Decolourization of textile industry wastewater by the photocatalytic degradation process

The photocatalytic degradation of various dyes (Orange II, Orange G, Congo Red, Indigo Carmine, Crystal Violet, Malachite Green, Remazol Blue and Methyl Yellow) has been studied, using P25 Degussa as catalyst. All dye solutions underwent a decolourization. The kinetics of reaction have been studied and were found to be zero or first order with respect to the dyes. This was compared with the adsorption properties. The effect of the addition of hydrogen peroxide has been studied. An enhancement of the rate has been observed in all cases and the order with respect to the additive was found to be almost zero. It is difficult to give a general picture of the kinetics using these very different dyes but the process was found to be effective for the decolourization of textile wastewater.