A membrane distillation (MD) system includes a membrane module and reduced graphene oxide-carbon nanotube immobilized membrane for organic solvent separation. The MD module could include a feed inlet and outlet, a sweep gas inlet, and a sweep gas outlet. Thermostats are positioned at the feed inlet and outlet to measure the change in temperature. Preferential sorption of the organic, specifically tetrahydrofuran (THF), on a hybrid reduced graphene oxide-carbon nanotube immobilized membrane contributes to enhanced solvent removal of the MD system.

Provided is a method of producing a graphitic film, comprising: (a) providing a suspension of a mixture of graphene oxide (GO) and aromatic molecules selected from petroleum heavy oil or pitch, coal tar pitch, a polynuclear hydrocarbon, a halogenated variant thereof, or a combination thereof, dispersed or dissolved in a liquid medium; (b) dispensing and depositing the suspension onto a surface of a supporting substrate to form a wet layer, wherein the procedure includes subjecting the suspension to an orientation-inducing stress or strain; (c) partially or completely removing the liquid medium; and (d) heat treating the resulting dried layer at a first temperature selected from 20° C. to 3,200° C. so that the GO and aromatic molecules are cross-linked, merged or fused into larger aromatic molecules to form the graphitic film, wherein the larger aromatic molecules or graphene planes in the graphitic film are substantially parallel to each other.

A graphene-based membrane and a method of producing the same are disclosed. The graphene-based membrane may include a graphene-polymer composite, wherein the graphene-polymer composite may consist of an amine functionalized graphene and a polymer containing an anhydride group as a linker for linking the amine functionalized graphene to the polymer. The graphene-based membrane may be constructed of a single-layer. A method may include reacting a polymer containing an anhydride with an amine functionalized graphene in presence of a solvent to form an intermediate product; and thermal imidizing the intermediate product to form a graphene grafted polymer composite for use in fabricating a graphene-based membrane.

Nanofiltration of aqueous solutions or other water-based fluids in various applications, such as desalination, dialysis, seawater purification, for example, may be enhanced through precisely controlling a filtration cutoff within graphene oxide nanofilters. By initially compressing and constraining the stacked thickness of multiple graphene oxide layers deposited between porous substrates, the interlayer gap size, and thus, the filtration cutoff may be adjusted and optimized.

There is provided a system and method for angstrom confinement of trapped ions. The method including: receiving water molecules and ionic compounds in a first reservoir, an angstrom confinement assembly is positioned between the first reservoir and a second reservoir, the angstrom confinement assembly defining angstrom conduits; and repeatedly applying an electric field across a first electrode and a second electrode, the first electrode on a same side of the angstrom confinement assembly as the first reservoir and the second electrode on a same side of the angstrom confinement assembly as the second reservoir, the electric field applied such that, when the electric field is applied, positive ions of the ionic compounds are induced to flow through the angstrom conduits, and wherein, when the electric field is not applied, water molecules flow into the angstrom conduits due to capillary forces to confine the positive ions in the angstrom conduits.

This invention relates generally to a chitosan-graphene oxide membrane and process of making the same. The nanocomposite membrane can filter water and remove contaminants without fouling like other commercially-available polymer-based water filters. The membrane can be used as a flat sheet filter or can be engineered in a spiral filtration module. The membrane is scalable and tunable for many water contaminants including pharmaceuticals, pesticides, herbicides, and other organic chemicals. The membrane uses chitosan, which is low-cost, renewable biopolymer typically considered to be a waste product and the second most abundant biopolymer on Earth, thus making the membrane an environmentally-friendly product choice.

A nanopore system provided herein includes first and second fluidic reservoirs in fluidic communication with a nanopore forming a fluidic path between the reservoirs. An enzyme clamp, provided in the first fluidic reservoir, abuts the nanopore and is reversibly bound to a sequential plurality of polymer subunits of a target polymer molecule in ionic solution. The clamp has an outer clamp diameter that is greater than the nanopore diameter. An electrical circuit includes an electrode in each of the reservoirs for applying a voltage bias across the nanopore. A pulse generator is connected in the electrical circuit to apply control pulses across the nanopore to step the clamp along sequential polymer subunits of the target polymer molecule. The system includes no fuel or source of fuel for the clamp. A controller is connected in the electrical circuit for controlling the collection of electrical indications of polymer subunits.

Described herein is a crosslinked graphene and biopolymer (e.g. lignin) based composite membrane that provides selective resistance for solutes while providing water permeability. The membrane may include optional additional functional additives in a crosslinked material matrix that provides enhanced salt separation from water. Methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Described herein is a graphene oxide and polymer based selectively permeable element that provides selective gas, and vapor resistance for dehumidification applications. The graphene oxide is cross-linked with polyvinyl alcohol, the polymer comprises an ammonium salt polymer such as poly(diallyldimethylammonium) chloride. Also described is a selectively permeable element where the graphene may be selected from reduced graphene oxide, graphene oxide, and is also functionalized or crosslinked. Also described is a selectively permeable element where there is crosslinking between the graphene and/or the polymers to provide enhanced gas resistance with water vapor permeability. A selectively permeable device is also described that incorporates the selectively permeable element and further comprises a substrate and a protective coating, encompassing the selectively permeable element. Also described are methods for making the aforementioned selectively permeable elements and related devices.

Described herein are crosslinked graphene oxide and polycarboxylic acid based composite membranes that provide selective resistance for gases while providing water vapor permeability. Such composite membranes have a high water/air selectivity in permeability. The methods for making such membranes, and using the membranes for dehydrating or removing water vapor from gases are also described.