TiO_2-mediated photocatalytic degradation of a triphenylmethane dye (gentian violet), in aqueous suspensions

摘要

TiO_2-mediated photocatalytic degradation of a triphenylmethane dye (gentian violet, 1), was investigated in aqueous suspension s of titanium dioxide under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV-spectroscopic analysis and decrease in total organic carbon (TOC) content as a function of irradiation time. The degradation of dye was studied under a variety of conditions such as pH, catalyst concentration, substrate cocnentration, different types of TiO_2 and in the presence of electron acceptors such as hydrogen peroxide (H_2O_2) and ammonium persulphate ((NH_4)_2S_2O_8) besides molecualr 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 with other photocatalysts. The degradation products were analysed by GC-MS technique and probable pathways for the formation of the products were proposed.