A novel free-standing polyvinyl butyral-polyacrylonitrile/ZnAl-layered double hydroxide nanocomposite membrane for enhanced heavy metal removal from wastewater

A novel free-standing polyvinyl butyral-polyacrylonitrile/ZnAl-layered double hydroxide nanocomposite membrane (PVB-PAN/ZnAl-LDH NCM) was prepared through a phase inversion method and employed for salts and heavy metals removal from their aqueous solutions. The structural and physicochemical characteristics of the prepared substances were investigated by XRD, FT-IR, FE-SEM, EDX, AFM, and water contact angle analyses. The effect of ZnAl-LDH contents (5, 10 and 15 wt%) on the mechanical strength and separation performance of the fabricated NCMs was studied. The results revealed that the mechanical strength, surface porosity, roughness, hydmphilicity, mean pore diameter and morphology of the membranes were remarkably improved by introducing ZnAl-LDH nanosheets into the NCMs. Moreover, the separation performance of the fabricated NCMs was investigated by measuring the rejection rates of salt solutions such as Na2SO4, CaSO4, CaCl2, and NaCl under acidic, neutral, and basic conditions. The effect of initial concentration and pH on the removal efficiency of Pb2+ and Cd2+ cations by the prepared NCMs was inspected. The reusability of the fabricated NCMs for removal of Pb2+ from its aqueous solution was examined through three successive cycles. According to the results, the prepared PVB-PAN/ZnAl-LDH NCMs showed high efficiency for removal of Pb2+ and Cd2+ cations from aqueous solutions.