Solar photocatalytic mineralization of commercial pesticides: Methamidophos

Aqueous solutions of methamidophos (O,S-dimethyl phosphoramidothioato) are mineralised in sunlight in the presence of dispersed particles of TiO2 in a pre-industrial pilot plant. A commercial pesticide (Tamaron 50(R). 50% Met hamidophos) is used as a model to demonstrate the application of the treatm ent. Total Organic Carbon (TOC) and PO43- are analysed to confirm the miner alization of the contaminants. The concentration of organics in water was s et at TOC approximate to 100 mg/L, but with only illuminated TiO2, minerali zation was slow. Oxidation of the organics present in the formulation is en hanced 18 times by use of an appropriate electron scavenger (peroxydisulpha te) compared to TiO2 alone. (C) 1998 Elsevier Science Ltd. All rights reser ved.