An article that includes a functionalized copolymer and the use thereof, particularly in a process for binding biomaterials, such as in a process for separating aggregated proteins from monomeric proteins in a biological solution; wherein the article includes: a) a porous substrate; and b) a copolymer covalently attached to the porous substrate, the copolymer comprising a hydrocarbon backbone and a plurality of pendant groups attached to the hydrocarbon backbone, wherein 1) each of a first plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and 2) each of a second plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and wherein the first plurality of pendant groups are different than the second plurality of pendant groups; and wherein a mole ratio of the first plurality of pendant groups to the second plurality of pendant groups is in a range of 95:5 to 5:95.

A composite ion exchange membrane comprising components (a) and (b): (a) a membrane layer comprising ionic groups, two opposing surfaces and optionally a porous support; (b) a layer comprising sulpho groups bound to at least one of the at least two opposing surfaces of the membrane layer (a);
wherein the layer comprising sulpho groups has a thickness of less than 100 nm and the composite ion exchange membrane has a surface zeta potential of 0 to −7.5 mV.

An ion permeable membrane for selective permeation of a target ion, preferably lithium, through the membrane, the membrane comprising a target ion permeable composite comprises a target ion permeable ceramic and at least one organic polymer associated with the target ion permeable ceramic.

An acidic gas separation membrane is selectively permeable to an acidic gas, and includes a first porous layer and a resin composition layer formed on the first porous layer with use of a resin composition. The resin composition contains a modified polyamine obtained by introducing at least one of an acidic dissociable group and a salt thereof into a polyamine. The acidic dissociable group is at least one selected from the group consisting of a carboxy group, a sulfonic acid group, an oxysulfonic acid group, a phosphoric acid group, and an oxyphosphoric acid group. The polyamine is at least one selected from the group consisting of polyethyleneimine, polyallylamine, and polyvinylamine.

A composite membrane comprising a supporting membrane that includes polyphenylene oxide and a separation layer that is disposed on one main surface of the supporting membrane, wherein the poiyphenylene oxide is sulfonated on the one main surface of the supporting membrane and the separation layer includes polyvinyl alcohol having an ionic functional group.

Asymmetric composite membranes and methods for their preparation are disclosed. The membranes comprise a cross-linked poly(vinyl alcohol) polymer coated on a film of cross-linked sulfonated poly(ether ether ketone) adhered to a sheet of hydrophilicitized microporous polyolefin. The microporous polyolefin is typically microporous poly(ethylene). The membranes have improved selectivity with the regard to the rejection of solutes in reverse osmosis and ultrafiltration applications.

A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: ##STR00001##
wherein R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

There is provided an apparatus for removing fine particles having membranes for removing fine particles in a liquid, wherein a microfiltration membrane or ultrafiltration membrane having a positive charge and a microfiltration membrane or ultrafiltration membrane having a negative charge are arranged in series. There is also provided a method for removing fine particles using the apparatus. Liquids may be passed through the membrane having a negative charge and the membrane having a positive charge in order; thereby, extrafine particles having a particle size of 50 nm or smaller, especially of 10 nm or smaller, in the liquids can be removed highly. The liquid passing may be carried out in the order reverse thereto.

Embodiments are directed to composite membranes having: increased volume of the microporous polymer structure relative to the total volume of the PEM; decreased permeance and thus increased selectivity; and lower ionomer content. An increased amount of polymers of the microporous polymer structure is mixed with a low equivalent weight ionomer (e.g., <460 cc/mole eq) to obtain a composite material having at least two distinct materials. Various embodiments provide a composite membrane comprising a microporous polymer structure that occupies from 13 vol % to 65 vol % of a total volume of the composite membrane, and an ionomer impregnated in the microporous polymer structure. The acid content of the composite membrane is 1.2 meq/cc to 3.5 meq/cc, and/or the thickness of the composite membrane is less than 17 microns. The selectivity of the composite membrane is greater than 0.05 MPa/mV, based on proton conductance and hydrogen permeance.

A polysulfone membrane is modified so that monomers are grafted onto the surface of the membrane. The polysulfone membranes can be grafted by contacting the membrane with a grafting solution and exposing the membrane to electromagnetic radiation, typically within the ultraviolet portion of the spectrum. The monomers that are grafted are typically anionic or cationic. The grafted membranes can be used for filtering impurities, such as positively and negatively charged particles, from a liquid. Anionic membranes provide improved filtration of negatively charged impurities, while cationic membranes provide improved filtration of positively charged impurities.