Photodegradation of metamitron (4-amino-6-phenyl-3-methyl-1,2,4-triazin-5(4H)-one) on TiO2

Photodegradation of metamitron in aqueous solution (i) on a plate photoreac tor with immobilized TiO2 layer and (ii) in a tube photoreactor in the pres ence of quantum sized Q-TiO2 particles was investigated and compared. Both processes, heterogeneous photocatalysis and homogeneous direct photolysis, took part on the overall photodegradation of metamitron. Deaminometamitron (6-phenyl-3-methyl-1,2.4-triazin-5(4H)-one), hydroxymetamitron (4-amino-6-( 2'-hydroxyphenyl)-3-methyl-1,2,4-triazin-5(4H)-one) and deaminohydroxymetam itron (6-(2'-hydroxyphenyl)-3-methyl-1,2,4-triazin-5(4H)-one) were identifi ed as main products. A reaction scheme of these phototransformations was pr oposed. (C) 2001 Elsevier Science B.V. All rights reserved.