Synergistic remediation of arsenite and cadmium co-contaminated water using Fe-Mn oxides modified graphene oxide

A novel graphene oxide composite incorporating iron (Fe) and manganese (Mn) (GO-FM) was synthesized by co-precipitating Fe and Mn oxides onto graphene oxide to remediate As 3+ and Cd 2+ contaminants in water. The spectrum of SEM-EDS and XRD analyses confirmed the successful integration of Fe₂O₃ and MnFe₂O₄ into the graphene oxide matrix. FT-IR characterization indicated increased number of –OH on GO-FM following the incorporation. The adsorption behavior of As 3+ and Cd 2+ varied with initial pH. Cd 2+ reached equilibrium within 2 h, whereas As 3+ stabilized after 24 h, with adsorption efficiency improving with temperature. Maximum adsorption capacities were recorded at 90.34 mg∙g − 1 for Cd 2+ and 141.69 mg∙g − 1 for As 3+ . In the co-adsorption system, As 3+ and Cd 2+ interactions displayed both synergistic and antagonistic effects. At low pH (2–3), Cd 2+ inhibited As 3+ adsorption, demonstrating antagonism. At neutral pH (7), a synergistic effect was observed, where As 3+ increased Cd 2+ adsorption by 12.4%–429%, and Cd 2+ elevated As 3+ adsorption capacity by 1.7%–11%. This synergy was driven partly by electrostatic forces and ternary surface complex formation, but co-precipitation as the dominant process. These findings offer critical insights into the interaction dynamics of As 3+ and Cd 2+ on GO-FM, highlighting the potential for effective remediation applications.