Mechanistic studies of surface catalyzed H2O2 decomposition and contaminant degradation in the presence of sand

• Published in: Water research (Oxford) 1999-08, Vol.33 (12), p.2805-2816
• Main Authors: MILLER, C. M, VALENTINE, R. L
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and physicochemical phenomena; Exact sciences and technology; Natural water pollution; Pollution; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/s0043-1354(98)00500-4

The oxidation of contaminants by hydrogen peroxide was studied in the presence of 2 natural metal oxide-coated sands from a river bed and an aquifer. The selected contaminants phenol and quinoline with their degradation products were analysed by high performance liquid chromatography . Batch experiments were conducted with sand concentrations of 0.2 and 1.0 g per ml. The role of several oxygen radicals was ascertained by inhibition and probe measurements. Phenol degradation products were consistent with the action of the hydroxyl radical, a conclusion supported by the inhibitory effect of the hydroxyl scavenger butanol. Studies with superoxide dismutase indicated that the superoxide anion participated in hydroxyl radical formation. It was likely that the superoxide anion was able to persist sufficiently long in the bulk solution where it reacted with hydrogen peroxide to yield hydroxyl radicals. A mechanism was formulated to account for these observations, the hydrogen peroxide decomposition kinetics and the complex decay behaviour of the contaminants. There are 36 references.