Journal of the Chemical Society Faraday Transactions 1 Physical Chemistry in Condensed Phases · 1973 · 62 citations · 0 references
EngineeringChemical EngineeringMaterials ScienceMembrane ScienceSeparation ProcessesTransport PhenomenaGas Separation MembranesGas TransferMembrane FiltrationMembrane MaterialsMembrane PermeabilityMembrane ThermodynamicsBinary MixturesFractionationGas FlowGas PermeationGas Transport PropertiesMicroporous MembranesSemipermeable MembranesSteady-state Flow
A study has been made of steady-state flow of the single species He, H2, D2, N2 and NH3, and of the binary mixtures H2+ N2, He + NH3, H2+ NH3 and N2+ NH3 through a microporous membrane of high area compressed carbon powder. For the weakly sorbed species (He, H2, D2, N2) the permeability, K, was independent of pressure and hence of amount sorbed and isotherm curvature. With the strongly sorbed ammonia K increased with pressure and, at lower temperatures, reached a maximum and then rapidly declined. Experiments with mixtures of ammonia and a weakly sorbed gas showed that blockage of gas phase flow by the sorbed ammonia could be severe. Under appropriate conditions this resulted in extremely high fractionation factors approaching those expected for an ideal semipermeable membrane. Ammonia permeated rapidly but the weakly sorbed gases were retained on the high pressure side of the membrane.