A composite semipermeable membrane capable of forming, on a surface of a porous support in a highly reproducible manner, a separation layer that is extremely thin and that exhibits superior separability. It provides, on a surface of a porous support, a composite semipermeable membrane that has an organic/inorganic hybrid separation layer that is extremely thin and that exhibits superior separability. A method for manufacturing a composite semipermeable membrane includes forming, on a surface of a porous support, a separation layer containing a cross-linked condensate having a siloxane bond by bringing an organic solution that contains an organic silicon compound containing three or more reactive functional groups, each of which is at least one type selected from a hydrolyzable group and a hydroxyl group, into contact with water or an aqueous solution on the porous support, and by performing interfacial polycondensation of the organic silicon compound.

Provided are a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose retained in the porous membrane, in which the average pore size differs between two surfaces of the porous membrane, the hydroxyalkyl cellulose distributed in the thickness direction of the hydrophilic porous membrane exhibits two or more peaks of detection intensity in GPC, and the weight-average molecular weight Mw.sub.min of the peak that is detected latest among the above-mentioned peaks is less than 100,000; and a method for producing a hydrophilic porous membrane, the method including separately preparing a hydrophilizing liquid including a hydroxyalkyl cellulose having a smaller weight-average molecular weight and a hydrophilizing liquid including a hydroxyalkyl cellulose having a larger weight-average molecular weight, and applying each of the hydrophilizing liquids on two surfaces of the porous membrane or sequentially on one surface thereof.

A composite membrane of a special highly enhanced fluorine-containing proton or ion exchange membrane, a composite membrane electrode, a special highly enhanced fluorine-containing chlor-alkali battery membrane, a special release membrane and a preparation method thereof are provided. The composite membrane of the special highly enhanced fluorine-containing proton or ion exchange membrane comprises at least two layers of microporous reinforced membranes, where both sides of each layer of microporous reinforced membranes are filled with a fluorine-containing proton or ion exchange resin, the biaxial tensile strength of the composite membrane is greater than 40 MPa, the room temperature ionic conductivity is greater than 0.007 S/cm, the air permeability is extremely low, and the time required for 100 ml of air to pass through the composite membrane measured by Gurley densometer is more than 5 minutes.

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.

A bipolar membrane in which a cation-exchange membrane and an anion-exchange membrane are joined to each other, wherein a leakage ratio of gluconic acid at 60 C. is not more than 1.0%, and the cation-exchange membrane is supported by a polyolefin reinforcing member and, further, contains a polyvinyl chloride.

A filtering medium includes first and second porous membranes mainly composed of fluororesin, and a plurality of air permeable supports to support the first and second membranes. The second membrane is disposed downstream of the first membrane. When air containing polyalphaolefin particles with a count median diameter of 0.25 ?m is continuously passed through at a flow rate of 5.3 cm/sec and pressure loss is increased by 250 Pa, the first membrane has a dust retention amount larger than the second membrane. The filtering medium has a pressure loss of less than 200 Pa when air is passed through at a flow rate of 5.3 cm/sec. A collecting efficiency of NaCl particles with a particle diameter of 0.3 ?m is 99.97% or more when air containing the NaCl particles is passed through at a flow rate of 5.3 cm/sec. The dust retention amount is 25 g/m.sup.2 or more.

A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.

Mesoporous membranes have shown promising separation performance with a potential to lower the energy consumption, leading to a dramatic cost reduction. Recently, an extensive effort has been made on the design of membranes which brought a significant progress toward the synthesis of well-defined porous morphologies, most of which synthesized by surfactant-template methodology. Currently, the most well-designed state-of-the-art membranes using this technique are made from metals, polymers, carbon, silica, etc. In the present invention, we demonstrate mesoporous calcium-silicate particles having superior separation capacity and optimal permeability, thereby leading to reduced energy consumption for selective separation of gases/liquids and/or the combination thereof. We explore various methods to improve the calcium-silicate membranes properties by tuning pore density during the synthesis/aging process, while favoring the formation of uniformly distributed nanopores. Lowering particle density by controlling calcium to silicon ratio along with optimizing the surface area are essential in achieving our objective.

A method for manufacturing a self-healing hydrogel-filled separation membrane for water treatment includes soaking a porous support comprising pores in a monomer solution to fill the pores with the solution, removing the excessively filled monomer solution from the porous support, and forming a hydrogel in the pores by crosslinking the monomer. The separation membrane does not require an additional repair process when damage occurs to the separation membrane and can exhibit superior self-healing effect and physical stability.

Cation exchange membranes and materials including silica-based ceramics, and associated methods, are provided. In some aspects, cation exchange membranes that include a silica-based ceramic that forms a coating on and/or within a porous support membrane are described. The cation exchange membranes and materials may have certain structural or chemical attributes (e.g., pore size/distribution, chemical functionalization) that, alone or in combination, can result in advantageous performance characteristics in any of a variety of applications for which selective transport of positively charged ions through membranes/materials is desired. In some embodiments, the silica-based ceramic contains relatively small pores (e.g., substantially spherical nanopores) that may contribute to some such advantageous properties. In some embodiments, the cation exchange membrane or material includes sulfonate and/or sulfonic acid groups covalently bound to the silica-based ceramic.