Photodegradation of γ-HCH by α-Fe2O3 and the influence of fulvic acid

The purpose of this study was to examine photodegradation of gamma-hexachlorocyclohexane (gamma-HCH) by alpha-Fe2O3 and the influence of fulvic acid (FA) in this photochemical process. A 300 W high-pressure mercury lamp was employed as the light source. The result showed that the UV light alone could play an important role in the degradation of gamma-HCH. The presence of alpha-Fe2O3 was found to promote the photodegradation of gamma-HCH. The photodegradation of gamma-HCH by alpha-Fe2O3 follows pseudo-first-order reaction kinetics. The effect of the FA on the photodegradation of gamma-HCH was also performed. The result revealed that the FA slowed the photodegradation rate of gamma-HCH. Oxidation products were also identified by gas chromatography with a mass spectroscopy detector. This process is of interest in both a remedial process induced by iron oxides in natural water surfaces and alpha-Fe2O3-mediated photodegradation method for purifying natural water containing gamma-HCH and humic substances. (c) 2005 Elsevier B.V. All rights reserved.