Condensation‐Assisted Separation of Alkanes by Silica Membranes with Wide Pore Size Distribution

Abstract

Abstract Purification of gases by membranes can provide enormous energy savings. Inorganic membranes offer good stability and regenerability, but large margin manufacturing is limited. Silica membranes are an exception since they can be produced by coating with molecular precursors. However, such membranes do not have a defined pore structure, which limits their applicability in mass separation. Nevertheless, it is possible to fill the pores of silica membranes with condensate of a component to be separated from gas mixtures. In this work, this applicability of a micro‐mesoporous silica membrane was demonstrated exemplarily by the separation of n ‐butane (C 4 ) from mixtures containing methane (C 1 ). The main result, which was supported by grand canonical Monte Carlo (GCMC) simulations, is that capillary condensation contributes significantly to the performance. The experimental results showed that the n ‐butane separation efficiency (permeate flux and separation selectivity) through the silica membrane under the condensation conditions is excellent and thus can serve as a model for similar separation tasks.