A gas detector comprises a gas detection unit and a filter introducing surrounding atmosphere to the gas detection unit. The filter comprises a gas-permeable organic polymer membrane having an acidic group or a basic group.

Disclosed herein are polycationic microfibers comprising a high-aspect-ratio polymeric core, the polymeric core comprising a blend of a first core polymer and a second core polymer, and a polycationic polymer immobilized on the surface of the polymeric core. The polycationic microfibers are capable of sequestering or clearing nucleic acids, proteins, biomolecular complexes, exosomes, or microparticles from solutions and samples and may be formed into filters or integrated into filtration apparatuses. Also disclosed are methods for sequestering or clearing solutes from solutions and fluids, methods for the treatment of diseases or conditions, and methods for the prevention of diseases or conditions.

A method of providing fouling control in a membrane system includes generating a sacrificial protective layer (PL) on a surface of a membrane of the membrane system by coating the membrane with at least one polyelectrolyte layer, removing the PL from the membrane with a saline solution after the PL is fouled, and regenerating a new PL on the surface of the membrane by coating the membrane with at least one polyelectrolyte layer such that foulants present in a feed water accumulate on the PL, rather than on the membrane. The method further comprises one or more of the following: a) the saline solution is being applied with a shear force; b) the pH value of the saline solution is substantially neutral; c) the saline solution is non-toxic; d) the PL is removed without a backwash; e) the PL is not an active filtration layer, wherein a pore size of the PL is greater than a pore size of the membrane; and/or f) the PL is not disposed in pores of the membrane.

An ion exchange membrane material is composed of a crosslinked polymer network including a first poly(styrene-b-ethylene-r-butylene-b-styrene) triblock copolymer (SEBS), and second SEBS, and a linker crosslinking the first SEBS and the second SEBS. At least one phenyl group from the first SEBS and the second SEBS is functionalized with an alkyl group, and the carbon at the benzylic position of these alkyl groups is saturated with at least two additional alkyl groups. The linker is a diamine bound to the alkyl functional groups. The ion exchange membrane material is made via a substantially simultaneous quaternization and crosslinking reaction between the diamine linker and SEBS functionalized with alkyl halide groups. Increasing concentration of crosslinker in produces membranes with reduced water uptake, leading to an expectation of enhanced stability under hydrated conditions and greater durability. Advantageously, this reduction in water uptake came with little change to ion exchange capacity.

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. The selective polymer layer can comprise an oxidatively stable carrier and a borate additive dispersed within a hydrophilic polymer matrix. The oxidatively stable carrier can comprise a quaternaryammonium hydroxide carrier (e.g., a mobile carrier such as a small molecule quaternaryammonium hydroxide, or a fixed carrier such as a quaternaryammonium hydroxide-containing polymer), a quaternaryammonium fluoride carrier (e.g., a mobile carrier such as a small molecule quaternaryammonium fluoride, or a fixed carrier such as a quaternaryammonium fluoride-containing polymer), or a combination thereof. The borate additive can comprise a borate salt, a boric acid, or a combination thereof. 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 bipolar membrane comprising a cation exchange mat of one or more cation exchange polymers, an anion exchange mat of one or more anion exchange polymers, and an internal 3D bipolar interface, disposed between the cation and anion exchange layers, including a mixture of at least one cation exchange polymer and at least one anion exchange polymer, such that an interface of the at least one cation exchange polymer and the at least one anion exchange polymer is the internal 3D bipolar interface that has a large area, and the at least one cation exchange polymer in the 3D bipolar interface is connected to the one or more cation exchange polymers of the cation exchange layer, and the at least one anion exchange polymer in the 3D bipolar interface is connected to the one or more anion exchange polymers of the anion exchange layer.

A separation membrane (10) of the present disclosure includes: a separation functional layer (30) composed of a polyamide containing, as a monomer unit, at least one selected from the group consisting of piperazine and a piperazine derivative; and a coating (40) covering the separation functional layer (30) and containing a polymer having a repeating unit represented by the following formula (1). In the formula (1), N.sup.+ is a nitrogen atom constituting a quaternary ammonium cation, and R.sup.1 and R.sup.2 are each independently a substituent containing a carbon atom bonded to the nitrogen atom.

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An electrolyte membrane is prepared from a liquid composition comprising at least one member selected from the group consisting of trivalent cerium, tetravalent cerium, bivalent manganese and trivalent manganese; and a polymer with a cation-exchange group. The liquid composition is preferably one containing water, a carbonate of cerium or manganese, and a polymer with a cation-exchange group, and a cast film thereof is used as an electrolyte membrane to prepare a membrane-electrode assembly. The present invention successfully provides a membrane-electrode assembly for polymer electrolyte fuel cells being capable of generating the electric power in high energy efficiency, having high power generation performance regardless of the dew point of the feed gas, and being capable of stably generating the electric power over a long period of time.

The present invention relates to a method for the production of a positively charged membrane. Furthermore the present invention relates to a positively charged membrane obtainable by the methods of present invention and the use of these positively charged membranes.

There is provided a thin film composite (TFC) membrane comprising a support layer and a selective layer, formed of a cross-linked polyamide comprising Na.sup.+-functionalised carbon quantum dots (NaCQD), on a surface of the support layer. There is also provided a method of forming the TFC membrane.