Removal of 2,4,6-Trichlorophenol in Simulated Wastewater via Ozonation

Abstract

This study aimed to investigate the ability of ozonation to degrade 2,4,6-trichlorophenol (2,4,6-TCP) in simulated wastewater. Independent variables such as initial 2,4,6-TCP concentration and pH were investigated. The results showed that 100.0% degradation efficiency was achieved for an initial 2,4,6-TCP concentration of 10 ppm and reaction time of 25 minutes. Higher initial concentrations had lower degradation rates. The results also revealed that the degradation of 2,4,6-TCP fitted well with first order reaction kinetics, with an apparent rate constant of 0.0947 min-1 at an initial concentration of 10 ppm. The degradation of 2,4,6-TCP increased significantly with the increase in initial pH of the solution from pH 4 to pH 7 and then to pH 10. The highest degradation effect was found at pH 10.0 with a rate constant of 0.0443 min-1, which was attributed to the production of more powerful hydroxyl radicals. Evaluation of BOD5/COD ratios showed some enhancement in the biodegradability of the effluent treated by ozonation. A chemical oxygen demand (COD) reduction of 42.10% was achieved after ozonation treatment and this result indicated that only partial mineralization of 2,4,6-TCP could be achieved by ozonation alone. These findings suggest that future studies should focus on the application of catalytic ozonation or a combination of ozonation with other conventional treatments such as biodegradation or filtration in order to achieve complete degradation of this toxic organic contaminant.