Radical to non-radical conversion during PMS activation triggered by optimized electronic structure: Orientational regulation of oxidation pathway for water remediation

• Published in: Separation and purification technology 2025-05, Vol.357, p.130034, Article 130034
• Main Authors: Tan, Jianke, Chang, Lian, Zhang, Xiaodan, Chai, Hongxiang, Huang, Yuming
• Format: Article
• Language: English
• Subjects: Co(OH)2; Oxidation pathway; Peroxymonosulfate; Radical to non-radical conversion; Se doping
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.130034

The Se-doped Co(OH)2 hollow spheres were fabricated via selenic acid etching and NaBH4 reduction after calcination. Se doping modulates the electronic configuration, causes downshift of d-band center of Co and enhances the surface adsorption capacity of PMS, triggering the radical to non-radical conversion of gatifloxacin degradation, dominated by 1O2 and assisted by electron transport processes. [Display omitted] •Se doping induces radical to non-radical conversion during PMS activation.•Non-radical routes are dominated by 1O2 and assisted by electron transport.•Downshift of d-band of Co 3d and O−H bond stretch in PMS via Se doping of Co(OH)2.•Se-doped Co(OH)2 shows universality and reusability in PMS-based AOP.•Directionally regulated oxidation route facilitates the AOP’s practical potential. The orientational regulation of non-radical pathways is significant in the peroxymonosulfate (PMS)-based AOP for practical potential, but remains challenge. Here, the Se-doped Co(OH)2 hollow spheres (CoHS-Se-CR) were designed for PMS activation to rapidly degrade gatifloxacin (GAT) antibiotic, with over 95 % GAT removal in 20 min. DFT and experimental trials reveal the downshift of d-band center of Co 3d and O−H bond stretch in PMS via Se doping of Co(OH)2. The active HSO5•− generated via the breaking of O–H bond triggers the radical to the non-radical conversion of the degradation mechanism, dominated by 1O2 and assisted by electron transport process. Both oxygen vacancy and Se(Ⅵ) were involved in 1O2 generation and Co(III)/Co(II) cycle. The CoHS-Se-CR/PMS system showed high efficiency for GAT removal in a wide pH range and strong resistance to anionic interference. This work provides a new strategy for designing PMS activators to construct orientational non-radical AOP.