Spray-coated tough thin film composite membrane for pervaporation desalination

Water flux of pervaporation (PV) desalination membranes can be increased by reducing thickness of the selective layer and/or reducing the resistance of the support layer. However, low resistant support layer typically has large surface pores that requires a thick selective layer to avoid fracture. To solve this problem, we used poly(acrylic acid-co-2-acrylamido-2-methyl propane sulfonic acid) (P(AA-AMPS)) to crosslink PVA to improve the mechanical property of the coating layer. The PVA layer was deposited on to a highly porous PTFE substrate via spray-coating. By optimizing the spray-coating conditions, a thin and defect-free P(AA-AMPS) crosslinked PVA/PTFE composite membrane with a selective layer thickness of 1.1 mu m was prepared. The water flux of the composite membrane reached to 256.6 +/- 31.3 kg/(m(2) h) at 75 degrees C with a NaCl rejection rate over 99.9% when desalinating a 3.5 wt.% NaCl solution. The membrane flux is higher than all reported PV desalination membranes. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

A thin composite membrane of crosslinked PVA/PTFE with a thickness of 1.1 μm was successfully prepared, achieving high water flux and high salt rejection rate.