Waste-to-resource conversion of copper tailings into multifunctional catalytic adsorptive materials for Hg0 removal via H₂O₂/K₂S₂O₈ oxidation

The accumulation of copper tailings has caused significant environmental concerns due to land occupation and potential heavy metal risks, while efficient control of elemental mercury (Hg 0 ) emissions from industrial flue gas remains challenging. This study presents a waste-to-resource strategy by converting thermally activated copper tailings into multifunctional catalytic adsorptive materials for Hg 0 removal through a wet H₂O₂/K₂S₂O₈ oxidation system. The abundant mineral components and transition metal species (Fe and Mn) in copper tailings provided catalytic active sites for oxidant activation, promoting the transformation of Hg 0 into stable oxidized mercury species. Under optimized conditions (solid–liquid ratio of 10%, reaction temperature of 45 °C, SO₂ concentration of 2000 mg/m³, NOₓ concentration of 600 mg/m³, and O₂ content of 10%), the catalytic system achieved a Hg 0 removal efficiency of 91.99%. The enhanced performance was attributed to the synergistic interaction between activated copper tailings and composite oxidants, as well as the improved surface reactivity of the catalyst. Furthermore, the catalyst exhibited good resistance to flue gas components and operational stability, demonstrating the feasibility of copper tailings as low-cost catalysts for mercury emission control. This work provides a sustainable pathway for simultaneous copper tailings valorization and atmospheric mercury pollution mitigation.