Preparation and characterization of Ru-TiO₂/PC/Fe₃O₄ composite catalyst with enhanced photocatalytic performance and magnetic recoverability under simulated solar light

This research focuses on the development of a novel Ru-doped TiO₂/grapefruit peel biochar/Fe₃O₄ (Ru-TiO₂/PC/Fe₃O₄) composite catalyst, which exhibits exceptional photocatalytic efficacy under simulated solar light irradiation. The catalyst is highly effective in the degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), as well as actual industrial dye wastewater (IDW), and can be recovered magnetically for multiple reuse cycles. Significantly, the PCTRF-100 sample exhibited degradation efficiencies of 99.4% for RhB and 99.8% for MB within 60 min, and 98.04% for MO within 120 min. In the case of actual dye wastewater, a reduction in chemical oxygen demand from 1540 mg L^-1 to 784 mg L^-1 was achieved within 300 min, corresponding to a degradation rate of 46.81%. The remarkable photocatalytic activity observed is primarily attributed to the synergistic interactions among Ru-TiO₂, biochar, and Fe₃O₄, which effectively facilitate the separation and migration of electron-hole pairs in TiO₂.