Photocatalytic Degradation of Antiviral Drugs Chloroquine Phosphate and Lamivudine by Bi₂O₃–TiO₂/PAC under a Xe Lamp: Insights into Reactive Oxygen Species’ Action and Toxicity Reduction

Recently, owing to the prevalence of epidemic and pandemic viral diseases, the widespread use of antiviral drugs (ATVs) such as chloroquine phosphate (CQ) and lamivudine (3TC) has raised environmental concerns regarding their presence in wastewater. In this study, we explore our previously developed Bi2O3-doped TiO2 composites supported by powdered activated carbon (Bi2O3–TiO2/PAC; BT/C) catalysts for degrading CQ and 3TC as a green and efficient approach. Under suitable conditions (C0[ATV] = 10 mg/L, pH = 7, and catalyst dose = 250 mg/L), the degradation rates of CQ and 3TC reached 95.1% and 57.1% after radiation for 30 and 120 min, respectively. In situ irradiation X-ray photoelectron spectroscopy results and density functional theory simulations confirmed that BT/C enhanced interfacial electron transfer from TiO2 to Bi2O3 and suppressed carrier recombination. Quenching experiments and electron paramagnetic resonance results confirmed ·O2– generation, leading to subsequent ·OH and 1O2 production. In addition, degradation pathways for CQ and 3TC were proposed. Toxicity assessments indicated reduced overall toxicity during photocatalysis. BT/C catalysts proved effective across diverse water qualities and maintained stable performance through repeated use. This study offers new insights into photocatalytic ATV-removal mechanisms and opens avenues for innovative hybrid treatment technologies.