N,S-codoped biochar outperformed N-doped biochar on co-activation of H2O2 with trace dissolved Fe(Ⅲ) for enhanced oxidation of organic pollutants

Mengna Lai; Jianfa Li; Huiming Li; Yao Gui; Jinhong Lü

doi:10.1016/j.envpol.2023.122208

N,S-codoped biochar outperformed N-doped biochar on co-activation of H₂O₂ with trace dissolved Fe(Ⅲ) for enhanced oxidation of organic pollutants

Environ Pollut. 2023 Oct 1:334:122208. doi: 10.1016/j.envpol.2023.122208. Epub 2023 Jul 14.

Authors

Mengna Lai¹, Jianfa Li², Huiming Li¹, Yao Gui¹, Jinhong Lü¹

Affiliations

¹ College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang, 312000, China.
² College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang, 312000, China. Electronic address: ljf@usx.edu.cn.

PMID: 37454716
DOI: 10.1016/j.envpol.2023.122208

Abstract

Co-activation of H₂O₂ with biochar and iron sources together provides an attractive strategy for efficient removal of refractory pollutants, because it can solve the problems of slow Fe(Ⅱ) regeneration in Fenton/Fenton-like processes and of low ^•OH yield in biochar-activated process. In this study, a wood-derived biochar (WB) was modified by heteroatom doping for the objective of enhancing its reactivity toward co-activation of H₂O₂. The performance of the co-activated system using doped biochars and trace dissolved Fe(Ⅲ) on oxidation of organic pollutants was evaluated for the first time. The characterizations using X-ray photoelectron spectroscopy (XPS), Raman spectra and electrochemical analyses indicate that heteroatom doping introduced more defects in biochar and improved its electron transfer capacity. The oxidation experiments show that heteroatom doping improved the performance of biochar in the co-activated process, in which the N,S-codoped biochar (NSB) outperformed the N-doped biochar (NB) on oxidation of pollutants. The reaction rate constant (k_obs) for oxidation of sulfadiazine in NSB + Fe + H₂O₂ is 2.25 times that in NB + Fe + H₂O₂, and is 72.9 times that in the Fenton-like process without biochar, respectively. The mechanism investigations indicate that heteroatom doping enhanced biochar's reactivity on catalyzing the decomposition of H₂O₂ and on reduction of Fe(Ⅲ) due to the improved electron transfer/donation capacity. In comparison with N-doping, N,S-codoping provided additional electron donor (thiophenic C-S-C) for faster regeneration of Fe(Ⅱ) with less amount of doping reagent used. Furthermore, co-activation with NSB maintained to be efficient at a milder acidic pH than Fenton/Fenton-like processes, and can be used for oxidation of different pollutants and in real water. Therefore, this research provides a novel, sustainable and cost-efficient method for oxidation of refractory pollutants.

Keywords: Advanced oxidation; Biochar; Fenton process; Heteroatom doping; Pollution control.

MeSH terms

Ferric Compounds*
Ferrous Compounds
Hydrogen Peroxide / chemistry
Oxidation-Reduction
Water Pollutants, Chemical* / analysis

Substances

biochar
Ferric Compounds
Hydrogen Peroxide
Water Pollutants, Chemical
Ferrous Compounds