Condensability sieving porous coordination polymer membranes for preferential permeation of C1–C4 alkanes over H2

Abstract

Refinery gas contains abundant H2 and a small amount of C1–C4 hydrocarbons. Here, we propose a condensability sieving strategy to realize preferential permeation of hydrocarbons over H2 by developing halogen-induced porous coordination polymer (PCP) mixed matrix membranes (MMMs) that display condensability sieving gas transport. The 4-Cl-PCP, 5-Cl-PCP and 5-Br-PCP are synthesized by using Zr4+ and X-isophthalic acid (where X ​= ​4-Cl or 5-Cl or 5-Br) exhibit increased gas adsorption capacity with the increase in carbon number of the feed gas, but with almost no H2 adsorption. MMMs containing the PCPs with different charge distributions enhance condensability sieving selectivity and inhibit diffusion selectivity. The permeances of the MMMs originated from condensability sieving are consistent with the polarizability-dependent adsorption of the PCP. The selectivity of the obtained MMMs for n-C4H10/H2, C3H8/H2, C2H6/H2, and CH4/H2 achieve ∼40, ∼15, ∼5, and ∼2, respectively, exhibiting promising applications in refinery gas purification owing to their lower energy consumption compared with H2-preferential permeation membranes.

Keywords

• Condensability sieving
• Porous coordination polymer
• Gas separation membrane
• Hydrocarbon/hydrogen separation
• Mixed matrix membrane