Synthesis of a SAPO-34 membrane on macroporous supports for high permeance separation of a CO2/CH4 mixture

Abstract

Nowadays, purifying methane from a CO₂/CH₄ mixture is an important process for the efficiently use of fuel. The molecular sieve membrane is an efficient way for solving that problem due to its uniform pore size and high stability. Though the molecular sieve membrane has high selectivity for separation of a gas mixture, the relatively low permeance has limited its commercial application. In this work, we obtained a SAPO-34 membrane on the stainless-steel-net by seeded growth. A powder X-ray diffraction (PXRD) pattern and a scanning electron microscope (SEM) photograph show the membrane is highly oriented and continuous, which has originated from the self-assemble of the piece-like nanocrystals and the following hydrothermal treatment. The gas separation experiment shows this oriented membrane displays separation selectivity of about 9 and CO₂ permeance as high as 2.5 × 10⁻⁶ mol m⁻² s⁻¹Pa⁻¹. This highest CO₂ permeance, as far as we know, comes from the thin film grown on macroporous support for mixture separation. This result may have contribute to a commercial application in CO₂/CH₄ separation.