A composite polyamide reverse osmosis membrane comprising a polyamide layer; where the polyamide layer has a thickness in the range of 50-250 nm, and large open spaces (i.e., free volumes); where the open spaces are defined by a ratio of water flux, J.sub.w, (gfd) divided by the average surface roughness, Ra, (nm) of the polyamide layer; wherein the composite polyamide reverse osmosis membrane has the ratio of J.sub.w/Ra>0.35 gfd/nm when tested at 65 psi, using an aqueous solution containing 250 ppm of NaCl; and a microporous support with a thickness ranging from 100-150 μm. The present invention also relates to processes of fabricating the composite polyamide reverse osmosis membrane.

An electrochemical system utilizes an anion conducting layer disposed between an anode and a cathode for transporting a working fluid. The working fluid may include carbon dioxide that is dissolved in water and is partially converted to carbonic acid that is equilibrium with bicarbonate anion. An electrical potential across the anode and cathode creates a pH gradient that drives the bicarbonate anion across the anion conducting layer to the cathode, wherein it is reformed into carbon dioxide. Therefore, carbon dioxide is pumped across the anion conducting layer.

Disclosed are super-hydrophobic, super oleophilic membranes comprising a metal mesh comprising copper, a coating comprising a carbohydrate derivative, wherein the carbohydrate derivative is covalently or ionically bonded to a metal mesh surface and methods of preparation thereof. The disclosed membranes are useful for wastewater treatment in the oil industry, in particular for oil/water separation processes.

The disclosure provides a method for preparing a hollow fiber membrane by melt spinning-stretching and selective swelling, including: preparing a nascent hollow fiber by melt spinning in an inert gas protective atmosphere by using an amphiphilic block copolymer as a film forming material, and stretching the nascent hollow fiber in the cooling process, a stretch rate being controlled at 200-540 mm/min, and a stretch ratio being controlled at 150-600%; immersing the obtained hollow fiber in a swelling solvent, and treating the hollow fiber in a water bath at 65° C. for 1 h; and then transferring the hollow fiber into a long-chain alkane solvent, treating the hollow fiber at the same temperature for 1-12 h, and after the completion of the treatment, immediately taking out the hollow fiber and drying the hollow fiber to obtain the hollow fiber membrane with a bicontinuous porous structure. By combining the melt spinning-stretching and the selective swelling, the method of the disclosure can synchronously and continuously improve the permeability and selectivity of the hollow fiber membrane. The treatment in the long-chain alkane solvent can make the polar chain excessively enriched on the surface of the membrane migrate inward, thereby improving the performance of the hollow fiber membrane.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

A method for synthesizing a supported molecular sieve membrane by microwaves includes the steps of aging, heating and synthesizing. The aging step is to make a support in contact with a synthetic liquid at 25° C. to 70° C. for 10 hours to 24 hours; the heating step is to raise a temperature of an aged system from an aging temperature to a synthesis temperature within 1 minute to 10 minutes; and the synthesizing step is to synthesize at 80° C. to 120° C. for 2 minutes to 15 minutes. The steps of heating and synthesizing are powered by microwaves.

A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent and a solvent is provided. The dissolvable polyimide is represented by formula 1: ##STR00001## wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A′ is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1≤X≤0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A wet phase inversion process is performed on the polyimide membrane.

An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained. The asymmetric carbon membrane may be useful to separate gases such as olefins from their corresponding paraffins, hydrogen from syngas or cracked gas, natural gas or refinery gas, oxygen/nitrogen, or carbon dioxide and methane.

Water-filtration compositions, membranes, devices, and manufacturing processes including graphene oxide with hydrophilic functional groups. Disclosed are a composition comprising graphene oxide with an average particle diameter of no more than about 1 μm and has an oxygen atomic percentage of at least about 30%, a membrane comprising the composition, a water-permeable device comprising the membrane, a method of making the membrane using the composition, and several methods of generating the composition.

The invention provides a method of producing multi-walled carbon nanotube blended polyvinylidene fluoride (MWCNTs/PVDF) membranes for membrane distillation (MD) treatment of saline water using non-solvent induced phase separation (NIPS), said method including mixing two solvents with different solubility parameters and the use of a dual coagulation bath system to control the formation of membrane pore structures and enhance surface hydrophobicity whereby blended PVDF membranes are produced for application in MD processes.