The efficient degradation of organic pollutants by Z-scheme MIL-88A@TiO2 heterojunction photo-Fenton catalyst: The synergistic effect of photocatalysis and Fenton catalysis

Abstract

The combination of photocatalysis technology and Fenton technology to realize photo-Fenton degradation of organic pollutants is an effective way to improve the catalytic performance of materials. In this paper, a novel heterojunction photo-Fenton catalyst MIL-88A@TiO2 (MT-X) has been prepared using MIL-88A and TiO2 as substrate by one-pot hydrothermal method. The formation of MT-X heterogeneous structure not only improves the electron-hole separation performance of the composites, but also accelerates the regeneration of Fe2+. Under the synergistic action of photocatalysis and Fenton catalysis, MT-2 with the best performance can completely degrade methylene blue (MB, 100 mL, 20 mg/L) within 16 min and can mineralize 76.23 % MB into small molecule products. Meanwhile, MT-2 also has excellent adsorption and degradation properties for tetracycline (TC), which can degrade 99 % TC (100 mL, 50 mg/L) within 20 min, the reaction kinetic constant k = 0.27938 min‐1 is higher than most reported photocatalysts. Hydroxyl radical is identified as the main active species in the degradation process by quenching and hydroxyl radical capture experiments, and a possible degradation mechanism is proposed (Z-scheme electron transfer mechanism). Therefore, this study provides an efficient and feasible photo-Fenton catalyst for pollutant treatment, which is helpful to further understand the synergistic effect of photocatalysis and Fenton catalysis.