Fe-MOFs/graphene oxide-derived magnetic nanocomposite for enhanced adsorption of As(V) in aqueous solution

Abstract

The urgent need to remove arsenic from groundwater stems from the irreversible damage it causes to aquatic systems and biological health. In this study, unique magnetic Fe3O4/graphene oxide (GO) nanocomposites derived from MIL-100(Fe)/GO precursor were rationally and precisely developed by combination of solvothermal synthesis and pyrolysis methods. The optimized MIL-100(Fe)/1%GO-400 magnetic nanocomposite (where 1% and 400 represent the mass ratio of GO to MIL-100(Fe) and pyrolysis temperature, respectively) exhibited exceptional adsorption capacity for As(V) and possessed magnetic separation properties. The novel nanocomposite had complete MOF morphology and crystal structure, as well as good resistance to interference from ions and could be used effectively over a wide pH range (2–9) for adsorption of As(V). The As(V) adsorption on the nanocomposite was found to follow the pseudo-second-order (PSO) kinetic model and Temkin adsorption isotherm model, as well as a spontaneous endothermic process dominated by chemisorption. The incorporation of GO and pyrolysis of the Fe-MOFs was proven to enhance the adsorption capacity of nanocomposite, water stability, and magnetic recovery ability. The adsorption mechanism was attributed to the synergistic effect of chemical complexation, hydrogen binding and electrostatic interaction. This work not only presents a feasible strategy for the development of Fe-MOFs-based derivatives, but also offers a promising approach to expanding the application of functional Fe-MOFs-based derivatives in arsenic-contaminated wastewater treatment.