Degradation of bisphenol a using peroxymonosulfate activated by single-atomic cobalt catalysts: Different reactive species at acidic and alkaline pH

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 439; p. 135002
• Main Authors: Wang, Qi, Liu, Cun, Zhou, Dongmei, Chen, Xiurong, Zhang, Meng, Lin, Kuangfei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: Density function theory; High-valent Co; Peroxymonosulfate; Single-atom cobalt catalyst; Singlet oxygen; High-valent Co; Singlet oxygen; Peroxymonosulfate; Single-atom cobalt catalyst; Density function theory
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.135002

[Display omitted] •Single-atomic Co catalysts were prepared for PMS activation.•High-valent cobalt species [Co(IV)] and singlet oxygen (1O2) were demonstrated to be the predominant reactive species.•The generation routes of reactive oxygen species at acidic and alkaline pH were explicated.•The SA-CoCN catalysts exhibited a high stability. Peroxymonosulfate-assisted advanced oxidation processes (PMS-AOPs) catalyzed by single-atom catalysts have become state-of-the-art technologies for environmental remediation. In this study, Cobalt single-atom catalysts supported by graphitic carbon nitride (SA-CoCN) containing Co-N4 active sites were developed as PMS activators for bisphenol A (BPA) degradation. BPA (10 mg L−1) was completely removed with 0.1 g L−1 SA-CoCN and 0.5 mM PMS, and this process was pH-dependent. Instead of the widely recognized generation of free radicals (SO4·– and ‧OH), high-valent cobalt [Co(IV)] and singlet oxygen (1O2) were the predominant reactive species for pollutant degradation under acidic and alkaline conditions, respectively. The conversion of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO2), electron paramagnetic resonance tests and radical scavenger experiments were used to probe these reactive species. According to density functional theory calculations, the formation of Co(IV) and 1O2 was thermodynamically favorable, and the generation pathways of Co(IV) and 1O2 were further discussed. This study provides an insight into the single-atom cobalt catalyst/PMS process.