Decomposition of 2-chlorophenol in aqueous solution by ozonation

The decomposition of 2-chlorophenol by the ozonation process is studied and compared under various solution with different pH values and O-3 input mass flow rates to investigate the removal efficiency of reactants and organic intermediates. The disappearance rate of 2-chlorophenol and the mineralization rate of organic intermediates by ozonation are found to increase in relation to increased O-3 input dosages and solution pH values. For alkaline solutions where HCO3- and CO32- species may accumulate as free radical scavengers, the mineralization of organic intermediates is found to be insignificant. The mineralization of organic intermediates is also found to be ineffective for acidic solutions because some organic acids form and are refractory for the ozone molecule. The 2-chlorophenol in aqueous solutions are completely destroyed by ozonation within 30 minutes. The dechlorination of 2-chlorophenol by ozonation was studied in solutions at various pH values. It is found that hydroxyl radicals may enhance dechlorination and destroy the 2-chlorophenol in the solution. The detachment of chlorine atoms from the benzene ring is found to be the first step of the decomposition of 2-chlorophenol in aqueous solutions. The two-step consecutive kinetic model is found to fit the decomposition of 2-chlorophenol by ozonation in aqueous solutions well.