ZnFe_2O_4/TiO_2光催化剂制备及乙酰甲胺磷降解性能研究

Preparation and Photodegradation of Acephate Pesticide of Visible Light Nano-sized TiO_2 Photocatalyst

分别采用共沉淀法和溶胶-凝胶法制备了ZnFe2O4和掺杂ZnFe2O4的纳米级TiO2光催化剂,进行了XRD、TEM和UV visDRS表征,以卤素灯为光源对纳米TiO2降解水溶液中乙酰甲胺磷农药进行了研究。考察了反应液初始pH值、催化剂用量、H2O2用量对降解率的影响。实验结果表明,焙烧温度为400℃、掺杂量为0.5%的ZnFe2O4/TiO2纳米粉体降解效果最佳,在相同条件下,反应2h后农药降解率可比纯TiO2提高20%左右。正交实验优化了降解反应条件,在常温常压下,起始pH值为12、H2O2浓度为12mmol/L、催化剂浓度为0.5g/L、反应3h后,初始浓度为1.0×10-4mol/L的乙酰甲胺磷农药降解率可达61.2%。

ZnFe2O4 and ZnFe2O4 doped TiO2 nanoparticles were prepared by coprecipitation and sol-gel methods respectively, characterized by means of XRD, TEM and UV-visDRS. Photodegradation of acephate pesticide in aqueous solution by nano-sized TiO2 process was studied, which was irradiated by a 500w halogen lamp. The effect of factors including initial pH value, catalyst dosage and concentration of H2O2 were investigated. Results showed that TiOz nanoparticles which was baked under 400℃ and intermingled with 0.5% ZnFe2O4 had the best degradation effect, degradation efficiency of pesticide can be improved about 20% relative to pure TiO2 nanomaterials after 2h under the same conditions. Conditions that affect the degradation efficiency of organophosphorus pesticide were optimized by orthogonal experiment. In the optimal conditions with the initial pH 12, concentration of H2O2 12mmol/L and concentration of catalyst 0.5g/L, degradation rate of acephate pesticide with the initial concentration of 1.0×10^-4 mol/L can reach up to 61.2%.