Peroxymonosulfate-Activated Magnetic Nanobiochar/TiO2 for Photocatalytic Dye Mineralization: Performance Evaluation, Mechanism and Reaction Pathways

The discharge of dye-loaded textile effluents poses serious environmental concerns due to their high stability. In this study, a magnetic Fe2O3/TiO2/NBC (FNT) heterostructure, derived from Cannabis sativa-based nanobiochar (NBC), was developed for crystal violet (CrV) degradation via peroxymonosulfate (PMS) activation. The crystalline structure, surface functional groups, morphology, and elemental composition were analyzed using advanced characterized of the synthesized catalyst. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Fe3+, Ti4+, and abundant surface oxygen species. Under UV light, efficient electron transfer across the FNT interface promoted PMS decomposition into hydroxyl and sulphate radicals. Electrochemical results indicated reduced charge recombination and enhanced electron mobility. Under optimal conditions (PMS = 75 mg/L, FNT = 30 mg/L, pH 7), 98.9% CrV degradation was achieved within 120 min. The catalyst maintained over 97% efficiency after five cycles, demonstrating excellent stability and reusability. Overall, this research demonstrates a robust and sustainable catalytic system for efficient dye degradation, offering strong potential for practical wastewater treatment applications.