In situ anchoring strategy to enhance dual nonradical degradation of sulfamethoxazole with high loading manganese doped carbon nitride

• Published in: Chemosphere (Oxford) 2022-09, Vol.303 (Pt 2), p.135035-135035, Article 135035
• Main Authors: Hu, Youyou, Sun, Siyu, Guo, Jialin, Cheng, Fan, Li, Zhengkui
• Format: Article
• Language: English
• Subjects: Anti-interference performance; Dual nonradical pathway; High loading manganese catalyst; Phenanthroline; PMS activation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.135035

A low-cost catalyst with high metal loading and unique catalytic activities is highly desired for peroxymonosulfate (PMS) activation in environmental remediation. Herein, in situ anchoring strategy using 1,10-phenanthroline is reported to construct manganese doped carbon nitride (PMCN) with 8.2 wt% manganese loading and dramatically enhanced PMS adsorption and sulfamethoxazole (SMX) removal efficiency. Our study revealed that the PMCN/PMS system readily reacted with contaminants with electron-rich groups, where complete degradation of sulfamethoxazole (SMX) was achieved within 60 min. Combining quenching experiments, EPR tests, and electrochemical analysis, we proposed a dual nonradical pathway dominated by high-valent manganese oxygen species (Mn(V) = O) and electron transfer. Systematic investigation elucidated that the introduction of 1,10-phenanthroline constructed denser catalyst active sites, and identified the manganese center and pyridine nitrogen as the active sites for PMS activation. Furthermore, PMCN exhibited excellent pH anti-interference ability and good reusability, achieving more than 90% SMX degradation efficiency after four cycles. This study provides new insights into the regulation of Mn–N active sites and promotes the mechanistic understanding of the synergistic effect of manganese and pyridine nitrogen in PMS activation. [Display omitted] •In situ anchoring preparation of high loading manganese-doped g-C3N4.•Selective oxidation of pollutants with low ionization potential.•1,10-phenanthroline boosted the anchoring and loading of manganese ions.•The synergism of manganese species and pyridine nitrogen sites was determined.•A dual non-radical pathway was elucidated via Mn(V) = O and electron transfer.