Tailoring the microstructure of poly(vinyl alcohol)-intercalated graphene oxide membranes for enhanced desalination performance of high-salinity water by pervaporation

Abstract

Laminated graphene oxide (GO) membrane is promising in desalination owing to allowing unimpeded water permeation through the tunable interlayer nanochannels. To achieve highly efficient and stable desalination performance of GO membrane is crucial. Herein, GO membranes intercalated and cross-linked by poly(vinyl alcohol) (PVA) and supported on cellulose microfiltration membrane were fabricated via pressure-assisted filtration method for application in pervaporation desalination of high-salinity water. The interlayer spacing and microstructure of the GO membranes is successfully tailored by searching for appropriate intercalated PVA amount for cross-linking. The nanochannel microstructure was probed and its effect on the mass transport property of the membranes was revealed. The results show that the permeability of the GO-PVA membranes was dependent on both d-spacing and 3D cross-linking network between GO nanosheets. The optimized GO-PVA membranes displayed an outstanding water flux of over 98 kg/m2h and 99.99% salt rejection in desalinating 10 wt% NaCl solution at 85 °C. Benefiting from the formation of brick-mortar structure of GO layers with high adhesion strength provided by the cross-linked PVA chains with GO nanosheets, the membranes could toughly resist sonication destruction test and exhibited stable and reliable performance in pervaporation. The study helps understanding and optimizing the constitution of inner structure of intercalated GO membrane for efficient separation.