Degradation of Ametryn in aqueous solution by solar/ S-doped titanium dioxide process

摘要

The removal efficiency of ametryn in water and the influencing factors by the combined process of solar irradiation and S-doped TiO_2 were studied in detail, in which S-doped TiO_2 photo-catalyst with high sunlight activity was prepared by acid catalyzed hydrolysis method with thiourea as sulfur source; As a comparison, solar/TiO_2 process was studied in the meantime; The experiment results showed that ametryn could be more effectively oxidized by the solar/S-doped TiO_2 process than the solar/ TiO_2 one, while the removal efficiency of 60% and 40% respectively after 30 min's irradiation; Pseudo-first-order model could be used to simulate the oxidation process in which the degradation rate coefficients were independent of the initial concentration of ametryn; Degradation rate could be greatly affected by the concentration of H_2O_2, the optimum concentration for the system of solar/S-doped TiO_2 was found to be 20mg/L, which was 5mg/L higher than that of solar/TiO_2 system; Lower water pH favored the degradation of ametryn for the change of charge density of both the ametryn molecular and photo-catalyst surface.