Fabrication of ZIF-8-NH2/Organosilica Hybrid Membranes for Pervaporation Desalination

Abstract

Industrial activities such as oil and gas drilling, power plant desulfurization and seawater desalination produce large amounts of high-salinity waste water. The effective treatment of the high-salinity waste water is the key to achieve zero liquid discharge. In the present study, ZIF-8-NH2/organosilica hybrid membranes were fabricated via the incorporation of ZIF-8-NH2 nanoparticles into BTESE-derived organosilica networks, using porous α-Al2O3 membranes as the supports. The as-prepared ZIF-8-NH2/BTESE hybrid membranes were applied to the desalination of high-salinity waste water by pervaporation. The effects of ZIF-8-NH2 content, feed temperature and feed concentration on desalination performances were systematically investigated. Compared with BTESE and ZIF-8/BTESE membranes, the amine-functionalized ZIF-8-NH2/BTESE hybrid membranes showed a simultaneous improvement in water permeance and salt rejection. In addition, the ZIF-8-NH2/BTESE hybrid membrane exhibited a high structural stability during the continuous pervaporation test up to 50 h, always delivering very high NaCl rejections of >99.95% and water permeances of >6.3×10-11 m3/(m2×s×Pa). Moreover, the NaCl rejection of the membrane was almost constant regardless of feed temperature and feed concentration, showing great promise as a highly efficient membrane for the application in the desalination of high-salinity water.