Iron/nitrogen co-doped biochar derived from salvaged cyanobacterial for efficient peroxymonosulfate activation and ofloxacin degradation: Synergistic effect of Fe/N in non-radical path

Yuxuan Yang; Yanxiao Chi; Kunlun Yang; Zengshuai Zhang; Peng Gu; Xueli Ren; Xiaorui Wang; Hengfeng Miao; Xinhua Xu

doi:10.1016/j.jcis.2023.08.096

Iron/nitrogen co-doped biochar derived from salvaged cyanobacterial for efficient peroxymonosulfate activation and ofloxacin degradation: Synergistic effect of Fe/N in non-radical path

J Colloid Interface Sci. 2023 Dec 15;652(Pt A):350-361. doi: 10.1016/j.jcis.2023.08.096. Epub 2023 Aug 16.

Authors

Yuxuan Yang¹, Yanxiao Chi¹, Kunlun Yang², Zengshuai Zhang¹, Peng Gu¹, Xueli Ren¹, Xiaorui Wang¹, Hengfeng Miao¹, Xinhua Xu³

Affiliations

¹ School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China.
² School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Suzhou Institute of Environmental Sciences, Postdoctoral Innovation and Practice Base of Jiangsu Province, Suzhou 21500, China. Electronic address: yangkunlun@jiangnan.edu.cn.
³ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.

PMID: 37598435
DOI: 10.1016/j.jcis.2023.08.096

Abstract

A green, low-cost, high-performance Fe/N co-doped biochar material (Fe-N@C) was synthesized using salvaged cyanobacteria without other extra precursors for peroxymonosulfate (PMS) activation and ofloxacin (OFX) degradation. With the increased pyrolysis temperature, the graphitization degree, the specific surface area and the corresponding groups like OH, COO etc. for Fe-N@C tended to increase, resulting in a greater OFX adsorption. However, the total amount of Fe-N_X and graphitic nitrogen groups in the Fe-N@C composites was firstly increased and then decreased, which reached the highest at 800 °C (Fe-N@C-800). All these changes of functional species ascribed to the strong interaction between Fe, N and C led to the highest defect degree of Fe-N@C-800, resulting the highest OFX removal efficiency of 95.0 %. OFX removal experiments indicated the adsorption process promoted the total OFX degradation for different functional groups on Fe-N@C composites separately dominated the process of OFX adsorption and PMS catalysis. Radical quenching and electron paramagnetic resonance (EPR) measurements proved free radical and non-free radical pathways participated in Fe-N@C/PMS system. The non-free radicals based on ¹O₂ and high-valent iron-oxo species played a more important role in OFX degradation, leading to the minimal effect of co-existing anions and the high universality for other antibiotic pollutants. Fe-N_X was utilized as the main catalytic sites and graphitic nitrogen contributed more to the electron transfer for PMS activation, whose synergistic effect efficiently facilitated OFX degradation. Finally, the possible degradation route of OFX in the Fe-N@C-800/PMS system was proposed. All these results will provide the new insights into the intrinsic mechanism of Fe/N species in carbon-based materials for PMS activation.

Keywords: Fe-N(X) sites; Non-radical pathway; Ofloxacin; Peroxymonosulfate activation; Salvaged cyanobacterial.

MeSH terms

Cyanobacteria*
Iron*
Nitrogen
Ofloxacin
Peroxides

Substances

peroxymonosulfate
biochar
Iron
Ofloxacin
Nitrogen
Peroxides