Co nanoparticle-embedded N, O-codoped porous carbon nanospheres as an efficient peroxymonosulfate activator: singlet oxygen dominated catalytic degradation of organic pollutants. Issue 27 (19th June 2020)

• Record Type: Journal Article
• Authors: Zhu, Genxing; Zhu, Jialu; Fu, Xinlong; Liu, Qi; Cao, Fengyi; Li, Yu-nan; Qin, Qi; Jiao, Mingli
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 27(2020)
• Page Start: 15340
• Page End: 15353
• Publication Date: 2020-06-19
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp00679c
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A mesoporous N, O-doped carbon@Co composite with good magnetism for efficient catalytic elimination of organic pollutants via peroxymonosulfate activation. Abstract : In this study, Co nanoparticle-embedded N, O-codoped porous carbon nanospheres (C@Co) with abundant N and O doping, high graphitization, large specific surface area (319 m 2 g −1 ) and a well-developed mesoporous structure were synthesized and characterized thoroughly, and were applied to activate peroxymonosulfate (PMS) for the degradation of methylene blue (MB). Various influential factors affecting the catalytic performance including C@Co dosage, PMS dosage, MB concentration, initial pH, temperature, and co-existing common anions and humic acid (HA) on the MB degradation were systematically investigated. The increase of the C@Co dosage (15–60 mg), PMS dosage (25–100 mg) and reaction temperature (278–308 K) promoted the MB degradation in the C@Co/PMS system. The best performance of the C@Co/PMS system was observed under weakly acidic or nearly neutral conditions. Both the MB concentration (25–100 mg L −1 ) and Cl − (5–100 mM), NO3 − (10–500 mM), CO3 2− (10–300 mM), HCO3 − (1–30 mM) and HA (2–40 mg L −1 ) had an inhibitory effect on MB degradation, and the degree of decrease in MB degradation increased as their concentrations were enhanced. Interestingly, HPO4 2− (1–100 mM) had an overall inhibitory effect on the degradation process of MB; however, in comparison with lower concentrations (1–10 mM), an attenuation of the inhibitory effect at higher concentrations (50–100 mM) could be observed. Moreover, the C@Co/PMS system also exhibited general applicability in eliminating various organic pollutants from water such as methyl orange, malachite green, safranine T, Congo red, Rhodamine B, ofloxacin and tetracycline. Classical radical-quenching tests and EPR measurements showed that both the non-radical pathway (major route, involving 1 O2 ) and radical pathway (minor route, involving ˙OH, ˙SO4 − and ˙O2 − ) contribute to the MB degradation. DFT calculations disclosed that the combination of Co–C interactions with graphitic N doping brought in catalytically active sites in C@Co where the charge states of some C atoms were significantly increased. The degradation intermediates of MB during the catalytic reaction were also identified by HPLC-MS and the possible degradation pathway was proposed. Overall, the resultant C@Co can be developed as a novel and efficient heterogeneous catalyst for activating PMS to degrade organic pollutants, and has potential application in environmental remediation.