Efficient removal of acyclovir by UV/peracetic acid: A dual-function process for oxidation and disinfection

UV/PAA achieves efficiency ACV removal across a broad pH. • Both •OH and R-C• synergistically drive ACV oxidation. • DFT and LC-MS/MS identify distinct pathways yielding low-toxicity products. • The dual-function system highly inactivates chlorine-resistant B. subtilis . Acyclovir (ACV) is an emerging antiviral contaminant posing risks to aquatic ecosystems. This study proposed the application of the UV/peracetic acid (UV/PAA) process as a novel dual-function technology for simultaneous ACV elimination and water disinfection. The UV/PAA process achieved 97.6% ACV removal within 30 min under the optimized conditions (2.5 mM PAA and 1800 μW/cm 2 UV intensity) while maintaining stable degradation performance across a broad pH range (3.0–11.0). Mechanistic analysis indicated that ACV degradation was governed by the combined action of hydroxyl radicals (•OH) and carbon-centered radicals (R-C•), with •OH serving as the dominant reactive species (57.4–65.6%). Density functional theory (DFT) coupled with LC-MS/MS revealed distinct addition and substitution pathways that structurally transform ACV into low-toxicity products. Furthermore, addressing a critical biosecurity challenge, the process exhibited exceptional biocidal synergy, achieving a 3.79 log inactivation of chlorine-resistant Bacillus subtilis spores. Overall, the results provided mechanistic insight into ACV degradation by UV/PAA and supported its potential application for the simultaneous control of pharmaceutical contaminants and microbial risks in water treatment. Download: Download high-res image (255KB) Download: Download full-size image