Title: Photocatalytic oxidation of methomyl in the presence of semiconducting oxides

Authors: I. Poulios, M. Kositzi, K. Pitarakis, S. Beltsios, I. Oikonomou

Addresses: Laboratory of Physical Chemistry, Department of Chemistry, University of Thessaloniki, Thessaloniki 54124, Greece. ' Laboratory of Physical Chemistry, Department of Chemistry, University of Thessaloniki, Thessaloniki 54124, Greece. ' Water Supply and Sewerage Municipal Enterprise of Larisa, Terma Ticherou, Larisa 41222, Greece. ' Water Supply and Sewerage Municipal Enterprise of Larisa, Terma Ticherou, Larisa 41222, Greece. ' Water Supply and Sewerage Municipal Enterprise of Larisa, Terma Ticherou, Larisa 41222, Greece

Abstract: The photocatalytic degradation of methomyl, a broad spectrum carbamate insecticide, has been investigated in aqueous heterogeneous solutions containing semiconductor oxides as photocatalysts. It was observed that, in the presence of the catalysts, quantitative degradation of the organic molecule occurs after four hours of illumination. As mineralisation products, CO₂ and SO₄²⁻ ions have been identified, whereas the nitrogen atom forms NH₄⁺ and NO₃⁻ ions. Various commercial catalysts were compared with respect to their overall photocatalytic efficiency, while the initial photonic efficiency (ζ) of mineralisation under various experimental conditions have been calculated.

Keywords: heterogeneous photocatalysis; methomyl; zinc oxide; titanium dioxide; insecticides; photooxidation; sunlight induced degradation; semiconducting oxides; photocatalytic oxidation; wastewater treatment; wastewater reuse; water scarcity.

DOI: 10.1504/IJEP.2006.010872

International Journal of Environment and Pollution, 2006 Vol.28 No.1/2, pp.33 - 44

Published online: 11 Sep 2006 *

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