Acid-modified red mud biochar for the degradation of tetracycline: Synergistic effect of adsorption and nonradical activation

Bohan Xu; Qiang An; Shuman Deng; Zheng Li; Zihao Yang; Haoyu Wu; Zhihong Ye

doi:10.1016/j.jenvman.2023.119077

Acid-modified red mud biochar for the degradation of tetracycline: Synergistic effect of adsorption and nonradical activation

J Environ Manage. 2023 Dec 1:347:119077. doi: 10.1016/j.jenvman.2023.119077. Epub 2023 Sep 28.

Authors

Bohan Xu¹, Qiang An², Shuman Deng¹, Zheng Li¹, Zihao Yang¹, Haoyu Wu¹, Zhihong Ye¹

Affiliations

¹ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China.
² The Key Laboratory of Eco-Environment in Three Gorges Reservoir Region, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: anqiang@cqu.edu.cn.

PMID: 37776788
DOI: 10.1016/j.jenvman.2023.119077

Abstract

In this study, a novel acid-modified red mud biochar catalyst (MMBC) was synthesized by industrial waste red mud (RM) and peanut shell (PSL) to activate peroxodisulfate (PDS) for the degradation of TC. Meanwhile, MMBC exhibited remarkable adsorption capacity, reaching a 60% removal ratio of TC within 60 min (equilibrium adsorption capacity = 12 mg/g). After adding PDS, MMBC/PDS system achieved a 93.8% removal ratio of TC within 60 min. Quenching experiments and electron paramagnetic resonance (EPR) results showed that ¹O₂ played a dominant role in the degradation of TC and O₂^•- was the mainly precursor for the production of ¹O₂ in the MMBC/PDS system. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the surface Fe(II), -OH and -COOH provided the active sites for the activation of PDS by MMBC. In addition, acid modification optimised the surface structure of the catalyst and enhanced the conversion of Fe (mainly Fe(III) to Fe(II)), thereby improving the adsorption and catalytic efficiency of MMBC. This study confirmed that modified red mud biochar is an efficient composite with both adsorption and catalysis, providing new ideas for the practical treatment of antibiotic wastewater and the resource utilization of red mud.

Keywords: Adsorption; Persulfate; Red mud; Singlet oxygen; Tetracycline.

MeSH terms

Adsorption
Anti-Bacterial Agents
Charcoal / chemistry
Ferric Compounds* / chemistry
Ferrous Compounds
Tetracycline
Water Pollutants, Chemical* / chemistry

Substances

biochar
Ferric Compounds
Charcoal
Anti-Bacterial Agents
Tetracycline
Ferrous Compounds
Water Pollutants, Chemical