The present invention relates to a dialysate regeneration method that reduces a urea concentration of a urea-containing aqueous solution, the method including a reverse osmosis process of obtaining, from the urea-containing aqueous solution, a concentrate having a higher urea concentration and a permeate having a lower urea concentration by using a reverse osmosis membrane element at an operating pressure of 0.5 MPa or more and 2.0 MPa or less, in which the urea concentration of the urea-containing aqueous solution is 0.5 g/L or more, the reverse osmosis membrane element includes a reverse osmosis membrane, and the reverse osmosis membrane has a pore diameter of 7.0 Å or less as measured by a positron annihilation lifetime measurement method.

Described are filter membranes coated with a polyamide, filters and filter cartridges that include the filter membranes, and methods of using and making the filter membranes.

Described are filter membranes coated with a polyamide, filters and filter cartridges that include the filter membranes, and methods of using and making the filter membranes.

A gas separation membrane, a method for making the gas separation membrane, and a method for using the gas separation membrane are provided. An exemplary gas separation membrane includes a polyether-block-polyamide (PEBA) matrix and a cross-linked network including functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles dispersed through the PEBA matrix.

Apparatuses and methods for fabricating thin film composite hollow fiber membranes. In some implementations, an apparatus is used to remove excess first solution from a hollow fiber that has been immersed in a first solution. In some implementations, the method and apparatuses include flowing a gas, for example, compressed gas or ambient air, past a surface of a hollow fiber that has been immersed in a first solution prior to immersion in a second solution. In some implementations, the gas is flowed past the surface under positive pressure, while in other implementations the gas is flowed under negative pressure, for example, vacuum. The apparatuses and devices can be used to produce thin film composite hollow fiber membranes without pressing or damaging the hollow fiber.

A water treatment membrane and method of making water treatment membranes includes an interfacially formed polyamide layer residing upon a microporous support film and having a plurality of graphene oxide quantum dots attached to an outer surface of the polyamide layer. The polyamide layer has a permeate flux and a salt rejection performance. The permeate flux is increased by the presence of the graphene oxide quantum dots attached to the outer surface of the polyamide.

A water treatment membrane and method of making water treatment membranes includes an interfacially formed polyamide layer residing upon a microporous support film and having a plurality of graphene oxide quantum dots attached to an outer surface of the polyamide layer. The polyamide layer has a permeate flux and a salt rejection performance. The permeate flux is increased by the presence of the graphene oxide quantum dots attached to the outer surface of the polyamide.

A method for making a titania-polymer nanocomposite by simultaneously forming TiO.sub.2 nanoparticles in situ from a TiO.sub.2 precursor in the presence of urea and interfacially polymerizing polyamide precursors thereby producing a titania-polymer nanocomposite. A titania-polymer nanocomposite made by this method. A method for removing a dye or metal from water comprising contacting contaminated water with the titania-polymer nanocomposite.

A method for making a titania-polymer nanocomposite by simultaneously forming TiO.sub.2 nanoparticles in situ from a TiO.sub.2 precursor in the presence of urea and interfacially polymerizing polyamide precursors thereby producing a titania-polymer nanocomposite. A titania-polymer nanocomposite made by this method. A method for removing a dye or metal from water comprising contacting contaminated water with the titania-polymer nanocomposite.

A substrate comprising a crosslinked polymer primer layer, and grafted thereto a ligand-functionalized polymer is provided. The grafted polymer has the requisite affinity for binding neutral or negatively charged biomaterials, such as cells, cell debris, bacteria, spores, viruses, nucleic acids, and proteins, at pH's near or below the pI's of the biomaterials.