Large-scale preparation of UV photo-crosslinked composite membrane with high pervaporation desalination properties and excellent fouling resistance

Abstract

In this study, we developed a high-performance composite membrane with rapid cross-linking and large-scale technology for PV desalination. Some strategies were adopted to achieve this purpose. First, photo cross-linking was used to shorten the cross-linking time of PVA within 60 s. Second, a PTFE microfiltration membrane was utilized as the substrate that mitigated the transport resistance of the supporting layer. Third, an large-scale spray-coating device was built-up which completed the amplification preparation of composite PV membrane. Finally, ZIF-8 nano-particle was introduced into the PVA layer that increased the free volume and amorphous region of PVA, enhancing the water flux of membrane. When desalted a 3.5 wt% NaCl solution at 80 °C, a water flux of 307.58 ± 15.09 kg/m2·h was achieved for the PVA/ZIF-8/PTFE composite membrane. To better reflect the membrane performance, the permeance of PVA/ZIF-8/PTFE membrane was also calculated, which was reached to 674.37 kg/m2 h bar, exceeding 18.4% than the highest reported property of PVA/PAN nanofiber membrane (569.55 kg/m2 h bar). In addition, the composite membrane showed stable water flux and salt rejection when treating highly concentrated brine solution containing organic pollutant. When desalinated a 10 wt% NaCl solution with 1 wt% HA at 80 °C, the PVA/ZIF-8/PTFE membrane produced water with low conductivity of 15.78 μs/cm and a high water flux of 129.95 kg/m2·h in a period of 180 min.