Reactive oxygen species-mediated UV photocatalytic removal of cyclophosphamide by Fe₃O₄/Ti₃C₂T_x

Cyclophosphamide (CP), a widely used cytostatic drug, poses significant environmental challenges due to its persistence and potential toxicity in aquatic systems. In this study, the photocatalytic and optical properties of a magnetic MXene (Fe₃O₄/Ti₃C₂T_x) composite were systematically investigated under UV illumination. Abiotic probe assays confirmed the generation of reactive oxygen species (ROS), including hydroxyl radicals (•OH) and superoxide (O₂•⁻), thereby validating the material's intrinsic photocatalytic activity. Photocatalytic degradation experiments demonstrated that decorating MXene (Ti₃C₂T_x) with iron oxide (Fe₃O₄) enhanced light utilization, promoted charge separation, and improved CP adsorption affinity. Structural analysis further revealed partial surface oxidation of Ti₃C₂T_x into TiO₂, contributing to its photocatalytic activity. Under optimized conditions (50 mg/L catalyst dose, pH 5.6), the composite achieved 83.4 ± 1.1% CP degradation within 120 min and retained performance over four cycles, confirming stability and reusability. The synergistic effect of Fe²⁺-driven Fenton-like reactions, photoactive TiO₂ domains, and the conductive Ti₃C₂T_x matrix ensured sustained ROS production and suppressed electron-hole recombination. Liquid chromatography–mass spectrometry (LC–MS/MS) identified three transformation products (TPs), with hydroxylation and hydrolysis as the dominant degradation pathways.