Sustainable water treatment: Harnessing mining waste as catalysts for Sicomet green degradation

This paper presents a novel circular economy approach to water remediation that focuses on creating sustainable systems by utilizing mining waste from El-Ouenza, Tebessa, in the east of Algeria. Waste materials are employed as catalysts in Fenton and photo-Fenton processes. Two cases were studied: the conventional and the modified heterogeneous photo-Fenton at a pH of 3 and under modified pH conditions for degrading Sicomet Green food dye ZS120. Catalysts were characterized through various analyses. Catalyst performance and dye degradation were examined for raw and calcined waste at 500 °C. Parameters like catalyst amount, sodium sulfite concentration, oxalic acid, and pH were optimized for both systems, with and without ligand. The first system achieved 91.5 % mineralization using 0.15 g L⁻¹ catalyst, pH of 3, and 0.45 mM Na₂SO₃ in 90 min under sunlight. The second reached 78.5 % efficiency with variable conditions. Kinetic models demonstrated a first-order model for both photo-Fenton degradation and mineralization under sunlight. These findings guide eco-friendly dye degradation via mining waste-based catalysts in photo-Fenton systems, supporting sustainable wastewater treatment.