Enhanced heterogeneous photo-Fenton-like degradation of tetracycline over CuFeO2/biochar catalyst through accelerating electron transfer under visible light

• Published in: Journal of environmental management 2021-05, Vol.285, p.112093, Article 112093
• Main Authors: Xin, Shuaishuai, Ma, Bingrui, Liu, Guocheng, Ma, Xiaoming, Zhang, Chunlei, Ma, Xiaohan, Gao, Mengchun, Xin, Yanjun
• Format: Article
• Language: English
• Subjects: Biochar; CuFeO2; Electron transfer; Heterogeneous photo-Fenton-like degradation; Tetracycline; Visible light
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2021.112093

The visible-light induced heterogeneous photo-Fenton-like (HPF-like) process is regarded as a promising technique for organic pollutants degradation due to its efficient utilization of solar energy and high H2O2 activation activity. This study prepared the CuFeO2/biochar catalysts via hydrothermal technique at no extra reductant and systematically investigated their band structure and photoelectric properties. The dispersed distribution of CuFeO2 particles in CuFeO2/biochar composites narrowed bandgap of CuFeO2 and promoted electron transport of CuFeO2. Compared with CuFeO2, the CuFeO2/biochar containing 1.0 g biochar in the preparation (CuFeO2/biochar-1.0) possessed higher carrier density and longer photoelectron lifetime, which is beneficial to higher catalytic performance. The apparent rate constant for tetracycline as target pollutant degradation by CuFeO2/biochar-1.0 was 2.0 times higher than that by CuFeO2. The acquired optimum conditions for tetracycline degradation were 220 mg L−1 CuFeO2/BC-1.0, 22 mM H2O2 and pH 6.4 using response surface methodology. The quenching experiments and ESR analysis revealed that OH was the predominant active species, and photoelectron and O2− were auxiliary species. The photoelectron could promote in-situ recycling of Cu2+ to Cu+ and Fe3+ to Fe2+, which significantly improved H2O2 activation by CuFeO2. The possible pathway of tetracycline was proposed according to intermediates identified by HPLC/MS. The toxicity analysis demonstrated that the overall toxicity of the identified intermediates was reduced in HPF-like system. [Display omitted] •Biochar narrowed bandgap and facilitated interface electron transfer of CuFeO2.•Biochar extended photoelectron lifetime and enhanced carrier density of CuFeO2.•Efficient degradation of tetracycline by CuFeO2/biochar in HPF-like system.•OH, e− and O2− rather than h+ played a role in tetracycline degradation.•The photoelectron greatly promoted in-situ recycling of Cu2+ to Cu+ and Fe3+ to Fe2+.