Surface plasma etching of ZIF-8/PEBA mixed matrix membranes for enhanced ethanol permselective pervaporation

For various molecular separations, mixed matrix membranes (MMMs) shown exceptional stability and great performance. Given the density disparity between the fillers and the polymer solution, the polymer matrix tends to enrich on the upper surface domain of MMMs, impairing the membrane performance. In this study, the long-distance and dynamic low-temperature (LDDLT) plasma treatment was used to etch the asymmetric surface of ZIF-8/PEBA MMMs for improved ethanol permselective pervaporation. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to determine the crystal structure, morphology, and chemical composition of the membranes. The separation layer's thickness decreased and the amount of ZIF-8 on the separation layer raised after the LDDLT plasma etching. For separating 3 wt% ethanol aqueous solution at 40 ^oC, the etched ZIF-8/PEBA MMMs exhibited a good permeation flux of 1320 g·m^-2·h^-1 and a separation factor of 5.1. These results reveal that plasma etching will precisely adjust the surface of MMMs for better membrane performance.