Study on the efficacy and mechanism of Fe-TiO visible heterogeneous Fenton catalytic degradation of atrazine.

In order to improve the catalytic activity and recycling performance of heterogeneous Fenton catalyst, a heterogeneous Fenton catalyst Fe/TiO based on TiO supported visible light response was prepared by a simple method using TiO synthesized by sol-gel method as carrier and ferric nitrate as Fe source. It was characterized by SEM, EDX, XRD, UV-vis instruments. The influencing factors of catalytic degradation of atrazine by visible light heterogeneous Fenton of Fe/TiO were studied and the reaction kinetics were fitted. The mineralization degree of atrazine was reflected by the removal rate of TOC. The intermediate products by the degradation of the catalytic system was analyzed and the reaction mechanism of Fe/TiO-HO visible light system was discussed. The XRD results showed that Fe was highly dispersed on the surface of TiO in the form of α-FeO. The Fe/TiO catalyst with heterogeneous Fenton and visible light photocatalytic activity was successfully optimized, forbidden bandwidth of Fe/TiO after Fe supported was narrower, the scope of light absorption red-shifted, the electron-hole pairs were more generated, and there was a significant synergistic effect between the carrier TiO and the supported Fe, which exhibited good oxidation capacity for degradation of 10 mg L atrazine in pH of 3, the concentration of HO was 1.6 mM, and the catalyst was added at 1 g L, achieving over 95% removal efficiency within 30 min, and, in the range of pH 3-7, the degradation rate of the reaction for 30 min can be maintained above 75%, which greatly broadened the range of pH application and had good recycling performance. The degradation process conformed to the quasi-first-order kinetic model. Through LC-MS analyzed, 12 intermediate products were formed during the degradation of atrazine, the final products were all cyanuric acid, and then the triazine ring was mineralized into inorganic substances such as CO, HO and NO by oxidation of ·OH, and the possible degradation pathways were inferred.