Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

Composite membranes having a film of poly(ethenol) (polyvinyl alcohol; PVA) adhered to a microporous sheet of polyolefin are disclosed. The microporous sheet is made hydrophilic by grafting of the polyolefin, e.g. poly(ethylene), with a preformed polymer before adherence of the film of PVA. The composite membranes are chlorine tolerant with high levels of protein rejection making them particularly suitable for use in the extraction or recovery of water from feed streams in the beverage and food industries, including dairy.

Described herein is a filtration media comprising: (i) a first filtration medium comprising an anion exchange nonwoven substrate, wherein the anion exchange nonwoven substrate comprises a plurality of quaternary ammonium groups; and (ii) a second filtration medium comprising a functionalized microporous membrane wherein the functionalized microporous membrane comprises a plurality of guanidyl groups; wherein the first filtration medium is positioned upstream of the second filtration medium.

A supported membrane is provided comprising an inorganic, solid porous filtration membrane supported by an inorganic, solid porous support, said supported membrane comprising nanoparticles of a metal coordination polymer with CN ligands comprising M.sup.n+ cations, where M is a transition metal and n is 2 or 3; and Alk.sup.+.sub.y[M(CN).sub.m].sup.x? anions where Alk is an alkaline metal, y is 0, 1 or 2, M is a transition metal, x is 3 or 4, and m is 6 or 8; said M.sup.n+ cations of the coordination polymer being bound through an organometallic or coordination bond to an organic group of an organic graft chemically attached to the surface of the filtration membrane, inside the pores of the filtration membrane, and optionally inside the pores of the support. The supported membrane may be used in a process for separating at least one metal cation and solid particles from a liquid medium containing the same.

An article that can be used for biomaterial capture comprises (a) a porous substrate; and (b) borne on the porous substrate, a polymer comprising interpolymerized units of at least one monomer consisting of (1) at least one monovalent ethylenically unsaturated group, (2) at least one monovalent ligand functional group selected from acidic groups, basic groups other than guanidino, and salts thereof, and (3) a multivalent spacer group that is directly bonded to the monovalent groups so as to link at least one ethylenically unsaturated group and at least one ligand functional group by a chain of at least six catenated atoms.

A graphene-based membrane and a method of producing the same are disclosed. The graphene-based membrane may include a graphene-polymer composite, wherein the graphene-polymer composite may consist of an amine functionalized graphene and a polymer containing an anhydride group as a linker for linking the amine functionalized graphene to the polymer. The graphene-based membrane may be constructed of a single-layer. A method may include reacting a polymer containing an anhydride with an amine functionalized graphene in presence of a solvent to form an intermediate product; and thermal imidizing the intermediate product to form a graphene grafted polymer composite for use in fabricating a graphene-based membrane.

An article that can be used for biomaterial capture comprises (a) a porous substrate; and (b) borne on the porous substrate, a polymer comprising interpolymerized units of at least one monomer consisting of (1) at least one monovalent ethylenically unsaturated group, (2) at least one monovalent ligand functional group selected from acidic groups, basic groups other than guanidino, and salts thereof, and (3) a multivalent spacer group that is directly bonded to the monovalent groups so as to link at least one ethylenically unsaturated group and at least one ligand functional group by a chain of at least six catenated atoms.

Solvent and acid stable ultrafiltration and nanofiltration membranes including a non-cross-linked base polymer having reactive pendant moieties, the base polymer being modified by forming a cross-linked skin onto a surface thereof, the skin being formed by a cross-linking reaction of reactive pendant moieties on the surface with an oligomer or another polymer as well as methods of manufacture and use thereof, including, inter alia separating metal ions from liquid process streams.

A method for making a composite polyamide membrane including a porous support and a thin film polyamide layer including the steps of applying a polyfunctional amine monomer and a combination amine-reactive compounds to a surface of the porous support and reacting the constituents to form a thin film polyamide layer, wherein the amine-reactive compounds include: i) a polyfunctional amine-reactive monomer including two to three amine-reactive moieties selected from acyl halide, sulfonyl halide and anhydride, ii) a polyfunctional amine-reactive monomer including at least four amine-reactive moieties selected from acyl halide, sulfonyl halide and anhydride, and iii) an acid compound including at least on carboxylic acid moiety or salt thereof and at least one amine-reactive moiety selected from acyl halide and sulfonyl halide.

Provided are (1) a vinyl alcohol graft copolymer grafting polymerizable unsaturated monomers as a graft chain onto a side-chain mercapto group-containing vinyl alcohol polymer backbone, the graft chain being attached to the polymer backbone at a mercapto group, and the backbone including: a vinyl alcohol unit and a unit represented by the following formula (I): ##STR00001##
wherein R.sup.1 is a hydrogen atom or a carboxyl group; R.sup.2 is a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group; and X is a divalent C.sub.1-22 group which contains a carbon atom and a hydrogen atom and may contain a nitrogen atom and/or an oxygen atom; and (2) an ion-exchange membrane having controlled swelling in water and excellent flex resistance, the membrane including a vinyl alcohol graft copolymer as described above.