Degradation of 2-chlorophenol by Fenton and photo-Fenton processes--a comparative study

The oxidation potentiality of simulated aqueous solution of 2-chlorophenol (2-CP) by Fenton's reagent was assessed for wastewater treatment. Batch experiments were carried out to investigate the effects of pH, hydrogen peroxide (H2O2), and ferrous ion (Fe2+) concentrations. Degradation reaction occurred within a limited pH range of 2.5-4.0. Maximum degradation occurred at a concentration of 22 mM of H2O2 and at 0.45 mM of Fe2+. Influence of temperature on degradation of 2-CP was investigated. Arrhenius plot for the degradation of 2-CP at various temperatures was plotted based on the experimental data. The role of solar light and UV in photo-fenton degradation of 2-CP was investigated and compared with Fenton process. In both Fenton and photo-fenton processes, free chloride ion generated from 2-CP degradation process reached a maximum concentration at a very short interval of time. Maximum DOC removal of 39% was achieved in Fenton's process (i.e.,) only 2/5th of compound was mineralized. The efficiency of mineralization was considerably improved to 95-97% in photo-fenton processes. Low molecular weight aliphatic organic compounds like oxalic acid and acetic acid formed during the reaction were monitored for Fenton's process. The fate of these stable intermediates compounds in photo-fenton processes were also discussed.