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 poly-ethyleneimine (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 andMgCl(2) salts, and a water flux as high as 8 kg/m(2) h with a high salt rejection ( > 99.9%) was obtained for all the tested salts at various temperatures and feed concentrations.