Role of nitrite ligands in enhancing sulfate radical production via catalytic peroxymonosulfate activation by cobalt complexes

Jaemin Choi, Hyoung il Kim, Jaesang Lee, Hongshin Lee

Research output: Contribution to journalReview articlepeer-review

5 Citations (Scopus)

Abstract

In this study, hexanitrocobaltate (HN-Co(III)) was compared against Co2+ with respect to the capability for peroxymonosulfate (PMS) activation. The role of NO2 ligands in enhancing Co(II)/Co(III) cycling was confirmed based on the two-fold increase in the benzoic acid (BA) degradation efficiency of HN-Co(III)/PMS vs. Co2+/PMS and the negligible reduction in the activation performance of HN-Co(III) over repeated use. This was in line with accelerated BA degradation and catalytic activity recovery upon NO2 addition to Co2+/PMS. A negative shift in the anodic peak potential of the Co(II)/Co(III) couple and an increase in the anodic current over time imply that NO2 coordination promoted the capacity of Co(II) for PMS activation and facilitated the Co(III)-to-Co(II) conversion through hydrolysis. Along with sulfate radical as the primary oxidant, high-valent cobalt acted as the non-radical secondary oxidant based on the transformation of phenyl methyl sulfoxide to the corresponding sulfone in the HN-Co(III)/PMS mixtures.

Original languageEnglish
Article number119698
JournalSeparation and Purification Technology
Volume279
DOIs
Publication statusPublished - 2021 Dec 15

Keywords

  • Cobalt complexation
  • Enhanced recyclability
  • High-valent cobalt
  • Peroxymonosulfate activation
  • Sulfate radical

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation

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