Lanthanum-substituted bimetallic magnetic materials assembled carboxylate-rich graphene oxide nanohybrids as highly efficient adsorbent for perfluorooctanoic acid adsorption from aqueous solutions

Perfluorooctanoic acid (PFOA) is a persistent organic contaminant, and it has recently been recognized as a contaminant in aquatic environments worldwide because of its effects on human health. Herein, we report the synthesis of graphene oxide decorated with highly stable lanthanum-substituted manganese ferrites (LMF) at various concentrations (LMFx%@GO). After the substitution of lanthanum on MF, the surface charge density and the crystalline nature were altered significantly, as supported by the zeta potential, transmission electron and scanning electron microscopy images, and powder X-ray diffraction patterns. Among the concentrations of x = 25, 50, and 75% wt./wt., LMF75%@GO exhibited the highest PFOA removal densities. Electrostatic interaction and hydrogen bonding played vital roles in the adsorption of PFOA, as evidenced by various spectro-analytical techniques, including FTIR, XPS, and TEM-EDX. Several conditions such as contact time, pH, coexisting substances, and quantities of LMF nanoparticles were evaluated to provide information about the PFOA removal process. Moreover, the presence of coexisting pollutants such as anions, cations, and other organic compounds had no remarkable influence on PFOA adsorption using LMF75%@GO nanohybrids. The results suggest that the prepared LMF75%@GO nanohybrids may be a promising candidate for the removal of PFOA from an aqueous environment.