Heterogeneous photocatalytic degradation of organic contaminant in water over high-activity Fe-TS-1 under the radiation of solar light

Abstract

The Fe-supported titanium silicate molecular sieve (Fe-TS-1) was synthesized and its solar light responsive activity was evaluated by the degradation of acid orange 7 (AO7) in the heterogeneous photo-Fenton system. The vital operational parameters as mass ratio of the iron and the TS-1 (Q (m (Fe): m (TS-1)), concentration of H2O2 and the initial solution pH value have been extensively studied. The obtained results showed that the solar light radiation could to enhance the catalytic efficiency of the Fe-TS-1 catalyst and there was a synergistic effect of the solar light and the Fe-TS-1 catalyst. The decoloration of AO7 in the photo-Fenton system followed the pseudo-first-order kinetics model and the optimal conditions for the degradation of AO7 of a concentration of 100 mg/L were obtained under the condition of 0.2 Q, 10 mL/L H2O2 addition and 3.0 solution initial pH value. The achieved decoloration of AO7 was 97.7% and corresponding TOC removal was 52.7%. The degradation pathway of AO7 was also inferred by the change of pH, and UV–vis spectrum in the process of reaction in the paper and the possible catalytic degradation mechanism of the Fe-TS-1 was proposed. The high-efficiency degradation of AO7 in the photo-Fenton system was the result of interaction of photosensitivity of dye, adsorption and photocatalysis of TS-1 and Fenton reaction. The whole process of degradation proceeded as follow: “adsorption-degradation-regeneration”.