Comparison of different advanced oxidation processes degrading p-chlorophenol in aqueous solution

ABSTRACT

In present study, degradation of p-chlorophenol using several oxidation systems involving advanced oxidation processes such as ultraviolet/H[2]O[2], microwave/H[2]O[2] and both in the absence of hydrogen peroxide in batch mode by photolytic pilot plant and modified domestic microwave oven was evaluated. The oxidation rate was influenced by many factors, such as the pH value, the amount of hydrogen peroxide, irradiation time and microwave power. The optimum conditions obtained for the best degradation rate were pH=7 and H[2]O[2] concentration of 0.05 mol/L for ultraviolet/H[2]O[2] system and pH=10.5, H[2]O[2] concentration of about 0.1 mol/L and microwave irradiation power of about 600W for microwave/H[2]O[2] system at constant p-chlorophenol concentration. The degradation of p-chlorophenol by different types of oxidation processes followed first order rate decay kinetics. The rate constants were 0.137,0.012,0.02 and 0.004/min[1] for ultraviolet/H[2]O[2], microwave/H[2]O[2], ultraviolet and microwave irradiation alone, respectively. Finally a comparison of the specific energy consumption showed that ultraviolet/ H[2]O[2] process reduced the energy consumption by at least 67% compared with the microwave H[2]O[2] process