MODELING OF CHLOROPHENOL TREATMENT IN AQUEOUS-SOLUTIONS - 1 - OZONATION AND OZONATION COMBINED WITH UV-RADIATION UNDER ACIDIC CONDITIONS

Treatment of 2-chlorophenol (2-CP), 4-chlorophenol (4-CP) and 2,4-dich lorophenol (2,4-DCP) in aqueous solutions with direct photolysis (254 nm), ozonation and ozonation with photolysis was studied. A model was developed to simulate chlorophenol treatment in a semibatch column usi ng these processes under acidic conditions in which the chemical react ions are slow. Satisfactory results were obtained in simulating the ch lorophenol and ozone concentrations, and the concentrations of an arom atic quinone, hydrogen peroxide and chloride ions formed in the course of the processes. Chlorophenol oxidation systems, however, appeared t o be very complex and the formation of intermediate and final products were dependent on the reaction conditions. The degradation rate of ch lorophenols was not enhanced by the combination of ozone with UV radia tion compared with ozonation alone. Oxidation at low pH in both proces ses proceeded mainly through reactions with molecular ozone.