The synergistic catalytic mechanism between different functional sites of boron/iron on iron oxides in Fenton-like reactions

The detoxification and harmless treatment of toxic organic industrial wastewater are essential guarantees for the global water environment and human life safety. As an important treatment technology for this wastewater, the advanced oxidation process is limited by the catalytic rate due to the low reduction rate, and the modulation and acceleration of electron transfer at the catalytic sites become the focus and difficulty in this field. Herein, we synthesized boron-doped iron oxide (FeOx-B) to enhance the interfacial electron transfer during peroxymonosulfate (PMS) catalysis, resulting in efficient degradation (91.73 %) of the contaminant (TTCH, Tetracycline hydrochloride). Compared with the commercial Fe2O3 and Fe3O4, the removal rate of TTCH is improved by 47.89 % and 24.45 %, respectively. As a new active site, B-O interacts with the contaminant and accelerates the reduction of Fe (III). The reactive species also change from sulfate radical (SO4 center dot-), hydroxyl radical ((OH)-O-center dot), and singlet oxygen (O-1(2)) to surface reactive complexes. The system is pH-adaptive (pH = 3-11) and presents excellent resistance to humic acid (HA) and anions (10 mM). Toxicity assessment reveals that the degradation products are low toxic or harmless. This work suggests a new strategy for the development of highly reactive iron-based materials and provides theoretical insights into the mechanism of the PMS activation processes.

Automated summary

The detoxification and harmless treatment of toxic organic industrial wastewater are crucial for the global water environment and human life safety. In this study, boron-doped iron oxide (FeOx-B) was synthesized to enhance the electron transfer during peroxymonosulfate (PMS) catalysis, leading to efficient degradation of the contaminant TTCH. Compared with commercial Fe2O3 and Fe3O4, FeOx-B exhibited significantly higher removal rate of TTCH. The interaction between B-O and the contaminant promoted the reduction of Fe(III) and changed the reactive species in the system.