Effects of temperature and pH on the GSM and 2-MIB degradation by UV-LEDs/HClO advanced oxidation

While Ozone-based processes have demonstrated good performance treating 2-methylisoborneol (2-MIB) and geosmin (GSM) in drinking water, their reaction efficiency decreases at low temperatures. To overcome this limitation, UV-based advanced oxidation processes (AOPs) have emerged as promising alternatives. This study proposes an innovative UV-LED/HClO AOP system and systematically evaluates its removal performance for GSM and 2-MIB under varying temperature and pH conditions. results indicated that the degradation processes of 2-MIB and GSM followed first-order kinetic models ( R 2 > 0.72, p < 0.001). Reaction rates significantly increased at 20°C and pH 6 for both odorous compounds ( k 2-MIB = 1.86 × 10 -3 cm 2 mJ -1 , k GSM = 2.38 × 10 -3 cm 2 mJ -1 ), compared to those at 4°C. The apparent rate constants increased by approximately 20 to 30% when temperature rose from 4 to 20 °C, which is smaller than the 30–50% temperature-induced deterioration reported for ozone-based processes in previous studies. In coagulated water collected from an operating treatment plant, good linear relationships between fluence and degradation were maintained ( R 2 = 0.83 to 0.94, p < 0.001). Overall, the UV-LEDs/HClO AOP exhibited reduced sensitivity to low temperatures, highlighting its potential as an effective odor-control strategy for drinking water treatment in cold environments. ● UV/HClO-AOPs were applied for GSM and 2-MIB using 280 nm UV-LED. ● Effects of water temperature on the degradation were examined. ● Degradation was compared at different target concentrations, pH, and HClO levels. ● Efficiencies declined at 4°C compared to 20°C but in a milder manner than ozonation. ● Lower efficiencies in samples from a real plant, showing challenges for the future.