Degradation of Tetracycline in Water by Fe-Modified Sterculia Foetida Biochar Activated Peroxodisulfate

Abstract

Tetracycline (TC) is a broad-spectrum antibiotic commonly, made use of in aquaculture and animal husbandry. After entering water bodies, it will represent a major threat to human health. In this study, sterculia foetida biochar (SFC) was readied by the combined hydrothermal pyrolysis (co-HTP) method with sterculia foetida as raw materials. Fen-SFC (Fe2-SFC, Fe3-SFC, and Fe4-SFC) was obtained by doping SFH with different concentrations of FeCl3. Finally, activation of peroxodisulfate (PDS) was achieved, using Fe3-SFC to degrade TC. The degradation of TC obeyed pseudo-second-order kinetics, and the constant of the reaction rate was 0.491 L mg−1 min−1. Radical trapping experiments, EPR test and electrochemical tests evidenced that the high catalytic performance of the Fe3-SFC/PDS system was ascribed to free radical pathway (•OH and SO4•−) and non-radical pathway (1O2 and electron transfer), in which the latter plays a dominant role. This research not only demonstrates a new kind of biochar as an effective catalyst for PS activation, but also offers an avenue for the value-added reuse of sterculia foetida.