Cation exchange membranes and materials including silica-based ceramics, and associated methods, are provided. In some aspects, cation exchange membranes that include a silica-based ceramic that forms a coating on and/or within a porous support membrane are described. The cation exchange membranes and materials may have certain structural or chemical attributes (e.g., pore size/distribution, chemical functionalization) that, alone or in combination, can result in advantageous performance characteristics in any of a variety of applications for which selective transport of positively charged ions through membranes/materials is desired. In some embodiments, the silica-based ceramic contains relatively small pores (e.g., substantially spherical nanopores) that may contribute to some such advantageous properties. In some embodiments, the cation exchange membrane or material includes sulfonate and/or sulfonic acid groups covalently bound to the silica-based ceramic.

The invention provides polymer-grafted and functionalized nonwoven membranes adapted for use in bioseparation processes, the membranes including a nonwoven web of polyester fibers having an average fiber diameter of less than about 1.5 microns, each of the plurality of polyester fibers having grafted thereon a plurality of polymer segments constructed of a methacrylate polymer, each polymer segment carrying a functional group adapted for binding to a target molecule. The invention also provides a method of bioseparation comprising passing a solution comprising the target molecule, such as a protein, through the nonwoven membrane of the invention such that at least a portion of the target molecule in the solution binds to the nonwoven membrane. A method for preparing a polymer-grafted and functionalized nonwoven membrane adapted for use in bioseparation processes is also provided.

The invention provides polymer-grafted and functionalized nonwoven membranes adapted for use in bioseparation processes, the membranes including a nonwoven web of polyester fibers having an average fiber diameter of less than about 1.5 microns, each of the plurality of polyester fibers having grafted thereon a plurality of polymer segments constructed of a methacrylate polymer, each polymer segment carrying a functional group adapted for binding to a target molecule. The invention also provides a method of bioseparation comprising passing a solution comprising the target molecule, such as a protein, through the nonwoven membrane of the invention such that at least a portion of the target molecule in the solution binds to the nonwoven membrane. A method for preparing a polymer-grafted and functionalized nonwoven membrane adapted for use in bioseparation processes is also provided.

A composite membrane for selectively pervaporating a first liquid from a mixture comprising the first liquid and a second liquid. The composite membrane includes a porous substrate comprising opposite first and second major surfaces, and a plurality of pores. A PVP- or PVL-containing polymer is disposed in at least some of the pores so as to form a layer having a thickness within the porous substrate and/or disposed on top of the pores to form a layer.

A composite membrane for selectively pervaporating a first liquid from a mixture comprising the first liquid and a second liquid. The composite membrane includes a porous substrate comprising opposite first and second major surfaces, and a plurality of pores. A PVP- or PVL-containing polymer is disposed in at least some of the pores so as to form a layer having a thickness within the porous substrate and/or disposed on top of the pores to form a layer.

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.

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.

The present invention belongs to the technical field of membranes, and in particular relates to a polyamide composite reverse osmosis membrane and to a preparation method thereof. The polyamide composite reverse osmosis membrane provided by the present invention comprises: a nascent membrane and a temperature-responsive polypeptide grafted to a surface of the nascent membrane; the nascent membrane comprises a support layer and a polyamide separation layer joined to the support layer; the temperature-responsive polypeptide is a homopolymeric (L-glutamate) containing oligo(ethylene glycol). The polyamide composite reverse osmosis membrane provided in the present invention has excellent pollution resistance and oxidation resistance capabilities, has a low difficulty of cleaning, and has extremely broad market prospects.

The present invention belongs to the technical field of membranes, and in particular relates to a polyamide composite reverse osmosis membrane and to a preparation method thereof. The polyamide composite reverse osmosis membrane provided by the present invention comprises: a nascent membrane and a temperature-responsive polypeptide grafted to a surface of the nascent membrane; the nascent membrane comprises a support layer and a polyamide separation layer joined to the support layer; the temperature-responsive polypeptide is a homopolymeric (L-glutamate) containing oligo(ethylene glycol). The polyamide composite reverse osmosis membrane provided in the present invention has excellent pollution resistance and oxidation resistance capabilities, has a low difficulty of cleaning, and has extremely broad market prospects.

A dual-layer membrane and a method for preparing thereof. By adding a modifying monomer containing an active group and a characteristic group to a dope solution or spinning solution during the preparation of the dual-layer membrane, the grafting reaction occurs between the active group of the monomer and the polymer in the dope solution or spinning solution, and the intermolecular interaction with other polymers is enhanced by the characteristic group of the monomer, to improve the miscibility between the polymers. The method is suitable for preparing both a dual-layer flat sheet membrane and a dual-layer hollow fiber membrane, and can realize the preparation of a dual-layer membrane with an interpenetrated structure at the interface under mild preparation conditions.