3D hierarchical Fe-doped Bi4O5I2 microflowers as an efficient Fenton photocatalyst for tetracycline degradation over a wide pH range

Abstract

Fenton reaction is proved to be an efficient method for degrading organic pollutants in wastewater. However, the narrow pH range greatly restricts the application of Fenton reaction. Herein, the 3D hierarchical Fe-doped Bi4O5I2 microflowers have been synthesized via a hybrid solvothermal-calcination method and applied in a photo-Fenton system for efficient removal of tetracycline (TC). The optimized Fe-doping Bi4O5I2 (11Fe-BOI) microflowers present more than 90% degradation efficiency over the pH range of 3.0–9.0 in Fenton system under visible light irradiation, and the reaction rate constant in 11Fe-BOI/H2O2/Vis system is 2.79 × 10−2 min−1, which is 19.11, 1.85 and 7.71 times higher than that of H2O2/Vis (1.46 × 10−3 min−1), 11Fe-BOI/Vis (1.51 × 10−2 min−1) and 11Fe-BOI/H2O2 (3.61 × 10−3 min−1) systems, respectively. The synergy effect of photocatalysis and Fenton reaction plays a pivotal role for the TC degradation process via accelerating the separation of carriers and the generation of reactive oxygen species. The scavenging experiments and EPR results manifest that O2– and OH are dominant active species during the TC degradation process. This work provides great prospect to fabricate an efficient non-noble metal photocatalyst for photo-Fenton degradation of antibiotics.