Contribution of irradiation and dihydroxybenzenes on iron(III) reduction in fenton process

Abstract

The contribution of irradiation and the dihydroxybenzenes (DHB), catechol (CAT) and hydroquinone (HQ), added or formed as phenol oxidation intermediates, was evaluated for the reduction of FeIII and for phenol degradation via Fenton processes. The formation of CAT and HQ was observed during phenol degradation starting with Fe2+ or Fe3+ in the presence or absence of irradiation and their presence increased the rate of phenol degradation, more remarkably when initially added. Initial phenol degradation rate in the presence of DHB in the dark was much higher in comparison to their absence due to the initial higher and faster formation of Fe2+. However, degradation slows down due to the rapid oxidation of DHB, while under irradiation of free iron or citrate complex much higher mineralization is achieved in shorter time.