Ligands-triggered evolution of catalytic intermediates during periodate activation via soluble Mn(II) for organic contaminants’ abatement

Whose Oxygen Atom Is Transferred to the Products? A Case Study of Peracetic Acid Activation via Complexed MnII for Organic Contaminant Degradation

“…For instance, the overlooked roles of Mn V /Mn VI , Cr IV /Cr V , Co IV , and Fe IV species were revealed in Mn VII /bisulfite, Cr VI /bisulfite, Co II /peroxymonosulfate (PMS) (or Co II /PAA), and Fe II /PMS (or Fe II /HClO) processes, respectively. However, several studies pointed out that sometimes the generation of high-valence metal-oxo species was thermodynamically unpracticable, so the metal–peroxy complex, as the precursor of high-valence metal-oxo species, should be the reactive oxidant for the degradation of EOCs. , According to the above valuable findings, our previous study successfully identified the high-valence Mn V -oxo species generated in periodate (PI) activation via complexed Mn II by combining sulfoxide-probe transformation tests and 18 O isotope-tracing experiments . Further, we found that the complexed Mn II could also activate peracetic acid (PAA; AcOOH) to degrade EOCs from water.…”

“…O matrix based on our previous study, 14 and UPLC−MS results are shown in Figure 2c,d (m/z = 159.036) were successfully distinguished by narrowing the extracted width to m/z = 0.001 (Figure 2a), and no 18 Olabeled PMSO 2 was detected in the PMSO 2 standard. We performed 18 O isotope-tracing experiments in Mn II / NTA/PAA, Mn II /NTA/PI, Fe II /PMS, and Fe II /PDS (wellrecognized AOPs that could produce high-valence Fe IV -oxo species) systems, and the detailed extracted ion chromatograms and correlated MS results are shown in Figures S11− S22.…”

“…12,13 According to the above valuable findings, our previous study successfully identified the high-valence Mn Voxo species generated in periodate (PI) activation via complexed Mn II by combining sulfoxide-probe transformation tests and 18 O isotope-tracing experiments. 14 Further, we found that the complexed Mn II could also activate peracetic acid (PAA; AcOOH) to degrade EOCs from water. As a green oxidant, PAA has been extensively investigated for oxidation and disinfection in water treatment.…”

“…Additionally, our previous study found a similar phenomenon in the Mn II / NTA/PI system and identified the generation and contribution of high-valence Mn V -oxo species for the degradation of organic contaminants. 14 Oxidation processes induced by high-valence metal-oxo species exhibited a unique oxygen-atom-exchange (OAE) reaction with the H 2 O molecule as the most distinguishing feature. 3,47,48 Taking the oxidation of sulfoxides as an example, the oxo-groups were considered to be a powerful moiety of high-valence metal-oxo intermediates, which could exchange its oxo oxygen atom with the H 2 O molecule and subsequently incorporate the O atom (from H 2 O) into sulfone products.…”

“…Our previous study revealed that high-valence Mn V -oxo species were the dominant reactive oxidant in the Mn II /NTA/ PI system in the presence of sufficient ligands. 14 Thus, it is of great interest to comparatively investigate the decontamination features between the NTA-Mn II -PAA* complex and highvalence Mn V -oxo species, and the results are shown in Figures S45a and S46. These results indicate that both of the above reactive manganese intermediates could oxidize aniline and phenolic contaminants, and the NTA-Mn II -PAA* complex was more likely to oxidize aniline contaminants rapidly.…”