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

The purpose of this study was to examine photodegradation of γ-hexachlorocyclohexane (γ-HCH) by α-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 γ-HCH. The presence of α-Fe2O3 was found to promote the photodegradation of γ-HCH. The photodegradation of γ-HCH by α-Fe2O3 follows pseudo-first-order reaction kinetics. The effect of the FA on the photodegradation of γ-HCH was also performed. The result revealed that the FA slowed the photodegradation rate of γ-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 α-Fe2O3-mediated photodegradation method for purifying natural water containing γ-HCH and humic substances.