A pervaporation membrane may be an acid-resistant polybenzidimazole (PBI) membrane. The acid-resistant PBI membrane may be a PBI membrane chemically modified by a process selected from the group consisting of sulfonation, phosphonation, cross-linking, N-substitution, and/or combinations thereof. The membrane may be thermally stabilized. A method for the dehydration of an acid material may include the steps of: contacting an acidic aqueous solution with a membrane of an acid-resistant polybenzidimazole; taking away a permeate stream rich in water; and taking away a concentrate steam rich in the acid material. The acidic aqueous solution may be acetic acid.

Embodiments described herein relate generally to durable graphene oxide membranes for fluid filtration. For example, the graphene oxide membranes can be durable under high temperatures non-neutral pH, and/or high pressures. One aspect of the present disclosure relates to a filtration apparatus comprising: a support substrate, and a graphene oxide membrane disposed on the support substrate. The graphene oxide membrane has a first lactose rejection rate of at least 50% with a first 1 wt % lactose solution at room temperature. The graphene oxide membrane has a second lactose rejection rate of at least 50% with a second 1 wt % lactose solution at room temperature after the graphene oxide membrane is contacted with a solution that is at least 80° C. for a period of time.

The composite anion exchange membrane includes: a surface layer on a single surface or both surfaces of an anion exchange membrane substrate, in which the above-described surface layer contains a copolymer of a monomer A which is a water-soluble polyfunctional monomer and a monomer B which is a cationic monomer, an anion exchange capacity of the above-described surface layer is 0.05 meq/cm.sup.3 to 0.50 meq/cm.sup.3, and an anion exchange capacity of the above-described anion exchange membrane substrate is 1.0 meq/cm.sup.3 to 5.0 meq/cm.sup.3.

A gas separation membrane has a gas separation layer containing a crosslinked cellulose resin. The crosslinked cellulose resin has a particular linking structure in a crosslinked structure. The gas separation layer contains an organic solvent in a particular amount.

Membranes suitable for use in membrane distillation are provided. Such membranes may include nano-fibrous layers with adjustable pore sizes. The membranes may include a hydrophobic nano fibrous scaffold and a thin hydrophilic protecting layer that can significantly reduce fouling and scaling problems.

An improved method for concentrating dispersions of graphene oxide, coating a substrate with a layer of a graphene oxide solution, and producing a supported graphene membrane stabilised by controlled deoxygenation; and graphene-based membranes that demonstrate ultra-fast water transport, precise molecular sieving of gas and solvated molecules, and which show great promise as novel separation platforms.

A membrane for selective transport of substances includes: a porous substrate with a comb polymer. The comb polymer contains a polymer main chain and several lateral chains covalently bonded to the polymer main chain. At least one of the several lateral chains has at least one Lewis-acid and/or Lewis-base functionality.

Novel low-pressure nanofiltration membrane composites for rejecting organic compounds are prepared by interfacial polymerization on a microporous hollow fiber supporting membrane. The interfacial polymerization reaction is carried out using an essentially monomeric polyamine reactant having at least two amine functional groups per molecule, and an essentially monomeric amine-reactive polyfunctional aromatic or cycloaliphatic acyl halide having at least two acyl halide groups per molecule. The composite can be fabricated by stepwise polymerization reactions with different reactant recipes at each step.

A filtration membrane comprising cellulose fibres, the membrane having a pore size distribution such that the modal pore diameter is between 10 nm and 25 nm and/or wherein less than 5% of the pore volume comprises pores of greater than 40 nm and having a total porosity greater than 30%.

Two-dimensional materials having apertures in their basal planes are described, where at least a portion of the apertures are occluded with a selectively introduced occluding moiety. Occluding moieties that pass into apertures function to occlude apertures. Composite membranes are described having a porous substrate with a two-dimensional material disposed on the membrane and covering only a portion of the pores, wherein at least a portion of uncovered substrate pores are occluded. Pore occlusion can be achieved by introduction of an occluding particle optionally followed by chemical reaction, deformation or swelling of the particle to facilitate occlusion of pores. Two-dimensional materials covering substrate pores can be size-selected and optionally functionalized providing for selective permeability through composite membranes. Methods for occluding defects and apertures in two-dimensional materials and for selectively occluding pores in composite membranes are provided. Selectively occluded materials and membranes are useful in filtration and other applications.