Preparation of ZIF‐8—Pebax 1657 nanocomposite membranes for n‐hexane/nitrogen separation as a representative of gasoline vapour recovery

Abstract

AbstractGasoline vapour emission is hazardous to both human health and the ecosystem and also results in capital loss, altogether revealing the necessity of its recovery. Some ZIF‐8–Pebax flat nanocomposite membranes were fabricated by the method of solution casting and used for gasoline vapour recovery as represented by n‐hexane vapour/nitrogen separation. Microporous ZIF‐8 nanoparticles were synthesized and characterized by Fourier transform infrared (FTIR) and Brunauer–Emmett–Teller (BET) analysis. BET results revealed specific surface area, total volume, and average pore diameter of 940.8 m2 · g−1, 0.36 cm3 · g−1, and 1.54 nm, respectively. Pure nitrogen and n‐hexane vapour/nitrogen gas mixture permeabilities were measured through the membranes. There was a decline in both permeation rate and selectivity up to 5.0 wt.% of ZIF‐8 loading and the next increment at their higher loadings to considerably more values that the pristine membrane. The maximum n‐hexane vapour permeability and selectivity at 10.0 wt.% loading of ZIF‐8 nanoparticles, the feed flow rate of 173 mL · min−1, and permeate side pressure of −200 mbar were observed as 280.1 Barrer and 106.7, respectively, revealing 60.0% and 36.9% improvements compared with those of the pristine Pebax membrane. Observed 86%–92% n‐hexane vapour recovery approves the successful application of the ZIF‐8–Pebax nanocomposite membranes for n‐hexane/nitrogen separation. The long‐term separation performance of 5.0 wt.% ZIF‐8 loaded nanocomposite membrane was improved by 76.5% compared with that of the pristine Pebax membrane.