AWWA WQTC62588

Advanced oxidation processes (AOPs) represent those technologies that bringabout enhanced oxidative degradation of pollutants in aqueous solution by the generationof hydroxyl radical (·OH). US Environmental Protection Agency (USEPA) published, inFebruary 2005, the second Contaminant Candidate List (CCL), which specifies 51unregulated priority contaminants for the Agency's drinking water program. Variouspesticides are included in the CCL since their extensive use worldwide was found to haveserious environmental consequences with major impacts on water quality (Chiron et al.,2000). The purpose of this study was to determine kinetic rate constants of the chemicalreactions resulting from the application of UV and UV/H₂O₂ to the CCL pesticides:linuron, diuron, prometon, terbacil, diazinon, dyfonate, terbufos, and disulfoton.Batch kinetic experiments were conducted with either UV alone or in the presenceof up to 100 mg/L H₂O₂. In quasi collimated beam experiments, 20 mM phosphate buffersolution at pH 7 of the studied pesticides, were exposed to average UV fluence (200-300nm) levels between 0 and 600 mJ/cm². Competition kinetics was used to evaluate thepesticides rate constants with hydroxyl radicals (k_OH). In this method an organic substratecompetes for hydroxyl radicals with a reference compound whose reactivity toward thehydroxyl radicals is known, under identical conditions (Einschlag et al., 2003). Includes 6 references, table, figure.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

4

File Size:

1 file , 88 KB