Nanoporous ceramic membranes modified by carbon nanotubes used to separate gaseous mixtures

Abstract

Studies devoted to the development of ceramic membranes, which are capable of separating gaseous mixtures, first and foremost of H₂–CH₄, are presented in this paper. The membranes from alumina prepared on the basis of thermochemical activation (TCA) products of gibbsite contain a considerable amount of macropores and possess low selectivity in gas separation. In order to reduce the contribution of macropores to the porous structure of membranes, we have introduced glass additives, which sinter more easily than alumina. Tests of the samples, in which a part of TCA product is replaced by glass, have shown that the factor of separation for gaseous mixtures of H₂–CH₄ increases to 2.2. In the next part of this work, we synthesize the ceramic membranes, which were modified by carbon nanotubes (CNTs) with an external diameter of 3–5 nm. It is shown that when CNTs are introduced into the composition of a ceramic membrane, the selectivity in the separation of gaseous mixtures of H₂–CH₄ increases to 2.4.