Efficient activation of peroxymonosulfate mediated by Co(II)-CeO2 as a novel heterogeneous catalyst for the degradation of refractory organic contaminants: Degradation pathway, mechanism and toxicity assessment

• Published in: Journal of hazardous materials 2022-08, Vol.435, p.129013-129013, Article 129013
• Main Authors: Di, Siyuan, Wang, Jiahao, Zhai, Yixin, Chen, Pin, Ning, Tao, Shi, Chunxiang, Yang, Hucheng, Bao, Yue, Gao, Qiang, Zhu, Shukui
• Format: Article
• Language: English
• Subjects: Co(II)-doped CeO2; Degradation mechanism; DFT calculations; Ecotoxicological assessment; Enhanced catalytic efficiency
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129013

A series of Co(II)-CeO2 mixed metal oxides were synthesized by a facile hydrothermal-calcination procedure for activating peroxymonosulfate (PMS) and degrading toxic and difficult biodegradable organics. Co(II)-CeO2 showed excellent degradation performance toward rhodamine B (RhB), toluidine blue, methylene blue and diclofenac. RhB is a refractory organic contaminant, and ecotoxicological evaluation unraveled its harmfulness to the biosphere. RhB was selected as the model pollutant to investigate catalytic mechanisms. Parameters affecting degradation performance were profoundly investigated, including Co:Ce feed ratio, initial pH, PMS dosage, catalyst dosage, RhB concentration, coexisting ions and reaction temperature. Reaction mechanisms were proposed based on density functional theory calculations and identifications of reactive oxygen species. Improvements have been achieved in seven aspects compared to previous studies, including 100% degradation ratio in both real water samples and each reuse of the catalyst, ultrafast degradation rate, cost-effectiveness of the catalyst, toxicity-attenuation provided by the developed degradation method, high degree of mineralization for the model pollutant, negligible leaching of active sites, and the enhancement of catalytic performance by utilizing trace leached cobalt, endowing the technique with broad applicability and prospect. [Display omitted] •Ultrafast RhB degradation rate was achieved and the proposed method is cheap.•Ecotoxicological assessment was firstly used in Co(II)-CeO2/PMS/RhB system.•DFT calculation revealed the significance of Co(II) decoration.•Converting active site leaching to degradation effect rise is first realized.•The catalyst is suitable for diverse organics, wide pH ranges and real samples.