| "Tetrachloroethylene (PCE) and trichloroethylene (TCE) are common industrial solvents, and are also major contaminants found in drinking water supplies. In an attempt to purify the VOC- contaminated water by previous researchers, advanced oxidation processes have been extensively studied because of their ability to destroy refractory compounds. This study, focusing on sonophotolysis of PCE and TCE, addressed the role of hydroxyl radicals (●OH) occurring in an aqueous solution during the treatments using ultrasound (US), ultraviolet light (UV), and the combination of the two (UVUS). The experiments were carried out in two types of reactors: a reactor without a partition (single compartment reactor) and a reactor with a partition (three- compartment reactor). The obtained experimental data were compared with the results from the mathematical models that include the first-order or zero-order reaction. The results showed that: 1) the decreases in the concentrations of PCE and TCE correspond inversely to the increase in the concentration of ●OH, suggesting that ●OH is the major reactive species involved in the oxidation of PCE and TCE; 2) the generation of ●OH during the US and UVUS treatments follows the zero-order kinetics; and 3) the kinetics of XOH generation under UV irradiation is neither first-order nor zero-order." |
