Electrospray fabrication of anti-fouling nanocellulose desalination membrane with high flux

Abstract

Cellulose acetate (CA) desalination membranes encounter poor fouling resistance and water permeability, which can be mitigated by modifying their surfaces. Herein, we demonstrate highly controllable membrane porosity and thickness by introducing electrospray-mediated coating of cellulose nanocrystals (CNCs). The results revealed that due to the increased porosity from CNC plasticizing effect, the pure water permeability coefficient reached as high as 7.89 L m−2 h−1 bar−1 with one electrospray scan of 0.50% w/v CNC, while retaining above 80% ion rejection efficiencies (Na+, Mg2+, Cl−, and SO42−) against brackish water. The hydrophilic CNC coordinated the preparation of a low viscoelastic and swollen active layer associated with improved fouling resistance, remarkably achieving as high as 96.3% flux recovery and 88.1% reduction in bacterial colonization with 0.50% CNC-coated CA membrane. The excellent desalination performance of CNC electrospray-coated membranes was found to be comparatively higher than any other CA membranes reported in literature. Therefore, this study aims to provide future guidelines on how to effectively improve antifouling and water flux properties using electrospray technique and CNC nanofillers.