A spin dope composition produces a polymeric fiber useful in non-cryogenic gas separation. The composition includes polysulfone as the polymeric component, two solvents, in which the polymer is soluble, and a non-solvent, in which the polymer is insoluble. The solvents preferably include N-methyl-pyrrolidone (NMP) and N,N-dimethyl acetamide (DMAC), and the non-solvent preferably includes triethylene glycol (TEG). Fibers made from the present composition have been found to exhibit superior properties of gas flux and selectivity, as compared with fibers made from spin dopes having only one solvent component.

Methods of producing a deformed porous hollow fiber membrane by thermally induced phase separation, particularly by discharging a fusion kneaded product containing a thermoplastic resin and an organic liquid through an orifice of a hollow fiber-forming deformed nozzle; cooling and solidifying the fusion kneaded product discharged through the deformed nozzle to form the product into a hollow fiber-like material having a deformed cross section at a cross section vertical to a discharging direction; and extracting away the organic liquid from the hollow fiber-like material to obtain the deformed porous hollow fiber membrane, wherein an inorganic fine powder is kneaded in the fusion kneaded product.

A hollow fiber filtration membrane in which even when a relatively small contaminant having a size close to that of a permeation effective component is present in a filtration solution, Flux decrease over time during filtration is suppressed, and a useful component can be efficiently recovered, the hollow fiber filtration membrane including a polysulfone-based polymer and a hydrophilic polymer and having a large number of pores, the hollow fiber filtration membrane having a gradient asymmetric porous structure in which an average pore diameter of the pores increases from an outer surface portion toward an inner surface portion of the membrane, a content of the hydrophilic polymer of the membrane being from 6.0 to 10.0% by mass, a ratio between a content of the hydrophilic polymer at the inner surface portion and the content of the hydrophilic polymer of the membrane being in the range of from 0.50 to 0.80.

The purpose of the present invention is to provide a porous hollow fiber membrane that can efficiently separate and remove the substances to be removed such as small-particle virus contained in a solution and, at the same time, useful recovering substances such as protein can be efficiently permeated and the decrease of its transmission rate with elapse of time is small. The porous hollow fiber membrane of the present invention is characterized in that the filtration downstream surface thereof has dot-shaped or slit-shaped pores, the filtration upstream surface thereof is a network structure or a fine particle aggregate structure, the central region of the membrane is composed of a substantially homogeneous structure, the membrane wall is composed of a structure having substantially no macrovoids, the permeability for pure water is 10 to 300 L/(h.Math.m.sup.2.Math.bar) and the permeability for a 0.1% by weight solution of bovine γ-globulin is 30 to 100% of the permeability for pure water. Also, the hollow fiber membrane is characterized in that the permeability for a 0.1% by weight solution of bovine γ-globulin in a 20 mmol/L phosphate buffer is 30 to 100% of the permeability for a 0.1% by weight solution of bovine γ-globulin in a 20 mmol/L phosphate-buffered physiological saline solution.

Novel low-pressure nanofiltration membrane composites for rejecting organic compounds are prepared by interfacial polymerization on a microporous hollow fiber supporting membrane. The interfacial polymerization reaction is carried out using an essentially monomeric polyamine reactant having at least two amine functional groups per molecule, and an essentially monomeric amine-reactive polyfunctional aromatic or cycloaliphatic acyl halide having at least two acyl halide groups per molecule. The composite can be fabricated by stepwise polymerization reactions with different reactant recipes at each step.

A membrane-forming dope for carbon membranes, comprising polyphenylene oxide in an amount giving a concentration of 15 to 40 wt. % in the membrane-forming dope, and sulfur in an amount giving a ratio of 0.1 to 5.0 wt. %, preferably 0.2 to 3.0 wt. %, of the total weight of the polyphenylene oxide and the sulfur, both of which are dissolved in a solvent that can dissolve these components. A hollow fiber carbon membrane is produced by molding the membrane-forming dope for carbon membranes in a hollow shape by means of a wet or dry-wet spinning method using a double tubular nozzle, subjecting the molded product to an infusibilization treatment by heating at 150 to 350° C. in the air, and then subjecting it to a carbonization treatment by heating at 600 to 800° C. in an inert atmosphere or under vacuum. When the product molded in a hollow shape by means of a wet or dry-wet spinning method is subjected to an infusibilization treatment by heating in the air while stretching the product with a stress of 0.002 to 0.005 MPa, a hollow fiber carbon membrane having excellent gas permeability and a further high gas separation factor (He/CH.sub.4) can be obtained.

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.

The present disclosure relates to a dialyzer comprising a bundle of semipermeable hollow fiber membranes which is suitable for blood purification, wherein the dialyzer has an increased ability to remove larger molecules while at the same time it is able to effectively remove small uremic toxins and efficiently retain albumin and larger proteins. The invention also relates to using said dialyzer in hemodialysis.

System, devices, and method for the production of thin film composite hollow fiber membranes on a hollow fiber support structure. The system includes a comb and roller device, or comb and dual roller device, which can be used to define a submerged travel path in a first solution bath for a hollow fiber. The combs and rollers control the amount of time the hollow fiber spends in the first solution. The first solution contains a first monomer, and the hollow fiber is impregnated with the first monomer. The amount of impregnation depends on the time spent in the first solution. Subsequent immersion in a second solution containing a second monomer results in the formation of a thin film composite hollow fiber membrane.

The present invention generally relates to polymeric membrane materials formed, at least in part, from monomeric material selected from 2,3,3,3-tetrafluoropropene (CF.sub.3CF═CH.sub.2, HFO-1234yf) or trans-1,3,3,3-tetrafluoropropene (CF.sub.3CH═CFH, HFO-1234ze), and to membrane preparations and uses thereof in water desalination, filtration, membrane distillation, pervaporation, and selective gas separation.