Microwave synthesis of NaA zeolite membranes on coarse macroporous α-Al2O3 tubes for desalination

Abstract

Abstract Membrane-based desalination technology is progressing continuously to meet world fresh water supply. However, selection of suitable membrane materials for this technology is still a challenge. Zeolite membranes are one of the promising candidates for molecular separations, but due to low water flux their applications in desalination technology are very limited. In this work, NaA zeolite membranes on coarse macroporous α-Al2O3 tubes synthesized by microwave-assisted heating method were explored for desalination by pervaporation aiming at improving the water flux. Under the optimized synthesis conditions, the fabricated membrane showed the highest water flux of 9.58 kg/(m2·h) with ion rejection (>99.9%) for the separation of 3.5 wt % (0.6 mol/L) NaCl aqueous solution at 348 K. The effect of operating temperature, feed concentration, and different saline solutions on the desalination performance of the membranes were also investigated in detail. The synthesized NaA zeolite membrane delivered excellent separation performance with stable water flux of 8.24 kg/(m2·h), and total ion rejection (>99.9%) within the investigated period of 72 h for simulated seawater desalination, demonstrating the NaA zeolite membranes would be potential candidates for desalination.