Magnetic biochar catalysts from anaerobic digested sludge: Production, application and environment impact

Yi-di Chen; Shunwen Bai; Ruixiang Li; Guanyong Su; Xiaoguang Duan; Shaobin Wang; Nan-Qi Ren; Shih-Hsin Ho

doi:10.1016/j.envint.2019.02.032

Magnetic biochar catalysts from anaerobic digested sludge: Production, application and environment impact

Environ Int. 2019 May:126:302-308. doi: 10.1016/j.envint.2019.02.032. Epub 2019 Feb 27.

Authors

Yi-di Chen¹, Shunwen Bai¹, Ruixiang Li¹, Guanyong Su², Xiaoguang Duan³, Shaobin Wang⁴, Nan-Qi Ren¹, Shih-Hsin Ho⁵

Affiliations

¹ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
² School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, PR China.
³ School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia. Electronic address: xiaoguang.duan@adelaide.edu.au.
⁴ School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.
⁵ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China. Electronic address: stephen6949@hit.edu.cn.

PMID: 30825749
DOI: 10.1016/j.envint.2019.02.032

Abstract

Regulated disposal or re-utilization of dewatered sludge is of economic benefits and can avoid secondary contamination to the environment; however, feasible and effective management strategies are still lacking. In this study, a peroxydisulfate/zero-valent iron (PDS-ZVI) system is proposed to destroy proteins in soluble extracellular polymeric substances (S-EPS) and loosely bound EPS (LB-EPS) in anaerobic digested sludge (ADS) to improve the dewaterability. Moreover, ADS derived biochars supported via iron oxides (Fe-ADSBC) were generated by dewatering and thermal annealing. Intriguingly, the iron species was discovered to gradually transform from Fe₃O₄ to FeO with increased pyrolysis temperatures from 600 to 1000 °C. The manipulated iron species on the biochar can remarkably impact the catalytic activity in PDS activation and degradation of sulfamethazine (SMT). The in situ radical scavenging and capturing tests revealed that the principal reactive oxygen species (ROS) in Fe-ADSBC/PDS system experienced a variation from OH into SO₄^- at higher annealing temperature (1000 °C). In addition, the carbonaceous ADSBC can promote the catalytic activity of iron oxides by synergistically facilitating the adsorption of reactants and charge transfer through COFe bonds at the interfaces. This study enables the first insights into the properties and catalytic performance of Fe-ADSBC, meanwhile unveils the mechanism, reaction pathways, and environmental impacts of the ultimate transformation products (TPs) from SMT degradation in the Fe-ADSBC/PDS system. The study also contributes to developing value-added green biochar catalysts from bio-wastes towards environmental purification.

Keywords: Anaerobic digested sludge; Biochar; Peroxydisulfate; Sulfamethazine.

Publication types

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

MeSH terms

Anaerobiosis
Catalysis
Charcoal / chemistry*
Environment
Iron / chemistry
Magnetic Phenomena
Oxidation-Reduction
Oxides / chemistry
Potassium Compounds / chemistry
Sewage / chemistry*
Sulfates / chemistry

Substances

Oxides
Potassium Compounds
Sewage
Sulfates
biochar
Charcoal
potassium persulfate
Iron