SAPO-34 membranes for xenon capture from air

Capturing Xe from gas mixtures represents one of the most challenging molecular gas separations. In this communication, we demonstrate the ability of a zeolite membrane, denoted as SAPO-34, to effectively capture Xe from air. Specifically, SAPO-34 membranes showed air permeances as high as 2.3x10(-7) mol/m(2) s Pa (690 GPU) and separation selectivities as high as 30.1 for a molar feed of 9:1 air/Xe. Molecular sieving, competitive adsorption, and diffusivity differences played a critical role in the overall separation performance. Membranes were air selective due to favorable molecular sieving and differences in diffusivity between gases present in the air mixture and Xe. Molecular sieving and diffusivity differences were identified as the dominant separation mechanisms. The high air permeances and separation selectivities make these membranes highly appealing as a potentially less energy intensive alternative to cryogenic distillation, the benchmark technology used to separate these gases.