PHOTOCATALYTIC REMOVAL OF ACETOCHLOR FROM AQUEOUS SOLUTIONS USING TiO2 NANOCATALYST

摘要

In the present study, the photocatalytic degradation of the herbicide acetochlor in aqueous solution has been studied by using titanium dioxide as a photocatalyst. Operational parameters such as catalyst loading, initial pollutant concentration, pH value, inorganic saltsand the type of light sources on the reaction rate were evaluated. The apparent first-order rate constants (k(ap)) were used to evaluate the degradation efficiency of acetochlor. The results of experiments showed that increasing in the initial concentration of acetochlor and catalyst loading decreases the photocatalytic degradation efficiency. The optimal TiO2 and acetochlor concentrations were 0.1 g/L and 50ppm, respectively. Higher degradation efficiency of acetochlor was observed at neutral pH values. The apparent pseudo first-order rate constants were 0.065, 0.064, 0.088 and 0.078 min(-1) at pH 3, 5, 7 and 9, respectively. However, the presence of HCO3- anion leads to an increase in the effectiveness of the photocatalytic degradation. Results showed considerable reductions of herbicides concentration, using UVC lamps and the TiO2 photocatalyst.