Chabazite Zeolite SAPO-34 Membranes for He/CH₄ Separation

Abstract

Natural gas reservoirs are the most abundant source of helium, despite helium being present only in trace amounts. Membrane technology represents an appealing and potentially cost-effective approach to recover helium from natural gas, consisting mainly of methane. Herein, we demonstrate that chabazite zeolite SAPO-34 membranes can effectively separate equimolar helium/methane mixtures. SAPO-34 membranes displayed helium 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 through molecular sieving and diffusivity differences. The best SAPO-34 membrane surpassed the Robeson limit upper bound, making these membranes appealing for helium recovery from natural gas.