Photocatalysed degradation of a fungicide, thiram in aqueous suspension of titanium dioxide

Photocatalysed degradation of a fungicide derivative, thiram has been investigated in aqueous suspensions of titanium dioxide as a function of irradiation time under a variety of conditions. The degradation kinetics were studied under different conditions such as pH, catalyst concentration, substrate concentration, different types oi TiO 2 and in the presence of electron acceptors such as hydrogen peroxide (H 2 O 2 ), potassium bromate (KBrO 3 ) and ammonium persulphate (NH 4 ) 2 S 2 O 8 besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst, Degussa P25 was found to be more efficient as compared to other photocatalysts tested. All the electron acceptors markedly enhanced the degradation of the compound under investigation. The efficiency of degradation was found to be slower under sunlight as compared to the artificial light source. The degradation products were analyzed by GC-MS technique and probable pathways for the formation of products are proposed.