Abstract: Provided is a vinylidene fluoride porous hollow fiber membrane excellent in fouling resistance due to reduced organic substance absorbance, preferably having preferable pore structures to enable to have high permeability, high fractionation performance, and good process controllability. The membrane includes a vinylidene fluoride resin and 0.5 to 10% by weight of a hydrophilic resin, having a ratio Pi/Po of 2.5 to 50 where Pi and Po denote an average pore size on inner surface and an average pore size on outer surface, respectively, and having a pure water permeation rate satisfying the following formula: (FLUXd/FLUXw)×100?40.0 wherein FLUXd represents a pure water permeation rate (L/m2/hr/98 kPa) of the hollow fiber membrane in a dry state, and FLUXw represents a pure water permeation rate (L/m2/hr/98 kPa) of the hollow fiber membrane in a wet state.

Abstract: There is provided a shaped article made of porous hydrogel that contains a polyvinyl alcohol acetalized with a dialdehyde, wherein the shaped article after freeze-drying has a pore size of 0.1 to 50 ?m. Preferably, the shaped article made of porous hydrogel further contains a water-soluble polysaccharide. Also preferably, an acetalization degree of the polyvinyl alcohol is 1 to 50 mol %. Also preferably, the shaped article made of porous hydrogel is in the form of particles with a sphere-equivalent diameter of 1 to 20 mm. Such a shaped article made of porous hydrogel exhibits high strength and good survivability of microorganisms.

Abstract: Provided is a vinylidene fluoride porous hollow fiber membrane excellent in fouling resistance due to reduced organic substance absorbance, preferably having preferable pore structures to enable to have high permeability, high fractionation performance, and good process controllability. The membrane includes a vinylidene fluoride resin and 0.5 to 10% by weight of a hydrophilic resin, having a ratio Pi/Po of 2.5 to 50 where Pi and Po denote an average pore size on inner surface and an average pore size on outer surface, respectively, and having a pure water permeation rate satisfying the following formula: (FLUXd/FLUXw)×100?40.0 wherein FLUXd represents a pure water permeation rate (L/m2/hr/98 kPa) of the hollow fiber membrane in a dry state, and FLUXw represents a pure water permeation rate (L/m2/hr/98 kPa) of the hollow fiber membrane in a wet state.

Abstract: There is provided a shaped article made of porous hydrogel that contains a polyvinyl alcohol acetalized with a dialdehyde, wherein the shaped article after freeze-drying has a pore size of 0.1 to 50 ?m. Preferably, the shaped article made of porous hydrogel further contains a water-soluble polysaccharide. Also preferably, an acetalization degree of the polyvinyl alcohol is 1 to 50 mol %. Also preferably, the shaped article made of porous hydrogel is in the form of particles with a sphere-equivalent diameter of 1 to 20 mm. Such a shaped article made of porous hydrogel exhibits high strength and good survivability of microorganisms.

Abstract: A porous membrane, made of polyvinylidene fluoride which is excellent in fractionating capability, permeating capability and physical strength and suitable for use in water treatment such as water purification, preparation of drinking water, preparation of water for industrial use and wastewater treatment, and which can be manufactured inexpensively and easily. The porous membrane has one surface formed with round or oval micropores and the opposite surface formed with substantially slit shaped micropores. The round or oval micropores have an average ratio between the major axis and the minor axis, which is within the range of 1:1 to 5:1, and the substantially slit shaped micropores have an average ratio between the major axis and the minor axis, which is not smaller than 5:1 and the particle cutoff of the membrane is not smaller than 0.2 ?m.

Abstract: A porous membrane, made of polyvinylidene fluoride which is excellent in fractionating capability, permeating capability and physical strength and suitable for use in water treatment such as water purification, preparation of drinking water, preparation of water for industrial use and wastewater treatment, and which can be manufactured inexpensively and easily. The porous membrane has one surface formed with round or oval micropores and the opposite surface formed with substantially slit shaped micropores. The round or oval micropores have an average ratio between the major axis and the minor axis, which is within the range of 1:1 to 5:1, and the substantially slit shaped micropores have an average ratio between the major axis and the minor axis, which is not smaller than 5:1 and the particle cutoff of the membrane is not smaller than 0.2 ?m.