Investigate the multipath erasure of nitrobenzene over nanoscale zero-valent-iron/N-doped biochar hybrid with extraordinary reduction performance

Zhihua Xu; He Gu; Mengmeng Xiong; Yongheng Wang; Chenyang Ma; Siyi Gu; Ya Jin; Yaojia Meng; Daofang Zhang; Haijiao Xie; Weifang Chen

doi:10.1016/j.envres.2022.114724

Investigate the multipath erasure of nitrobenzene over nanoscale zero-valent-iron/N-doped biochar hybrid with extraordinary reduction performance

Environ Res. 2023 Jan 1;216(Pt 3):114724. doi: 10.1016/j.envres.2022.114724. Epub 2022 Nov 4.

Authors

Zhihua Xu¹, He Gu², Mengmeng Xiong², Yongheng Wang², Chenyang Ma², Siyi Gu², Ya Jin², Yaojia Meng², Daofang Zhang², Haijiao Xie³, Weifang Chen⁴

Affiliations

¹ School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, PR China. Electronic address: zhihuaxu_usst@126.com.
² School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, PR China.
³ Hangzhou Yanqu Information Technology Co., Ltd., Hangzhou, 310003, China.
⁴ School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, PR China. Electronic address: chenweifang@tsinghua.org.cn.

PMID: 36343712
DOI: 10.1016/j.envres.2022.114724

Abstract

In this study, the facile carbothermal reduction method was enforced using urea as dopant to modify the structure and chemical composition of nanoscale zero-valent-iron/biochar hybrid thereby boosting its reduction performance. Through fine-tuning the N-doped amount, the optimal nZVI/N-doped BC was obtained, which exhibited more active sites (nZVI, persistent free radicals (PFRs), pyrrolic-N) and superior electrochemical conductivity. With these blessings, the electrons originating from galvanic cell reaction could zip along the highway within the hybrid. Taking nitrobenzene (NB) as the target pollutant, the quantitative analysis revealed that the NB reduction and adsorption removal efficiency were dramatically improved by 2.42 and 2.78 times, respectively. What's more, combining the in-situ experimental detection and theoretical calculations, unexpected NB reductive multipath with respect to PFRs and pyrrolic-N accelerating the Fe³⁺/Fe²⁺ cycle within the nZVI/N-doped BC system was decoded. The enhancement of Fe³⁺/Fe²⁺ cycle improved the electron utilization efficiency and maintained the reduction reactivity of the hybrid. This work raised awareness of the mechanisms regarding the reduction performance of nZVI/N-doped BC elevated by N-doped and the pollutant reductive pathway within the system, uncovered the dusty roles of PFRs and N-species during the reduction process.

Keywords: Biochar; Fe(3+)/Fe(2+) cycle; N-doped; Nanoscale zero-valent-iron; Reductive pathways.