effect of uv light on pentachlorophenol removal in the electro-fenton process

Background: this research studied the effect of uv light on pentachlorophenol (pcp) removal in the electro-fenton (ef) process. methods: pcp was used as the pollutant in this study. the effects of fenton’s reagent, i.e. hydrogen peroxide concentration, solution ph, and treatment time by ef (ef) and photoelectro-fenton (pef) processes, were studied to determine rates of pcp removal. the results showed that a better performance and a high removal efficiency were achieved by coupling uv radiation and the ef process. results: ef processes required more time to remove pcp, while after a reaction time of 10 minutes, the pef achieved a removal efficiency of 90.4%; this value is higher than the maximum efficiency of the ef process (83.44% after 40 minutes). the kinetic mechanisms of both processes were examined and compared. the rate constants at optimum conditions were 0.0455 and 0.0579 min−1 for ef and pef processes, respectively. conclusion: removal efficiency was obtained in the order of pef > ef.