Abstract: A gas separation membrane module includes at least one hollow fiber membrane element and a casing. The hollow fiber membrane element includes hollow fiber membranes and a cylindrical body. The cylindrical body extends in a longitudinal direction of the hollow fiber membranes, and accommodates the hollow fiber membranes. The hollow fiber membrane element includes sweep gas introduction ports and mixed gas discharge ports. A first supply chamber, a first discharge chamber, a second supply chamber, and a second discharge chamber are positioned between the casing and the hollow fiber membrane element. The first supply chamber, the first discharge chamber, the second supply chamber, and the second discharge chamber are partitioned off from each other.

Abstract: A water treatment device includes: a measure that repeats measurement of pressures on a primary side and a secondary side of a hollow fiber membrane module every minute time of three seconds or less in one or more steps of water filling, backwashing, pressure relieving, bubbling, and draining; and an estimater that estimates: abnormality of an internal state of the hollow fiber membrane module or of a peripheral device; a time required from a start to an end of the one or more steps; an effect of physical washing or chemical washing; or a future increase in an membrane differential pressure, based on a temporal transition of a measurement result of at least one of the pressures, or based on a difference in the temporal transition between a plurality of times of the step.

Abstract: A composite hollow fiber membrane according to one aspect of the present invention is provided with a semipermeable membrane layer, a support layer that has a hollow fiber shape and is porous, and an intermediate layer interposed between the semipermeable membrane layer and the support layer. The semipermeable membrane layer contains a crosslinked polyamide formed of a polyfunctional amine compound and a polyfunctional acid halide compound. The intermediate layer includes a layer portion made of the same material as the support layer, and the crosslinked polyamide impregnating the layer portion.

Abstract: One aspect of the present invention is a composite hollow fiber membrane including: a semipermeable membrane layer; and a supporting layer that has a hollow fiber shape and is porous, wherein the semipermeable membrane layer contains a crosslinked polyamide polymer composed of a polyfunctional amine compound and a polyfunctional acid halide compound, the supporting layer has a gradient structure in which pores of the supporting layer gradually increase in size from one of an inner surface and an outer surface to the other, has a cut-off particle size of 0.001 to 0.3 ?m, and contains a crosslinked hydrophilic resin on at least a dense surface having smaller pores of the inner surface and the outer surface, and the semipermeable membrane layer is in contact with the dense surface of the supporting layer.

Abstract: One aspect of the present invention concerns a porous hollow fiber membrane containing a vinylidene fluoride-based resin. The hollow fiber membrane has a gradient structure in which a pore diameter of pores in the hollow fiber membrane gradually becomes smaller at least toward one of inner and outer peripheral surface sides and is hydrophilized by containing a crosslinked body of a polyvinylpyrrolidone-based resin.

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: One aspect of the present invention concerns a porous hollow fiber membrane containing a vinylidene fluoride-based resin. The hollow fiber membrane has a gradient structure in which a pore diameter of pores in the hollow fiber membrane gradually becomes smaller at least toward one of inner and outer peripheral surface sides and is hydrophilized by containing a crosslinked body of a polyvinylpyrrolidone-based resin.

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.