The present invention relates to a hollow fiber membrane module for outside-in cross-flow filtration including: a container having at least a raw water inlet, a raw water outlet, and a filtrate outlet; and a plurality of hollow fiber membranes housed in the container, in which in the plurality of hollow fiber membranes, an end portion on a raw water inlet side is sealed and an end portion on a filtrate outlet side is opened, and the plurality of hollow fiber membranes have a potting portion fixed by an adhesive at least in the end portion on the filtrate outlet side, and a pure water permeability K (m.sup.3/m.sup.2/hr/50 kPa) of the hollow fiber membranes and an inner diameter D.sub.i (μm) of the hollow fiber membranes satisfy the following requirements: 2.0≤K≤20.0; and 350≤D.sub.1≤600.

A cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

A hollow fiber membrane that is a hollow fiber type semipermeable membrane, wherein a Raman value is 70% or more, and the Raman value is a ratio of a minimum value to a maximum value of peak intensities, which are intensities of maximum peaks in each of multiple Raman spectra obtained by Raman spectroscopy at multiple points in a membrane thickness direction of a transverse cross-section of the hollow fiber membrane in a state of being swollen with water.

The present invention provides a coated hollow fiber membrane which has an isoporous inner skin and a porous outer support membrane, i.e. an inside-out isoporous composite hollow fiber membrane, and to a method of preparing such membranes. The coated hollow fiber membrane is prepared by a method comprising providing a hollow fiber support membrane having a lumen surrounded by the support membrane, and coating and the inner surface thereof by first passing a polymer solution of at least one amphiphilic block copolymer in a suitable solvent through the lumen of the hollow fiber support membrane and along the inner surface thereof, thereafter pressing a core gas stream through the lumen of the coated hollow fiber mebrane, and thereafter passing a non-solvent (precipitant) through the lumen of the coated hollow fiber membrane. In order to remove the solvent or solvents completely, the membranes are kept in water for 1-2 days and washed prior to use. In order to maintain the porosity of support membrane, membrane pretreatment is advantageous prior to coating which reduces the infiltration of block copolymer solution. The membranes are useful infiltration modules, in particular microfiltration modules, ultrafiltration modules, nano-filtration modules.

Stable maintenance of high separation performance of a separation membrane having a separation layer comprising a compact carbon layer is described in addition to a separation membrane having a separation layer comprising a compact carbon layer, wherein particles are attached to the compact carbon layer, recesses are present in the compact carbon layer, and the particles are at least partially stuck in the recesses.

Disclosed is a membrane humidifier for a fuel cell, comprising multi-channel hollow fiber membranes having a plurality of channels in various sizes, thus allowing humidifying performance to be maintained in the case of a high rate of flow and to be decreased in the case of a low rate of flow, and thereby preventing flooding. The membrane humidifier for a fuel cell, according to the present invention, comprises: a middle case in which a plurality of hollow fiber membranes are accommodated; a cap case coupled to the middle case; and a fixing unit in which ends of the plurality of hollow fiber membranes are potted, wherein a plurality of channels are formed in each of the hollow fiber membranes, and the difference between the biggest and smallest inner diameters among the inner diameters of the plurality of channels is 30-600 μm.

A hollow fiber porous membrane includes polyethersulfone or polysulfone. The hollow fiber porous membrane has an inner diameter from 300 to 600 μm, a thickness from 70 to 200 μm, a molecular weight cut-off of 10000 or lower, and a plurality of pores having a pore diameter from 0.1 to 0.5 μm throughout an outer surface; and a swelling rate of less than 5% as defined below: Swelling Rate (%): for 20 or more of the hollow fiber porous membranes, after a membrane thickness in a cross section of each one of the hollow fiber porous membranes in the width direction is measured at randomly selected 10 or more locations, an average membrane thickness is calculated based on 200 or more locations in total, and the swelling rate is calculated by a formula below: Swelling Rate (%)=(location numbers where the membrane thickness as measured exceeded 1.3 times the average membrane thickness)/(membrane thickness measurement numbers)×100.

A cord for supporting a biofilm has a plurality of yarns. At least one of the yarns comprises a plurality of hollow fiber gas transfer membranes. At least one of the yarns extends along the length of the cord generally in the shape of a spiral. Optionally, one or more of the yarns may comprise one or more reinforcing filaments. In some examples, a reinforcing yarn is wrapped around a core. A module may be made by potting a plurality of the cords in at least one header. A reactor may be made and operated by placing the module in a tank fed with water to be treated and supplying a gas to the module. In use, a biofilm covers the cords to form a membrane biofilm assembly.

An object of the present invention is to provide a nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a high amount pf permeate for methanol, and suitable for use as an organic solvent nanofiltration membrane. A nanofiltration membrane formed using a polyamide resin, the nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a methanol permeability of 0.03 L/(m.sup.2.Math.bar.Math.h) or more.

A virus removal membrane includes cellulose, and a primary-side surface through which the protein-containing solution is to be applied and a secondary-side surface from which a permeate that has permeated the virus removal membrane is to be flowed, wherein a bubble point is 0.5 MPa or more and 1.0 MPa or less; and when a solution containing gold colloids having a diameter of 30 nm is applied through the primary-side surface to the virus removal membrane to allow the virus removal membrane to capture the gold colloids for measurement of brightness in a cross section of the virus removal membrane, a value obtained by dividing a standard deviation of a value of an area of a spectrum of variation in the brightness by an average of the value of the area of the spectrum of variation in the brightness is 0.01 or more and 0.30 or less.