A method for increasing the thickness of a sheet of CNTs (146, 147, 246, 346), comprising: providing a wet sheet of CNTs, wherein the sheet of CNTs is either a continuous sheet of CNTs or a portion of sheet of CNTs, wherein the wet sheet of CNTs is the result of applying a process for manufacturing a sheet of CNTs; separating the wet sheet of CNTs from any filter or support element; drying the wet sheet of CNTs (146, 147, 246, 346) by applying heat (15, 25, 35) from a heat source (12, 22, 32). A method for manufacturing a continuous sheet of CNTs, comprising: in a container (41) filled with a liquid solution (42) comprising CNTs at certain concentration, submerging a vacuum tank (43) having a lower surface forming a grillage; moving an elongated filtering membrane (44) along the lower surface of the vacuum tank (43) while vacuum is applied on the elongated filtering membrane (44) in such a way that in the surface of the filtering membrane (44) opposed to the surface in contact with the lower surface of the vacuum tank (43) CNTs are deposited forming a continuous sheet of CNTs (45) of constant thickness; taking the filtering membrane (44) together with the continuous sheet of CNTs (45) out of the container (41); washing the continuous sheet of CNTs (55) disposed on the filtering membrane or on a support element (54) in a second container (51) filled with cleaning solution (52); taking the continuous sheet of CNTs (55) together with the filtering membrane or the support element (54) out of the second container (51); separating the continuous sheet of CNTs (55) from the filtering membrane or the support element (54); drying the continuous sheet of CNTs (55) by applying the method for increasing the thickness of a sheet of CNTs.

A reverse osmosis composite membrane includes: a porous support; and a reverse osmosis membrane arranged on the porous support and containing a crosslinked polyamide and carbon nanotubes. The reverse osmosis membrane contains the carbon nanotubes that are disentangled in the crosslinked polyamide. A distribution of closest distances between the carbon nanotubes in the reverse osmosis membrane has a peak that is within a range of a thickness of the reverse osmosis membrane, and a half width of the peak is equal to or less than the thickness of the reverse osmosis membrane.

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.

Nano filtering and pumping systems and methods of use thereof for nanoscale gaseous materials by utilizing materials having nanosized perforations through the materials. The perforations generally have an inner diameter similar to that of nanotubes, and in some embodiments, carbon nanotubes are disposed within the perforations. Such materials can partially organize molecules in random motion to move either some selectively or all of them, to create pressure differences and hence motive forces, or cause air flow into pressurized area. Because air is a cloud of particles separated by vacuum, the systems and method in air can be used to create motive force pushing any form of vehicle, lifting force for any form of air vehicle, air compression, power source for any form of machine, conveyor or generator, using the solar energy stored in the air in the form of heat, 24 hours a day, worldwide.

Membranes, methods of making the membranes, and methods of using the membranes are described herein. The membranes can comprise a support layer, and a selective polymer layer disposed on the support layer. In some cases, the support layer can comprise a gas permeable polymer and hydrophilic additive dispersed within the gas permeable polymer. In some cases, the selective polymer layer can comprise a selective polymer matrix and carbon nanotubes dispersed within the selective polymer matrix. The membranes can exhibit selective permeability to gases. As such, the membranes can be for the selective removal of carbon dioxide and/or hydrogen sulfide from hydrogen and/or nitrogen.

A method for purifying dye-containing wastewater based on a porous-polymer-modified metal carbon nanotube membrane includes: (1) preparing the porous-polymer-modified metal carbon nanotube membrane; and (2) passing the dye-containing wastewater through the porous-polymer-modified metal carbon nanotube membrane to remove dyes in the dye-containing wastewater. A device for purifying dye-containing wastewater is also disclosed. The device includes the porous-polymer-based metal carbon nanotube membrane.

The embodiments of the present disclosure relate to a method and apparatus for producing a carbon nanomaterial product (CNM) product that may comprise carbon nanotubes and various other allotropes of nanocarbon. The method and apparatus employ a consumable carbon dioxide (CO.sub.2) and a renewable carbonate electrolyte as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, operational conditions of the electrolysis reaction may be varied in order to produce the CNM product with a greater incidence of a desired allotrope of nanocarbon or a desired combination of two or more allotropes.

Disclosed herein is a complex generator including a hydrophilic fiber membrane coated with an adsorption material. Electrical energy is generated in such a manner that the adsorption material is adsorbed onto a polar solvent in some region of the hydrophilic fiber membrane by asymmetrical wetting of the polar solvent for the hydrophilic fiber membrane.

Carbon nanotube membranes that are flexible, non-fragile, stable at high temperatures, superhydrophobic, have submicrometer openings, and are resistant to delamination and corrosive conditions are provided. The carbon nanotube membranes comprise carbon nanotubes grown on a microporous, metal substrate, e.g. silver, quartz fiber filter, and HAST. Methods of fabricating the carbon nanotubes are also provided.

Membranes of the present disclosure possess very thin barrier layers, with high selectivity, high throughput, low fouling, and are long lasting. The membranes include graphene and/or graphene oxide barrier layers on a nanofibrous supporting scaffold. Methods for forming these membranes, as well as uses thereof, are also provided. In embodiments, an article of the present disclosure includes a nanofibrous scaffold; at least a first layer of nanoporous graphene, nanoporous graphene oxide, or combinations thereof on at least a portion of a surface of the nanofibrous scaffold; an additive such as crosslinking agents and/or particles on an outer surface of the at least first layer of nanoporous graphene, nanoporous graphene oxide, or combinations thereof.