result, the adsorption rate reached 87%.
[0026]
[Comparative Example 1]
20 mg of the spherical silica gel used in Examples 1 to 4 and 10 ml of an aqueous humic acid solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 20 hours using a constant temperature shaker at 25 ° C. Was. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. The adsorption rate was only 51%.
[0027]
From the comparison between Examples 1 to 4 and Comparative Example 1, it can be seen that the humic substance adsorbents described in Examples 1 to 4 have excellent humic acid adsorption ability.
[Example 5]
120 g of CaCl 2 .2H 2 O and 80 g of ion-exchanged water were mixed to prepare a 45% CaCl 2 aqueous solution. 75 g of this aqueous solution and 75 g of spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain a desired humic substance adsorbent. . The weight percentage of Ca relative to the supported silica gel is 16%.
[0028]
20 mg of this humic substance adsorbent and 10 ml of an aqueous solution of humic acid (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 15 minutes or 20 hours with a thermostat at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured with a UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the humic acid adsorption rate (%). It had reached 60%.
[0029]
[Example 6]
120 g of FeCl 3 .6H 2 O and 80 g of ion-exchanged water were mixed to prepare a 36% aqueous solution of FeCl 3 . 75 g of this aqueous solution and 75 g of fine powdered silica gel (Sylysia 440: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain a desired humic substance adsorbent. The weight percentage of Fe on the support silica gel is 12%.
[0030]
20 mg of the humic substance adsorbent and 10 ml of a fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 15 minutes or 20 hours using a thermostat at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the fulvic acid adsorption rate (%). It had reached 76%.
[0031]
[Example 7]
151 g of MgCl 2 .6H 2 O and 74 g of ion-exchanged water were mixed to prepare a 31% MgCl 2 aqueous solution. 225 g of this aqueous solution and 150 g of fine powdered silica gel (Sylysia 440: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried to obtain an intended humic substance adsorbent. The weight percentage of Mg relative to the support silica gel is 12%.
[0032]
20 mg of this humic substance adsorbent and 10 ml of a fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken with a thermostat at 25 ° C. for 15 minutes. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the fulvic acid adsorption rate (%). The adsorption rate reached 92% in 15 minutes. .
[0033]
Example 8
By mixing a MgCl 2 · 6H 2 O 252g of ion-exchanged water 148 g, to prepare a 29.5% MgCl 2 aqueous solution. 350 g of this aqueous solution and 250 g of spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater, and dried. The weight percentage of Mg relative to the supported silica gel is 11%.
[0034]
A mixture of 8 g of aminosilane (made by Shin-Etsu Silicone) and 112 g of city water was mixed with 100 g of the dried product to obtain an intended aminated humic substance adsorbent.
20 mg of this aminated humic substance adsorbent and 10 ml of Suwanee River fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken with a thermostatic shaker at 25 ° C. for 15 minutes or 20 hours. I let it. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the fulvic acid adsorption rate (%) was determined. It had reached 96%.
[0035]
[Example 9]
By mixing a MgCl 2 · 6H 2 O 252g of ion-exchanged water 148 g, to prepare a 29.5% MgCl 2 aqueous solution. 350 g of this aqueous solution and 250 g of fine powdered silica gel (Sylysia 440: manufactured by Fuji Silysia Chemical Ltd.) were mixed, heated to 170 ° C. with an electric heater and dried to obtain a desired humic substance adsorbent. The weight percentage of Mg relative to the supported silica gel is 11%.
[0036]
The surface of the dried product was hydrophobized using a polyalkylsiloxane (manufactured by Toshiba Silicone Co., Ltd.) to obtain the desired adsorbent for hydrophobized humic substances.
20 mg of the hydrophobized humic substance adsorbent and 10 ml of Suwanee River fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken at 25 ° C. for 15 minutes or 20 hours with a thermostatic shaker. I let it. The filtrate filtered through a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the fulvic acid adsorption rate (%). It had reached 62%.
[0037]
[Comparative Example 2]
20 mg of the spherical silica gel used in Example 8 and 10 ml of Suwanny River fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, capped, and placed on a thermostat shaker at 25 ° C. for 15 minutes or 20 hours. Shake vigorously. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the fulvic acid adsorption rate (%) was determined. It was less than 1%.
[0038]
The comparison between Example 8 and Comparative Example 2 shows that the humic substance adsorbent described in Example 8 has excellent fulvic acid adsorption ability.
[Comparative Example 3]
In 10 ml of humic acid aqueous solution (7.6 mg / l), put 0.1 ml of MgCl 2 aqueous solution (equivalent to Mg content in 20 mg of Mg-supported silica gel of Example 4) in a brown container, cover the container, and cool to 25 ° C. The mixture was vigorously shaken for 15 minutes using a constant temperature shaker. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. The adsorption rate was only 23% in 15 minutes. This indicates that only about １ ／ of Example 4 was removed.
[0039]
[Comparative Example 4]
0.1 ml of CaCl 2 aqueous solution (equivalent to Ca content in 20 mg of Ca-supported silica gel of Example 5) was placed in 10 ml of humic acid aqueous solution (7.6 mg / liter) in a brown container, and the container was closed at 25 ° C. The mixture was vigorously shaken for 15 minutes using a constant temperature shaker. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the humic acid adsorption rate (%) was determined. The adsorption rate was only 44% in 15 minutes.
[0040]
[Comparative Example 5]
A mixture of 8 g of aminosilane (manufactured by Shin-Etsu Silicone) and 112 g of city water was mixed with 100 g of the spherical silica gel (Carrieract Q-50: manufactured by Fuji Silysia Chemical Ltd.) used in Example 8 to obtain an aminated silica gel. .
[0041]
20 mg of this aminated silica gel and 10 ml of Suwanee River fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 15 minutes or 20 hours using a thermostatic shaker at 25 ° C. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm), and the fulvic acid adsorption rate (%) was determined. Met.
[0042]
From the comparison between Example 8 and Comparative Example 5, it can be seen that the humic substance adsorbent described in Example 8 has excellent fulvic acid adsorption ability.
[Comparative Example 6]
The surface of the fine powdered silica gel (Silicia 440: manufactured by Fuji Silysia Chemical Ltd.) used in Example 9 was subjected to hydrophobizing treatment using polyalkylsiloxane (manufactured by Toshiba Silicone Co., Ltd.). Obtained.
[0043]
20 mg of this hydrophobized fine powder silica gel and 10 ml of Suwanee River fulvic acid aqueous solution (7.6 mg / liter) were placed in a brown container, covered with a lid, and vigorously shaken for 15 minutes or 20 hours using a thermostatic shaker at 25 ° C. Was. The filtrate filtered with a 0.45 μm filter was measured by UV-VIS spectrum (250 nm, 350 nm, 450 nm) to determine the fulvic acid adsorption rate (%). It was less than 1%.
[0044]
The comparison between Example 9 and Comparative Example 6 shows that the humic substance adsorbent described in Example 9 has excellent fulvic acid adsorption ability.
As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described specific embodiments, and can be implemented in various other modes.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002308598A JP4095877B2 (en) | 2002-10-23 | 2002-10-23 | Humic substance adsorbent and humic substance removal method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002308598A JP4095877B2 (en) | 2002-10-23 | 2002-10-23 | Humic substance adsorbent and humic substance removal method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004141752A true JP2004141752A (en) | 2004-05-20 |
| JP4095877B2 JP4095877B2 (en) | 2008-06-04 |
Family
ID=32454696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002308598A Expired - Fee Related JP4095877B2 (en) | 2002-10-23 | 2002-10-23 | Humic substance adsorbent and humic substance removal method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4095877B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013027821A (en) * | 2011-07-28 | 2013-02-07 | Takuma Co Ltd | Sand filtration device, and method for producing filter sand therefor |
-
2002
- 2002-10-23 JP JP2002308598A patent/JP4095877B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013027821A (en) * | 2011-07-28 | 2013-02-07 | Takuma Co Ltd | Sand filtration device, and method for producing filter sand therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4095877B2 (en) | 2008-06-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Haldar et al. | MOFs for the treatment of arsenic, fluoride and iron contaminated drinking water: A review | |
| Hasanpour et al. | Application of three dimensional porous aerogels as adsorbent for removal of heavy metal ions from water/wastewater: A review study | |
| Prashantha Kumar et al. | Nanoscale materials as sorbents for nitrate and phosphate removal from water | |
| Xu et al. | Adsorption and removal of arsenic (V) from drinking water by aluminum-loaded Shirasu-zeolite | |
| Mahmoud et al. | Enhanced biosorptive removal of cadmium from aqueous solutions by silicon dioxide nano-powder, heat inactivated and immobilized Aspergillus ustus | |
| Albayati et al. | Adsorption of binary and multi heavy metals ions from aqueous solution by amine functionalized SBA-15 mesoporous adsorbent in a batch system | |
| Tiwari et al. | Hybrid materials in the removal of diclofenac sodium from aqueous solutions: Batch and column studies | |
| Qiu et al. | Fabrication and evaluation of a regenerable HFO-doped agricultural waste for enhanced adsorption affinity towards phosphate | |
| Kheshtzar et al. | Facile synthesis of smartaminosilane modified-SnO2/porous silica nanocomposite for high efficiency removal of lead ions and bacterial inactivation | |
| US20080058206A1 (en) | Arsenic absorbing composition and methods of use | |
| Arenas et al. | Removal efficiency and adsorption mechanisms of CeO2 nanoparticles onto granular activated carbon used in drinking water treatment plants | |
| Siddeeg et al. | Application of functionalized nanomaterials as effective adsorbents for the removal of heavy metals from wastewater: a review | |
| Nussinovitch et al. | Hydrocolloid liquid-core capsules for the removal of heavy-metal cations from water | |
| Li et al. | Facile method to granulate drinking water treatment residues as a potential media for phosphate removal | |
| Lei et al. | Effectiveness and mechanism of aluminum/iron co-modified calcite capping and amendment for controlling phosphorus release from sediments | |
| Salmani et al. | Synthesis, characterization and application of mesoporous silica in removal of cobalt ions from contaminated water | |
| EP2733119A1 (en) | Agent for removing dissolved phosphorus compounds from water | |
| Pawlaczyk et al. | Efficient removal of Ni (II) and Co (II) ions from aqueous solutions using silica-based hybrid materials functionalized with PAMAM dendrimers | |
| by CBN | Heavy metals removal using carbon based nanocomposites | |
| Bhagyaraj et al. | Modified os sepiae of Sepiella inermis as a low cost, sustainable, bio-based adsorbent for the effective remediation of boron from aqueous solution | |
| Sharifian et al. | Reusable granulated silica pillared clay for wastewater treatment, selective for adsorption of Ni (II) | |
| JP4095877B2 (en) | Humic substance adsorbent and humic substance removal method | |
| Hul et al. | Insights into polystyrene nanoplastics adsorption mechanisms onto quartz sand used in drinking water treatment plants | |
| Marszałek | Encapsulation of halloysite with sodium alginate and application in the adsorption of copper from rainwater | |
| Malsawmdawngzela et al. | Facile synthesis and implications of novel hydrophobic materials: Newer insights of pharmaceuticals removal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20051014 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20071121 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20071127 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20080128 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20080219 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20080310 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110314 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130314 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140314 Year of fee payment: 6 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |