Removal of 2-Chlorophenol by Ozonation Under Strongly Alkaline Conditions in a Jet Loop Reactor

This study aimed to investigate the removal of 2-chlorophenol (2CP) using ozonation in a jet loop reactor under high pH (strongly alkaline conditions). The effects of initial 2CP concentration and ozone dosage on the removal of 2CP, chemical oxygen demand (COD), and total organic carbon (TOC) were determined. As the initial 2CP concentration increased, the removal efficiencies of 2CP, COD, and TOC decreased, whereas an increase in ozone dosage resulted in higher removal efficiencies. The initial concentration of 100 mg/L of 2CP was completely removed within approximately 12.5 min at an ozone dosage of 13.1 gO3/h, while after 180 min of ozonation, the COD and TOC removal efficiencies were 97% and 60%, respectively. The removal of 2CP and COD followed pseudo-first-order kinetics in a two-stage process. When examining the kinetics of 2CP removal, the rate constants observed in the second-stage were higher than those observed in the first-stage. In the case of COD removal, unlike in the 2CP, the rate constant values observed in the first-stage were higher than those observed in the second-stage. For both 2CP and COD removal, the rate constant values in both stages exponentially decreased with an increase in the initial 2CP concentration, whereas they linearly increased with an increase in ozone dosage.