An operation method of a hollow fiber membrane module is described, the operation method including: a filtration step of performing cross-flow filtration by supplying a feed to an outer surface side of a hollow fiber membrane, in which in the filtration step, a ratio of a viscosity .sub.f of the feed to a viscosity .sub.p of a filtrate satisfies a relation of .sub.f/.sub.p1.5, and a flow rate ratio of a flow rate v.sub.p of the filtrate to a flow rate v.sub.f of the feed satisfies a relation of 0.02v.sub.p/v.sub.f0.3.

A hollow fiber membrane and a method of preparing the same. The hollow fiber membrane has an inner surface and an outer surface, wherein the inner surface has a zebra-stripe pattern in which a dense portion and a porous portion are alternately formed in a longitudinal direction of the hollow fiber membrane.

A problem to be solved by the present invention is to provide a separation membrane having excellent separation performance, having high membrane strength and high permeation performance, and mainly including a cellulose-based resin. The present invention is concerned with a separation membrane including a cellulose ester, having, in the interior thereof, voids each having a specified structure, and having a tensile elasticity of 1,000 to 6,500 MPa.

A tubular braid, a hollow fiber membrane using the same, and a manufacturing method thereof. A hollow fiber membrane can maximize or increase adhesion between a polymer coating film and a tubular braid; significantly reduce degradation of film properties caused by non-uniform coating, that is, reduce leakage; obtain a higher percent rejection; and achieve high water permeability since the hollow fiber membrane has a larger inner diameter.

A hollow fiber porous membrane includes polyethersulfone or polysulfone. The hollow fiber porous membrane has an inner diameter from 300-600 m, a thickness from 70-200 m, a molecular weight cut-off of 10000 or lower, and a plurality of pores having a pore diameter from 0.1-0.5 m throughout an outer surface; and a bulging rate of less than 5%. 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 bulging rate is calculated by a formula below: Bulging Rate (%)=(location numbers where the membrane thickness as measured exceeded 1.3 times the average membrane thickness)/(membrane thickness measurement numbers)100.

The present disclosure provides a high-efficiency degassing polyolefin hollow fiber membrane and a preparation therefor and use thereof. The membrane comprises a main body, wherein one side of the main body is an inner surface facing an inner cavity, the other side of the main body is an outer surface, a non-directional tortuous pathway is formed in the main body, the outer surface is a dense surface, and the area ratio of air pores in the inner surface is 10%-30%; the average thickness of the hollow fiber membrane is 45-65 m and the ratio of the average outer diameter to the average inner diameter of the hollow fiber membrane is 1.45-1.55; the TOC dissolving-out amount of the hollow fiber membrane itself is less than or equal to 0.5 g/L; and the deoxidation efficiency of the hollow fiber membrane is greater than 80%.

An improved method for CO.sub.2 separations using a physical solvent is provided. The method includes: (a) contacting the lumen side or the shell side of a plurality of porous hollow fibers with a CO.sub.2-containing gas from a point source; (b) contacting the other of the lumen side or the shell side of the plurality of porous hollow fibers with a liquid phase, the liquid phase including a physical solvent for physisorption of CO.sub.2 into the liquid phase; (c) desorbing the CO.sub.2 from the liquid phase by reducing the pressure of the liquid phase; and (d) recirculating the liquid phase to the plurality of porous hollow fibers. As discussed herein, the improved method provides a modular, scalable process to facilitate gas-liquid contact for CO.sub.2 separations. In addition, the improved method offers significant advantages over existing ionic liquid and amine-based technologies in terms of cost-effectiveness, energy efficiency, process scalability, and environmental stability.

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 m.

The present disclosure relates to semipermeable membranes which are suitable for blood purification, e.g. by hemodialysis, which have an increased ability to remove larger molecules while at the same time effectively retaining albumin. The membranes are characterized by a molecular retention onset (MWRO) of between 9.0 kD and 14.5 kD and a molecular weight cut-off (MWCO) of between 55 kD and 130 kD as determined by dextran sieving curves and can be prepared by industrially feasible processes excluding a treatment with salt before drying. The invention therefore also relates to a process for the production of the membranes and to their use in medical applications.

A hollow fiber membrane module including at least two types of hollow fiber membranes having different inner diameters, comprising first hollow fiber membranes and second hollow fiber membranes, and the equation |P.sub.AP.sub.0||P.sub.BP.sub.0| where P.sub.0 is an initial pressure applied to upper open ends of the first and second hollow fiber membranes, and P.sub.A and P.sub.B are respective pressures at lower open ends of the first and second hollow fiber membranes.