Embodiments described herein relate generally to graphene oxide membranes for fluid filtration and more specifically to graphene oxide membranes having tunable permeability, rejection rate, and flux. Some embodiments of the graphene oxide membranes disclosed herein are characterized as having a flux of at least about 2.510.sup.4 gallons per square foot per day per psi with a 1 wt % lactose solution at room temperature, and a lactose rejection rate of at least 50% with a 1 wt % lactose solution.

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.

This invention provides a new high selectivity stable facilitated transport membrane comprising a polyethersulfone (PES)/polyethylene oxide-polysilsesquioxane (PEO-Si) blend support membrane, a hydrophilic polymer inside the pores on the skin layer surface of the PES/PEO-Si blend support membrane; a hydrophilic polymer coated on the skin layer surface of the PES/PEO-Si blend support membrane, and metal salts incorporated in the hydrophilic polymer coating layer and the skin layer surface pores of the PES/PEO-Si blend support membrane, and methods of making such membranes. This invention also provides a method of using the high selectivity stable facilitated transport membrane comprising PES/PEO-Si blend support membrane for olefin/paraffin separations such as propylene/propane and ethylene/ethane separations.

A filter medium including: a porous first support; nanofiber webs respectively stacked at the upper and lower parts of the first support, and made of a plurality of nanofibers of which the diameters have a standard deviation of 300 nm or less; and a porous second support interposed between the first support and the nanofiber web. The filter medium is implemented by fibers having uniform diameters, and thus is easily manufactured to have a predetermined pore diameter and simultaneously has excellent uniformity of the pore diameters, thereby having excellent filtering efficiency and being more suitable when selectively separating specific objects. Backwashing is enabled at uniform pressure during backwashing such that high cleaning power is obtained. The filter medium has excellent water permeability and excellent mechanical strength so as to minimize the shape and structural deformation and damage of the filter medium.

A composition of five parts by mass of chitosan and one part graphene oxide is suspended in water. The composition may be used to form filtration layers of any size or shape and may be reinforced by additional layers. The composition may be used to construct a large filtration apparatus of any size or shape and may be used to form highly resilient, antimicrobial structures and surfaces for a variety of applications.

A composition of five parts by mass of chitosan and one part graphene oxide is suspended in water. The composition may be used to form filtration layers of any size or shape and may be reinforced by additional layers. The composition may be used to construct a large filtration apparatus of any size or shape and may be used to form highly resilient, antimicrobial structures and surfaces for a variety of applications.

A filter assembly including a filtration medium comprising a nanofiber, having a three-dimensional network structure, and having a fiber web layer comprising a hydrophilic coating layer that covers at least a part of the outer surface of the nanofiber; and a first support body that supports the filtration medium, which is provided on both surfaces thereof, and has a channel formed therein. Accordingly, the filtration medium has excellent chemical resistance and improved hydrophilicity such that the flow rate can increase substantially. In addition, the improved hydrophilicity is maintained for a long period of time such that the utilization period can be extended substantially. Furthermore, any change in the pore structure of the filtration medium during the hydrophilicity endowing process is minimized such that the initially designed physical characteristics of the filtration medium can be fully exhibited.

The present invention provides a semipermeable membrane having enhanced alkaline stability and a method of forming a semipermeable membrane having enhanced alkaline stability, comprising steps of: providing an ultrafiltration (UF) base membrane, immersing said UF membrane in a solution comprising at least one substance selected from the group consisting of a polymer preferably polyethylenimine (PEI), a condensate solution and a mixture thereof, thereby forming reactive moieties upon said UF membrane, and forming at least one first layer upon at least portion of said UF base support membrane by immersing said UF base support membrane of step (b) in a solution comprising at least one ingredient selected from the group consisting of polymer preferably polyethylenimine (PEI), condensate solution and a mixture thereof thereby forming a cross-linked skin on the surface of said base membrane.

This invention provides a new high selectivity stable facilitated transport membrane comprising a polyethersulfone (PES)/polyethylene oxide-polysilsesquioxane (PEO-Si) blend support membrane, a hydrophilic polymer inside the pores on the skin layer surface of the PES/PEO-Si blend support membrane; a hydrophilic polymer coated on the skin layer surface of the PES/PEO-Si blend support membrane, and metal salts incorporated in the hydrophilic polymer coating layer and the skin layer surface pores of the PES/PEO-Si blend support membrane, and methods of making such membranes. This invention also provides a method of using the high selectivity stable facilitated transport membrane comprising PES/PEO-Si blend support membrane for olefin/paraffin separations such as propylene/propane and ethylene/ethane separations.

A composition of five parts by mass of chitosan and one part graphene oxide is suspended in water. The composition may be used to form filtration layers of any size or shape and may be reinforced by additional layers. The composition may be used to construct a large filtration apparatus of any size or shape and may be used to form highly resilient, antimicrobial structures and surfaces for a variety of applications.