Photocatalytic Oxidation of Dimethyl Methylphosphonate in Aqueous Suspensions of TiO2

Abstract

Heterogeneous photocatalysis using simulated solar irradn. in the presence of titanium dioxide was studied using di-Me methylphosphonate (DMMP) as a surrogate for organophosphorus compds. including pesticides and chem. warfare agents. A redn. in soln. pH accompanied DMMP degrdn. with the pH approaching the pKa of DMMP. Addn. of peroxide before reaction increased the amt. of DMMP degraded. Nearly complete destruction of DMMP was only achieved with the largest addn. of peroxide. Photoreaction of DMMP in a pH 10 soln. and a pH 10 carbonate buffer degraded a similar percent of the solute, with a more gradual reaction obsd. for the buffered soln. Variations in reaction conditions were studied to evaluate the effect of potential spill conditions. The presence of fulvic acid in the soln. slightly enhanced the oxidn. of DMMP and the absence of dissolved oxygen inhibited DMMP oxidn. DMMP solns. prepd. in simulated sea water reached similar degrdn. percentages as pure solns., however, reacted more slowly. [on SciFinder(R)]