JP2004182511A

JP2004182511A - Activated carbon and method of manufacturing the same

Info

Publication number: JP2004182511A
Application number: JP2002350054A
Authority: JP
Inventors: Kenichi Shinohara; 研一篠原; Mitsushi Matsumoto; 充司松本; Toyoki Uyama; 豊樹宇山; Yoshitaka Nakahigashi; 義貴中東; Tsutomu Sakaida; 勤坂井田; Keiji Sakai; 啓二堺
Original assignee: AD ALL CO Ltd; AD'ALL CO Ltd; Osaka Gas Chemicals Co Ltd; Unitika Ltd
Current assignee: AD ALL CO Ltd; AD'ALL CO Ltd; Osaka Gas Chemicals Co Ltd; Unitika Ltd
Priority date: 2002-12-02
Filing date: 2002-12-02
Publication date: 2004-07-02

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling the meso-fine pore distribution of activated carbon. <P>SOLUTION: In a method of using pitch containing 0.01-5 wt.% at least one kind of a metal element of Mg, Mn, Fe, Y, Pt and Gd as an activated carbon precursor, making the precursor infusible or carbonizing the precursor and activating, the kind of the metal element is changed to control the meso-fine pore mode diameter of the resultant activated carbon. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、新規な活性炭及びその製造方法に関する。なお、本発明において、「ミクロ細孔」とは細孔直径が２０Å未満の細孔をいい、「メソ細孔」とは細孔直径が２０Å以上５００Å未満の細孔をいう。
【０００２】
【従来の技術】
多様な細孔分布を持つ活性炭の細孔の中でも、被吸着物質の分子サイズの約１．５〜２倍程度の細孔が最も吸着に適していると言われており、低濃度領域では多くの被吸着物質が細孔直径２０Å未満のミクロ細孔に吸着される。従って、被吸着物質に適したサイズのミクロ細孔容積が大きい活性炭がより高い吸着能力を有することになる。ところが、水中の低濃度有機物質（例えば、トリハロメタン類等）は、静的吸着に対して動的吸着では極端に吸着量が低くなる。その要因としては、被吸着物質とミクロ細孔の接触効率の低さ、非吸着物質と細孔表面との親和性の影響等が考えられている。
被吸着物質と吸着サイトであるミクロ細孔との接触効率を上げる手段としては、ミクロ細孔への導入孔としてメソ細孔を活性炭に発現させる方法が一般に知られている。特に、一定比率のメソ細孔を有する活性炭は、ミクロ細孔のみの活性炭よりも動的吸着量が大幅に向上する。
メソ細孔を活性炭に発達させるために、有機金属を活性炭前駆体に添加する方法が提案されている（特許文献１など参照）。また、トリハロメタン、黴臭等の有機化合物の吸着能力を高めるためにメソ細孔を発達させる方法も提案されている（特許文献２、特許文献３など参照）。
しかしながら、これらの技術でも、２０〜５００Åの広い範囲のメソ細孔を制御するには至っておらず、どの細孔径が吸着能力を高めるのに有効であるかは解明されていない。
【０００３】
【特許文献１】特許第３１４３６９０号
【０００４】
【特許文献２】特開平１１−２４０７０７公報
【０００５】
【特許文献３】特開２０００−３５１６１３公報
【０００６】
【発明が解決しようとする課題】
接触効率を効果的に上げるのに最適な活性炭のメソ細孔サイズ及び容積比率は、被吸着物質の種類、流速等によって異なることが予想される。メソ細孔容積が大き過ぎ、ブロードな細孔分布をもつ活性炭はかえって動的吸着量が減少する傾向にある。また、メソ細孔を発達させることは生産効率が悪化する要因にもなることから、活性炭の用途に応じてメソ細孔直径及び容積を制御することが望ましい。
このように、活性炭のメソ細孔分布を所望の範囲に制御することができれば、被吸着物質の種類、流速等に応じた最適な材料を提供することが可能になるものの、そのような技術は未だ開発されていないのが現状である。
従って、本発明の主な目的は、活性炭のメソ細孔分布を制御できる方法を提供することにある。
【０００７】
【課題を解決するための手段】
本発明者は、従来技術の問題に鑑みて鋭意研究を重ねた結果、特定の金属元素を一定の範囲で添加することによって所望のメソ細孔分布を有する活性炭が得られることを見出し、本発明を完成するに至った。
【０００８】
すなわち、本発明は、下記の活性炭及びその製造方法に係るものである。
【０００９】
１．７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、かつ、全細孔容積に対する上記範囲のメソ細孔容積の割合が５〜４５％である活性炭。
【００１０】
２．Ｍｇ、Ｍｎ、Ｆｅ、Ｙ、Ｐｔ及びＧｄの少なくとも１種の金属成分を０．０１〜５重量％含有するピッチを活性炭前駆体として用い、当該前駆体を不融化処理又は炭素化処理し、賦活処理する方法において、
上記金属成分の種類を変えることによって、得られる活性炭のメソ細孔モード直径を制御することを特徴とする活性炭の製造方法。
【００１１】
３．得られる活性炭のメソ細孔モード直径を３０〜４５Åの範囲で制御する前記項２記載の製造方法。
【００１２】
４．Ｍｇを０．０１〜５重量％含有するピッチを活性炭前駆体として用い、当該前駆体を不融化処理又は炭素化処理し、賦活処理して得られる活性炭であって、
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対する上記範囲のメソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が３０〜３６Åである活性炭。
【００１３】
５．Ｍｎ、Ｙ、Ｐｔ及びＧｄの少なくとも１種を０．０１〜５重量％含有するピッチを活性炭前駆体として用い、当該前駆体を不融化処理又は炭素化処理し、賦活処理して得られる活性炭であって、
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対する上記範囲のメソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が３４〜４０Åである活性炭。
【００１４】
６．Ｆｅを０．０１〜５重量％含有するピッチを活性炭前駆体として用い、当該前駆体を不融化処理又は炭素化処理し、賦活処理して得られる活性炭であって、
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対する上記範囲のメソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が４０〜４５Åである活性炭。
【００１５】
【発明の実施の形態】
１．本発明活性炭
本発明の活性炭は、７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、かつ、全細孔容積に対する上記範囲のメソ細孔容積の割合（以下「メソ細孔容積率」とも言う。）が５〜４５％である。
【００１６】
本発明の活性炭の細孔分布は、７７．４Ｋにおいて窒素吸着等温線に基づいて算出される。具体的には、次のようにして窒素吸着等温線が作成される。活性炭を７７．４Ｋ（窒素の沸点）に冷却し、窒素ガスを導入して容量法により窒素ガスの吸着量Ｖ［ｃｃ／ｇ］を測定する。このとき、導入する窒素ガスの圧力Ｐ［ｍｍＨｇ］を徐々に上げ、窒素ガスの飽和蒸気圧Ｐ_０［ｍｍＨｇ］で除した値を相対圧力Ｐ／Ｐ_０として、各相対圧力に対する吸着量をプロットすることにより窒素吸着等温線が作成される。窒素ガスの吸着量は、市販の自動ガス吸着量測定装置（例えば、商品名「ＡＵＴＯＳＯＲＢ−６」（ＱＵＡＮＴＣＨＲＯＭＥ製）等）を用いて実施できる。本発明では、窒素吸着等温線に基づき、公知の解析方法に従って細孔分布を求めることができる。この解析は、上記装置に付属する解析プログラム等のような公知の手段を用いることができる。
【００１７】
本発明のメソ細孔容積は、上記の細孔分布に基づきＢＪＨ法で計算する。ＢＪＨ法自体は公知の方法であり、例えば「Ｊ．Ａｍｅｒ．Ｃｈｅｍ．Ｓｏｃ．，７３，３７３（１９５１））」に開示された方法に従って行うことができる。
【００１８】
また、本発明の全細孔容積は、上記の窒素ガスの吸着量の測定結果における窒素の最大吸着量から計算することができる。
【００１９】
本発明の活性炭は、細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇ（好ましくは０．０５〜０．２０ｃｃ／ｇ）であり、かつ、全細孔容積に対する上記メソ細孔容積の割合が５〜４５％（好ましくは１０〜２５％）である。かかる範囲内に上記メソ細孔容積及び上記割合を制御することによって、各種の被吸着物質（特にトリハロメタン類）の吸着に適した材料とすることができる。
【００２０】
なお、メソ細孔の学術的な細孔直径の範囲は２０Å以上５００Å未満であるところ、本発明ではそのようなメソ細孔のうち細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積を規定するものである。
【００２１】
本発明の活性炭は、その形態は限定的ではないが、一般的には繊維状であることが望ましい。すなわち、本発明は、活性炭素繊維であることが望ましい。この場合の比表面積（ＢＥＴ法）は７００〜１４００ｍ^２／ｇ程度、全細孔容積０．３０〜０．９０ｃｃ／ｇ程度、ミクロ細孔容積０．３０〜０．６０ｃｃ／ｇ程度、メソ細孔モード直径３０〜４５Å程度であることが好ましい。なお、本発明における「メソ細孔モード直径」とは、２０〜５００Åのメソポア領域における細孔容積分布のピークが位置する細孔直径を意味する。
【００２２】
好ましくは、本発明の活性炭は、Ｍｇ、Ｍｎ、Ｆｅ、Ｙ、Ｐｔ及びＧｄの少なくとも１種の金属成分を含有する。これらの金属成分を含むことによって、特定のメソ細孔モード直径を有する活性炭となり得る。例えば、含有する金属成分の種類に応じて次のような構造・特性を有する活性炭となる。
（ａ）Ｍｇを含む場合
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対する上記メソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が３０〜３６Åである活性炭
（ｂ）Ｍｎ、Ｙ、Ｐｔ、Ｇｄの少なくとも１種を含む場合
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対するメソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が３４〜４０Åである活性炭
（ｃ）Ｆｅを含む場合
７７．４Ｋにおける窒素吸着等温線よりＢＪＨ法で求めた細孔分布において細孔直径３０Å以上５０Å未満の範囲のメソ細孔容積が０．０２〜０．４０ｃｃ／ｇであり、全細孔容積に対するメソ細孔容積の割合が５〜４５％であり、かつ、メソ細孔モード直径が４０Å〜４５Åである活性炭
本発明の活性炭は、公知の活性炭と同様の用途に用いることができる。また、液相用途又は気相用途のいずれにも用いることが可能である。とりわけ、本発明活性炭は、液相中（特に浄水中）に含まれる有機化合物（特にトリハロメタン類）を濾過・除去するために用いる材料として好適に用いることができる。浄水中に含まれる有機化合物の濾過用材料として用いる場合は、公知の浄水器等における吸着材に代えて本発明材料をそのまま使用すれば良い。このときの通水量、本発明材料の使用量等も公知の方法・条件に従えば良い。
２．活性炭の製造方法
本発明の活性炭は、上記のような特性を有するものが得られる限り、どのような方法で製造しても良いが、例えば次のような製造方法によることが望ましい。
【００２３】
すなわち、Ｍｇ、Ｍｎ、Ｆｅ、Ｙ、Ｐｔ及びＧｄの少なくとも１種の金属成分を０．０１〜５重量％含有するピッチを活性炭前駆体として用い、当該前駆体を不融化処理又は炭素化処理し、賦活処理する方法において、
上記金属成分の種類を変えることによって、得られる活性炭のメソ細孔モード直径を制御することを特徴とする活性炭の製造方法によって、本発明の活性炭をより確実に得ることができる。
【００２４】
まず、活性炭前駆体として、Ｍｇ、Ｍｎ、Ｆｅ、Ｙ、Ｐｔ及びＧｄの少なくとも１種の金属成分を０．０１〜５重量％含有するピッチを用いる。上記金属成分を２種以上併用する場合、その組み合わせ、その割合等は活性炭の用途、使用目的等に応じて適宜設定すれば良い。
【００２５】
金属成分の含有量は活性炭前駆体中０．０１〜５重量％、好ましくは０．１〜２重量％になるように調整する。金属成分の含有量が０．０１重量％未満の場合は、賦活反応時の金属の作用が弱くなる等の理由により、本発明の活性炭が得られなくなることがある。逆に５重量％を超える場合は、活性炭中で金属成分が凝縮しやすくなり、活性炭の物理的強度が著しく低下するため、濾過材等としての実用性を欠くことがある。
【００２６】
なお、本発明では、金属成分の含有量は、金属化合物としての含有量ではなく金属元素換算の含有量を示し、ＩＣＰ発光分析法により測定した値を示す。
【００２７】
本発明の製造方法では、含有させる金属成分の種類を変化させることによって、得られる活性炭のメソ細孔モード直径を少なくとも制御できる。特に、得られる活性炭のメソ細孔モード直径を３０〜４５Åの範囲で制御することができる。例えば、活性炭前駆体に添加する金属をＭｇ、Ｍｎ、Ｆｅ、Ｙ、Ｐｔ及びＧｄの中から選択することによって、３種類の異なるメソ細孔モード直径を有する活性炭を製造することが可能である。
【００２８】
すなわち、（ａ）活性炭前駆体にＭｇを上記所定量添加した場合に得られる活性炭のメソ細孔モード直径は３０〜３６Å、（ｂ）活性炭前駆体にＭｎ、Ｙ、Ｐｔ及びＧｄの少なくとも１種を上記所定量添加した場合に得られる活性炭のメソ細孔モード直径は３４〜４０Å、（ｃ）活性炭前駆体にＦｅを上記所定量添加した場合に得られる活性炭のメソ細孔モード直径は４０〜４５Åにそれぞれ制御することができる。
【００２９】
本発明において、金属成分の含有量（添加量）及び賦活条件によってメソ細孔容積は変化するが、メソ細孔モード直径はほとんど変化しない。このため、金属成分の種類を変更することによって、所望のメソ細孔モード直径を有する活性炭を得ることが可能になる。
【００３０】
また、これら活性炭のうち、メソ細孔容積０．０２〜０．４０ｃｃ／ｇ、かつ、メソ細孔容積率５〜４５％であるものは、特に液相中の有機化合物の動的吸着能力に優れるという点で望ましい。
【００３１】
活性炭前駆体は、例えば上記金属成分を含む化合物（金属化合物）とピッチとを混合することによって調製することができる。
【００３２】
上記ピッチとしては、不融化、炭素化等により活性炭になり得るものであって、しかも金属化合物と混合可能なものであれば特に限定されない。例えば、石油系ピッチ、石炭系ピッチ、合成ピッチ等のいずれも使用できる。また、光学的性質としても、等方性又は異方性のいずれであっても良い。
【００３３】
なお、活性炭前駆体を調製する場合、例えばピッチの原料であるコールタールと金属化合物とを溶媒中で混合・攪拌した後、減圧蒸留することによりピッチと金属成分を含む活性炭前駆体を得ることもできる。
【００３４】
金属化合物としては、上記金属成分が含まれていれば特に限定されず、無機化合物及び有機化合物のいずれも使用することができる。無機化合物としては、例えば塩化物、硝酸塩、酢酸塩等の無機塩類を使用することができる。より具体的には、塩化鉄、硝酸鉄、酢酸鉄等を例示することができる。また、有機化合物としては、上記金属成分とアセチルアセトンやシクロペンタジエン等との有機金属錯体が挙げられる。より具体的には、トリスアセチルアセトナト鉄、トリスシクロペンタジエニル鉄、アセチルアセトナート鉄、アセチルアセトナートマグネシウム、アセチルアセトナートマンガン、アセチルアセトナートイットリウム、アセチルアセトナート白金、アセチルアセトナートガドリニウム等を例示することができる。
【００３５】
金属化合物とピッチとの混合方法は、均一に混合できれば限定されない。例えば、金属化合物とピッチとをそのまま混合したり、あるいは適当な溶媒中で両者を混合しても良い。特に、金属化合物とピッチとを溶媒中で混合することが好ましい。
【００３６】
溶媒としては、金属化合物及びピッチの双方を溶解できるものであれば特に限定されない。例えば、キノリン、ベンゼン、ジクロロメタン、トルエン、キシレン、テトラヒドロフラン、メタノール、エタノール等の公知の溶媒の中から、用いるピッチの種類、金属化合物の種類に応じて適宜選択すれば良い。例えば、鉄化合物としてアセチルアセトン錯体を用い、ピッチとして石炭系等方性ピッチを用いる場合には、キノリン等を用いることができる。
【００３７】
溶媒の使用量は、均一な活性炭前駆体が得られる限り特に限定されず、使用する溶媒、金属化合物等の種類に応じて適宜設定すれば良い。
【００３８】
次いで、得られた活性炭前駆体を、必要に応じて予め紡糸した後、不融化処理又は炭素化処理し、次いで賦活処理を施すことによって本発明活性炭（活性炭素繊維）を得ることができる。上記紡糸方法、不融化処理、炭素化処理、賦活処理等は、以下に示す方法で実施することが好ましい。
【００３９】
紡糸方法は、公知の溶融紡糸方法に従って行うことができる。溶融温度及び紡糸温度は、一般に活性炭前駆体の軟化点温度以上の温度とし、好ましくは軟化点よりも３０〜１００℃高い温度に設定する。溶融した活性炭前駆体は、紡糸機のノズル部へ送液され、多数の細孔を穿ったノズル面より、紡糸温度以下に制御された雰囲気中に繊維を形成しつつ吐出される。
【００４０】
不融化処理は、不活性ガス雰囲気又は酸素含有ガス雰囲気下において活性炭前駆体をその融点以下の温度から昇温速度０．１〜１０℃／分で４００℃程度まで加熱することによって実施することができる。
【００４１】
炭素化処理は、窒素ガス、アルゴンガス等の不活性ガス雰囲気下において、活性炭前駆体を昇温速度５〜１０℃／分で８００〜１２００℃程度まで加熱し、そのときの最大温度を最大限１０分程度維持することにより実施することができる。
【００４２】
賦活処理は、水蒸気、二酸化炭素、酸素及びこれらの混合ガス並びにこれらのガスを窒素等の不活性ガスで希釈したガス雰囲気中において、不融化処理及び／又は炭素化処理が施された活性炭前駆体を８００〜１２００℃程度の温度で５〜１２０分程度保持することにより実施することができる。
【００４３】
【発明の効果】
本発明の活性炭の製造方法によれば、所望のメソ細孔分布に制御できることから、被吸着物質及び使用条件に合せて最適なメソ細孔分布の活性炭を製造することができる。例えば、トリハロメタン類の吸着用活性炭を製造する場合には、Ｆｅ添加活性炭が水中の有機化合物除去の吸着材として最も優れた効果を発揮することができる。
【００４４】
また、本発明の製造方法では、任意のメソ細孔に制御することによって、不必要な細孔の発現を抑えることができるので、生産性の向上にも寄与できる。
【００４５】
【実施例】
以下、実施例及び比較例を示し、本発明の特徴とするところをよりいっそう明確に示す。ただし、本発明は、これら実施例に限定されるものではない。
【００４６】
なお、本実施例では、活性炭の窒素ガス吸着量は、商品名「ＡＵＴＯＳＯＲＢ−６」（ＱＵＡＮＴＣＨＲＯＭＥ製）を用いて測定し、細孔分布の解析は付属の解析プログラムで実施した。全細孔容積は、窒素の最大吸着量から計算した。また、メソ細孔容積は、ＢＪＨ法（Ｊ．Ａｍｅｒ．Ｃｈｅｍ．Ｓｏｃ．，７３，３７３（１９５１））により計算した。
【００４７】
実施例１
水分及びキノリン不溶分を除去したコールタール１０００ｇを窒素雰囲気下９０℃に加温し、そこにアセチルアセトナトマグネシウム２１ｇを溶解したキノリン混合液１５０ｍｌを徐々に滴下し、９０分間攪拌した。次に、これを減圧蒸留し、さらに３Ｌ／分の割合で空気を吹き込みながら３３０℃で３時間反応することにより、マグネシウム含有コールタールピッチを得た。このピッチの鉄含有量は０．１４重量％であった。得られたマグネシウム含有コールタールピッチを溶融温度３２０℃で溶融押出紡糸してピッチ繊維を得た。紡糸されたピッチ繊維を空気中で常温から昇温速度１〜１０℃／分で加熱し、最高温度３５４℃で４分保持し、全不融化時間５８分をかけて不融化処理を行った。次いで、不融化したピッチ繊維を窒素雰囲気下８５０℃で２５分間飽和水蒸気に暴露し、賦活処理を行うことにより、マグネシウム含有活性炭素繊維を得た。得られた活性炭素繊維の諸特性を製造条件とともに表１に示す。
【００４８】
実施例２〜４及び比較例２
表１に示す製造条件としたほかは、実施例１と同様にして活性炭素繊維を製造した。得られた活性炭素繊維の諸特性を表１に示す。
【００４９】
【表１】

【００５０】
表１に示すように、マグネシウム含有活性炭素繊維の細孔分布には、メソ細孔の領域にピークが発現した。すなわち、金属含有量、賦活条件等にかかわらず、メソ細孔モード直径が３４Åという一定の値をもつ活性炭素繊維が得られることがわかる。
【００５１】
比較例１
表１に示すように、金属成分を添加しなかったほかは、実施例１と同様にして活性炭素繊維を製造した。得られた活性炭素繊維の諸特性を表１に示す。
【００５２】
実施例５〜９
表２に示す製造条件としたほかは、実施例１と同様にして活性炭素繊維を製造した。すなわち、イットリウム、マンガン、白金又はガドリニウムを含有する活性炭素繊維をそれぞれ製造した。得られた活性炭素繊維の諸特性を表２に示す。
【００５３】
【表２】

【００５４】
表２からも明らかなように、イットリウム、マンガン、白金又はガドリニウムを含有する各活性炭素繊維の細孔分布には、メソ細孔の領域にピークが発現した。すなわち、金属含有量、賦活条件等にかかわらず、メソ細孔モード直径が３５〜３９Åという一定の値をもつ活性炭素繊維が得られることがわかる。
【００５５】
実施例１０〜１３及び比較例３
表３に示す製造条件としたほかは、実施例１と同様にして鉄含有活性炭素繊維を製造した。得られた活性炭素繊維の諸特性を表３に示す。
【００５６】
【表３】

【００５７】
表３からも明らかなように、鉄含有活性炭素繊維の細孔分布には、メソ細孔の領域にピークが発現した。すなわち、金属含有量、賦活条件等にかかわらず、メソ細孔モード直径が４２〜４３Åという一定の値をもつ活性炭素繊維が得られることがわかる。
【００５８】
試験例１
各実施例及び比較例で得られた活性炭素繊維の一部について、クロロホルム除去能力試験及び総トリハロメタン除去能力試験を行った。その結果を表１〜表３に示す。なお、各試験方法は以下の方法により実施した。
（１）クロロホルム除去能力試験
ミルド化した活性炭８．４ｇをアクリル容器に充填し、直径４８ｍｍ、高さ３０ｍｍの円柱形状の活性炭カラムを作成した。ＪＩＳ−Ｓ−３２０１『家庭用浄水器試験方法』に基づいてクロロホルム濃度が１００±２０ｐｐｂの試料水を調整し、流量３Ｌ／分（空塔速度１０００ｈ^−１）で上記カラムに通水した。試料水及び濾過水のクロロホルム濃度は、ＥＣＤガスクロマトグラフ分析装置（商品名『ＧＣ−１４Ｂ』、島津製作所製）を使用し、ヘッドスペース法で測定した。活性炭のクロロホルム吸着が破過し、濾過水の濃度が２０ｐｐｂを超えるまで連続して試料水を通水し、２０ｐｐｂを破過するまでの通水量（Ｌ）を活性炭のクロロホルム除去能力とした。
（２）総トリハロメタン除去能力試験
ミルド化した活性炭８．４ｇをアクリル容器に充填し、直径４８ｍｍ、高さ３０ｍｍの円柱形状の活性炭カラムを作成した。ＪＩＳ−Ｓ−３２０１『家庭用浄水器試験方法』に基づいて総トリハロメタン（ＣＨＣｌ_３：ＣＨＣｌ_２Ｂｒ：ＣＨＣｌＢｒ_２：ＣＨＢｒ_３＝４５：３０：２０：５）濃度が１００±２０ｐｐｂの試料水をそれぞれ調整し、流量３Ｌ／分（空塔速度１０００ｈ^−１）で活性炭カラムに通水した。試料水及び濾過水の濃度は、ＥＣＤガスクロマトグラフ分析装置（商品名『ＧＣ−１４Ｂ』、島津製作所製）を使用し、ヘッドスペース法で測定した。活性炭の総トリハロメタン吸着が破過し、濾過水の濃度が２０ｐｐｂを超えるまで連続して試料水を通水し、２０ｐｐｂを破過するまでの通水量（Ｌ）を活性炭の総トリハロメタン除去能力とした。
【００５９】
クロロホルム除去能力試験では、表１〜表３に示すように、実施例の活性炭素繊維では高いクロロホルム除去能力が得られ、比較例１に比べて最大で６倍ものクロロホルム除去能力が得られた。これに対し、比較例２及び３では、実施例の半分程度までその能力が低下した。
【００６０】
総トリハロメタン除去能力試験では、表１〜表３に示すように、実施例の活性炭素繊維では高い総トリハロメタン除去除去能力が得られ、比較例１に比べて最大で７．５倍もの総トリハロメタン除去能力が得られた。
【００６１】
また、図１には、実施例１、実施例５、実施例１２及び比較例１の活性炭素繊維を用いた場合の総トリハロメタン破過曲線を示す。図１からも明らかなように、メソ細孔直径が最大になる鉄含有活性炭素繊維（実施例１２）が最も高い総トリハロメタン除去能力を示し、これより空塔速度１０００ｈ^−１の条件下ではより大きなメソ細孔直径が有効であることがわかる。
【図面の簡単な説明】
【図１】実施例１、実施例５、実施例１２及び比較例１の活性炭素繊維を用いた場合の総トリハロメタン破過曲線を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel activated carbon and a method for producing the same. In the present invention, “micropores” refer to pores having a pore diameter of less than 20 °, and “mesopores” refer to pores having a pore diameter of not less than 20 ° and less than 500 °.
[0002]
[Prior art]
Among activated carbon pores having various pore distributions, pores having a molecular size of about 1.5 to 2 times the molecular size of the substance to be adsorbed are said to be most suitable for adsorption, and are often used in low concentration regions. Is adsorbed on micropores having a pore diameter of less than 20 °. Therefore, activated carbon having a large micropore volume and a size suitable for the substance to be adsorbed has a higher adsorption capacity. However, the amount of low-concentration organic substances in water (for example, trihalomethanes) is extremely low in dynamic adsorption compared to static adsorption. The factors are considered to be low contact efficiency between the substance to be adsorbed and the micropores and the influence of the affinity between the non-adsorbed substance and the surface of the pores.
As a means for increasing the contact efficiency between the substance to be adsorbed and the micropores serving as the adsorption site, a method of expressing mesopores in activated carbon as introduction holes into the micropores is generally known. In particular, activated carbon having a fixed ratio of mesopores has a significantly higher dynamic adsorption amount than activated carbon having only micropores.
In order to develop mesopores into activated carbon, a method of adding an organic metal to an activated carbon precursor has been proposed (see Patent Document 1 and the like). In addition, there has been proposed a method of developing mesopores in order to increase the ability to adsorb organic compounds such as trihalomethane and moldy odor (see Patent Documents 2 and 3).
However, even with these techniques, it has not been possible to control a mesopore in a wide range of 20 to 500 °, and it has not been clarified which pore diameter is effective for increasing the adsorption capacity.
[0003]
[Patent Document 1] Japanese Patent No. 3143690
[Patent Document 2] JP-A-11-240707
[Patent Document 3] Japanese Patent Application Laid-Open No. 2000-351613
[Problems to be solved by the invention]
The optimum mesopore size and volume ratio of activated carbon for effectively increasing the contact efficiency are expected to vary depending on the type of the substance to be adsorbed, the flow rate, and the like. Activated carbon having a mesopore volume that is too large and has a broad pore distribution tends to decrease the dynamic adsorption amount. In addition, since the development of mesopores is a factor that deteriorates production efficiency, it is desirable to control the mesopore diameter and volume according to the use of activated carbon.
As described above, if the mesopore distribution of activated carbon can be controlled to a desired range, it is possible to provide an optimal material according to the type of the substance to be adsorbed, the flow rate, and the like. It has not been developed yet.
Accordingly, a main object of the present invention is to provide a method capable of controlling the mesopore distribution of activated carbon.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in view of the problems of the prior art, and as a result, have found that an activated carbon having a desired mesopore distribution can be obtained by adding a specific metal element in a certain range. Was completed.
[0008]
That is, the present invention relates to the following activated carbon and a method for producing the same.
[0009]
1. In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4K, the mesopore volume in the range of a pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon wherein the ratio of the mesopore volume in the above range to the volume is 5 to 45%.
[0010]
2. A pitch containing 0.01 to 5% by weight of at least one metal component of Mg, Mn, Fe, Y, Pt and Gd is used as an activated carbon precursor, and the precursor is infusibilized or carbonized to activate. In the method of processing,
A method for producing activated carbon, characterized in that the mesopore mode diameter of the obtained activated carbon is controlled by changing the type of the metal component.
[0011]
3. Item 3. The method according to Item 2, wherein the mesopore mode diameter of the obtained activated carbon is controlled in the range of 30 to 45 °.
[0012]
4. Activated carbon obtained by using a pitch containing 0.01 to 5% by weight of Mg as an activated carbon precursor, infusing or carbonizing the precursor, and activating the precursor,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 30 to 36 °.
[0013]
5. A pitch containing at least one of Mn, Y, Pt and Gd in an amount of 0.01 to 5% by weight is used as an activated carbon precursor, and the precursor is infusibilized or carbonized, and activated carbon obtained by activation treatment. So,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 34 to 40 °.
[0014]
6. Activated carbon obtained by using a pitch containing 0.01 to 5% by weight of Fe as an activated carbon precursor, infusibilizing or carbonizing the precursor, and activating the precursor,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 40 to 45 °.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
1. Activated carbon of the present invention The activated carbon of the present invention has a mesopore volume in the range of a pore diameter of 30 ° or more and less than 50 ° in a pore distribution determined by the BJH method from a nitrogen adsorption isotherm at 77.4 K of 0.02 to 0.40 cc /. g, and the ratio of the mesopore volume in the above range to the total pore volume (hereinafter also referred to as “mesopore volume ratio”) is 5 to 45%.
[0016]
The pore distribution of the activated carbon of the present invention is calculated at 77.4K based on a nitrogen adsorption isotherm. Specifically, a nitrogen adsorption isotherm is created as follows. The activated carbon is cooled to 77.4 K (boiling point of nitrogen), nitrogen gas is introduced, and the adsorption amount V [cc / g] of the nitrogen gas is measured by a volumetric method. At this time, gradually increased pressure P [mmHg] of the nitrogen gas to be introduced, the value obtained by dividing the saturated vapor pressure P _{0 [mmHg]} of the nitrogen gas as a relative pressure P / P _0, plotted adsorption amount for each relative pressure By doing so, a nitrogen adsorption isotherm is created. The amount of nitrogen gas adsorbed can be measured using a commercially available automatic gas adsorption amount measuring device (for example, "AUTOSORB-6" (trade name, manufactured by QUANTCHROME)). In the present invention, the pore distribution can be determined based on the nitrogen adsorption isotherm according to a known analysis method. For this analysis, known means such as an analysis program attached to the above device can be used.
[0017]
The mesopore volume of the present invention is calculated by the BJH method based on the above pore distribution. The BJH method itself is a known method, and can be performed, for example, according to the method disclosed in "J. Amer. Chem. Soc., 73, 373 (1951)".
[0018]
Further, the total pore volume of the present invention can be calculated from the maximum adsorption amount of nitrogen in the measurement result of the adsorption amount of nitrogen gas.
[0019]
The activated carbon of the present invention has a mesopore volume of 0.02 to 0.40 cc / g (preferably 0.05 to 0.20 cc / g) in the range of a pore diameter of 30 ° or more and less than 50 °, and The ratio of the mesopore volume to the pore volume is 5 to 45% (preferably 10 to 25%). By controlling the mesopore volume and the ratio within this range, a material suitable for adsorption of various substances to be adsorbed (particularly, trihalomethanes) can be obtained.
[0020]
Incidentally, the academic range of the mesopore diameter of the mesopores is not less than 20 ° and less than 500 °, and in the present invention, the mesopore volume of the mesopores having a pore diameter of not less than 30 ° and less than 50 ° is defined. Is what you do.
[0021]
Although the form of the activated carbon of the present invention is not limited, it is generally desirable that the activated carbon is fibrous. That is, the present invention is desirably an activated carbon fiber. In this case, the specific surface area (BET method) is about 700 to 1400 m ² / g, the total pore volume is about 0.30 to 0.90 cc / g, the micropore volume is about 0.30 to 0.60 cc / g, The hole mode diameter is preferably about 30 to 45 °. The “mesopore mode diameter” in the present invention means a pore diameter at which a peak of a pore volume distribution in a mesopore region of 20 to 500 ° is located.
[0022]
Preferably, the activated carbon of the present invention contains at least one metal component of Mg, Mn, Fe, Y, Pt and Gd. By including these metal components, an activated carbon having a specific mesopore mode diameter can be obtained. For example, the activated carbon has the following structure and characteristics according to the type of the metal component contained.
(A) In the case of containing Mg In the pore distribution obtained by the BJH method from the nitrogen adsorption isotherm at 77.4K, the mesopore volume in the range of a pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g. Activated carbon (b) at least one of Mn, Y, Pt, and Gd, wherein the ratio of the mesopore volume to the total pore volume is 5 to 45% and the mesopore mode diameter is 30 to 36 °. In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, When the ratio of the mesopore volume to the pore volume is 5 to 45% and the activated carbon (c) Fe has a mesopore mode diameter of 34 to 40 °, the nitrogen adsorption isotherm at 77.4K is used to obtain the BJH method. The details I sought In the distribution, the mesopore volume in the range of the pore diameter of 30 ° or more and less than 50 ° is 0.02 to 0.40 cc / g, the ratio of the mesopore volume to the total pore volume is 5 to 45%, and Activated carbon having a mesopore mode diameter of 40 ° to 45 ° The activated carbon of the present invention can be used for the same applications as known activated carbons. Further, it can be used for both liquid phase use and gas phase use. In particular, the activated carbon of the present invention can be suitably used as a material used for filtering and removing organic compounds (particularly, trihalomethanes) contained in a liquid phase (particularly, purified water). When used as a material for filtering organic compounds contained in purified water, the material of the present invention may be used as it is in place of a known adsorbent in a water purifier or the like. At this time, the amount of water passing, the amount of the material of the present invention, and the like may be in accordance with known methods and conditions.
2. Method for Producing Activated Carbon The activated carbon of the present invention may be produced by any method as long as it has the above-mentioned properties. For example, the following production method is desirable.
[0023]
That is, a pitch containing 0.01 to 5% by weight of at least one metal component of Mg, Mn, Fe, Y, Pt and Gd is used as an activated carbon precursor, and the precursor is infusibilized or carbonized. , In the method of activation treatment,
The activated carbon of the present invention can be more reliably obtained by a method for producing activated carbon characterized by controlling the mesopore mode diameter of the obtained activated carbon by changing the type of the metal component.
[0024]
First, a pitch containing 0.01 to 5% by weight of at least one metal component of Mg, Mn, Fe, Y, Pt and Gd is used as an activated carbon precursor. When two or more of the above metal components are used in combination, the combination, the ratio thereof, and the like may be appropriately set according to the use, purpose of use, and the like of the activated carbon.
[0025]
The content of the metal component is adjusted to be 0.01 to 5% by weight, preferably 0.1 to 2% by weight in the activated carbon precursor. If the content of the metal component is less than 0.01% by weight, the activated carbon of the present invention may not be obtained due to the weakening of the action of the metal during the activation reaction. On the other hand, when the content exceeds 5% by weight, the metal component tends to condense in the activated carbon, and the physical strength of the activated carbon is remarkably reduced.
[0026]
In the present invention, the content of the metal component is not a content as a metal compound but a content in terms of a metal element, and is a value measured by ICP emission spectrometry.
[0027]
In the production method of the present invention, at least the mesopore mode diameter of the obtained activated carbon can be controlled by changing the type of the metal component to be contained. In particular, the mesopore mode diameter of the obtained activated carbon can be controlled in the range of 30 to 45 °. For example, by selecting the metal to be added to the activated carbon precursor from among Mg, Mn, Fe, Y, Pt and Gd, it is possible to produce activated carbon having three different mesopore mode diameters.
[0028]
That is, (a) the activated carbon obtained by adding the above-mentioned predetermined amount of Mg to the activated carbon precursor has a mesopore mode diameter of 30 to 36 °, and (b) at least one of Mn, Y, Pt and Gd in the activated carbon precursor. The activated carbon obtained when the above-mentioned predetermined amount is added has a mesopore mode diameter of 34 to 40 °, and the activated carbon obtained when the above-mentioned predetermined amount of Fe is added to the activated carbon precursor (c) has a mesopore mode diameter of 40 to 40 °. 45 ° can be controlled.
[0029]
In the present invention, the mesopore volume changes depending on the content (addition amount) of the metal component and the activation conditions, but the mesopore mode diameter hardly changes. Therefore, by changing the type of the metal component, it becomes possible to obtain activated carbon having a desired mesopore mode diameter.
[0030]
Further, among these activated carbons, those having a mesopore volume of 0.02 to 0.40 cc / g and a mesopore volume ratio of 5 to 45% have a particularly high dynamic adsorption capacity for organic compounds in a liquid phase. Desirable in terms of excellence.
[0031]
The activated carbon precursor can be prepared, for example, by mixing a compound containing the above metal component (metal compound) and pitch.
[0032]
The pitch is not particularly limited as long as it can be activated carbon by infusibilization, carbonization, and the like, and can be mixed with a metal compound. For example, any of petroleum pitch, coal pitch, synthetic pitch and the like can be used. Further, the optical properties may be either isotropic or anisotropic.
[0033]
In the case of preparing an activated carbon precursor, for example, after mixing and stirring a coal tar and a metal compound, which are raw materials for pitch, in a solvent, an activated carbon precursor containing pitch and a metal component may be obtained by distillation under reduced pressure. it can.
[0034]
The metal compound is not particularly limited as long as the metal component is contained, and any of an inorganic compound and an organic compound can be used. As the inorganic compound, for example, inorganic salts such as chlorides, nitrates and acetates can be used. More specifically, iron chloride, iron nitrate, iron acetate and the like can be exemplified. Examples of the organic compound include an organic metal complex of the above metal component with acetylacetone, cyclopentadiene, or the like. More specifically, iron trisacetylacetonate, iron triscyclopentadienyl, iron acetylacetonate, magnesium acetylacetonate, manganese acetylacetonate, yttrium acetylacetonate, platinum acetylacetonate, gadolinium acetylacetonate, etc. Examples can be given.
[0035]
The method of mixing the metal compound and the pitch is not limited as long as they can be uniformly mixed. For example, the metal compound and the pitch may be mixed as they are, or they may be mixed in an appropriate solvent. In particular, it is preferable to mix the metal compound and the pitch in a solvent.
[0036]
The solvent is not particularly limited as long as it can dissolve both the metal compound and the pitch. For example, it may be appropriately selected from known solvents such as quinoline, benzene, dichloromethane, toluene, xylene, tetrahydrofuran, methanol, ethanol and the like according to the type of pitch used and the type of metal compound. For example, when an acetylacetone complex is used as the iron compound and a coal-based isotropic pitch is used as the pitch, quinoline or the like can be used.
[0037]
The amount of the solvent used is not particularly limited as long as a uniform activated carbon precursor can be obtained, and may be appropriately set according to the type of the solvent, the metal compound, and the like used.
[0038]
Next, the activated carbon precursor obtained is spun in advance as necessary, then subjected to infusibilization treatment or carbonization treatment, and then subjected to activation treatment, whereby the activated carbon (activated carbon fiber) of the present invention can be obtained. The spinning method, the infusibilization treatment, the carbonization treatment, the activation treatment, and the like are preferably performed by the following methods.
[0039]
The spinning method can be performed according to a known melt spinning method. The melting temperature and the spinning temperature are generally set to a temperature equal to or higher than the softening point temperature of the activated carbon precursor, and preferably set to a temperature 30 to 100 ° C. higher than the softening point. The molten activated carbon precursor is sent to a nozzle of a spinning machine, and discharged from a nozzle surface having many pores while forming fibers in an atmosphere controlled at a spinning temperature or lower.
[0040]
The infusibilization treatment can be performed by heating the activated carbon precursor from a temperature below its melting point to about 400 ° C. at a rate of 0.1 to 10 ° C./min in an inert gas atmosphere or an oxygen-containing gas atmosphere. it can.
[0041]
In the carbonization treatment, the activated carbon precursor is heated to about 800 to 1200 ° C. at a rate of 5 to 10 ° C./min in an inert gas atmosphere such as nitrogen gas or argon gas, and the maximum temperature at that time is maximized. It can be carried out by maintaining for about 10 minutes.
[0042]
The activation treatment is an activated carbon precursor that has been subjected to an infusibilization treatment and / or a carbonization treatment in a gas atmosphere obtained by diluting steam, carbon dioxide, oxygen, a mixed gas thereof, or an inert gas such as nitrogen. Is maintained at a temperature of about 800 to 1200 ° C. for about 5 to 120 minutes.
[0043]
【The invention's effect】
According to the method for producing activated carbon of the present invention, a desired mesopore distribution can be controlled, so that an activated carbon having an optimal mesopore distribution can be produced according to the substance to be adsorbed and the use conditions. For example, when producing activated carbon for adsorption of trihalomethanes, activated carbon with Fe can exert the most excellent effect as an adsorbent for removing organic compounds in water.
[0044]
In the production method of the present invention, unnecessary mesopores can be suppressed by controlling to arbitrary mesopores, which can contribute to an improvement in productivity.
[0045]
【Example】
Hereinafter, examples and comparative examples will be shown, and the features of the present invention will be shown more clearly. However, the present invention is not limited to these examples.
[0046]
In this example, the amount of nitrogen gas adsorbed on the activated carbon was measured using "AUTOSORB-6" (trade name, manufactured by QUANTCHROME), and the analysis of the pore distribution was carried out using an attached analysis program. The total pore volume was calculated from the maximum nitrogen adsorption. The mesopore volume was calculated by the BJH method (J. Amer. Chem. Soc., 73, 373 (1951)).
[0047]
Example 1
1000 g of coal tar from which water and quinoline insolubles had been removed was heated to 90 ° C. under a nitrogen atmosphere, and 150 ml of a quinoline mixed solution in which 21 g of acetylacetonatomagnesium was dissolved was gradually added dropwise, followed by stirring for 90 minutes. Next, this was distilled under reduced pressure, and further reacted at 330 ° C. for 3 hours while blowing air at a rate of 3 L / min to obtain a magnesium-containing coal tar pitch. The iron content of this pitch was 0.14% by weight. The obtained magnesium-containing coal tar pitch was melt-extruded and spun at a melting temperature of 320 ° C. to obtain pitch fibers. The spun pitch fibers were heated in the air at a rate of 1 to 10 ° C./min from room temperature, kept at a maximum temperature of 354 ° C. for 4 minutes, and infusibilized over a total infusibilization time of 58 minutes. Next, the infusibilized pitch fiber was exposed to saturated steam at 850 ° C. for 25 minutes in a nitrogen atmosphere to perform an activation treatment, thereby obtaining a magnesium-containing activated carbon fiber. Table 1 shows the properties of the obtained activated carbon fiber together with the production conditions.
[0048]
Examples 2 to 4 and Comparative Example 2
Activated carbon fibers were produced in the same manner as in Example 1 except that the production conditions shown in Table 1 were used. Table 1 shows properties of the obtained activated carbon fiber.
[0049]
[Table 1]

[0050]
As shown in Table 1, in the pore distribution of the magnesium-containing activated carbon fiber, a peak appeared in a mesopore region. That is, it can be seen that an activated carbon fiber having a mesopore mode diameter of a constant value of 34 ° can be obtained irrespective of the metal content, the activation conditions and the like.
[0051]
Comparative Example 1
As shown in Table 1, activated carbon fibers were produced in the same manner as in Example 1 except that no metal component was added. Table 1 shows properties of the obtained activated carbon fiber.
[0052]
Examples 5 to 9
Activated carbon fibers were produced in the same manner as in Example 1 except that the production conditions shown in Table 2 were used. That is, activated carbon fibers containing yttrium, manganese, platinum or gadolinium were produced, respectively. Table 2 shows various properties of the obtained activated carbon fiber.
[0053]
[Table 2]

[0054]
As is clear from Table 2, in the pore distribution of each activated carbon fiber containing yttrium, manganese, platinum or gadolinium, a peak appeared in the region of mesopores. That is, it is understood that an activated carbon fiber having a mesopore mode diameter having a constant value of 35 to 39 ° can be obtained regardless of the metal content, the activation conditions, and the like.
[0055]
Examples 10 to 13 and Comparative Example 3
An iron-containing activated carbon fiber was produced in the same manner as in Example 1, except that the production conditions shown in Table 3 were used. Table 3 shows properties of the obtained activated carbon fiber.
[0056]
[Table 3]

[0057]
As is clear from Table 3, in the pore distribution of the iron-containing activated carbon fiber, a peak appeared in the region of mesopores. That is, it is understood that an activated carbon fiber having a mesopore mode diameter having a constant value of 42 to 43 ° can be obtained irrespective of the metal content and the activation conditions.
[0058]
Test example 1
Some of the activated carbon fibers obtained in each of the examples and comparative examples were subjected to a chloroform removal ability test and a total trihalomethane removal ability test. The results are shown in Tables 1 to 3. In addition, each test method was implemented by the following method.
(1) Chloroform removal ability test 8.4 g of milled activated carbon was filled in an acrylic container to prepare a columnar activated carbon column having a diameter of 48 mm and a height of 30 mm. Sample water having a chloroform concentration of 100 ± 20 ppb was adjusted based on JIS-S-3201 “Test Method for Household Water Purifier”, and was passed through the column at a flow rate of 3 L / min (superficial velocity 1000 h ⁻¹ ). The chloroform concentration of the sample water and the filtered water was measured by a headspace method using an ECD gas chromatograph analyzer (trade name “GC-14B”, manufactured by Shimadzu Corporation). The sample water was continuously passed until the chloroform adsorption of the activated carbon broke down and the concentration of the filtered water exceeded 20 ppb, and the amount of water flow (L) up to the breakthrough of 20 ppb was defined as the ability of the activated carbon to remove chloroform.
(2) Total trihalomethane removal ability test An acrylic container was filled with 8.4 g of milled activated carbon to prepare a columnar activated carbon column having a diameter of 48 mm and a height of 30 mm. Sample water having a total trihalomethane (CHCl ₃ : CHCl ₂ Br: CHClBr ₂ : CHBr ₃ = 45: 30: 20: 5) concentration of 100 ± 20 ppb based on JIS-S-3201 “Test Method for Household Water Purifier” was used. It was adjusted and water was passed through the activated carbon column at a flow rate of 3 L / min (superficial velocity 1000 h ^-1 ). The concentrations of the sample water and the filtered water were measured by a headspace method using an ECD gas chromatograph analyzer (trade name “GC-14B”, manufactured by Shimadzu Corporation). Sample water was continuously passed through until the total trihalomethane adsorption of the activated carbon exceeded and the concentration of the filtered water exceeded 20 ppb, and the amount of water flow (L) until the concentration exceeded 20 ppb was defined as the total trihalomethane removal ability of the activated carbon. .
[0059]
In the chloroform removal ability test, as shown in Tables 1 to 3, the activated carbon fiber of the example provided a high chloroform removal ability, and a maximum of six times the chloroform removal ability as compared with Comparative Example 1. On the other hand, in Comparative Examples 2 and 3, the performance was reduced to about half that of the examples.
[0060]
In the total trihalomethane removal capability test, as shown in Tables 1 to 3, the activated carbon fiber of the example provided a high total trihalomethane removal / removal capability, and the total trihalomethane removal capability was 7.5 times as large as that of Comparative Example 1. Ability has been obtained.
[0061]
FIG. 1 shows a total trihalomethane breakthrough curve when the activated carbon fibers of Example 1, Example 5, Example 12, and Comparative Example 1 were used. As is clear from FIG. 1, the iron-containing activated carbon fiber having the largest mesopore diameter (Example 12) shows the highest total trihalomethane removal ability, and thus, the higher the superficial superficial velocity of 1000 h ⁻¹ , the better. It turns out that a large mesopore diameter is effective.
[Brief description of the drawings]
FIG. 1 shows a total trihalomethane breakthrough curve when the activated carbon fibers of Examples 1, 5, and 12 and Comparative Example 1 were used.

Claims

In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon wherein the ratio of the mesopore volume in the above range to the volume is 5 to 45%.

A pitch containing 0.01 to 5% by weight of at least one metal component of Mg, Mn, Fe, Y, Pt and Gd is used as an activated carbon precursor, and the precursor is infusibilized or carbonized to activate. In the method of processing,
A method for producing activated carbon, characterized in that the mesopore mode diameter of the obtained activated carbon is controlled by changing the type of the metal component.

3. The method according to claim 2, wherein the mesopore mode diameter of the obtained activated carbon is controlled in the range of 30 to 45 [deg.].

Activated carbon obtained by using a pitch containing 0.01 to 5% by weight of Mg as an activated carbon precursor, infusing or carbonizing the precursor, and activating the precursor,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 30 to 36 °.

A pitch containing at least one of Mn, Y, Pt and Gd in an amount of 0.01 to 5% by weight is used as an activated carbon precursor, and the precursor is infusibilized or carbonized, and activated carbon obtained by activation treatment. So,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 34 to 40 °.

Activated carbon obtained by using a pitch containing 0.01 to 5% by weight of Fe as an activated carbon precursor, infusibilizing or carbonizing the precursor, and activating the precursor,
In the pore distribution determined by the BJH method from the nitrogen adsorption isotherm at 77.4 K, the mesopore volume in the range of pore diameter of 30 ° to less than 50 ° is 0.02 to 0.40 cc / g, and Activated carbon having a mesopore volume ratio in the above range of 5 to 45% and a mesopore mode diameter of 40 to 45 °.