Preparation of ZIF-69 membranes for gasoline vapor recovery

The compact ZIF-69 membranes have been prepared by seeded growth method for the recovery of gasoline vapor which is a major challenge in the petrochemical industry. The membrane performances for separating N2/n-alkane mixtures at various operating conditions (e.g. trans-membrane pressure difference, operating temperature, feed concentration, and stage cut) were systematically investigated. The highest separation factor was 2.60 with the corresponding permeance of 5.02 × 10−8 mol/(m2 s Pa) for the N2/n-C6H14 model mixtures. Moreover, the effects of n-alkane components (n-C5H12, n-C6H14, and n-C7H16) on the separation performances were studied, and the separation factors followed α(N2/n-C7H16) > α(N2/n-C6H14) > α(N2/n-C5H12), due to the different adsorption capacities of n-alkanes on ZIF-69 materials. The present work demonstrates that the ZIF-69 membrane is a highly promising candidate for the application in gasoline vapor recovery.