A composite porous membrane contains at least one porous base layer and at least one uniaxially stretched coating layer located on at least one side surface of the porous base layer. For example, the composite porous membrane comprises at least one porous base layer and at least one nanofiber-like non-polyolefin polymer porous layer oriented along the transverse stretching direction of the composite porous membrane and located on one or two side surfaces of the porous base layer, or the composite porous membrane comprises a biaxially stretched polypropylene porous base layer and a uniaxially stretched coating layer located on at least one side surface of the porous base layer. The composite porous membrane is coated with a coating solution prior to transversely stretching. The nanofiber-like non-polyolefin polymer porous layer may reduce cracking of the composite porous membrane in the machine direction.

A thin film composite gas separation membrane comprising a polyether block amide copolymer coating layer and a nanoporous asymmetric support membrane with nanopores on the skin layer surface of the support membrane and gelatin polymers inside the nanopores on the skin layer surface of the support membrane. A method for making the thin film composite gas separation membrane is provided as well as the use of the membrane for a variety of separations such as separations of hydrogen sulfide and carbon dioxide from natural gas, carbon dioxide removal from flue gas, fuel gas conditioning, hydrogen/methane, polar molecules, and ammonia mixtures with methane, nitrogen or hydrogen and other light gases separations, but also for natural gas liquids recovery and hydrogen sulfide and carbon dioxide removal from natural gas in a single step.

A bipolar membrane in which a cation-exchange membrane and an anion-exchange membrane are joined to each other, wherein a leakage ratio of gluconic acid at 60° C. is not more than 1.0%, and the cation-exchange membrane is supported by a polyolefin reinforcing member and, further, contains a polyvinyl chloride.

Described herein are mixed matrix filtration membranes and related, dendrimers, dendrimer particles, compositions, methods and systems and in particular mixed matrix filtration membranes with an embedded dendrimer particles and related compositions, methods, and systems wherein each dendrimer particle comprises at least two dendrimers each having at least two core chemical moieties having a core multiplicity Nc; branch cell units attached to the core chemical moiety or one to another, with the branch cell units attached one to another having a branch cells multiplicity Nb; and a number of surface functional groups Z presented on terminal branch cell units, wherein NcNb.sup.G with G≤3.

An anion-exchange membrane of the present invention includes a substrate made of polyolefin-based woven fabric and an anion-exchange resin, and has an electrical resistance measured using 0.5 M NaCl solution at 25° C. of 1.0 Ω•cm.sup.2 or more to 2.5 Ω•cm.sup.2 or less, a bursting strength of 0.7 MPa or more to 1.2 MPa or less, a water permeation rate measured using pressured water at 0.1 MPa of 300 ml/(m.sup.2•hr) or less, a thickness of the substrate of 90 .Math.m or more to 160 .Math.m or less, and an open area ratio of the substrate of 35% or more to 55% or less.

The present invention relates to an anti-fouling, semi-permeable membrane comprising a porous support layer, a thin film composite (TFC) layer formed on a surface of the support layer, and a cross-linked polyvinyl alcohol (PVA) layer formed on top of the TFC layer, wherein the cross-linked PVA layer is the reaction product of PVA and a cross-linking agent, said cross-linking agent being a polybasic acid comprising three or more acid groups or precursors thereof. The obtained membrane shows a high water flux and a low roughness suitable for an effective membrane notable for feed solution having a tendency of fouling the membrane.

Zero liquid discharge systems, processes, and techniques for treating a saltwater without evaporative crystallization. The saltwater is treated by a fluidic circuit comprising a high-pressure reverse osmosis (“HPRO”) unit configured to operate at a hydraulic pressure of at least 1,500 psi, a cooling crystallizer, and a solids-liquid separator. The saltwater is first concentrated by the HPRO unit to produce an HPRO brine, which is subsequently cooled to a designated crystallization temperature by the cooling crystallizer. The cooling crystallizer crystallizes salt crystals from the cooled HPRO brine and produces a salt-diminished brine. The solids-liquid separator separates the salt-diminished brine from the salt crystals. The salt-diminished brine from the solids-liquid separator is returned to the HPRO unit for further treatment, which allows additional salts to be crystallized from the returned salt-diminished brine.

A polyamide (PA) nanofiltration (NF) membrane and a preparation method thereof by regeneration from a scrapped microfiltration (MF) membrane are provided. The method adopts a cleaning-repairing-interfacial polymerization upgrading strategy, where, sodium hypochlorite and oxalic acid are used for deeply cleaning a scrapped MF membrane. PDA is used as a repairing agent to construct a reaction platform on the membrane surface, and finally a reaction system of piperazine and trimesoyl chloride (TMC) are used to form a PA NF membrane with a PA active layer. The repairing can construct a coating with a given thickness and prominent hydrophilicity on the membrane surface, which provides favorable base membrane conditions for upgrading and preparing an NF membrane.

Purification devices and methods remove perfluorinated compounds (PFCs) from PFC-contaminated water using temperature swing adsorption and desorption.

Provided herein are one-step methods for fabricating an asymmetric mixed-matrix membrane and the asymmetric mixed matrix membrane so fabricated. In the one step method an asymmetric polymer film is formed from a liquid polymer solution and a ligand precursor simultaneously with the formation of metal-organic framework filler particles therein. Also provided is a method for separating a mixture of gases or of liquids by flowing the mixture through the asymmetric mixed matrix membrane.