Alumina-mediated photocatalytic degradation of hexachlorobenzene in aqueous system: Kinetics and mechanism

Five kinds of Al2O3 were characterized by SEM, TEM, FT-IR and BET surface area, and then used as carriers to investigate the photochemical removal of hexachlorobenzene (HCB) in aqueous system. The results showed that HCB coated on the surfaces of all Al2O3 could be photodegraded rapidly, and Neutral-Al2O3 presented the best performance. Meanwhile, the efficient removal of HCB in real water matrices, including tap water, river water and secondary clarifier effluent showed the potential practical application of Al2O3. EPR and theoretical calculation revealed the generation of hydroxyl radicals on Al2O3 surface under 500 W Xe lamp irradiation. Nine intermediates and a small amount of Cl- were identified by GC/MS, LC/MS and IC analysis, which was further verified by transition state calculations. These results can provide a new technique for HCB removal in water and wastewaters, and give more insights into the environmental ecological risk assessment of this pollutant. (C) 2020 Elsevier Ltd. All rights reserved.