Metal-rich hyperaccumulator-derived biochar as an efficient persulfate activator: Role of intrinsic metals (Fe, Mn and Zn) in regulating characteristics, performance and reaction mechanisms

Xinhua Wang; Peng Zhang; Cuiping Wang; Hanzhong Jia; Xiaofu Shang; Jingchun Tang; Hongwen Sun

doi:10.1016/j.jhazmat.2021.127225

Metal-rich hyperaccumulator-derived biochar as an efficient persulfate activator: Role of intrinsic metals (Fe, Mn and Zn) in regulating characteristics, performance and reaction mechanisms

J Hazard Mater. 2022 Feb 15;424(Pt A):127225. doi: 10.1016/j.jhazmat.2021.127225. Epub 2021 Sep 15.

Authors

Xinhua Wang¹, Peng Zhang², Cuiping Wang¹, Hanzhong Jia³, Xiaofu Shang⁴, Jingchun Tang¹, Hongwen Sun¹

Affiliations

¹ MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China.
² MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China. Electronic address: nkzhangpeng@nankai.edu.cn.
³ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China.
⁴ Tianjin Academy of Environmental Science, Tianjin 300350, China.

PMID: 34600381
DOI: 10.1016/j.jhazmat.2021.127225

Abstract

Biochar has been widely used in advanced oxidation processes (AOPs) for the decomposition of organic contaminants. However, the role of intrinsic metals in hyperaccumulator biomass in the physico-chemical properties and performance of peroxodisulfate (PDS) activation by biochar is still unclear. This work employed hyperaccumulator biomass containing Fe, Mn and Zn, respectively. Result showed that as the pyrolysis temperature of the biochar increased, Fe was gradually reduced to iron oxide and Fe⁰, and Zn was reduced and volatilized; however, Mn remained in biochar in the form of MnS and CaMnO₃ with high valence states. These thermochemical behaviors of intrinsic metals also facilitated graphitized structure growth and pore development (for Zn) and persistent free radicals (PFRs) generation (for Mn and Zn) in biochar, and these processes were crucial for imidacloprid degradation in biochar/PDS systems. Moreover, Fe/Zn@PB9/PDS showed better imidacloprid degradation performance, while Mn species in Mn@PB were catalytically inert. In addition, the radical pathway depending on·SO₄^- and·OH was the dominant pathway for imidacloprid degradation in the Fe@PB9/PDS systems, while the·O₂^--mediated ¹O₂ pathway and ¹O₂-based nonradical pathway contributed more in the Zn@PB9/PDS systems. These results reveal the role of intrinsic metals in biochar-based catalysts and provide a reference for the preparation of green and efficient hyperaccumulator-derived biochar catalysts for AOPs.

Keywords: Advanced oxidation processes; Biochar; Hyperaccumulator; Persulfate; Transition metal.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Charcoal*
Metals*
Pyrolysis
Zinc

Substances

Metals
biochar
Charcoal
Zinc