A nonwoven web obtained by electrospinning, suitable for the filtration of nano- and/or submicron aerosols, including a multiplicity of fibers of composition C1, the composition C1 including at least 50% by weight of at least one polymer P1 based on the repeat unit resulting from vinylidene fluoride (VDF), the fibers of composition C1 having a degree of crystallinity in polar phase(s), preferentially in solely beta phase, of at least 65% by weight, with respect to their total weight. Also, a process for the manufacture of the web, to a membrane including the web and also to a process for the washing/sterilization of the web or of the membrane.

Disclosed is the preparation of composite fluid separation membranes based on poly (aryl ether ketone) (PAEK) polymers with the separation layer formed by a layer-by-layer reticular synthesis. The porous PAEK substrate is semicrystalline, exhibits a mesoporous surface structure, and is surface functionalized. The separation layer formed by the hierarchical layer-by-layer process is in the form of a covalent organic network integrally linked via covalent bonds to the functional groups of the substrate. The composite separation layer may be synthesized in situ in a preformed separation device on the surface of the PAEK substrate. Device configurations include flat sheet, spiral wound, monolith, and hollow fiber configurations with the hollow fiber configuration being preferred. Hollow fibers are formed from PAEK polymers with poly (ether ether ketone) and poly (ether ketone) particularly preferred. Composite PAEK membranes of the present invention are useful for a broad range of fluid separation applications.

The present invention provides a separation membrane suitable for separating water from a liquid mixture containing an alcohol and water. The separation membrane of the present invention includes a metal organic framework. On the separation membrane, at least one of requirements (i) and (ii) below holds: (i) a ratio R1 of a number N2 of molecules satisfying a specified condition (b) with respect to a number N1 of molecules satisfying a specified condition (a) is less than 0.29; (ii) a ratio R2 of an adsorption amount of water adsorbed by the metal organic framework under water vapor at 25° C. and 3.2 kPa with respect to an adsorption amount of ethanol adsorbed by the metal organic framework under an ethanol atmosphere at 25° C. and 7.4 kPa is more than 4.0.

An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained. The asymmetric carbon membrane may be useful to separate gases such as olefins from their corresponding paraffins, hydrogen from syngas or cracked gas, natural gas or refinery gas, oxygen/nitrogen, or carbon dioxide and methane.

An asymmetric hollow fiber (CMS) carbon molecular sieve is made by providing a dope solution comprised of a polvimide and a solvent, at a temperature greater than 250° C. that is less than the storage modulus at a temperature of 250° C., but no more than ten times less as measured using dynamic mechanical thermal analysis from 250° C. to a temperature where the polyimide carbonizes. The polvimide is shaped into a hollow polvimide fiber, the solvent removed and the polyimide hollow fiber is heated to pyroiyze the polvimide and form the asymmetric hollow carbon molecular sieve. The asymmetric hollow fiber carbon molecular sieve has a wall that is defined by an inner surface and outer surface of said fiber and the wall has an inner porous support region extending from the inner surface to an outer raicroporous separation region that extends from the inner porous support region to the outer surface. Surprisingly, when the polyimide has the particular storage modulus characteristics, the method allows for the hollow fiber CMS to be made without any pre-treatmenis or additives to inhibit stractural collapse of the inner microporous region.

An apparatus, system and redox membrane for efficient lithium-ion extraction from natural salt waters or geothermal brines or manmade sources such as from lithium battery recycling are provided. The redox membrane is selective for lithium ions over other spectator ions making the system capable of selectively extracting lithium-ions from multiple-ion source solutions. The system uses the redox membrane as an electrochemically active material acting as a Li-selective membrane for direct lithium extraction from a lithium-ion source. The redox membrane is also not porous to solvents and is stable in caustic and high temperature environments. The features of the redox membrane and system allow the recovery of lithium from low purity sources and the production of higher purity products at reduced costs and process steps over conventional processes.

A polymer membrane, methods of gas separation utilizing the polymer membrane, and methods of producing the polymer membrane are disclosed herein. The polymer membrane includes a crosslinked polyethylene glycol network polymer according to formula (I): ##STR00001##

The present disclosure provides methods of controlling the size of cellulose crystals by mixing a first composition comprising cellulose and coagulating this mixture with varying concentrations of hydrogen peroxide.

The present invention belongs to the membrane separation area, which provides an MXene material based composite nanofiltration membrane and corresponding method. The mentioned membrane is flat membrane, which has supporting layer and functional separation layer and supporting layer is under the functional separation layer. The functional separation layer is a kind of dense ultra-thin layer, no more than 50 m, prepared with MXene and crosslinking agent. This invention is about a flat composite nanofiltration membrane which has excellent separation performance, thermal resistance and chemical stability because of the novel MXene in the functional separation layer. It can be used in the treatment of the waste water with heavy metal ions, organic solvents or other highly oxidizing solution.

An isoporous membrane includes a multiblock copolymer film. The multiblock copolymer is crosslinked, and the film has a toughness of at least 50 kJ/m.sup.3 as a free-standing film when wet, as measured by integrating the area under a stress-strain curve for the film. Methods of forming isoporous membranes are also included.