Advancing Arsenic Removal: Leveraging the Efficiency of Magnetic Graphene Oxide Nanocomposite

The widespread contamination of water resources is a global concern. In this study, magnetic graphene oxide (MGO) was prepared from graphene oxide (GO), and both nanomaterials investigated as adsorbents for the removal of arsenic. GO synthesized by a modified Hummer's method was further modified with magnetite nanoparticles to obtain MGO. Subsequent characterization with a variety of techniques confirmed the structural integrity of both types of nanoparticles and the presence of functional groups essential for effective adsorption. Adsorption kinetics experiments on both materials were well modelled by the pseudo-second order and Weber-Morris models, suggesting that both chemisorption and intra-particle diffusion control the adsorption kinetics of As(V) on MGO and GO. The magnetite modification of GO was highly effective in increasing arsenic adsorption capacity, with the Langmuir isotherm model returning a q_max for MGO more than 5 times greater than GO alone. Response surface methodology (RSM) was used to investigate the impact of initial As concentration, pH and the presence of dissolved organic carbon (DOC) on the adsorption of As onto MGO. In addition to the As concentration, the RSM model revealed significant interaction effects between the pH and the other parameters investigated, highlighting the importance of this parameter whilst optimising adsorption processes. Finally, both GO and MGO maintained their integrity across 5 adsorption/desorption cycles, with the high performance of MGO confirming its long-term potential as an environmentally sustainable solution for arsenic removal.