Kinetics study of photocatalytic decolorization of Diamond green B in the presence of titanium dioxide nano particles

The photocatalytic degradation of Diamond green B, a triarylmethane dye, has been investigated in aqueous heterogeneous solutions containing TiO2 nano- particles as photocatalysts. The factors effective on the degradation of Diamond green B, such as the amount of catalyst, the original concentration of dye, the effect of pH and illumination time were investigated under 400 W high pressure mercury lamp at room temperature. The disappearance of the organic molecule follows approximately pseudo- first order kinetics according to the Langmuir- Hinshelwood model. The photodegradation rate constans, adsorption contants and observed rate constants were evaluated in the ranges of (217.40- 30.30) ×10- 2 mg. min- 1.L- 1, (2.72- 44.70) ×10- 2 L. mg- 1 and (3.5- 5.70) ×10- 2 min.- 1 respectively.