JP4309194B2 - Manufacturing method of filtration membrane for water treatment - Google Patents
Manufacturing method of filtration membrane for water treatment Download PDFInfo
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Description
【０００１】
【発明が属する技術分野】
本発明は、精密ろ過膜（ＭＦ）や限外ろ過膜（ＵＦ）に相当する、径が約０．０１〜１０μｍ以上の粒子状物質を分離する水処理ろ過膜の製造方法及び水処理用ろ過膜に関する。生活用浄水、産業用水、医療用水などのための処理ほか、し尿処理排水、下水、産業排水などの排水処理にも好適である。
【０００２】
【従来の技術】
最近の水処理分野における膜ろ過の進歩は著しく、ろ過膜の分離対象粒子の径は数オングストロームからミクロン単位の範囲におよぶ。また、装置をコンパクトに製作できる、生物的処理への応用が容易である、処理水質が安定するなど、数多くの利点があることから、多方面にわたる実用化が進んでいる。
【０００３】
【発明が解決しようとする課題】
一方で、従来の水処理用ろ過膜には、強度が低い、寿命が短く基本的に消耗品である、使用する装置が複雑であって、コスト面で不利であるという欠点があった。本発明は、コスト面で他の手段に遜色がなく丈夫で使いやすい実用性に富んだ水処理用ろ過膜を課題に研究の結果、完成したものである。
【０００４】
【課題を解決するための手段】
前記の課題を解決する手段として、本発明を開示し説明する。本発明は、前記の課題を解決するために、不織布に所定量の非水溶性樹脂の溶液（樹脂エマルジョン水溶液を含む）を含浸させて乾燥した後、得られた樹脂含浸不織布を加熱・圧縮することにより樹脂含浸不織布層内の細孔を所望の大きさに調整して得られるろ過膜を、ベースのろ過膜（又はベースろ過膜という）として使用する。
【０００５】
本発明は、前記の樹脂含浸不織布からなる、ベースのろ過膜の表面に、非水溶性樹脂の溶液（水溶液を除く）中に水溶性化合物の微粉末を混合・分散させて調合した樹脂ろ過膜の原材を塗布し、乾燥した後、水または熱水で処理して樹脂ろ過膜原材中の水溶性化合物を溶出させ、残る樹脂ろ過膜層中に微細孔を形成させて水処理用ろ過膜とする、ことを特徴とする水処理用ろ過膜の製造方法を開示する。
【０００６】
本発明はさらに、前記の水処理用ろ過膜の製造方法の別法として、離型紙に非水溶性樹脂の溶液（水溶液を除く）中に水溶性化合物の微粉末を混合・分散させて調合した樹脂ろ過膜の原材を塗布して、ベースのろ過膜の表面に転写又は接着させ、離型紙を除いて乾燥した後、水または熱水で処理して樹脂ろ過膜原材中の水溶性化合物を溶出させ、残る樹脂ろ過膜層中に微細孔を形成させて水処理用ろ過膜とする、ことを特徴とする水処理用ろ過膜の製造方法を開示する。前記したいずれの発明においても、使用する水溶性化合物としては、グルコン酸塩類又はブドウ糖の使用が好ましい。
【０００７】
２層からなるベースのろ過膜の層間に前記の樹脂ろ過膜原材の層を挟んで乾燥し、水または熱水で処理して樹脂ろ過膜原材層中の水溶性化合物を溶出し微細孔を形成させて一体に積層して３層からなる水処理用ろ過膜を製造することもできる。
【０００８】
そして本発明は、不織布に樹脂を含浸・付着させて層内に無数の細孔が形成されている樹脂含浸不織布層からなるろ過膜であって、加熱・圧縮により、好ましくは最小の分離対象粒子径、即ちろ液側とろ滓とに分離される最小の粒子径を１０〜０．１μｍの範囲に調整されている水処理用のろ過膜を、ベースのろ過膜として使用する。そして、前記の水処理ろ過膜製造方法によって製造される、樹脂ろ過膜材層を重ねた水処理用ろ過膜であって、樹脂ろ過膜材層中に形成される微細孔の径の大きさにより、最小の分離対象粒子径が１〜０．０１μｍの範囲に調整されている、ことを特徴とする水処理用ろ過膜を開示する。また、２層からなるベースのろ過膜の間に前記の樹脂ろ過膜原材の層を挟んで製造された水処理用ろ過膜であって、最小の分離対象粒子径を１〜０．０１μｍの範囲に調整した微細孔を有する樹脂ろ過膜層が挟まれて一体に積層されている、ことを特徴とする水処理用ろ過膜を開示する。
【０００９】
【発明の実施の形態】
本発明について実施の形態例をあげながら、適宜、図面を参照して具体的に説明する。まず、本発明は、不織布に非水溶性樹脂の溶液を含浸させて乾燥し熱プレスして、好ましくは最小の分離対象粒子径が１０〜０．１μｍの範囲に調整されているろ過膜を、ベースのろ過膜として使用する。
【００１０】
そして本発明は、前記ベースのろ過膜の表面に、水を溶媒としない非水溶性樹脂の溶液に水溶性化合物の微粉末を分散させた樹脂ろ過膜の原材を塗布し、乾燥して溶媒を揮散させた後、水又は熱水を用いて処理を行い水溶性物質を溶出させ乾燥することによって微細孔を有する樹脂ろ過膜層を形成、積層した、最小の分離対象粒子径が１〜０．０１μｍの範囲に調整されている水処理用ろ過膜製造方法及び水処理用ろ過膜を提供する。本発明に係る水処理用ろ過膜の分離対象粒径は、限外ろ過膜のそれに相当する。ただし、本発明の水処理用ろ過膜製造方法及び水処理用ろ過膜が分離対象とする粒子径は、上記に限定されるものではなく、熱プレスや水溶性化合物の粒度調整、あるいはろ過膜の積層によってさらに広範囲で利用することができる。
【００１１】
本発明水処理ろ過膜の基材として使用する不織布には、ポリエステル、ナイロン、ビニロン、ポリプロピレン、フッ素系ポリマー等の有機合成繊維、ガラス繊維、セラミックファイバー等の無機繊維、天然繊維、これらの繊維の混合繊維からなる不織布を使用できる。通常の不織布のほか溶融紡糸、延伸後、直ちに分散成形する長繊維不織布も使用できる。使用する不織布の種類、厚さ、繊維密度などについては使用条件により適宜に決めればよく、市販の不織布を利用できる。不織布の厚さは繊維密度にもよるが、一般的には２〜１０ｍｍ程度がよい。繊維密度は０．００５〜０．０３ｇ／ｃｍ３程度が好ましい。
【００１２】
前記樹脂溶液に含まれる非水溶性樹脂としては、アクリル樹脂、ポリエステル樹脂、フェノール樹脂、エポキシ樹脂、ポリウレタン樹脂等の合成樹脂や天然樹脂、またはこれらの樹脂を適宜に混合して使用できる。これらの樹脂の中ではポリエステル樹脂、ポリウレタン樹脂が使いやすい。
【００１３】
樹脂溶液の溶媒としては、トルエン、キシレン、酢酸エチル、酢酸ブチル、アセトン、メチルシクロヘキサン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサン、エチルアルコール、メチルシクロヘキサン、イソプロピルアルコール等を使用できる。樹脂ろ過膜の原材に使用する樹脂溶液を除く樹脂溶液は、前記の樹脂をエマルジョンにして分散・混合した水溶液を利用することができる。
【００１４】
樹脂ろ過膜の原材に使用する樹脂溶液は、通常、不織布に含浸させた樹脂溶液に用いたのと同じ樹脂、溶媒（水を除く）を使用するが、条件が許せばそれにこだわる必要はない。樹脂ろ過膜原材に分散させる水溶性化合物粉末は、水に易溶性であって樹脂溶液には溶解しない物質から選ばれ、具体的にはグルコン酸ナトリウム、グルコン酸カルシウム、クエン酸、クエン酸ナトリウム、クエン酸カリウム、砂糖、果糖、蔗糖、ブドウ糖などの微粉末があげられる。これらの中ではグルコン酸塩やブドウ糖を好ましく利用することができる。また、前記水溶性化合物粉末は、分離対象粒子の径によるが一般には１〜０．０１μｍの微細孔を形成するためには３００〜１０００メッシュ程度のものを使用する。このほか、前記の樹脂溶液には、いずれも必要が有れば、分散剤や沈降防止剤、増粘剤、抗菌剤や防藻剤を添加してもよい。
【００１５】
つぎに、本発明に用いるベースろ過膜は、不織布に所定量の樹脂溶液を含浸させて乾燥し溶媒を分離して細孔を形成し、さらに、不織布表面に圧力を加えて加熱・圧縮し細孔を所要の大きさに調整して製造することができる。含浸させる樹脂量は、乾燥後において元の不織布重量の３０〜１５０％程度、一般には約５０〜１００％の範囲であるが、条件によってはこれらの範囲に限られるものではない。加熱・圧縮には、加熱プレス、加熱ロールなどを用いるとよい。加熱温度は含浸樹脂の軟化温度にもとづいて決める。圧縮比は、元の不織布厚さに対し通常１／２〜１／８程度であり、ろ過分離される対象粒子の大きさを調整するのに重要な操作である。ただし、上記した数字は、最終的には操作条件や原料などの相互の関連、ろ過する懸濁物質の大きさなどによって決まるので、最終的には経験と実験とにより適宜に設定することが多い。
【００１６】
この様にして製造されたベースろ過膜の表裏両面を顕微鏡及び走査型電子顕微鏡（ＳＥＭ）により拡大して観察したところ、繊維が重なって構成される内部は均一な大きさの空隙が形成されていた。これは逆洗およびエヤースクランビングを行うときファウリングを防ぎ、有機物吸着の圧密化を防ぐとともに、加圧、吸引に対し、緩衝材として働く。
【００１７】
本発明の水処理用ろ過膜は、ベースろ過膜の表面に、非水溶性樹脂溶液中に水溶性化合物の粉末を混合し分散させた樹脂ろ過膜の原材を塗布して乾燥し樹脂を固定した後、水又は熱水で処理して水溶性化合物を水側に抽出し微細孔を形成して樹脂ろ過膜にすることによって製造できる。混合する水溶性化合物粉末量は、樹脂ろ過膜原材中の樹脂に対して、２００〜５００重量％の範囲が好ましい。塗布方法にとくに制限はなく、ロールコータ、スプレーコータやナイフコータを用いることができる。また、離型紙上に樹脂ろ過膜原剤を塗布し、そのままベースのろ過膜表面に転写あるいは接着させてもよい。接着には水溶性化合物粉末を分散、混合した樹脂ろ過膜原材を利用する。一般に、樹脂ろ過膜２の厚さは０．２〜１．５ｍｍ程度、ベースろ過膜の厚さに対して１０〜１００％程度にするとよい。
【００１８】
樹脂ろ過膜は、一般にベースろ過膜１の片面に形成一体化し、使用時には通常上流側に配置される。逆洗し易いのと強度上有利なことによる。しかし、ろ過圧力や被ろ過液のＳＳ濃度が大きい場合には、樹脂ろ過膜の両面にベースろ過膜を積層して用い、樹脂ろ過膜の保護を図るとよい。また、ベースろ過膜と樹脂ろ過膜２と負荷の差が大きい場合には、両膜間のろ過対象粒子径を調整して製造し負荷バランスをはかるとことができる。勿論のこと、前記した本発明の水処理用ろ過膜は、複数枚を積層し相互に固着させて一体に構成し使用することができるし、適宜に組み合わせて独立配置することもできる。
【００１９】
ろ過膜の使用形態について説明する。ろ過膜モジュウルの形式としては、平面膜、円管膜、スパイラル膜、中空糸膜が一般的である。大きな膜面積を得られモジュール交換が容易である点ではスパイラル膜、中空糸膜が有利であるが懸濁物質の多い液を流すと内部閉塞を起こすおそれがある。本発明に係るろ過膜は高強度であり、高濃度ＭＬＳＳ（ Mixed Liquor Suspended Solid：排水等に含まれる浮遊固形物）などに有用であるところから、四角平板モジュールを望ましく利用することができる。簡易なろ過槽に簡便、安全、低コストで所望のろ過膜を設置できる。逆洗やエヤースクランビング、ろ過膜の交換は容易である。
【００２０】
本発明水処理ろ過膜の具体的な使用形態として、バッチ式ろ過装置の一例を図２にフローシートで示して説明する。ろ過原水槽１１に貯留された原水は、自然流下によって原水供給配管１２からバッチ式ろ過水器１３の底部に供給される。バッチ式ろ過器１３の下部には支持部材が設けられて本発明水処理ろ過膜１４のモジュールが水平に取り付けられ、供給されたろ過原水はろ過膜１４の下面側から上面側に通過しろ過される。ろ過されたろ過水はろ過膜１４の上面側に貯留され、適時ろ過水抜出配管１５を通りろ過水貯留槽１６に抜き出され再利用水のために貯留される。
【００２１】
ろ過原水槽１１及びバッチ式ろ過器１２にはそれぞれ液面検出制御計１７ａ、１７ｂを取り付けておく。ろ過膜１４に目詰まりが生じ、ろ過原水槽１１の水位が高くなると液面検出制御計１７ａから注意信号が発せられる。逆洗ポンプ１８が作動して上面側に逆洗水が投入される。逆洗水は逆洗出口１９（ドレーン弁開閉口）から排出される。
【００２２】
【実施例】
本発明の効果を確認するために小規模試験を実施したので、その結果を具体的に説明する。
【００２３】
実施例１
まず、ベースろ過膜を試作したのでその手順及びその特性について説明する。厚さ５ｍｍのポリエステル繊維からなる不織布に水性ポリウレタン樹脂を含浸させ、乾燥した。不織布重量に対しポリウレタン樹脂は約８０重量％であった。これを１４０℃で加熱プレスして１ｍｍの厚さにし、ベースろ過膜にした。このろ過膜の引裂強度は、縦方向が３５ｋｇ／ｃｍ２、横方向が５０ｋｇ／ｃｍ２であった。従来からよく利用されているろ過膜よりも強く靭性があった。
【００２４】
また、このろ過膜を直径約１０ｃｍ、内容量１．８リットルのステンレス鋼製円筒の底にフランジで固定し、かつ原水側にろ過圧力を加えてろ過速度を変更できるよう加圧装置を接続して、ろ過の試験装置に用いた。まず、透明度が殆ど０に近い水田の水をろ過したところ透明度を５０ｃｍ以上にすることができた。つぎにＡ市下水処理場の曝気前の都市下水を無加圧のまま、ろ過し、濁度及び浮遊粒子の除去率を測定した（レーザー回折散乱法による）。その結果を表１に示す。なお、ろ過前の原水中の粒度分布を測定したので結果を図３に示す。
【００２５】
実施例２
ポリエステル樹脂（パイロン２００：東洋紡績（株）製）が３０重量％になるように、トルエン／メチルエチルケトン／酢酸エチル（容量比：６０／２０／２０）の混合溶液に溶解した。さらにポリエステル樹脂の２７０重量％のグルコン酸ナトリウム微粉末（１０００メッシュ）を加えて分散させた。この分散溶液を離型紙に約０．８ｍｍの厚さに塗布して乾燥し、同じ分散溶液を用い、実施例１において製造したベースろ過膜に接着させた。よく乾燥させた後、７０℃の水に浸漬してグルコン酸ナトリウムを溶出させた後、乾燥して２層からなる本発明ろ過膜を製造した。得られたろ過膜を乾燥後顕微鏡および走査型電子顕微鏡（ＳＥＭ）により拡大して観察したところ、０．０１〜０．１μｍの微細孔が形成されているのを確認できた。さらに実施例１と同様にして都市下水をろ過しろ過水の上澄中の大腸菌を調べたが観察されなかった。
【００２６】
実施例３
ポリウレタンエラストマーが３５重量％になるようにトルエン／酢酸エチル（容量比：５０／５０）に溶解した。さらにポリウレタンに対して３００重量％のブドウ糖の微粉末（１０００メッシュ）を分散させた。得られた分散溶液を離型紙に厚さ１ｍｍに塗布して乾燥し、同じ分散液を用い、実施例１において製造したベースろ過膜に接着させた。よく乾燥させた後、７０℃の水に浸漬してブドウ糖を溶出させた後、乾燥して２層からなる本発明ろ過膜を製造した。得られたろ過膜を乾燥後顕微鏡および走査型電子顕微鏡（ＳＥＭ）により拡大して観察したところ、０．０１〜０．１μｍの微細孔が形成されているのを確認できた。さらに実施例１のろ過水を被処理水として、ろ過圧力を調整しろ加速度を変えた以外は実施例１と同様にして、ろ過試験を実施した。その結果を表１に示す。ろ過水の上澄水中の大腸菌を調べたが観察されなかった。
【００２７】
【表１】
【発明の効果】
本発明に係る水処理用ろ過膜は、分離対象となる粒子径の調整が容易であって、強度及び靭性が極めて大きく逆洗も容易であって、長期使用が可能である。取り付け、取り外し、および使用後の処理が簡単で保守費用は安価である。
【図面の簡単な説明】
【図１】 本発明第２形態ろ過膜の断面図
【図２】 本発明水処理用ろ過膜を用いたバッチ式ろ過装置の一例を示すフローシート
【図３】 実施例１〜３に用いた原水中の固形物粒度分布
【符号の説明】
１：ベースのろ過膜（ベースろ過膜）
２：樹脂ろ過膜（層） ３：本願発明に係る水処理用ろ過膜
４：ろ過工程の流れ
１１：ろ過原水槽 １２：原水供給配管
１３：バッチ式ろ過器 １４：本発明水処理用ろ過膜
１５：ろ過水抜出配管 １６：ろ過水貯留槽
１７ａ，１７ｂ：液面検出制御計 １８：逆洗ポンプ
１９：逆洗水出口[0001]
[Technical field to which the invention belongs]
The present invention relates to a method for producing a water treatment filtration membrane for separating particulate matter having a diameter of about 0.01 to 10 μm or more, which corresponds to a microfiltration membrane (MF) or an ultrafiltration membrane (UF), and a filtration for water treatment. Relates to the membrane. In addition to treatment for domestic water, industrial water, medical water, etc., it is also suitable for wastewater treatment such as human waste treatment wastewater, sewage, and industrial wastewater.
[0002]
[Prior art]
Recent progress in membrane filtration in the water treatment field is remarkable, and the size of particles to be separated in the filtration membrane ranges from several angstroms to microns. In addition, since there are a number of advantages such as the ability to manufacture the apparatus in a compact manner, easy application to biological treatment, and stable treatment water quality, it has been put to practical use in various fields.
[0003]
[Problems to be solved by the invention]
On the other hand, conventional filtration membranes for water treatment have the disadvantages of low strength, short life and basically consumables, complicated equipment used, and disadvantageous in terms of cost. The present invention has been completed as a result of research on a water treatment filter membrane that is durable and easy to use, inferior to other means in terms of cost.
[0004]
[Means for Solving the Problems]
The present invention will be disclosed and described as means for solving the above-mentioned problems. In order to solve the above problems, the present invention impregnates a nonwoven fabric with a predetermined amount of a water-insoluble resin solution (including a resin emulsion aqueous solution) and dries it, and then heats and compresses the resulting resin-impregnated nonwoven fabric. Thus, a filtration membrane obtained by adjusting the pores in the resin-impregnated nonwoven fabric layer to a desired size is used as a base filtration membrane (or a base filtration membrane).
[0005]
The present invention provides a resin filtration membrane prepared by mixing and dispersing a fine powder of a water-soluble compound in a water-insoluble resin solution (excluding an aqueous solution) on the surface of a base filtration membrane made of the resin-impregnated nonwoven fabric. Apply and dry the raw material, and then treat with water or hot water to elute the water-soluble compounds in the resin filtration membrane raw material and form fine pores in the remaining resin filtration membrane layer to filter for water treatment Disclosed is a method for producing a filtration membrane for water treatment , characterized in that it is a membrane .
[0006]
The present invention is further prepared by mixing and dispersing a fine powder of a water-soluble compound in a solution of a water-insoluble resin (excluding an aqueous solution) on a release paper as an alternative method for producing the water treatment filter membrane. Apply the resin filtration membrane raw material, transfer or adhere to the surface of the base filtration membrane, remove the release paper and dry, then treat with water or hot water to dissolve the water-soluble compound in the resin filtration membrane raw material A method for producing a filtration membrane for water treatment is disclosed, in which fine pores are formed in the remaining resin filtration membrane layer to form a filtration membrane for water treatment. In any of the above-described inventions, it is preferable to use gluconates or glucose as the water-soluble compound to be used.
[0007]
The resin filtration membrane raw material layer is sandwiched between two layers of a base filtration membrane, dried, and treated with water or hot water to elute the water-soluble compounds in the resin filtration membrane raw material layer and to form fine pores. It is also possible to produce a three-layer water treatment filter membrane by forming the layers integrally.
[0008]
The present invention is a filtration membrane comprising a resin-impregnated nonwoven fabric layer in which a resin is impregnated / attached to a nonwoven fabric and innumerable pores are formed in the layer, and preferably the smallest particles to be separated by heating / compression A filtration membrane for water treatment in which the diameter, that is, the minimum particle size separated into the filtrate side and the filter cake is adjusted to a range of 10 to 0.1 μm, is used as the base filtration membrane. And it is the filtration membrane for water treatment which piled up the resin filtration membrane material layer manufactured by the above-mentioned water treatment filtration membrane manufacturing method, and according to the size of the diameter of the fine hole formed in the resin filtration membrane material layer Disclosed is a filtration membrane for water treatment, wherein the minimum separation target particle diameter is adjusted to a range of 1 to 0.01 μm. Moreover, it is a filtration membrane for water treatment produced by sandwiching the resin filtration membrane raw material layer between two layers of a base filtration membrane, and has a minimum separation target particle diameter of 1 to 0.01 μm. Disclosed is a filtration membrane for water treatment, characterized in that a resin filtration membrane layer having fine pores adjusted to a range is sandwiched and laminated integrally.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described with reference to the drawings as appropriate while referring to the embodiments. First, the present invention impregnates a non-water-soluble resin solution into a non-woven fabric, and after drying and hot pressing, preferably a filtration membrane whose minimum separation target particle diameter is adjusted to a range of 10 to 0.1 μm, Used as base filtration membrane .
[0010]
In the present invention, a base material of a resin filtration membrane in which a fine powder of a water-soluble compound is dispersed in a solution of a water-insoluble resin that does not use water as a solvent is applied to the surface of the base filtration membrane, dried, and solvent After volatilizing, the resin filtration membrane layer having micropores is formed by laminating and drying the water-soluble material by drying with water or hot water, and the minimum separation target particle size is 1 to 0 Provided is a method for producing a water treatment filter membrane and a water treatment filter membrane adjusted to a range of 0.01 μm . The separation target particle size of the water treatment filter membrane according to the present invention corresponds to that of the ultrafiltration membrane. However, the particle size to be separated by the method for producing a water treatment filter membrane and the water treatment filter membrane of the present invention is not limited to the above. It can be used in a wider range by laminating.
[0011]
Non-woven fabric used as the base material for the water treatment filtration membrane of the present invention includes organic synthetic fibers such as polyester, nylon, vinylon, polypropylene, and fluoropolymer, inorganic fibers such as glass fibers and ceramic fibers, natural fibers, and the like of these fibers. Nonwoven fabric made of mixed fibers can be used. In addition to ordinary nonwoven fabrics, long-fiber nonwoven fabrics that are dispersed and formed immediately after melt spinning and stretching can also be used. What is necessary is just to determine suitably according to use conditions about the kind of nonwoven fabric to be used, thickness, fiber density, etc., and a commercially available nonwoven fabric can be utilized. The thickness of the nonwoven fabric is generally about 2 to 10 mm, although it depends on the fiber density. The fiber density is preferably about 0.005 to 0.03 g / cm 3 .
[0012]
As the water-insoluble resin contained in the resin solution, a synthetic resin such as an acrylic resin, a polyester resin, a phenol resin, an epoxy resin, or a polyurethane resin, or a natural resin, or an appropriate mixture of these resins can be used. Among these resins, polyester resins and polyurethane resins are easy to use.
[0013]
As a solvent for the resin solution, toluene, xylene, ethyl acetate, butyl acetate, acetone, methylcyclohexane, methylethylketone, methylisobutylketone, cyclohexane, ethyl alcohol, methylcyclohexane, isopropyl alcohol and the like can be used. As the resin solution excluding the resin solution used as the raw material of the resin filtration membrane, an aqueous solution obtained by dispersing and mixing the above resin into an emulsion can be used.
[0014]
The resin solution used for the raw material of the resin filtration membrane is usually the same resin and solvent (excluding water) used for the resin solution impregnated in the nonwoven fabric, but it is not necessary to stick to it if conditions permit . The water-soluble compound powder to be dispersed in the resin filtration membrane raw material is selected from substances that are readily soluble in water and not soluble in the resin solution. Specifically, sodium gluconate, calcium gluconate, citric acid, sodium citrate And fine powders of potassium citrate, sugar, fructose, sucrose, glucose and the like. Among these, gluconate and glucose can be preferably used. The water-soluble compound powder is generally about 300 to 1000 mesh in order to form fine pores of 1 to 0.01 μm depending on the diameter of the particles to be separated. In addition, a dispersant, an anti-settling agent, a thickening agent, an antibacterial agent, and an anti-algae agent may be added to the above resin solution if necessary.
[0015]
Next, the base filtration membrane used in the present invention is impregnated with a predetermined amount of a resin solution in a non-woven fabric and dried to separate the solvent to form pores. It is possible to manufacture by adjusting the hole to a required size. The amount of resin to be impregnated is about 30 to 150%, generally about 50 to 100% of the weight of the original nonwoven fabric after drying, but is not limited to these ranges depending on conditions. For the heating / compression, a heating press, a heating roll or the like may be used. The heating temperature is determined based on the softening temperature of the impregnating resin. The compression ratio is usually about 1/2 to 1/8 of the original nonwoven fabric thickness, and is an important operation for adjusting the size of target particles to be filtered and separated. However, since the above numbers are ultimately determined by the relationship between operating conditions, raw materials, etc., the size of suspended solids to be filtered, etc., they are often set appropriately based on experience and experiment. .
[0016]
When the front and back surfaces of the thus manufactured base filtration membrane were magnified and observed with a microscope and a scanning electron microscope (SEM), a uniform-sized void was formed in the interior composed of overlapping fibers. It was. This prevents fouling when backwashing and air scrambling, prevents compaction of organic adsorption, and acts as a buffer against pressurization and suction.
[0017]
The filtration membrane for water treatment of the present invention is applied to the surface of the base filtration membrane by applying a resin filtration membrane raw material in which a water-soluble compound powder is mixed and dispersed in a water-insoluble resin solution and then dried to fix the resin. Then, it can be produced by treating with water or hot water to extract a water-soluble compound on the water side to form fine pores to form a resin filtration membrane. The amount of the water-soluble compound powder to be mixed is preferably in the range of 200 to 500% by weight with respect to the resin in the resin filtration membrane raw material. There is no restriction | limiting in particular in a coating method, A roll coater, a spray coater, and a knife coater can be used. Alternatively, the base material of the resin filtration membrane may be applied onto the release paper and transferred or adhered to the surface of the base filtration membrane as it is. For bonding, a resin filtration membrane raw material in which water-soluble compound powder is dispersed and mixed is used. Generally, the thickness of the
[0018]
The resin filtration membrane is generally formed and integrated on one side of the
[0019]
The usage pattern of the filtration membrane will be described. As a form of filtration membrane module, a flat membrane, a circular tube membrane, a spiral membrane, and a hollow fiber membrane are generally used. Spiral membranes and hollow fiber membranes are advantageous in that a large membrane area can be obtained and modules can be easily replaced. However, if a liquid containing a large amount of suspended matter is flowed, internal clogging may occur. Since the filtration membrane according to the present invention has high strength and is useful for high-concentration MLSS (Mixed Liquor Suspended Solid), a square plate module can be desirably used. A desired filtration membrane can be installed in a simple filtration tank with ease, safety and low cost. Backwashing, air scrambling and filtration membrane replacement are easy.
[0020]
As a specific usage pattern of the water treatment filtration membrane of the present invention, an example of a batch type filtration apparatus will be described with reference to a flow sheet in FIG. The raw water stored in the filtered
[0021]
Liquid level
[0022]
【Example】
A small-scale test was conducted to confirm the effect of the present invention, and the results will be specifically described.
[0023]
Example 1
First, since a base filtration membrane was prototyped, its procedure and its characteristics will be described. A nonwoven fabric made of polyester fiber having a thickness of 5 mm was impregnated with an aqueous polyurethane resin and dried. The polyurethane resin was about 80% by weight based on the weight of the nonwoven fabric. This was heated and pressed at 140 ° C. to a thickness of 1 mm to form a base filtration membrane . Tear strength of this filtration membrane, the vertical direction is 35 kg / cm 2, the horizontal direction was 50 kg / cm 2. It was stronger and tougher than conventional filtration membranes.
[0024]
The filtration membrane is fixed to the bottom of a stainless steel cylinder with a diameter of about 10 cm and an internal volume of 1.8 liters with a flange, and a pressure device is connected so that the filtration pressure can be changed by applying filtration pressure to the raw water side. And used in a filtration test apparatus. First, when the water of the paddy field whose transparency was almost 0 was filtered, the transparency could be 50 cm or more. Next, the city sewage before aeration in the city A sewage treatment plant was filtered without pressure, and the turbidity and the removal rate of suspended particles were measured (by laser diffraction scattering method). The results are shown in Table 1. In addition, since the particle size distribution in raw | natural water before filtration was measured, a result is shown in FIG.
[0025]
Example 2
The polyester resin (pylon 200: manufactured by Toyobo Co., Ltd.) was dissolved in a mixed solution of toluene / methyl ethyl ketone / ethyl acetate (volume ratio: 60/20/20) so as to be 30% by weight. Further, 270% by weight of a polyester resin, sodium gluconate fine powder (1000 mesh) was added and dispersed. This dispersion solution was applied to a release paper to a thickness of about 0.8 mm and dried, and the same dispersion solution was used and adhered to the base filtration membrane produced in Example 1. After thoroughly drying, it was immersed in water at 70 ° C. to elute sodium gluconate, and then dried to produce a two-layer filtration membrane of the present invention. When the obtained filtration membrane was expanded and observed with a microscope and a scanning electron microscope (SEM) after drying, it was confirmed that fine pores of 0.01 to 0.1 μm were formed. Further, the municipal sewage was filtered in the same manner as in Example 1 to examine E. coli in the supernatant of the filtered water, but it was not observed.
[0026]
Example 3
The polyurethane elastomer was dissolved in toluene / ethyl acetate (volume ratio: 50/50) to 35% by weight. Furthermore, 300% by weight of glucose fine powder (1000 mesh) was dispersed in polyurethane. The obtained dispersion solution was applied to a release paper to a thickness of 1 mm, dried, and then adhered to the base filtration membrane produced in Example 1 using the same dispersion solution. After thoroughly drying, it was immersed in water at 70 ° C. to elute glucose, and then dried to produce a two-layer membrane of the present invention. When the obtained filtration membrane was expanded and observed with a microscope and a scanning electron microscope (SEM) after drying, it was confirmed that fine pores of 0.01 to 0.1 μm were formed. Furthermore, the filtration test was carried out in the same manner as in Example 1 except that the filtered water of Example 1 was treated water and the filtration pressure was adjusted to change the filtration acceleration. The results are shown in Table 1. E. coli in the supernatant of filtered water was examined but not observed.
[0027]
[Table 1]
【The invention's effect】
The filtration membrane for water treatment according to the present invention can easily adjust the particle size to be separated, has extremely high strength and toughness, and can be easily backwashed, and can be used for a long time. Easy to install, remove, and use after use, and maintenance costs are low.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a second embodiment of the filtration membrane of the present invention. FIG. 2 is a flow sheet showing an example of a batch-type filtration device using the filtration membrane for water treatment of the present invention. Solid particle size distribution in raw water [Explanation of symbols]
1: Base filtration membrane (base filtration membrane)
2: Resin filtration membrane (layer) 3: Filtration membrane for water treatment according to the present invention 4: Flow of filtration process 11: Raw filtration water tank 12: Raw water supply pipe 13: Batch type filter 14: Filtration membrane for water treatment of the present invention 15: Filtration water extraction pipe 16: Filtration
Claims (6)
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| CN112978987A (en) * | 2021-02-19 | 2021-06-18 | 北京九泉科技有限公司 | Novel water purification unit made of environment-friendly materials |
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| JP2005349310A (en) * | 2004-06-10 | 2005-12-22 | Aroma Kagaku Kikai Kogyo:Kk | Filter medium for precise filtration |
| JP4825013B2 (en) * | 2006-01-23 | 2011-11-30 | 中村建設株式会社 | Method for producing flat membrane filter medium for suspended water filter |
| KR101732368B1 (en) * | 2016-10-11 | 2017-05-24 | 오원이 | Pleatable nonwoven fabric for filter media |
| JP2019011892A (en) * | 2017-06-29 | 2019-01-24 | 三菱製紙株式会社 | Humidification filter medium and humidification filter |
| CN114853202A (en) * | 2022-03-30 | 2022-08-05 | 陕西尚远水务有限公司 | Reclaimed water softening process for steel mill |
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| CN112978987A (en) * | 2021-02-19 | 2021-06-18 | 北京九泉科技有限公司 | Novel water purification unit made of environment-friendly materials |
| CN112978987B (en) * | 2021-02-19 | 2021-11-12 | 北京九泉科技有限公司 | Novel water purification unit made of environment-friendly materials |
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