Abstract: A gas separation member comprises a porous substrate, e.g., a membrane or a wall, and a polymer film deposited by plasma polymerization on the surface of the substrate and composed of at least two layers, i.e., a first layer contiguous with the substrate and a second layer superimposed on the first layer. The polymer film of the first layer possesses a uniform chemical composition or chemical structure in the direction of film thickness, while the polymer film of the second layer has a chemical composition or chemical structure which changes continuously or stepwise in the direction of film thickness. The gas separation member combines high gas separation factor and a high gas permeation rate, permitting separation of a specific gas in a concentrated form from a mixed gas. It also excels in weatherability.

Abstract: This invention provides an apparatus for separating condensable gas, which is provided with, as a membrane for separating condensable gas, an inorganic porous membrane which has a layer having a multiplicity of micropores communicating in the thickness direction of the membrane and having a pore radius, as determined by the nitrogen absorption method, of up to 50 .ANG., and preferably up to 20 .ANG., and which has an affinity for said condensable gas or is hydrophilic. This apparatus yields highly selective permeation of condensable gas, such as water vapor or organic gases.

Abstract: There is provided a method for preparation of porous glass films, preferably in the form of a hollow filament, comprising heating glass films, formed from sodium borosilicate glass having a composition which can be phase-separated by heat-treatment into a soft phase easily eluted with a hot acid solution and a hard phase not easily eluted with the same solution, to separate the glass phase into the two phases and then subjecting the glass film to plasma etching in an atmosphere containing gaseous fluorine-containing compound(s) before or after acid elution of the soft phase. The thus obtained porous glass films have a uniform pore diameter and smooth surfaces and can be used as a variety of separating membranes.

Abstract: Method and apparatus for determination of the concentration of a component in a solution, such as ethyl alcohol in gasohol, acetic acid in hexane-acetic acid solution, or the like. Such determination is made with ease and accuracy based on a rate of pressure change caused in a closed container due to mass transfer occurring between two liquids through porous material.

Abstract: A gas separating member of the present invention comprises a porous substrate in the form of a film, wall or hollow fiber and a polymer film formed on a surface of the substrate by plasma polymerization. The gas separation factor (O.sub.2 /N.sub.2) ranges from 2.3 to 3.9 with the corresponding gas permeability ranging from 12 to 0.16 liter/min. m.sup.2 atm. pres.-air.A modified gas separating member of the present invention, which comprises a porous substrate in the aforementioned form and two polymer films formed on a surface of the substrate by plasma polymerization, has the gas separation factor (He/H.sub.2) ranging from 14 to 45.