Microwave (MW)-assisted design of cobalt anchored 2D graphene-like carbon nanosheets (Co@GCNs) as peroxymonosulfate activator for tetracycline degradation and insight into the catalytic mechanism

• Published in: Separation and purification technology Vol. 295; p. 121358
• Main Authors: Liu, Lei, Yu, Meiying, Li, Yunfei, Han, Chunjiang, Ding, Guofang, Liu, Shengnan, Xie, Yunxuan, Liu, Jia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-08-2022
• Subjects: Co@GCNs; Microwave-assisted; Non-radical pathway; Peroxymonosulfate; Tetracycline; Microwave-assisted; Peroxymonosulfate; Co@GCNs; Non-radical pathway; Tetracycline
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.121358

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•Co@GCNs were synthesized through rapid catalytic coordination driven by MW.•The Co@GCN-1 exhibited superior catalytic performance for PMS activation.•Non-radical pathway represented by 1O2 was the dominant degradation mechanism.•2D GCNs as electron mediators promoted the Co3+/Co2+ cycle.
Developing a rapid and cost-effective strategy to design catalysts for advanced oxidation processes (AOPs) has significant implications for environmental remediation. In this study, cobalt anchored 2D graphene-like carbon nanosheets (Co@GCNs) catalysts were fabricated by simple coordination of metal precursors into agarose through microwave (MW)-assisted method to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. Among them, the Co@GCN-1 exhibited excellent dispersibility and catalytic performance. The Co@GCN-1/PMS system could completely degrade TC (20 mg L–1) within 20 min, whose reaction rate constant (0.273 min−1) was about 6.5 times that of the Co3O4/PMS system (0.0362 min−1) and 14.1 times of the GCN/PMS system (0.0194 min−1), respectively. Additionally, the degradation performance was applicable in a wide pH range (3.84–9.03) and still reached an efficiency of>90% after five cycles. Non-radical pathway represented by 1O2 served as the main contributor to TC degradation besides radicals (i.e., SO4−, OH, and O2−). Density functional theory (DFT) calculations unveiled the synergistic interaction of Co@GCNs, where 2D GCNs as electron mediators promoted the Co3+/Co2+ cycle. Based on the LC-MS analysis, three main degradation pathways of TC including fourteen possible intermediates were proposed based on different ROS reactions. This work provides a facilely prepared and promising 2D metal-based carbonous catalyst to activate PMS for the efficient degradation of TC.