JP3756586B2

JP3756586B2 - Adsorbent

Info

Publication number: JP3756586B2
Application number: JP23613296A
Authority: JP
Inventors: 智則石川; 健理千種; 博幸高見; 浩一郎中井
Original assignee: Unitika Ltd
Current assignee: Unitika Ltd
Priority date: 1996-09-06
Filing date: 1996-09-06
Publication date: 2006-03-15
Anticipated expiration: 2016-09-06
Also published as: JPH1076250A

Description

【０００１】
本発明は、活性炭繊維を主成分とし、液層吸着や生物処理用担体として好適な吸着材に関するものである。
【０００２】
【従来の技術】
活性炭は，吸着材として工業的に極めて有用であり，例えば脱色や有機物の除去等に粉末状あるいは粒状の活性炭が広く用いられている。
しかしながら，粉末状の活性炭は，活性炭の取り出し，分離の操作が複雑であり，さらに圧力損失が大きいという欠点がある。また，粒状の活性炭は，粒径をある程度大きくすれば，圧力損失を低減させることはできるものの，吸着表面が減少して吸着速度が低下する等の問題がある。
【０００３】
一方，繊維状の活性炭，すなわち，活性炭繊維を用いれば，粉末状あるいは粒状の活性炭とは異なり，被処理ガスや被処理液との分離が容易であり，また，表面積が大きく，吸着速度が速い等の利点がある。
しかしながら，従来の活性炭繊維はフエルト状やクロス状等で市販されることが多く，吸着材として使用する場合，吸着塔の形状や大きさ等に応じて切断したりして形を整える必要がある。
【０００４】
特公平３-47893号公報では，活性炭繊維のみで成形した塊状の吸着材が提案されているが，この吸着材は，特に使用中に形状が崩れたり，繊維片が系外へ流出しやすいなどの問題があり，使用し難いという欠点がある。
【０００５】
一方，水中の有機物やアンモニア等の分解処理を行う水処理方法の一つとして微生物を利用する方法がある。この方法には，曝気槽中の活性汚泥を用いる方法や，担体表面に生物膜を形成し，それに被処理水を接触させて含有不純物を処理する方法がある。
そして，後者の方法で用いられる生物処理用の担体としては，合成樹脂製の回転円盤，ハニカムチューブ，合成繊維製の簾状物，不織布あるいは球状物，砂，アンスラサイト，セラミックス，粒状活性炭等の粒状物がある。
【０００６】
合成樹脂製の回転円板，ハニカムチューブや波形状のものを生物処理用担体として用いた場合，高速で処理することが可能で，水中の無機物及び有機物の懸濁性物質による閉塞が起こり難いため，多量の水を処理する場合に広く用いられている。しかしながら，表面積が小さいため生物膜の付着量が少なく，処理効率も低いという問題があった。
【０００７】
また，合成繊維製の簾状物や不織布を生物膜の担体として用いると，被処理水との接触で不織布が揺動して接触が抑制されたり，目詰まりを起こしたりして処理能力が低下するという問題がある。合成繊維製不織布のこれらの欠点を補うために，不織布に樹脂を含浸させて補強したり，担体の強度を維持するための支持板等を設けた担体が提案されている（特開平１−274836号公報）が，この担体は生物処理に直接関係のない補強材等が必要になるという問題がある。
【０００８】
また，生物処理用担体として，砂，アンスラサイト等の比較的粒径の小さい粒状物を用いると，微生物の付着する表面積は大きくなるが，通液抵抗が大きくなり，流速を速くすることができない。しかも，被処理水中の懸濁性物質によって閉塞しやすいという問題がある。
粒径の大きなセラミックスを用いると，通液抵抗が小さくなり，閉塞も生じ難くなるが，微生物の付着する表面積が小さくなり，処理効率も低くなる。さらに，担体重量が大きくなるため，ハンドリング性に関しても好ましくない。
【０００９】
近年，生物処理用担体として活性炭が用いられ，活性炭の有用性が認識されている。しかしながら，粒状の活性炭は，砂等と同様に圧力損失が大きく，さらに，被処理水中の懸濁性物質によって閉塞しやすいという問題がある。この閉塞を防止するために逆洗を実施すれば，活性炭が破砕もしくは摩耗して粉末化するという問題もある。
【００１０】
一方，担体の表面積を増やす方法として，合成繊維を球状に成形して用いる方法がある。この方法では，球状繊維内部に微生物が多量に繁殖するが，球状繊維内部への水の流通が乏しく，また，酸素の供給が不十分となるため，生物膜を効果的に活用することができなかった。さらに，この繊維塊は連続的に製造し難く，単繊維の太さ，長さにより得られる繊維塊の寸法に大きなバラツキが生じやすいという問題があった。
【００１１】
【発明が解決しようとする課題】
本発明は，上記の問題を解決し，取り扱いが容易で，製品のバラツキが少なく，そのままの形状で吸着塔内に充填するだけで使用することが可能であり，また，吸着速度が速く，さらに，生物処理用担体としても好適な吸着材と，この吸着材を生物処理用担体として用いる水処理方法を提供することを技術的な課題とするものである。
【００１２】
【課題を解決するための手段】
本発明者らは，上記の課題を解決するため鋭意検討した結果，吸着材を活性炭繊維と熱可塑性合成繊維とで棒状繊維集束体に形成すれば，取り扱い性が容易で，製品のバラツキが少なく，炭塵や繊維片も発生し難く，しかも，この吸着材は生物処理用担体としても好適なことを見出して本発明に到達した。
【００１３】
すなわち、本発明は、次の構成を有するものである。
（１）活性炭繊維２０〜８０重量％と熱可塑性合成繊維８０〜２０重量％とからなる繊維束を熱処理して繊維束内部の繊維を部分的に接合させ内部に均一な空隙を形成させた棒状繊維集束体からなり、その断面形状が、円状、楕円状、ドーナッツ状、トリローバル状、十字形状または星形形状のいずれかの形状であり、生物処理用担体として用いることを特徴とする吸着材。
（２）上記１記載の吸着材に生物膜を形成させ、次いで、この吸着材をそのまま処理槽に充填するか、充填筒に充填した状態で処理槽に装着した後、前記吸着材に被処理水を接触させることを特徴とする水処理方法。
（３）上記１記載の吸着材をそのまま処理槽に充填するか、充填筒に充填した状態で処理槽に装着した後、前記吸着材に生物膜を形成させながら、被処理水を接触させることを特徴とする水処理方法。
【００１４】
以下, 本発明について詳細に説明する。
本発明の吸着材は，活性炭繊維と熱可塑性合成繊維とで構成されているが，活性炭繊維としては，ポリアクリロニトリル系，セルローズ系，ビニロン系，あるいはピッチ系等のものを使用することができる。
本発明で使用する活性炭繊維の性状は特に限定されるものではないが，比表面積 700〜2000m²/g，平均細孔径４〜20Åのものが好ましい。
【００１５】
次に，活性炭繊維とともに吸着材を構成する熱可塑性合成繊維としては，ポリプロピレン繊維，ポリアミド繊維，ポリエステル繊維，ポリアクリロニトリル繊維，ポリエチレン繊維等を使用することができる。また，熱可塑性合成繊維の一種であるバインダー繊維，例えば芯部分がポリエチレンテレフタレート（ＰＥＴ），鞘部分が共重合ＰＥＴである芯鞘構造のポリエステル系繊維でもよい。
【００１６】
吸着材中の活性炭繊維と熱可塑性合成繊維の含有率は、吸着特性と形状安定性を同時に満足させるために、活性炭繊維２０〜８０重量％と、熱可塑性合成繊維８０〜２０重量％であることが必要である。活性炭繊維が２０重量％未満で、熱可塑性合成繊維が８０重量％を超えると、活性炭繊維の吸着特性が十分発揮されなくなる。また、活性炭繊維が８０重量％を超え、熱可塑性合成繊維が２０重量％未満になると、繊維同士が絡まり合い塊状にはなるものの、使用中に形状が崩れたり、繊維片が系外へ流出しやすくなる。
【００１７】
上記のように，本発明の吸着材は，活性炭繊維と熱可塑性合成繊維とで構成されているが，本発明の効果を損なわない範囲で，綿等の天然繊維，再生繊維，ガラス繊維等を含有させてもよい。また，活性炭繊維と複数種の熱可塑性合成繊維とで吸着材を形成してもよい。
【００１８】
本発明の吸着材の形状は棒状繊維収束体であるが、その最大直径が２ｍｍ以上で、断面が円状、楕円状、ドーナッツ状、トリローバル状、十字形状、星形状のものが、吸着処理操作の際に取り扱いやすく、生物処理用担体としても適している。
なお、本発明における最大直径とは、球状、ドーナッツ状の場合は直径、楕円状の場合は長軸の長さ、その他の形状の場合はその最大長さを意味するものである。
【００１９】
吸着材の長さは，製造のしやすさ，取り扱いやすさの面から，２mm以上，特に２〜50mmが好ましい。また，本発明の吸着材を吸着塔等の充填筒に充填する場合，吸着材の長さと直径をほぼ同じ長さにしたものは，その充填に際して異方性が少なく，充填筒内に異常な空隙を生ずることなく充填できるので好ましい。さらに，吸着材の長さを充填筒の長さとほぼ同じにすれば, 吸着材を充填筒の断面方向に充填するだけでよい。
【００２０】
本発明の吸着材は、活性炭繊維と熱可塑性合成繊維とからなる繊維束を熱処理して熱可塑性合成繊維を融着させた棒状繊維収束体であるが、熱可塑性合成繊維の融着程度を調整して収束体内部の繊維を部分的に接合させる。そのようにすれば、内部に均一な空隙を有し、圧縮によりその空隙を容易に縮小できるものとなる。そして、この吸着材は、充填筒への充填密度を上げても、圧力損失が少なくて偏流を起こすことがない。
【００２１】
次に、本発明の吸着材の製造方法について説明する。まず、活性炭繊維と、なま糸状あるいは捲縮を有する熱可塑性合成繊維とを、好ましくは２０〜１５０ｍｍに切断し、紡績用カード機で開繊、混合してスライバー状としたり、あるいは、活性炭繊維と捲縮を有する熱可塑性繊維とを開繊、混合してトウ状で引き取り、繊維束を得る。
次いで、この繊維束に熱処理して熱可塑性合成繊維を、部分的に融着させて棒状繊維収束体とするが、熱処理方法としては、熱風を吹き付ける方法や高温雰囲気中を通過させる方法等を採用することができる。具体的な熱処理方法としては、繊維束を円筒形や異形筒形の加熱体中に通して熱可塑性合成繊維を部分的に融着させればよく、次いで圧縮して冷却することにより、棒状繊維収束体を連続成形することができる。この棒状繊維収束体を、必要に応じた長さに切断すれば、本発明の吸着材となる。このように、本発明の吸着材は、簡単な工程で安定して効率的に製造することができる。
【００２２】
本発明の吸着材を得るために, 短繊維状の活性炭繊維と熱可塑性合成繊維を用いる場合，その繊維長は，開繊，混合する際の各繊維間の絡まりやすさの点から１mm以上，特に20〜 150mmであることが好ましい。繊維長が１mm未満であれば，繊維同士の絡まり合いが少なく，使用時に成型体としての形状が維持できなくなったり，微粉化し炭塵を発生させる原因となりやすい。
【００２３】
前述したように、本発明の吸着材は、活性炭繊維２０〜８０重量％と熱可塑性合成繊維８０〜２０重量％とが棒状繊維収束体となっているので、取り扱いが容易で、そのままの形状で吸着塔等の充填筒内に充填するだけで液相の吸着処理に使用することが可能であり、また、吸着速度が速く、使用中に活性炭繊維が脱落することがなく、生物処理用担体としても好適な吸着材である。
【００２４】
本発明の吸着材を生物処理用担体として用い，水処理するに際しては，例えば次の２つの方法がある。
第１の方法は，予め生物膜を形成させた吸着材を処理材として用いる方法である。吸着材に予め生物膜を形成させる方法としては，例えば吸着材を樹脂筒等の充填筒に充填した後，有機物分解菌，硝化菌等の微生物を含有した培養液や廃水を通水する方法や，吸着材をそのまま培養液や廃水の槽に投入した後，曝気あるいは攪拌する方法等がある。
【００２５】
そして，予め生物膜を形成させた吸着材を用いる具体的な水処理方法にも２つの方法がある。１つ目は吸着材を固定床として用いる方法で，生物膜を形成した吸着材を充填筒に充填して処理槽に装着し，被処理液を通液して吸着材表面の生物膜に接触させ，含有する有機物等を分解，処理するものである。
また，２つ目は吸着材を流動床として用いる方法で，生物膜を形成した吸着材をそのまま被処理液の処理槽に充填し，曝気して被処理液を吸着材表面の生物膜に接触させ，含有する有機物等を分解，処理するものである。
そして，これらの方法では，生物膜を形成させる筒状体や槽を，廃水を処理する処理槽と共用してもよい。
【００２６】
また，本発明の吸着材を生物処理用担体として用い，水処理するに第２の方法は，生物膜を形成させる前の吸着材を用いる方法である。この場合にも，吸着材を固定床として用いる方法と流動床として用いる方法があり，吸着材を充填筒に充填して処理槽に装着するか，あるいは吸着材をそのまま被処理液の処理槽に充填し，処理槽に通液したり，処理槽を曝気あるいは攪拌して吸着材表面に生物膜を形成させながら，被処理液を生物膜に接触させ，含有する有機物等を分解，処理するものである。
【００２７】
本発明の吸着材を生物処理用担体として用い，この吸着材に生物膜を形成させれば，上水，中水，あるいは工場等の用，廃水の処理に利用することが可能であり，例えば，上水分野ではアンモニアの硝化，農薬やトリハロメタン前駆物質等の有害物質の分解，中水分野では家庭用風呂水の浄化再生，大衆浴場やプール，観賞魚，活魚，養殖魚用の水槽等における水の循環再生，工場廃水では各種洗浄水の再生，廃水，下水の一次処理や高度処理等に好適である。
また，本発明の吸着材は，生物活性炭の機能と，形状の優位性を生かした生物処理用担体として，例えば上水道処理，工場廃水あるいは下水処理の一次処理又は高度処理，下水処理施設から発生する悪臭の生物脱臭に極めて有用である。
【００２８】
【実施例】
実施例１
直径17μｍ，平均細孔半径８Å，比表面積1000m²/gのピッチ系活性炭繊維 (繊維長80mm) 50重量％と，単糸繊度15デニールで，繊維長76mmの芯鞘型ポリエステル複合未延伸繊維（芯部：ＰＥＴ，鞘部：酸成分としてイソルタル酸を40モル％共重合させたＰＥＴ）50重量％とをカーディングマシーンで開繊, 混合し，１ｍ当たり6gのカードスライバーとした。
【００２９】
このカードスライバーを 150℃のエアジェットが吹き込まれた円筒状ヒータ内を通過させて加熱し，芯鞘型ポリエステル複合未延伸繊維を溶融させて繊維間を部分的に接着させた後，常温の空気が吹き込まれた直径７mmの円筒状体に75cm／分で導入して圧縮しながら冷却し，直径７mmの棒状繊維集束体を得た。この棒状繊維集束体を長さ８mmに切断し，円柱状の吸着材とした。
【００３０】
得られた吸着材を用い，直径25mmのガラスカラムに 100mmの高さまで充填し，100ppmのメチレンブルー水溶液を30ml／分の流量で下向流にて通水し，メチレンブルーを吸着させた。
処理水のメチレンブルー濃度を吸収スペクトル法で測定した結果，吸着除去率は97％以上であった。また，上記の吸着試験中，処理水中に活性炭繊維が脱落することはなかった。
【００３１】
実施例２
直径17μｍ，平均細孔半径８Å，比表面積1000m²/gのピッチ系活性炭繊維（繊維長80mm）50重量％と，単糸繊度10デニールで，繊維長76mmのポリエステル系サイドバイサイド型複合未延伸繊維（重合度 110のＰＥＴ／重合度80のＰＥＴ）50重量％とをカーディングマシーンで開繊, 混合し，１ｍ当たり6gのカードスライバーとした。
【００３２】
このカードスライバーを 150℃のエアジェットが吹き込まれた円筒状ヒータ内を通過させて加熱し，サイドバイサイド型複合未延伸繊維を溶融させて繊維間を部分的に接着させた後，常温の空気が吹き込まれた直径８mmのトリローバル型筒状体に75cm／分で導入して圧縮しながら冷却し，直径８mmの棒状繊維集束体を得た。この棒状繊維集束体を長さ10mmに切断し，トリローバル断面形状の吸着材とした。
【００３３】
得られた吸着材を生物処理用担体として用い，この吸着材をそのまま直径150mm ×高さ1600mmのアクリル樹脂製活性汚泥槽に５リットル充填し，活性汚泥層下部に散気管を設けて曝気を行った。
被処理水としてＢＯＤ1500mg／リットル，ＣＯＤ1000mg／リットルの合成繊維製造廃水を用い，この廃水を上記の活性汚泥槽に通液した。滞留時間を20時間に調整し，４カ月間の連続運転を実施したが，処理水のＢＯＤ，ＣＯＤは共に250mg/リットル以下に抑えられ，トラブルなく安定した運転が行えた。
【００３４】
実施例３
実施例１，２で得られた吸着材を生物処理用担体として用い，直径 150mm×高さ1600mmのアクリル樹脂製円筒に高さ1000mmまでそれぞれ充填し, アクリル樹脂製円筒の下部には散気管を設けた。
被処理水としてＢＯＤ120mg/リットル，ＣＯＤ100mg/リットルの食品産業廃水二次処理水を用い，この廃水を上記の樹脂筒に下方から通液した。滞留時間を１時間に調整し，４カ月間の連続運転を実施したが，いずれの吸着材を用いた場合にも，処理水のＢＯＤとＣＯＤは共に10mg／リットル以下に抑えられ，かつ，１週間に１回の割合で散気管から放出される空気量を増やして空気逆洗を行うことで，トラブルなく安定した運転ができた。
【００３５】
【発明の効果】
本発明の吸着材は，取り扱いが容易で，そのままの形状で吸着塔等の充填筒内に充填するだけで使用することが可能であり，また，吸着速度が速く，さらに，使用中に活性炭繊維が脱落することがない。
したがって，本発明の吸着材は，水の浄化用吸着材として，例えば上水道処理，工業廃水の高度処理あるいは下水の高度処理等に広く利用することができ，特に水道水の浄化において，トリハロメタンあるいはその前駆物質といわれるフミン酸等の微量有機物の除去に好適に用いることができる。
【００３６】
さらに、本発明の吸着材は、生物活性炭の機能と、形状の優位性を生かした生物処理用の担体として、例えば上水処理、工業廃水あるいは下水処理の一次処理又は高度処理、下水処理施設から発生する悪臭の生物脱臭に有用である。[0001]
The present invention relates to an adsorbent containing activated carbon fiber as a main component and suitable as a carrier for liquid layer adsorption or biological treatment .
[0002]
[Prior art]
Activated carbon is extremely useful industrially as an adsorbent. For example, powdered or granular activated carbon is widely used for decolorization and removal of organic substances.
However, powdered activated carbon has the disadvantages that the operation of taking out and separating the activated carbon is complicated and the pressure loss is large. In addition, although the granular activated carbon can reduce the pressure loss if the particle size is increased to some extent, there are problems such as a decrease in the adsorption surface and a decrease in the adsorption speed.
[0003]
On the other hand, if activated carbon fiber, ie activated carbon fiber, is used, unlike powdered or granular activated carbon, it can be easily separated from the gas or liquid to be treated, has a large surface area, and has a high adsorption rate. There are advantages such as.
However, conventional activated carbon fibers are often sold in the form of felt or cloth, and when used as an adsorbent, it is necessary to cut the shape according to the shape and size of the adsorption tower, etc. .
[0004]
Japanese Examined Patent Publication No. 3-47893 proposes a massive adsorbent molded only with activated carbon fibers, but this adsorbent is particularly deformed during use, and fiber fragments tend to flow out of the system. There is a problem that it is difficult to use.
[0005]
On the other hand, there is a method of using microorganisms as one of water treatment methods for decomposing organic substances and ammonia in water. This method includes a method of using activated sludge in an aeration tank and a method of forming a biofilm on the surface of a carrier and treating the contained impurities by contacting the water to be treated.
The biological treatment carriers used in the latter method include synthetic resin rotating disks, honeycomb tubes, synthetic fiber rods, nonwoven fabrics or spheres, sand, anthracite, ceramics, granular activated carbon, etc. There are granular materials.
[0006]
When a rotating disc made of synthetic resin, honeycomb tube or corrugated one is used as a biological treatment carrier, it can be processed at high speed, and it is difficult to block by inorganic and organic suspended substances in water. , Widely used when treating large amounts of water. However, since the surface area is small, there is a problem that the amount of biofilm attached is small and the processing efficiency is low.
[0007]
In addition, when a synthetic fiber cage or nonwoven fabric is used as a biofilm carrier, the nonwoven fabric swings in contact with the water to be treated, and the contact is suppressed or clogging occurs, resulting in a decrease in processing capacity. There is a problem of doing. In order to make up for these drawbacks of synthetic fiber nonwoven fabrics, a carrier is proposed in which a nonwoven fabric is impregnated with a resin and reinforced, or a support plate for maintaining the strength of the carrier is provided (Japanese Patent Laid-Open No. 1-274836). However, this carrier has a problem that a reinforcing material not directly related to biological treatment is required.
[0008]
In addition, if a granular material such as sand or anthracite is used as a biological treatment carrier, the surface area to which microorganisms adhere is increased, but the resistance to liquid flow increases and the flow rate cannot be increased. . Moreover, there is a problem that it is easily clogged by suspended substances in the water to be treated.
When ceramics with a large particle size are used, the resistance to liquid flow is reduced and clogging is less likely to occur, but the surface area to which microorganisms adhere is reduced and the processing efficiency is also reduced. Furthermore, since the weight of the carrier is increased, handling is not preferable.
[0009]
In recent years, activated carbon has been used as a biological treatment carrier, and the usefulness of activated carbon has been recognized. However, granular activated carbon has a large pressure loss like sand and the like, and further has a problem that it is easily clogged by suspended substances in the water to be treated. If backwashing is performed to prevent this blockage, there is a problem that the activated carbon is crushed or worn and powdered.
[0010]
On the other hand, as a method for increasing the surface area of the carrier, there is a method in which synthetic fibers are formed into a spherical shape. In this method, a large amount of microorganisms grow inside the spherical fiber, but the water flow into the spherical fiber is poor and the supply of oxygen is insufficient, so that the biofilm can be used effectively. There wasn't. Furthermore, this fiber lump is difficult to continuously produce, and there is a problem that the fiber lump size obtained by the thickness and length of the single fiber tends to vary greatly.
[0011]
[Problems to be solved by the invention]
The present invention solves the above-mentioned problems, is easy to handle, has little product variation, can be used simply by filling the adsorption tower in the same shape, has a high adsorption rate, Therefore, it is a technical object to provide an adsorbent suitable as a biological treatment carrier and a water treatment method using the adsorbent as a biological treatment carrier.
[0012]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that if the adsorbent is formed into a rod-shaped fiber bundle of activated carbon fibers and thermoplastic synthetic fibers, handling is easy and product variations are small. The present inventors have found that carbon dust and fiber fragments are hardly generated, and that this adsorbent is also suitable as a biological treatment carrier.
[0013]
That is, the present invention has the following configuration.
(1) rod shape to form a uniform voids therein by heat-treating the fiber bundle consisting of activated carbon fiber 20% to 80% by weight and 80 to 20 wt% thermoplastic synthetic fiber the fiber bundle inside the fiber is partially joined An adsorbent comprising a fiber bundle and having a cross-sectional shape of any one of a circular shape, an elliptical shape, a donut shape, a trilobal shape, a cross shape or a star shape, and is used as a biological treatment carrier .
(2) A biofilm is formed on the adsorbent described in 1 above, and then the adsorbent is filled in a treatment tank as it is or is attached to a treatment tank in a state where the adsorbent is filled, and then the adsorbent is treated. A water treatment method comprising contacting water.
(3) Filling the treatment tank with the adsorbent described in 1 above as it is, or mounting it on the treatment tank in a state of being filled in a filling cylinder, and then contacting the water to be treated while forming a biofilm on the adsorbent. A water treatment method characterized by the above.
[0014]
The present invention will be described in detail below.
The adsorbent of the present invention is composed of activated carbon fibers and thermoplastic synthetic fibers. As the activated carbon fibers, polyacrylonitrile-based, cellulose-based, vinylon-based, or pitch-based materials can be used.
The properties of the activated carbon fiber used in the present invention are not particularly limited, but those having a specific surface area of 700 to 2000 m ² / g and an average pore diameter of 4 to 20 mm are preferred.
[0015]
Next, polypropylene fiber, polyamide fiber, polyester fiber, polyacrylonitrile fiber, polyethylene fiber, etc. can be used as the thermoplastic synthetic fiber constituting the adsorbent together with the activated carbon fiber. Further, a binder fiber which is a kind of thermoplastic synthetic fiber, for example, a polyester-based fiber having a core-sheath structure in which a core part is polyethylene terephthalate (PET) and a sheath part is copolymerized PET.
[0016]
The content of the activated carbon fiber and the thermoplastic synthetic fiber in the adsorbent is 20 to 80% by weight of the activated carbon fiber and 80 to 20% by weight of the thermoplastic synthetic fiber in order to satisfy the adsorption characteristics and the shape stability at the same time. is required. When the activated carbon fiber is less than 20 % by weight and the thermoplastic synthetic fiber exceeds 80 % by weight, the adsorption characteristics of the activated carbon fiber are not sufficiently exhibited. Moreover, when the activated carbon fiber exceeds 80 % by weight and the thermoplastic synthetic fiber is less than 20 % by weight, the fibers are entangled to form a lump, but the shape collapses during use or the fiber pieces flow out of the system. It becomes easy.
[0017]
As described above, the adsorbent of the present invention is composed of activated carbon fibers and thermoplastic synthetic fibers. However, natural fibers such as cotton, regenerated fibers, glass fibers, etc. are used as long as the effects of the present invention are not impaired. You may make it contain. Moreover, you may form an adsorbent with activated carbon fiber and several types of thermoplastic synthetic fiber.
[0018]
The shape of the adsorbent of the present invention is a rod-like fiber converging body, but the maximum diameter is 2 mm or more, and the cross-section is circular, elliptical, donut-shaped, trilobal, cross-shaped, or star-shaped. It is easy to handle and suitable as a biological treatment carrier .
The maximum diameter in the present invention means the diameter in the case of a spherical shape or a donut shape, the length of the major axis in the case of an ellipse shape, and the maximum length in the case of other shapes.
[0019]
The length of the adsorbent is preferably 2 mm or more, particularly 2 to 50 mm from the viewpoint of ease of production and handling. In addition, when the adsorbent of the present invention is packed in a packed cylinder such as an adsorption tower, the adsorbent having the same length and diameter has little anisotropy during the packing, and there are abnormalities in the packed cylinder. This is preferable because it can be filled without generating voids. Furthermore, if the length of the adsorbent is approximately the same as the length of the filling cylinder, the adsorbent need only be filled in the cross-sectional direction of the filling cylinder.
[0020]
The adsorbent of the present invention is a rod-like fiber converging body in which a fiber bundle composed of activated carbon fibers and thermoplastic synthetic fibers is heat-treated to fuse the thermoplastic synthetic fibers, but the degree of fusion of the thermoplastic synthetic fibers is adjusted. Then, the fibers inside the convergent body are partially joined. By doing so, it has a uniform void inside, and the void can be easily reduced by compression. And even if this adsorbent raises the packing density to a filling cylinder, there is little pressure loss and it does not raise | generate a drift.
[0021]
Next, the manufacturing method of the adsorbent of this invention is demonstrated. First, the activated carbon fiber and the thermoplastic synthetic fiber having a chopped yarn shape or crimp are preferably cut into 20 to 150 mm, opened with a spinning card machine, mixed to form a sliver, or activated carbon fiber And crimped thermoplastic fibers are spread, mixed and taken up in a tow shape to obtain a fiber bundle.
Next, the fiber bundle is heat-treated to partially fuse the thermoplastic synthetic fiber into a rod-like fiber converging body. As a heat treatment method, a method of blowing hot air or a method of passing through a high-temperature atmosphere is adopted. can do. As a specific heat treatment method, the fiber bundle may be passed through a cylindrical or deformed cylindrical heating body to partially melt the thermoplastic synthetic fiber, and then compressed and cooled to form a rod-like fiber. The convergent body can be continuously formed. If this rod-shaped fiber converging body is cut into a length as required, the adsorbent of the present invention is obtained. Thus, the adsorbent of the present invention can be stably and efficiently manufactured by a simple process.
[0022]
In order to obtain the adsorbent of the present invention, when using short-fiber activated carbon fiber and thermoplastic synthetic fiber, the fiber length is 1 mm or more from the viewpoint of easy entanglement between fibers when opening and mixing, In particular, the thickness is preferably 20 to 150 mm. If the fiber length is less than 1 mm, there is little entanglement between the fibers, and the shape as a molded body cannot be maintained during use, or it tends to cause pulverization and generation of carbon dust.
[0023]
As described above, the adsorbent of the present invention, since 20 to 80 wt% activated carbon fiber and 80 to 20 wt% thermoplastic synthetic fibers and has a rod-like fibers converging body, easy to handle, as it is shaped It can be used for liquid phase adsorption treatment simply by filling in a packing cylinder such as an adsorption tower, and the adsorption speed is fast, so that activated carbon fibers do not fall off during use, and as a carrier for biological treatment. Is also a suitable adsorbent.
[0024]
For example, there are the following two methods for water treatment using the adsorbent of the present invention as a biological treatment carrier.
The first method is a method in which an adsorbent on which a biofilm is formed in advance is used as a treatment material. As a method of forming a biofilm in advance on the adsorbent, for example, after filling the adsorbent into a filling cylinder such as a resin cylinder, a method of passing a culture solution or waste water containing microorganisms such as organic matter degrading bacteria or nitrifying bacteria, There is a method of aeration or agitation after the adsorbent is put into a culture solution or wastewater tank as it is.
[0025]
There are two specific water treatment methods using an adsorbent on which a biofilm is formed in advance. The first method uses an adsorbent as a fixed bed. The adsorbent formed with a biofilm is filled in a filling cylinder and attached to a treatment tank, and the liquid to be treated is passed through to contact the biofilm on the surface of the adsorbent. It decomposes and treats organic substances contained in it.
The second method uses an adsorbent as a fluidized bed. The adsorbent on which the biofilm is formed is filled as it is into the treatment liquid treatment tank and aerated to bring the liquid to be treated into contact with the biofilm on the adsorbent surface. It decomposes and treats organic substances contained in it.
And in these methods, you may share the cylindrical body and tank which form a biofilm with the processing tank which processes wastewater.
[0026]
Further, the second method for water treatment using the adsorbent of the present invention as a biological treatment carrier is a method using an adsorbent before forming a biofilm. In this case as well, there are a method of using the adsorbent as a fixed bed and a method of using it as a fluidized bed. Fill and pass through the treatment tank, or aerate or agitate the treatment tank to form a biofilm on the surface of the adsorbent, bringing the liquid to be treated into contact with the biofilm and decomposing and treating the organic matter contained It is.
[0027]
If the adsorbent of the present invention is used as a carrier for biological treatment, and a biofilm is formed on the adsorbent, it can be used for the treatment of waste water, for use in clean water, middle water, or a factory. In the water supply field, ammonia nitrification, decomposition of harmful substances such as pesticides and trihalomethane precursors, in the middle water field, purification and regeneration of domestic bath water, public baths and pools, aquarium fish, live fish, aquaculture fish tanks, etc. In water recycling and factory wastewater, it is suitable for various cleaning water regeneration, primary treatment and advanced treatment of wastewater and sewage.
Further, the adsorbent of the present invention is generated from, for example, a primary treatment or advanced treatment of waterworks treatment, factory wastewater or sewage treatment, and a sewage treatment facility as a biological treatment carrier that takes advantage of the function and shape of biological activated carbon. Very useful for malodorous biological deodorization.
[0028]
【Example】
Example 1
Diameter 17 .mu.m, the average pore radius 8 Å, pitch-based activated carbon fiber (fiber length 80 mm) having a specific surface area of 1000 m ² / g 50 wt% and, in a single filament denier 15 denier, fiber length 76mm core-sheath type polyester composite unstretched fibers ( The core part: PET and the sheath part: 50% by weight of PET (copolymerized with 40 mol% of isolutaric acid as an acid component) were opened and mixed with a carding machine to obtain a card sliver of 6 g per meter.
[0029]
This card sliver is heated by passing through a cylindrical heater blown with a 150 ° C air jet to melt the core-sheath polyester composite unstretched fibers and partially bond the fibers together, and then air at room temperature. Was introduced into a cylindrical body having a diameter of 7 mm at 75 cm / min and cooled while being compressed to obtain a rod-shaped fiber bundle having a diameter of 7 mm. This rod-shaped fiber bundle was cut into a length of 8 mm to obtain a cylindrical adsorbent.
[0030]
Using the resulting adsorbent, a glass column with a diameter of 25 mm was packed to a height of 100 mm, and a 100 ppm methylene blue aqueous solution was passed downward at a flow rate of 30 ml / min to adsorb methylene blue.
As a result of measuring the methylene blue concentration of the treated water by the absorption spectrum method, the adsorption removal rate was 97% or more. Further, during the above adsorption test, the activated carbon fiber did not fall out in the treated water.
[0031]
Example 2
Diameter 17 .mu.m, the average pore radius 8 Å, pitch-based activated carbon fiber (fiber length 80 mm) having a specific surface area of 1000 m ² / g 50 wt% and, at a single yarn fineness of 10 deniers, fiber length 76mm polyester side-by-side type composite unstretched fibers ( 50% by weight of PET with a degree of polymerization of 110 / PET with a degree of polymerization of 80) was opened and mixed with a carding machine to obtain a card sliver of 6 g per meter.
[0032]
This card sliver is heated by passing through a cylindrical heater with a 150 ° C air jet blown, and the side-by-side composite unstretched fibers are melted and the fibers are partially bonded together. It was introduced into a trilobal cylindrical body having a diameter of 8 mm at 75 cm / min and cooled while being compressed to obtain a rod-shaped fiber bundle having a diameter of 8 mm. This rod-shaped fiber bundle was cut to a length of 10 mm to obtain an adsorbent with a trilobal cross-sectional shape.
[0033]
Using the obtained adsorbent as a biological treatment carrier, this adsorbent is filled as it is in an acrylic resin activated sludge tank with a diameter of 150 mm × height of 1600 mm, and aeration pipes are provided below the activated sludge layer for aeration. It was.
Synthetic fiber production wastewater with BOD 1500 mg / liter and COD 1000 mg / liter was used as treated water, and this wastewater was passed through the activated sludge tank. The residence time was adjusted to 20 hours and continuous operation was carried out for 4 months, but the BOD and COD of the treated water were both suppressed to 250 mg / liter or less, and stable operation was possible without any trouble.
[0034]
Example 3
Using the adsorbent obtained in Examples 1 and 2 as a biological treatment carrier, each of acrylic resin cylinders with a diameter of 150 mm and a height of 1600 mm was filled up to a height of 1000 mm, and an aeration tube was installed at the bottom of the acrylic resin cylinder. Provided.
As water to be treated, BOD 120 mg / liter, COD 100 mg / liter, secondary wastewater from the food industry was used, and this wastewater was passed through the resin cylinder from below. The residence time was adjusted to 1 hour and continuous operation was carried out for 4 months. However, when using any adsorbent, the BOD and COD of the treated water were both suppressed to 10 mg / liter or less, and 1 By increasing the amount of air released from the air diffuser once a week and backwashing the air, stable operation was possible without any trouble.
[0035]
【The invention's effect】
The adsorbent of the present invention is easy to handle, and can be used by simply filling it into a packing cylinder such as an adsorption tower, has a high adsorption speed, and is also activated carbon fiber during use. Will not fall off.
Therefore, the adsorbent of the present invention can be widely used as an adsorbent for water purification, for example, in waterworks treatment, advanced treatment of industrial wastewater, or advanced treatment of sewage. Especially in the purification of tap water, trihalomethane or its It can be suitably used for removing trace organic substances such as humic acid, which are called precursors.
[0036]
Furthermore, the adsorbent of the present invention can be used as a carrier for biological treatment taking advantage of the function and shape advantage of biological activated carbon, for example, primary treatment or advanced treatment of water treatment, industrial wastewater or sewage treatment, sewage treatment facilities. It is useful for biological deodorization of the malodor that occurs.

Claims

By heat-treating the fiber bundle consisting of 20 to 80 wt% and 80 to 20 wt% thermoplastic synthetic fibers of activated carbon fibers, rod-shaped fiber collecting having formed a uniform voids therein by joining fibers within fiber bundles partially An adsorbent comprising a body, the cross-sectional shape of which is any of a circular shape, an elliptical shape, a donut shape, a trilobal shape, a cross shape or a star shape, and is used as a biological treatment carrier .

A biofilm is formed on the adsorbent according to claim 1, and then the adsorbent is filled in a treatment tank as it is, or is attached to a treatment tank in a state of being filled in a filling cylinder, and then water to be treated is applied to the adsorbent. A water treatment method comprising contacting with each other.

The adsorbent according to claim 1 is filled in a treatment tank as it is, or is attached to a treatment tank in a state where the adsorbent is filled, and then the water to be treated is brought into contact while forming a biofilm on the adsorbent. Water treatment method.