Some embodiments comprise membranes comprising a first layer comprising a porous graphene-based material; a second layer comprising a porous graphene-based material; a channel positioned between the first layer and the second layer, wherein the channel has a tunable channel diameter; and at least one spacer substance positioned in the channel, wherein the spacer substance is responsive to the environmental stimulus. In some cases, the membranes have more than two layers of porous graphene-based material. Permeability of a membrane can be altered by exposing the membrane to an environmental stimulus. Membranes can be used in methods of water filtration, immune-isolation, timed drug release (e.g., sustained or delayed release), hemodialysis, or hemofiltration.

A method for manufacturing a porous device (10) is described. The method comprises creating (340) a carbon nanomembrane (40) on a top surface (22) of a base material (20) having latent pores (23) and etching (360) the latent pores (23) in the base material (20) to form open pores (24). The porous device (10) can be used as a filtration device.

Apparatus, methods and uses for separating gas mixtures of at least two different gases under magnetic field and employing a membrane are described.

A lithium extraction composite comprising: (i) a porous support and (ii) particles of a lithium-selective sorbent material coated on at least one surface of the support, wherein the support has a planar membrane, fiber (or rod), or tubular shape. A method for extracting and recovering a lithium salt from an aqueous solution by use of the above-described composition is also described, the method comprising (a) flowing the aqueous source solution through a first zone or over a first surface of the lithium extraction composite to result in selective lithium intercalation in the lithium-selective sorbent material in the first zone or first surface; and (b) simultaneously recovering lithium salt extracted in step (a) from said lithium-selective sorbent material by flowing an aqueous stripping solution through a second zone or over a second surface of the lithium extraction composite in which lithium ions from the first zone or first surface diffuse.

Distributed liquid-flow systems—in which flow spreads out from a system inlet and traverses the system through multiple discrete, smaller flow channels—are constructed to minimize variations in flow-resistance-induced pressure drop from the system inlet to entrances to the flow channels. Because flow-driving pressure will be more uniform at the entrances to the flow channels, flow along the channels will be more uniform. Disclosed embodiments may be particularly suitable or advantageous for use in gas-exchange/artificial lung devices.

A gas permeable, liquid impermeable membrane for use with gas sensors consists of a film forming polymer which incorporates nanoparticles selected to improve one or more of the following: permeability to gases, to selectively regulate permeability of selected gases through the membrane, to inhibit microbial growth on the membrane. A capsule shaped container consists of wall material biocompatible with a mammal GI tract and adapted to protect the electronic and sensor devices in the capsule, which contains gas composition sensors, pressure and temperature sensors, a microcontroller, a power source and a wireless transmission device. The microprocessor receives data signals from the sensors and converts the signals into gas composition and concentration data and temperature and pressure data for transmission to an external computing device. The capsule wall incorporates gas permeable nano-composite membranes with embedded catalytic and nano void producing nanoparticles, enhancing the operation, selectivity and sensitivity of the gas sensors.

The gas separation method is executed under a condition in which a partial pressure of a first gas (G1) in a feed gas that contains at least mutually different gases being the first gas (GI), a second gas (G2) and a third gas (G3) becomes less than or equal to the total pressure of a permeate-side space (S2) of a gas separation membrane (30). The gas separation method includes a step of causing flow of a sweep gas that contains at least the third gas (G3) into the permeate-side space (S2) of the gas separation membrane (30) while supplying a feed gas to a feed-side space (S1) of the gas separation membrane (30). The permeation rate of the first gas (G1) in the gas separation membrane (30) is greater than the permeation rate of the second gas (G2).

The gas separation method is executed under a condition in which a partial pressure of a first gas (G1) in a feed gas that contains at least mutually different gases being the first gas (G1) and a second gas (G2) becomes less than or equal to a total pressure of a permeate-side space (S2) of a gas separation membrane (30). The gas separation method includes a step of causing flow of a sweep gas that contains at least a third gas (G3) being a different gas from the first gas (G1) and the second gas (G2) into the permeate-side space (S2) of the gas separation membrane (30) while supplying a feed gas to a feed-side space (S1) of the gas separation membrane (30). The permeation rate of the first gas (G1) in the gas separation membrane (30) is greater than the permeation rate respectively of the second gas (G2) and the third gas (G3).

Disclosed herein are asymmetric multilayer carbon molecular sieve (“CMS”) hollow fiber membranes and processes for preparing the membranes. The processes include simultaneously extruding a core dope containing a polymer and suitable nanoparticles, a sheath dope, and a bore fluid, followed by pyrolysis of the extruded fiber.

Prepare a carbon molecular sieve membrane from a polyimide (e.g., a 6FDA/BPDA-DAM polyimide) that has a glass transition temperature of at least 400° C. and includes a bridged phenyl compound for separation of hydrogen and ethylene from one another whether present as a pure mixture of hydrogen and ethylene or as components of a cracked gas. Preparation comprises two sequential steps a) and b). In step a), place a membrane fabricated from defect-free fibers of the polyimide in contact with an oxygen-containing atmosphere under conditions of time and temperature sufficient to produce a pre-oxidized and pre-carbonized polymeric membrane that is insoluble in hot (110 C) n-methylpyrolidone and at least substantially free of substructure collapse. In step b) pyrolyze the pre-oxidized and pre-carbonized membrane in the presence of a purge gas under conditions of time and temperature sufficient to yield a carbon molecular sieve membrane that has at least one of a hydrogen permeance and a hydrogen/ethylene selectivity greater than that of a carbon molecular sieve membrane prepared from the same membrane using only pyrolysis as in step b).