Green synthesis of an advanced composite membrane for the purification of water contaminated with potentially toxic metals

Anthropogenic activities can lead to high contents of potentially toxic elements (PTEs) in soil and water. Thus, there is a worldwide need to find effective, environmentally friendly sorbents for remediating sites polluted with metals. In this study, we investigated how pectin/magnetite/pine sawdust (PE/Fe3O4/P) membranes serve as sorbents for the removal of Cd(II), Cr(VI), Cu(II), Mn(II), Ni(II), and Zn(II) from aqueous media containing multiple metals. Fourier-transform infrared (FTIR) spectra confirmed the efficient formation of crosslinked membrane chains during the synthesis of the biomass material. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves revealed that the biopolymer matrix remains stable at low temperatures and begins to degrade at temperatures above 260 °C. Scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDS) demonstrated changes in the morphology of the biomembrane. Among the six PTEs tested, the PE/Fe3O4/P5% membrane had the highest sorption capacity for Cu(II) (∼43 mg g−1). The metal/membrane interaction was confirmed by FTIR, TG, DTG, SEM, and EDS after the sorption assays. The findings of this work indicate that green sorbents constitute a promising strategy for the remediation of aquatic environments contaminated with PTEs.