A preparation method of sodium hyaluronate with a full molecular weight distribution (MWD) is provided, including: step 1): spraying hydrogen peroxide on a sodium hyaluronate solid raw material, and conducting an ultraviolet (UV) irradiation treatment; step 2): dissolving a sodium hyaluronate degradation material in water, and adjusting a pH to higher than 7.0; step 3): subjecting a sodium hyaluronate alkaline solution to an ultrasonic treatment; step 4): preparing the sodium hyaluronate solid raw material into a sodium hyaluronate solution with a concentration of 0.1% to 1% (w/v), and thoroughly mixing the sodium hyaluronate solution in an addition proportion of 20% to 60% (v/v) with the sodium hyaluronate alkaline solution obtained after the ultrasonic treatment; and step 5): subjecting a resulting mixed solution to an adsorption treatment with diatomaceous earth and activated carbon, filtering for concentration, and drying a resulting concentrate to obtain the sodium hyaluronate with a full MWD.

A porous membrane has a thickness of 150 m or greater. The pore diameters of a first surface are smaller than the pore diameters of a second surface. The average value of the pore diameters of the first surface is 60 nm or less, and the coefficient of variation of the pore diameters is 10% or greater and 50% or less.

A polyimide separation membrane is comprised of a polyimide, a halogen compound (e.g., halogenated aromatic epoxide) that is soluble in the polyimide and a hydrocarbon having 2 to 5 carbons (e.g., ethane, ethylene, propane or propylene). The gas separation membrane has improved selectivity for small gas molecules such as hydrogen compared to polyimide membrane not containing the halogen compound or hydrocarbon. The polyimide separation membrane may be made by shaping a dope solution comprised of a polyimide, a halogen containing compound that is soluble in the polyimide, removing the solvent and then exposing the untreated polyimide membrane to a treating atmosphere comprising a hydrocarbon having 2 to 5 carbons for a sufficient time to form the polyimide membrane.

Composite porous hydrophobic membranes are prepared by forming a perfluorohydrocarbon layer on the surface of a preformed porous polymeric substrate. The substrate can be formed from poly(aryl ether ketone) and a perfluorohydrocarbon layer can be chemically grafted to the surface of the substrate. The membranes can be utilized for a broad range of fluid separations, such as microfiltration, nanofiltration, ultrafiltration as membrane contactors for membrane distillation and for degassing and dewatering of fluids. The membranes can further contain a dense ultra-thin perfluorohydrocarbon layer superimposed on the porous poly(aryl ether ketone) substrate and can be utilized as membrane contactors or as gas separation membranes for natural gas treatment and gas dehydration.

The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced on a large-scale approach. The unique HNDCM holds great promise as components in separation and advanced carbon devices because they could offer unconventional fluidic transport phenomena on the nanoscale. Overall, the invention set forth herein covers a hierarchically structured, nitrogen-doped carbon membranes and methods of making and using such a membranes.

The present invention relates to a composite porous hollow-fiber membrane including a first layer and a second layer which each include a fluororesin-based polymer, in which the first layer has a columnar texture oriented in a longitudinal direction of the composite porous hollow-fiber membrane, the columnar texture has an average value v of a Raman orientation parameter calculated with the specific formula, and the second layer has a three-dimensional network texture and has an average surface-pore diameter of 5.0 nm to 5.0 m.

A porous membrane is made from a poly(phenylene ether) copolymer containing 10 to 40 mole percent repeat units derived from 2-methyl-6-phenylphenol and 60 to 90 mole percent repeat units derived from 2,6-dimethylphenol; and a block copolymer containing backbone or pendant blocks of poly(C.sub.2-4 alkylene oxide). The porous membrane is made by dissolving the poly(phenylene ether) copolymer in a water-miscible polar aprotic solvent to form a membrane-forming composition; and phase-inverting the membrane forming-composition in a first non-solvent composition to form the porous membrane. A method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, includes coextruding the membrane-forming composition through the annulus, and a first non-solvent composition through the bore, into a second non-solvent composition to form the hollow fiber.

A method for producing a filter, the method comprising providing a first layer above a substrate; providing a block copolymer layer above the first layer; converting the block copolymer layer to a mask by selectively removing domains of the block copolymer layer; etching pores through the first layer in regions exposed by the mask; and forming a channel through the substrate, the channel being configured to provide fluid communication between a first and a second end of the channel, the first end of the channel being directly below the etched pores of the first layer, whereby fluid passing through the channel and the pores is filtered by the pores, when the filter is in use.

Water-filtration compositions, membranes, devices, and manufacturing processes including graphene oxide with hydrophilic functional groups. Disclosed are a composition comprising graphene oxide with an average particle diameter of no more than about 1 ?m and has an oxygen atomic percentage of at least about 30%, a membrane comprising the composition, a water-permeable device comprising the membrane, a method of making the membrane using the composition, and several methods of generating the composition.

Provided are a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose retained in the porous membrane, in which the average pore size differs between two surfaces of the porous membrane, the hydroxyalkyl cellulose distributed in the thickness direction of the hydrophilic porous membrane exhibits two or more peaks of detection intensity in GPC, and the weight-average molecular weight Mw.sub.min of the peak that is detected latest among the above-mentioned peaks is less than 100,000; and a method for producing a hydrophilic porous membrane, the method including separately preparing a hydrophilizing liquid including a hydroxyalkyl cellulose having a smaller weight-average molecular weight and a hydrophilizing liquid including a hydroxyalkyl cellulose having a larger weight-average molecular weight, and applying each of the hydrophilizing liquids on two surfaces of the porous membrane or sequentially on one surface thereof.