Layer-by-layer assembly of polyethyleneimine/graphene oxide membranes for desalination of high-salinity water via pervaporation

This study reports on surface modification of thin-film-composite (TFC) polyamide membranes for desalination of high-salinity water via pervaporation. The membrane modification involves surface treatment of the polyamide membrane with chlorine, followed by layer-by-layer (LbL) deposition of positively charged polyethyleneimine (PEI) and negatively charged graphene oxide (GO). It was shown that the controlled membrane chlorination significantly increased water permeability and incorporating PEI and GO to the chlorine-treated polyamide membrane improved the salt rejection. The pure water flux through the PEI/GO LbL membrane was two times higher than that through the original membrane. The PEI/GO LbL membrane was tested for desalination of aqueous solutions containing NaCl, Na2SO4, MgSO4 andMgCl2 salts, and a water flux as high as 8 kg/m2h with a high salt rejection (>99.9%) was obtained for all the tested salts at various temperatures and feed concentrations.