Separation of olefin and paraffin is of great industrial importance. Membrane separation is an attractive energy efficient alternative which can replace expensive cryogenic distillation process. Several polymeric membranes have been reported to separate propylene from propane, but these membranes have issues with instability and poor performances. Zeolite membranes are robust, stable, and reported to be effective for fluid separation. The flux of unsaturated hydrocarbon through zeolite membrane is greater compared to saturated hydrocarbon due to stronger electrostatic interaction between the intra-zeolitic cation and double bond of unsaturated hydrocarbon. We adopted a novel rapid synthesis method to develop thin dense film FAU membranes within a porous polymer support. We propose that the selectivity of zeolite membrane for olefins can be improved by incorporating transition metal Ag (I) into zeolite microstructure. Ag (I) can complex with olefins via π-complexation leading to selective olefin transport, and the process is reversible. Ag-zeolite membrane (Ag-ZM) was prepared by ion-exchanging Ag (I) salts into zeolite membrane. PDMS (polydimethylsiloxane) was used to coat the membrane before transport measurements. Zeolite membranes (ZM) were tested at different temperature with 50/50 mixture of propane (PP) and propylene (PY). We found that Ag-ZM are better for PP and PY separation compared to ZM with higher PY selectivity. The best result showed that ZM had selectivity (PY/PP) of 1.2 with permeance 876 GPU at room temperature and increased to 1.8 with permeance of 1296 GPU at 75<sup>o</sup>C. Ag-ZM had selectivity of 1.3 with 164 GPU at room temperature and increased to 3.5 with permeance of 336 GPU at 75 <sup>o</sup>C.

Fabrication of zeolite membranes for propylene/propane separation

253rd National Meeting (2017)

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