Photocatalytic degradation of two selected dye derivatives, chromotrope 2B and amido black 10B, in aqueous suspensions of titanium dioxide

The photocatalytic degradation of two selected dye derivatives, chromotrope 2B (1) and amido black 10B (2), has been investigated in aqueous suspensions of titanium dioxide under a variety of conditions which is essential from an application point of view. The degradation was monitored by measuring the change in substrate concentration as a function of irradiation time employing UV spectroscopic analysis. In these studies, a number of byproducts are formed during the photooxidation process which can potentially be harmful to the environment, therefore, we have studied the mineralization of the pollutants by measuring the total organic carbon (TOC) as a function of irradiation time. The degradation of dyes were studied using different parameters such as types of TiO₂, reaction pH, catalyst concentration, substrate concentration and in the presence of different electron acceptors such as hydrogen peroxide (H₂O₂), potassium bromate (KBrO₃ and ammonium persulphate (NH₄)₂S₂ O₈ 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 with other photocatalysts. The dye derivative (1) was found to degrade faster as compared to the dye derivative (2).