Toxic metals removal by new membranes based on graphene oxide and a cationic Polymer: Influence of chemical and morphological aspects

• hPAN/PVPI/GO membranes were efficient for removing multiple toxic metals. • hPAN/PVPI/GO membrane expressed removal selectivity for the Cu 2+ , Cr 3+ and Pb 2+ . • Coordination complexes govern the adsorptive processes. • hPAN/PVPI/GO membrane outperforms other materials in removing toxic metals. Polymeric nanocomposite membranes are emerging as promising materials for water treatment. To explore the potential of new materials for the removal of toxic metals from water, novel hydrolyzed polyacrylonitrile (hPAN) membranes coated with graphene oxide (GO) by layer-by-layer (LbL) assembly, using poly(4-vinylpyridinium iodide) (PVPI) as binding agent, were prepared, characterized, and applied to remove toxic metals in multicomponent systems. The addition of PVPI and GO to the hPAN membrane modified the surface roughness, hydrophilicity, layers morphology, and introduced oxygenated functions to the pristine polymer. These features enhanced the material’s selectivity for Cu 2+ , Cr 3+ , and Pb 2+ , over Ni 2+ and Cd 2+ , with removal efficiencies of 50.4 %, 64.3 %, and 99.9 % in batch assays, at the concentrations of 4.1, 12.2, and 10.2 mg L −1 , and selectivities relative to Cd 2+ of 13.7, 24.2 and 13450, respectively. Governed by the formation of coordination complexes, the increment of nanocomposite layers adhered to the polymer improved the adsorbent/adsorbate interactions. The efficiency of hPAN membrane with three PVPI/GO bilayers in removing metal ions was attested in comparison to other polymer nanocomposite membranes from literature.