Degradation of trichloroethylene by biochar supported nano zero-valent iron (BC-nZVI): The role of specific surface area and electrochemical properties

Daibing Hou; Xuedan Cui; Meng Liu; Hantong Qie; Yiming Tang; Wenpeng Leng; Nan Luo; Huilong Luo; Aijun Lin; Wenjie Yang; Wenxia Wei; Tianwen Zheng

doi:10.1016/j.scitotenv.2023.168341

Degradation of trichloroethylene by biochar supported nano zero-valent iron (BC-nZVI): The role of specific surface area and electrochemical properties

Sci Total Environ. 2024 Jan 15:908:168341. doi: 10.1016/j.scitotenv.2023.168341. Epub 2023 Nov 6.

Authors

Daibing Hou¹, Xuedan Cui¹, Meng Liu¹, Hantong Qie¹, Yiming Tang¹, Wenpeng Leng², Nan Luo², Huilong Luo², Aijun Lin¹, Wenjie Yang³, Wenxia Wei⁴, Tianwen Zheng⁵

Affiliations

¹ College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
² Institute of Resources and Environment, Beijing Academy of science and technology, Beijing 100095, PR China.
³ Chinese Academy of Environmental Planning, Beijing 100012, PR China. Electronic address: yangwj@caep.org.cn.
⁴ Institute of Resources and Environment, Beijing Academy of science and technology, Beijing 100095, PR China. Electronic address: liepi_wwx@163.com.
⁵ Institute of Resources and Environment, Beijing Academy of science and technology, Beijing 100095, PR China. Electronic address: xiaotwzheng@163.com.

PMID: 37939947
DOI: 10.1016/j.scitotenv.2023.168341

Abstract

Direct electron transfer and the involvement of atomic hydrogen (H^⁎) are considered the main mechanisms for reductive dechlorination promoted by nano zero-valent iron (nZVI) supported on highly conductive carbon. It is still unclear how precisely H^⁎, the specific surface area, and the electrochemical characteristics contribute to biochar supported nano zero-valent iron (BC-nZVI) activity in chlorinated hydrocarbon contaminant removal. In this study, a range of BC-nZVIs were prepared by a liquid-phase reduction process, and the contributions of specific surface area and electrochemical performance to H^⁎ generation and electron transfer have been assessed. The mechanism of trichloroethylene (TCE) dechlorination by BC-nZVIs has been evaluated in terms of removal efficiency and the ultimate degradation products. The results have demonstrated that BC-nZVIs exhibit a higher specific surface area and TCE degradation efficiency compared with the bare nZVI. Ethane, ethylene, and acetylene were the principal TCE degradation products. The elimination of TCE was not significantly affected by differences in BC-nZVI specific surface area, but electron transfer and sustained generation of H^⁎ were dependent on the catalyst electrochemical characteristics. The electrochemical properties of biochar serve to lower the corrosion potential of nZVI, improving electronic transfer capability and reactivity and promoting direct electron transfer for the degradation of TCE. In addition, the enhanced electrochemical properties also facilitate the reaction of nZVI with water and can promote the sustained generation of H^⁎. Generation of H^⁎ played a key role in reductive dechlorination over BC-nZVIs, which was related to the properties of the biochar support. This study focuses on the role of H^⁎ and electrochemical performance in TCE reductive dechlorination, and provides a theoretical foundation and experimental support for the practical application of BC-nZVIs.

Keywords: Atomic hydrogen; Biochar; Electron transfer; Nano zero-valent iron; Specific surface area.

MeSH terms

Charcoal / chemistry
Iron / chemistry
Trichloroethylene* / chemistry
Water Pollutants, Chemical* / chemistry

Substances

Trichloroethylene
biochar
Iron
Charcoal
Water Pollutants, Chemical