Graphite (GP) induced activation of ferrate(VI) for degradation of micropollutants: The crucial reduction role of carbonyl groups on GP surface

Mengfan Luo; Heng Zhang; Peng Zhou; Jiali Peng; Ye Du; Zhaokun Xiong; Bo Lai

doi:10.1016/j.jhazmat.2022.128827

Graphite (GP) induced activation of ferrate(VI) for degradation of micropollutants: The crucial reduction role of carbonyl groups on GP surface

J Hazard Mater. 2022 Jul 15:434:128827. doi: 10.1016/j.jhazmat.2022.128827. Epub 2022 Apr 6.

Authors

Mengfan Luo¹, Heng Zhang², Peng Zhou¹, Jiali Peng¹, Ye Du¹, Zhaokun Xiong¹, Bo Lai¹

Affiliations

¹ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China.
² State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China. Electronic address: zhangheng01@scu.edu.cn.

PMID: 35405605
DOI: 10.1016/j.jhazmat.2022.128827

Abstract

The sluggish oxidation kinetics of ferrate (Fe(VI)) at neutral and slightly alkaline pH impedes its rapid abatement of micropollutants in practical application. This work discovers that graphite (GP), a metal-free carbonaceous material, can be a promising material to improve the reactivity of Fe(VI) in the pH range of 7.0 - 9.0. The performance of the GP/Fe(VI) process for sulfamethoxazole (SMX) removal was further evaluated via altering the dosages of Fe(VI), GP, and SMX. Probe analysis and quenching experiments identified Fe(IV) and Fe(V) as the primary active species responsible for the removal of organic compounds in the GP/Fe(VI) system. The detailed activation mechanism of GP is discussed via analyzing the surface chemical changes of GP exposed to Fe(VI). It is found that the carbonyl groups on GP surface execute a critical role in Fe(VI) activation. The GP/Fe(VI) system shows powerful anti-interference ability to environmental background substances. Therefore, the new oxidation process proposed in this work holds a great application prospect for contamination remediation. Finally, we discuss the underlying degradation pathways of SMX by the GP/Fe(VI) system. This study not only develops a promising system for the removal of micropollutants but also provides an in-depth insight into the activation mechanism of metal-free carbonaceous material in Fe(VI) oxidation process.

Keywords: Ferrate; Graphite; High-valent Fe species; Micropollutants; Oxidation.