Kinetic Aspects of Ethylene Glycol Degradation using UV-C Activated Hydrogen Peroxide (H2O2/UV-C)

Ethylene glycol (EG) is one of the contaminants in wastewater of airports because it is commonly used in the composition of aircraft deicing fluids during the cold season in northern regions. Ethylene glycol by itself has comparably low toxicity on mammals and aquatic life, but it can lead to substantial increase in chemical and biological oxygen demands. Contamination of water with EG facilitates the rapid growth of microbial biofilms that decreases the concentration of dissolved oxygen in water and negatively affects overall biodiversity. The development of simple method to decompose EG with a high efficiency and low operating costs is an important task. This study shows that ethylene glycol can be completely oxidized using UV-C activated hydrogen peroxide (H2O2/UV-C) with a high rate (up to 56 mg L–1 h–1) at optimum EG:H2O2 molar ratio of 1:10–1:15. Air purging the reaction solution at 1000 cm3 min–1 increases EG mineralization rate up to 2 times because simultaneous action of UV-activated H2O2 and O2 (H2O2 + O2/UV-C) leads to a synergistic effect, especially at low EG:H2O2 ratios. The kinetics and mechanism of EG degradation are discussed based on the kinetic plots of ethylene glycol and intermediate products.