Enhanced durable water purification via UV-triggered ozone micro-nano bubbles process: Exposure of free radicals and control of disinfection byproducts

The UV-triggered ozone micro-nanobubble (UV/O 3 -MNBs) system is specifically designed for long-lasting decontamination and control of disinfection byproducts (DBPs), demonstrating its effectiveness and promising potential. UV-triggered O 3 -MNBs efficiently induce O 3 decomposition to form hydroxyl radicals (·OH), thereby greatly boosting their contribution rates to over 98.0 % during water decontamination. By leveraging the powerful ·OH oxidation, the UV/O 3 -MNBs system exhibits superior performance in removing trace organic compounds from actual water bodies, and improving total organic carbon (TOC) removal efficiency. The constructed system showed high performance during long-term running with continuous entrance of pollutants. Notably, it reduces the generation potential of bromate (BrO 3 − ) by interfering with HOBr/OBr − through ·OH reactions. Meanwhile, it significantly reduces Cl/Br-THMs formation potential compared with direct chlorination disinfection (24 h), from 18.9 μg/L to 11.6 μg/L. Simultaneously addressing refractory micro-pollutant abatement and DBPs control, the UV/O 3 -MNBs effectively reduce energy consumption compared to the O 3 -MNBs oxidation alone. This study innovatively coupled the UV and O 3 -MNBs for micropollutants removal and DBPs control, which provides a novel insight into durable water purification and serves as a valuable reference for practical applications.