Light and nitrogen vacancy-intensified nonradical oxidation of organic contaminant with Mn (III) doped carbon nitride in peroxymonosulfate activation.

Recently, Mn-based materials have a great potential for selective removal of organic contaminants with the assistance of oxidants (PMS, H 2 O 2) and the direct oxidation. However, the rapid oxidation of organic pollutants by Mn-based materials in PMS activation still presents a challenge due to the lower conversion of surface Mn (III)/Mn (IV) and higher reactive energy barrier for reactive intermediates. Here, we constructed Mn (III) and nitrogen vacancies (Nv) modified graphite carbon nitride (MNCN) to break these aforementioned limitations. Through analysis of in-situ spectra and various experiments, a novel mechanism of light-assistance non-radical reaction is clearly elucidated in MNCN/PMS-Light system. Adequate results indicate that Mn (III) only provide a few electrons to decompose Mn (III)-PMS* complex under light irradiation. Thus, the lacking electrons necessarily are supplied from BPA, resulting in its greater removal, then the decomposition of the Mn (III)-PMS* complex and light synergism form the surface Mn (IV) species. Above Mn-PMS complex and surface Mn (IV) species lead to the BPA oxidation in MNCN/PMS-Light system without the involvement of sulfate (SO 4 • ̶) and hydroxyl radicals (•OH). The study provides a new understanding for accelerating non-radical reaction in light/PMS system for the selective removal of contaminant. [Display omitted] • Mn (III) and Nv were successfully constructed in MNCN to reduce its sluggishness. • Nv was a positive contribution in PMS activation by In-situ and DFT analysis. • Superoxide radical, Mn-PMS complexes and surface Mn (IV) were major active species. • The mechanism of PMS activation with light was unlike normal SO 4 •- and •OH radicals. • Excited photoelectrons rose BPA oxidation by Mn-PMS complex and Mn (IV) production. [ABSTRACT FROM AUTHOR]