JP2005305255A - Porous film - Google Patents
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- JP2005305255A JP2005305255A JP2004123678A JP2004123678A JP2005305255A JP 2005305255 A JP2005305255 A JP 2005305255A JP 2004123678 A JP2004123678 A JP 2004123678A JP 2004123678 A JP2004123678 A JP 2004123678A JP 2005305255 A JP2005305255 A JP 2005305255A
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- hollow fiber
- titanium dioxide
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 48
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 23
- 239000011148 porous material Substances 0.000 claims abstract description 16
- 239000011800 void material Substances 0.000 claims abstract description 8
- 239000005416 organic matter Substances 0.000 claims abstract description 3
- 239000012528 membrane Substances 0.000 claims description 68
- 239000012510 hollow fiber Substances 0.000 claims description 24
- 229920000620 organic polymer Polymers 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 15
- 239000011259 mixed solution Substances 0.000 claims description 14
- 239000002904 solvent Substances 0.000 claims description 14
- 150000003609 titanium compounds Chemical class 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000005245 sintering Methods 0.000 claims description 9
- 238000005191 phase separation Methods 0.000 claims description 5
- 230000003746 surface roughness Effects 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 239000010936 titanium Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 19
- 230000001699 photocatalysis Effects 0.000 abstract description 10
- 230000035699 permeability Effects 0.000 abstract description 4
- 239000000126 substance Substances 0.000 description 11
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 229920002492 poly(sulfone) Polymers 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- 108091003079 Bovine Serum Albumin Proteins 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 229940098773 bovine serum albumin Drugs 0.000 description 3
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 229920008347 Cellulose acetate propionate Polymers 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- BLBBMBKUUHYSMI-UHFFFAOYSA-N furan-2,3,4,5-tetrol Chemical compound OC=1OC(O)=C(O)C=1O BLBBMBKUUHYSMI-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910000484 niobium oxide Inorganic materials 0.000 description 1
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 238000007146 photocatalysis Methods 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Abstract
Description
本発明は、多孔質膜及びその製造方法に関する。 The present invention relates to a porous membrane and a method for producing the same.
二酸化チタンを用いた分離膜が特許文献１〜３に開示されているが、いずれも基材となる分離膜の表面又は細孔表面に二酸化チタンを担持・形成させた分離膜であり、表面のみの薄層部分に二酸化チタンが存在するものであるから、充分な光触媒作用が得られない。 Separation membranes using titanium dioxide are disclosed in Patent Documents 1 to 3, but all are separation membranes in which titanium dioxide is supported and formed on the surface of the separation membrane or the pore surface as a base material, only the surface Since titanium dioxide is present in the thin layer portion, sufficient photocatalytic action cannot be obtained.
特許文献４には、二酸化チタン膜を多層構造として膜厚を調整する方法が開示されているが、膜厚を５μｍ以上にすると気孔率が著しく低下してしまうため、透水性能が低下する。 Patent Document 4 discloses a method of adjusting the film thickness by using a titanium dioxide film as a multilayer structure. However, when the film thickness is 5 μm or more, the porosity is remarkably lowered, and thus the water permeability is lowered.
非特許文献１には、膜厚が厚い二酸化チタンの多孔質膜の製膜方法が記載されているが、１回の製膜工程で膜厚１μｍの膜が得られるものであるため、更に膜厚を厚くするには、多層構造としなければならず、その場合には透水性能が低下する。
本発明は、基材を必要とせず、多層構造とする必要もなく、充分な光触媒作用を発揮できる二酸化チタンからなる多孔質膜を提供することを課題とする。 An object of the present invention is to provide a porous film made of titanium dioxide that does not require a substrate and does not need a multi-layer structure and can exhibit a sufficient photocatalytic action.
また本発明は、簡便な方法により、単層構造でかつ厚みが大きく、充分な光触媒作用を発揮できる膜が得られる多孔質膜の製造方法を提供することを他の課題とする。 Another object of the present invention is to provide a method for producing a porous film that can obtain a film having a single layer structure and a large thickness and capable of exhibiting a sufficient photocatalytic action by a simple method.
本発明は、１つの課題の解決手段として、二酸化チタンを含み、有機物を実質的に含まない多孔質膜であり、膜表面の少なくとも一方の平均孔径が０．００１〜２μｍで、かつ膜内部に１０μｍ以上のボイド部を実質的に含まず、膜厚が１０〜５００μｍである多孔質膜を提供する。 As a means for solving one problem, the present invention is a porous membrane containing titanium dioxide and substantially free of organic matter, having an average pore diameter of at least one of the membrane surface of 0.001 to 2 μm, and inside the membrane. Provided is a porous film that does not substantially contain a void part of 10 μm or more and has a film thickness of 10 to 500 μm.
本発明は、他の課題の解決手段として、チタン化合物、有機ポリマー及び溶媒を含む混合溶液を用い、相分離法により多孔質膜を形成させる製膜工程、必要に応じて有機ポリマーを燃焼分解させる工程、及びチタンの焼結温度に維持して焼結させる工程を備えた多孔質膜の製造方法を提供する。 As a means for solving other problems, the present invention uses a mixed solution containing a titanium compound, an organic polymer and a solvent, and forms a porous film by a phase separation method, and combusts and decomposes the organic polymer as necessary. Provided is a method for producing a porous membrane comprising a step and a step of sintering while maintaining the sintering temperature of titanium.
本発明の多孔質膜は、二酸化チタンを含み、有機物を実質的に含まない単層構造の膜であり、膜厚も大きくできる。そして、膜表面が親水性であるため、膜表面への汚染物質の付着や目詰まりが起こりにくく、透水性能が高い。 The porous film of the present invention is a film having a single-layer structure containing titanium dioxide and substantially free of organic substances, and the film thickness can be increased. And since the film | membrane surface is hydrophilic, adhesion of a contaminant to a film | membrane surface and clogging do not occur easily, and water permeability performance is high.
本発明の多孔質膜は、実質的に二酸化チタンのみから形成することができるので、高い光触媒作用を発揮でき、膜表面に沈着した有機物を容易に分解除去することができるため、長期間にわたって高い透水性能を維持できる。 Since the porous film of the present invention can be formed substantially only from titanium dioxide, it can exhibit a high photocatalytic action, and can easily decompose and remove organic substances deposited on the film surface. Water permeability can be maintained.
本発明の多孔質膜は、用途に応じた形態の膜にすることができ、中空糸膜、平膜、管状膜等にすることができる。 The porous membrane of the present invention can be made into a membrane according to the application, and can be a hollow fiber membrane, a flat membrane, a tubular membrane or the like.
本発明の多孔質膜は、二酸化チタンを含み、有機物を実質的に含まない多孔質膜である。有機物は含まれないことが好ましいが、不純物程度として含まれる場合はあっても良い。 The porous film of the present invention is a porous film containing titanium dioxide and substantially free of organic substances. It is preferable that no organic substance is contained, but it may be contained as an impurity.
本発明の多孔質膜は、二酸化チタン（ＴｉＯ２）のみからなるものでも良いが、二酸化チタン以外で光触媒作用を示すもの、又は光触媒作用を損なわないもので製膜が可能であれば、他の無機物を含んでいても良い。二酸化チタンの結晶構造としては、アナターゼ型のものが、光触媒作用が高いので好ましい。他の無機物としては、酸化亜鉛、酸化ニオブ、チタン酸ストロンチウム、酸化ジルコニウム等を挙げることができる。
他の無機物を含む場合は、二酸化チタンの含有量が６０質量％以上であることが望ましい。なお、二酸化チタン以外の無機物が含まれている場合、前記無機物は二酸化チタンと共に膜全体に均一に分布している。
The porous membrane of the present invention may be composed only of titanium dioxide (TiO 2 ), but other than titanium dioxide, it exhibits a photocatalytic action or does not impair the photocatalytic action, so long as the film can be formed. An inorganic substance may be included. The crystal structure of titanium dioxide is preferably an anatase type because of its high photocatalytic action. Examples of other inorganic substances include zinc oxide, niobium oxide, strontium titanate, and zirconium oxide.
When other inorganic substances are included, the content of titanium dioxide is preferably 60% by mass or more. In addition, when inorganic substances other than titanium dioxide are contained, the said inorganic substance is uniformly distributed with the whole film | membrane with titanium dioxide.
本発明の多孔質膜は、膜表面の少なくとも一方の平均孔径が０．００１〜２μｍであることが好ましく、０．０１〜１μｍであることがより好ましく、０．１〜１μｍであることが更に好ましい。 In the porous membrane of the present invention, the average pore diameter of at least one of the membrane surfaces is preferably 0.001 to 2 μm, more preferably 0.01 to 1 μm, and further preferably 0.1 to 1 μm. preferable.
膜表面の少なくとも一方の平均孔径とは、平膜の場合は、一表面及び／又は他表面に存在する孔の平均孔径であり、中空糸膜の場合は、外表面及び／又は内表面に存在する孔の平均孔径である。 In the case of a flat membrane, the average pore size of at least one of the membrane surfaces is the average pore size of pores existing on one surface and / or the other surface, and in the case of hollow fiber membranes, it exists on the outer surface and / or inner surface. It is the average hole diameter of the holes to be processed.
平均孔径及び孔径は、次の方法により測定される。孔径は、走査型電子顕微鏡により膜表面を観察し、表面上の空孔部の定方向平行接線間隔の長さ（Feret径）から求める。平均孔径は、任意の２０個所で測定した孔径の平均値である。 The average pore diameter and the pore diameter are measured by the following method. The pore diameter is obtained from the length of the unidirectional parallel tangent interval (Feret diameter) of the pores on the surface by observing the film surface with a scanning electron microscope. The average pore diameter is an average value of pore diameters measured at 20 arbitrary positions.
本発明の多孔質膜は、膜内部に１０μｍ以上のボイド部を実質的に含んでいない。 The porous membrane of the present invention does not substantially contain a void portion of 10 μm or more inside the membrane.
膜内部に１０μｍ以上のボイド部を実質的に含んでいないとは、任意の位置において切断した膜断面を走査型電子顕微鏡で観察した場合、膜断面に対して、直径１０μｍ以上のボイド部の占める割合が１０％以下であることを意味する。 The fact that the void part having a diameter of 10 μm or more is substantially not included in the film means that the void part having a diameter of 10 μm or more occupies the film cross section when the film section cut at an arbitrary position is observed with a scanning electron microscope. It means that the ratio is 10% or less.
本発明の多孔質膜は、膜厚は１０〜５００μｍが好ましく、５０〜４００μｍがより好ましく、８０〜３００μｍが更に好ましい。 The porous membrane of the present invention preferably has a thickness of 10 to 500 μm, more preferably 50 to 400 μm, and still more preferably 80 to 300 μm.
本発明の多孔質膜が中空糸膜であるときは、内径は０．２〜２．０ｍｍが好ましく、０．４〜１．５μｍがより好ましく、０．６〜１．０μｍが更に好ましい。 When the porous membrane of the present invention is a hollow fiber membrane, the inner diameter is preferably 0.2 to 2.0 mm, more preferably 0.4 to 1.5 μm, still more preferably 0.6 to 1.0 μm.
本発明の多孔質膜は、膜表面の有効表面積を大きくするために、少なくとも一方の膜表面が凹凸を有していることが好ましく、少なくとも一方の膜表面の平均粗さが５０〜５００ｎｍであることが好ましく、８０〜４００ｎｍであることがより好ましく、１００〜３００ｎｍであることが更に好ましい。 In the porous membrane of the present invention, in order to increase the effective surface area of the membrane surface, it is preferable that at least one membrane surface has irregularities, and the average roughness of at least one membrane surface is 50 to 500 nm. It is preferably 80 to 400 nm, more preferably 100 to 300 nm.
平均面粗さは、ＪＩＳ Ｂ０６０１で定義されている中心線平均粗さ（Ｒａ）を測定面に対して適用できるように三次元に拡張したものであり、原子力間顕微鏡（ＡＦＭ）の測定面として１０μｍ２当たりで測定されるものである。 The average surface roughness is a three-dimensional extension of the centerline average roughness (Ra) defined in JIS B0601 so that it can be applied to the measurement surface. As the measurement surface of the atomic force microscope (AFM), It is measured per 10 μm 2 .
次に、本発明の多孔質膜の製造方法を工程ごとに説明する。なお、本発明の製造方法を適用して得られる多孔質膜は、上記したとおり、中空糸膜、平膜等の用途に応じた形態にすることができる。 Next, the manufacturing method of the porous membrane of this invention is demonstrated for every process. In addition, as above-mentioned, the porous membrane obtained by applying the manufacturing method of this invention can be made into the form according to uses, such as a hollow fiber membrane and a flat membrane.
第１工程の製膜工程において、チタン化合物、有機ポリマー及び溶媒を含む混合溶液を用い、相分離法により多孔質膜を形成させる。 In the first film-forming process, a porous film is formed by a phase separation method using a mixed solution containing a titanium compound, an organic polymer, and a solvent.
チタン化合物は、二酸化チタン及び必要に応じて他の無機物を含んでも良く、チタン化合物全体中の二酸化チタンの含有量は６０〜１００質量％である。 The titanium compound may contain titanium dioxide and other inorganic substances as necessary, and the content of titanium dioxide in the entire titanium compound is 60 to 100% by mass.
チタン化合物の粒径は、０．０１〜１．０μｍが好ましく、０．０５〜０．５μｍがより好ましく、０．１〜０．３μｍが更に好ましい。粒径は、二酸化チタンを水に分散させた分散液をレーザー回折式粒度分布測定装置を用いる光散乱法により測定される。 The particle size of the titanium compound is preferably 0.01 to 1.0 μm, more preferably 0.05 to 0.5 μm, and still more preferably 0.1 to 0.3 μm. The particle size is measured by a light scattering method using a laser diffraction type particle size distribution measuring device for a dispersion in which titanium dioxide is dispersed in water.
混合溶液中のチタン化合物の濃度は、２０〜８０質量％が好ましく、３０〜７０質量％がより好ましく、４０〜６０質量％が更に好ましい。 20-80 mass% is preferable, as for the density | concentration of the titanium compound in a mixed solution, 30-70 mass% is more preferable, and 40-60 mass% is still more preferable.
有機ポリマーはバインダーの作用をするものであり、ポリスルホン、ポリエーテルスルホン、ポリアクリロニトリル、ポリビニルアルコール、ポリビニルピロリドン、ポリ塩化ビニル、ポリフッ化ビニリデン、セルロース、酢酸セルロース、酢酸プロピオン酸セルロース、ポリエチレン、ポリプロピレン等を挙げることができる。 The organic polymer acts as a binder. Polysulfone, polyethersulfone, polyacrylonitrile, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl chloride, polyvinylidene fluoride, cellulose, cellulose acetate, cellulose acetate propionate, polyethylene, polypropylene, etc. Can be mentioned.
混合溶液中の有機ポリマーの濃度は、５〜４０質量％が好ましく、１０〜３５質量％がより好ましく、１５〜３０質量％が更に好ましい。 5-40 mass% is preferable, as for the density | concentration of the organic polymer in a mixed solution, 10-35 mass% is more preferable, and 15-30 mass% is still more preferable.
溶媒は有機ポリマーを溶解できる溶媒であれば良く、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキシド、Ｎ−メチル−２−ピロリドン、アセトン、テトラヒドロキシフラン、ポリエチレングリコール等を挙げることができる。 The solvent may be any solvent that can dissolve the organic polymer, and examples thereof include dimethylacetamide, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetone, tetrahydroxyfuran, and polyethylene glycol.
溶媒は、混合溶液の全体を１００質量％とする調整量であり、製膜方法に応じて、膜の形成が容易になるような混合溶液の濃度範囲を選択する。 A solvent is an adjustment amount which makes the whole mixed solution 100 mass%, and selects the density | concentration range of a mixed solution which becomes easy to form a film | membrane according to the film forming method.
製膜は、混合溶液を有機ポリマーの非溶媒を含む溶媒中に浸漬する相分離法が好適である。 For film formation, a phase separation method in which the mixed solution is immersed in a solvent containing a non-solvent of the organic polymer is suitable.
中空糸膜を製膜するときは、混合溶液を二重紡糸口金から押し出し、有機ポリマーの非溶媒中（室温）に導くことで中空糸膜を形成させる。 When forming a hollow fiber membrane, the mixed solution is extruded from a double spinneret and guided into a non-solvent of organic polymer (room temperature) to form the hollow fiber membrane.
平膜を製膜するときは、基板上に混合溶液を流延した後、有機ポリマーの非溶媒中（室温）に導くことで平膜を形成させる。 When forming a flat film, after casting the mixed solution on the substrate, the flat film is formed by introducing it into a non-solvent (room temperature) of an organic polymer.
有機ポリマーの非溶媒としては、水又は水と有機溶媒（上記したジメチルアセトアミド等）の混合物（例えば、容量比で水：有機溶媒＝１：１）を用いることができる。 As the non-solvent for the organic polymer, water or a mixture of water and an organic solvent (such as dimethylacetamide described above) (for example, water: organic solvent = 1: 1 by volume) can be used.
次に、必要に応じて、第２工程において前工程で製膜した膜中の有機ポリマーを燃焼分解させる。なお、第２工程に先立って、溶媒を除去する乾燥工程を設けることもできるし、第２工程は設けずに、続く第３工程に移行してもよい。 Next, if necessary, the organic polymer in the film formed in the previous step in the second step is burned and decomposed. Prior to the second step, a drying step for removing the solvent may be provided, or the second step may be omitted and the subsequent third step may be performed.
第１工程で製膜された膜は、有機ポリマーがバインダーとなって、チタン化合物からなる膜が形成された状態になっている。この工程では、膜をチタン化合物が焼結しない温度で、かつ有機ポリマーが燃焼分解する温度で加熱することで、膜に含まれている有機ポリマーを燃焼除去する。 The film formed in the first step is in a state where a film made of a titanium compound is formed using an organic polymer as a binder. In this step, the organic polymer contained in the film is burned and removed by heating the film at a temperature at which the titanium compound does not sinter and at a temperature at which the organic polymer burns and decomposes.
加熱条件は、３００〜８００℃で、０．１〜３時間が好ましく、一般的なオーブン等を用いることができる。 The heating conditions are 300 to 800 ° C., preferably 0.1 to 3 hours, and a general oven or the like can be used.
次に、第３工程において、チタンの焼結温度に維持して焼結させ、最終的に多孔質膜を得る。 Next, in the third step, sintering is performed while maintaining the sintering temperature of titanium to finally obtain a porous film.
焼結条件は、８００〜１５００℃で、０．５〜１０時間である。この工程では、前工程の温度雰囲気、又は室温から、前記焼結温度まで約５０〜２００℃／分で昇温させることが好ましい。 The sintering conditions are 800-1500 ° C. and 0.5-10 hours. In this step, it is preferable to raise the temperature from the temperature atmosphere of the previous step or from room temperature to about 50 to 200 ° C./min from the sintering temperature.
なお、第２工程を必須とする場合、第２工程と第３工程は、上記のとおり分離した別工程でも良いが、一つの工程として連続的に処理しても良い。 When the second step is essential, the second step and the third step may be separate steps separated as described above, but may be continuously processed as one step.
本発明の多孔質膜は、分離膜として被分離対象となるコロイドや有機物のような付着物が多孔質膜に付着することを抑制できるほか、多孔質膜に付着した付着物を光触媒作用で容易に分解させることができるため、各種工業プロセス用途、浄水処理や排水処理等の水処理用途等に使用することができる。 The porous membrane of the present invention can suppress the adherence of colloids and organic substances to be separated as separation membranes to the porous membrane, and easily adhere the deposits attached to the porous membrane by photocatalysis. Therefore, it can be used for various industrial process applications, water treatment applications such as water purification and wastewater treatment, and the like.
実施例１
ジメチルアセトアミド１８０ｇに、二酸化チタン（粒径０．１８μｍ）２４０ｇ、ポリスルホン８０ｇを加え、一昼夜攪拌して混合溶液を得た。
Example 1
To 180 g of dimethylacetamide, 240 g of titanium dioxide (particle size: 0.18 μm) and 80 g of polysulfone were added and stirred for a whole day and night to obtain a mixed solution.
次に、押出口外径１ｍｍ、内径０．７ｍｍの二重管ノズルの外周部から混合溶液を押し出しながら、二重管ノズルの内部にはジメチルアセトアミドと水（容量比１：１）の混合非溶媒を注入した。吐出した混合溶液は、ジメチルアセトアミドと水（容量比１：１）の凝固浴中に導いて浸漬し、相分離を誘起させて中空糸膜を得た。製膜は室温で行った。 Next, while extruding the mixed solution from the outer periphery of a double tube nozzle having an outer diameter of 1 mm and an inner diameter of 0.7 mm, the mixture of dimethylacetamide and water (volume ratio 1: 1) is not mixed inside the double tube nozzle. Solvent was injected. The discharged mixed solution was introduced and immersed in a coagulation bath of dimethylacetamide and water (volume ratio 1: 1) to induce phase separation to obtain a hollow fiber membrane. Film formation was performed at room temperature.
次に、前工程で得た中空糸膜を５００℃で２時間仮焼してポリスルホンを燃焼分解させた後、更に１３００℃で５時間焼成して、二酸化チタンを焼結させて中空糸膜を得た。 Next, the hollow fiber membrane obtained in the previous step is calcined at 500 ° C. for 2 hours to burn and decompose the polysulfone, and further fired at 1300 ° C. for 5 hours to sinter titanium dioxide to form a hollow fiber membrane. Obtained.
得られた中空糸膜の内表面及び外表面構造を走査型電子顕微鏡（ＳＥＭ）により観察し（図１及び図２）、中空糸膜の断面構造を同様にＳＥＭにより観察した（図３及び図４）。図１及び図２から明らかなとおり、仮焼及び焼結によりポリスルホンが消失し、二酸化チタン粒子のみが確認できた。図３及び図４から明らかなとおり、大きなボイド部は多数存在していないことが確認できた。その他の膜構造の詳細は次のとおりである。 The inner and outer surface structures of the obtained hollow fiber membrane were observed with a scanning electron microscope (SEM) (FIGS. 1 and 2), and the cross-sectional structure of the hollow fiber membrane was similarly observed with an SEM (FIGS. 3 and 4). As is clear from FIGS. 1 and 2, the polysulfone disappeared by calcination and sintering, and only titanium dioxide particles could be confirmed. As is clear from FIGS. 3 and 4, it was confirmed that many large void portions did not exist. Details of other film structures are as follows.
膜構造：中空糸膜内表面の平均孔径は０．１６μｍ、外表面の平均孔径は０．１８μｍであり、１０μｍ以上のボイド部の占有割合が５％以下の均一構造であった。 Membrane structure: The average pore diameter of the inner surface of the hollow fiber membrane was 0.16 μm, the average pore diameter of the outer surface was 0.18 μm, and the occupying ratio of the void portion of 10 μm or more was a uniform structure of 5% or less.
膜厚：１００μｍ（内径４００μｍ、外径６００μｍ）
平均面粗さ：１４０ｎｍ（外表面の任意の５個所で測定した平均面粗さの平均値）
得られた中空糸膜の純水透過速度（中空糸膜の内表面積当たりの値）を測定したところ、３１０L/m2h・atm（水温２５℃の換算値）であった。
Film thickness: 100 μm (inner diameter 400 μm, outer diameter 600 μm)
Average surface roughness: 140 nm (average value of average surface roughness measured at any five locations on the outer surface)
The pure water permeation rate (value per inner surface area of the hollow fiber membrane) of the obtained hollow fiber membrane was measured and found to be 310 L / m 2 h · atm (converted value at a water temperature of 25 ° C.).
試験例１
実施例１で得られた中空糸膜に外側からブラックライト（３５２ｎｍ）を１分間照射した後、直ぐに牛血清アルブミン（ＢＳＡ）の０．０５質量％水溶液に中空糸膜を１時間浸漬した。浸漬後の中空糸膜の純水透過速度を測定したところ、２８０L/m2h・atm（水温２５℃の換算値）であり、元の数値である３１０L/m2h・atmから１０％の低下に留まった。一方、ブラックライトを照射せず、同様にＢＳＡの０．０５質量％水溶液１時間浸漬後の純水透過速度を測定したところ、２００L/m2h・atm（水温２５℃の換算値）と３５％の低下率を示した。この結果は、中空糸膜による光触媒作用が発揮されたためであると認められる。
Test example 1
After irradiating the hollow fiber membrane obtained in Example 1 with black light (352 nm) from the outside for 1 minute, the hollow fiber membrane was immediately immersed in a 0.05 mass% aqueous solution of bovine serum albumin (BSA) for 1 hour. When the pure water permeation rate of the hollow fiber membrane after immersion was measured, it was 280 L / m 2 h · atm (converted value at a water temperature of 25 ° C.), which was 10% from the original value of 310 L / m 2 h · atm. Stayed in decline. On the other hand, when the pure water permeation rate after immersion for 1 hour in a 0.05 mass% aqueous solution of BSA was measured without irradiating black light, it was found to be 200 L / m 2 h · atm (converted value at a water temperature of 25 ° C.) and 35 % Reduction rate. This result is considered to be because the photocatalytic action by the hollow fiber membrane was exhibited.
Claims (6)
The method for producing a porous membrane, wherein the membrane-forming step in the production method of claim 5 is a step of forming a hollow fiber membrane by extruding from a double spinneret using a mixed solution containing a titanium compound, an organic polymer and a solvent.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100402438C (en) * | 2006-09-07 | 2008-07-16 | 重庆大学 | Method for preparing Nano thin film of medium pore of titania |
| JP2017517641A (en) * | 2014-04-03 | 2017-06-29 | サントレ ナティオナル ド ラ ルシェルシェ シアンティフィク | Method for producing TiO2 macroscopic fibers by continuous unidirectional extrusion, the resulting fibers and their use |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100402438C (en) * | 2006-09-07 | 2008-07-16 | 重庆大学 | Method for preparing Nano thin film of medium pore of titania |
| JP2017517641A (en) * | 2014-04-03 | 2017-06-29 | サントレ ナティオナル ド ラ ルシェルシェ シアンティフィク | Method for producing TiO2 macroscopic fibers by continuous unidirectional extrusion, the resulting fibers and their use |
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