Degradation of textile dye by solar light using TiO2 and ZnO photocatalysts

The photocatalytic degradation of a textile dye, reactive red 2 in presence of sunlight using TiO₂ and ZnO as photocatalysts is reported. The experimental studies have indicated complete decolourisation of the dye in a short period and degradation within 8 hr of irradiation. ZnO was found to be more effective in the removal of colour than TiO₂, but the degradation efficiency was found to be more with TiO₂. ZnO decomposes on prolonged irradiationwhile TiO₂ is not photocorrosive. The percent degradationof the dye is high for both the catalysts at an optimum concentration of the catalysts. The first order rate constant is found to increase with decreasing dye concentration. [ABSTRACT FROM AUTHOR]