Chabazite Zeolite SAPO-34 Membranes for He/CH₄ Separation

Abstract

Natural gas reservoirs\nare the most abundant source of helium,\ndespite helium being present only in trace amounts. Membrane technology\nrepresents an appealing and potentially cost-effective approach to\nrecover helium from natural gas, consisting mainly of methane. Herein,\nwe demonstrate that chabazite zeolite SAPO-34 membranes can effectively\nseparate equimolar helium/methane mixtures. SAPO-34 membranes displayed\nhelium permeance as high as 2.28 × 10^–7 mol/(m² s Pa) and separation selectivity as high as 13.8 for He/CH₄ mixtures. The separation of this binary mixture was favored\nthrough molecular sieving and diffusivity differences. The best SAPO-34\nmembrane surpassed the Robeson limit upper bound, making these membranes\nappealing for helium recovery from natural gas.