A nanofiltration membrane prepared by PDA-C3N4 for removal of divalent ions

In this study, a positively charged nanofiltration (NF) membrane was prepared by interfacial polymerization for separation of divalent cations, whereby a nanomaterial (modified graphitic carbon nitride (g-C 3 N 4 ) with poly(dopamine), PDA-C 3 N 4 ) was incorporated into the active layer of the NF membrane. PDA-C 3 N 4 sheets were synthesized from g-C 3 N 4 sheets prepared by thermal oxidation of melamine, and the preparation conditions of NF membrane were also optimized. The results show that the roughness of PDA-C 3 N 4 embedded NF membrane decreases, and the hydrophilicity and the permeation increase. The membrane also shows high rejection for divalent cations (Mg 2+ , Ca 2+ , Ba 2+ , Cu 2+ and Zn 2+ ) but low rejection (36.8%) for monovalent cation (Li + ), as well as good fouling resistance performance. The fabricated membrane has the potential for treatment of industrial wastewater.