Assessment of the Effect of Modification of ZIF-8 Nanoparticles by the CTAB Cationic Surfactant on the Performance of ZIF-8/PVA Mixed Matrix Membranes in Pervaporation Dehydration of Isopropanol

Dehydration of organic compounds to achieve highly pure and valuable products constitutes one of the most important chapters in the chemical industry. In the present study, mixed matrix membranes (MMMs) including poly(vinyl alcohol) and modified ZIF-8 mineral phase by cationic surfactant of CTAB, were evaluated in terms of their performance in dehydration of isopropanol in the pervaporation process. The prepared nanocrystals and membranes were characterized by Fourier-transform infrared spectroscopy, gas adsorption-desorption, Thermal gravimetric analysis, X-ray crystallography, and Field emission scanning electron microscopy. Microscopic images showed that the presence of CTAB changed the morphology of ZIF-8 nanoparticles from rhombic dodecahedral to truncated rhombic dodecahedral. The effect of unmodified ZIF-8 loading from 1 to 10 wt.% in membranes on the separation performance of isopropanol feed containing 10 wt.% water at 30 °C was investigated. Then, based on the optimal loading, the separation performance of MMM containing 5 wt.% of surfactant-modified nanoparticles was evaluated which proved success in achieving better performance in comparison with pure polymer membranes and MMM containing unmodified nanoparticles by presenting the permeation flux of 0.942 kg/m2h and separation factor of 174.