Abstract
The photocatalytic degradation of reactive orange 16 (RO 16) dye has been investigated using thin film tubular flow photoreactor with ZnO catalyst coating. The degradation efficiency of RO 16 dye with immobilized catalyst and freely suspended catalyst are compared. The effect of process parameters such as, aeration, flow rate, amount of catalyst coating, pH and initial concentration of RO 16 dye on the extent of photodegradation of the dye have been optimized. The RO 16 dye completely photo-mineralized into CO2 and simple inorganic ions, such as nitrate, ammonium and sulphate ions. The immobilized catalyst is approximately two times less effective than the freely suspended catalyst. The presence of air positively influences the photocatalytic activation. The optimum reaction parameters are flow rate 9 ml/min, 0.3 g catalyst coating (3.75 mg/cm(2)), pH 10 and 100 mu M RO 16 dye. The rate equation for the degradation based on Langmuir-Hinshelwood model has been proposed.