Graphene oxide-based layer-by-layer nanofiltration membrane using inkjet printing for desalination

Nanofiltration (NF) membrane was prepared using inkjet printing assisted layer-by-layer (LBL) assembly of polyethylenimine (PEI) and graphene oxide (GO) on a polyketone (PK) substrate surface then cross-linked with glutaraldehyde (GA). The membrane characterizations confirmed the successful formation of cross-linked multilayer PEI/GO membranes. PEI/GO membrane prepared with three bilayer numbers was found to have the optimal separation performances with the highest permeability and selectivity. The NF performances of the (PEI/GO)3 membrane were evaluated using different molecular weight dyes and different salts. Results revealed that the (PEI/GO)3 membrane exhibited rejections of 99.9 %, 98.1 %, 94.7 %, and 85.1 % for Rose Bengal (RB), Brilliant blue R (BBR), Eosin Y (EY), and methylene blue (MB), respectively. The selectivity of (PEI/GO)3 membrane for salts followed a sequence of MgSO4 > Na2SO4 > MgCl2 > NaCl. The influences of PEI and GO concentrations on membrane performances were investigated. The stability of (PEI/GO)3 was evaluated by chlorination test and long-term filtration test. The (PEI/GO)3 membrane exhibited desirable chlorine resistant property and excellent long-term filtration stability. Overall, our work provided new ways for the preparation of LBL membranes with good NF performances and excellent stability property.