Highly efficient α-Mn2O3α-MnO2-500 nanocomposite for peroxymonosulfate activation: Comprehensive investigation of manganese oxides

Aimal Khan, Huabin Wang, Yong Liu, Ali Jawad, Jerosha Ifthikar, Zhuwei Liao, Ting Wang, Zhuqi Chen

Research output: Journal PublicationArticlepeer-review

187 Citations (Scopus)

Abstract

In this paper a nanorod α-Mn2O3α-MnO2-500 nanocomposite demonstrated the highest efficiency and remarkable stability in persulfate activation compared with other manganese oxide based catalysts including α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, α-Mn2O3, Mn3O4, etc. This catalyst was easily fabricated using one spot calcination treatment at 500 °C, and a minimal amount of leached Mn ions was detected during the degradation of organic contaminants. The significant performance in persulfate activation was elucidated from the unique structure and physical-chemical properties of α-Mn2O3α-MnO2-500. Evidenced by XRD and HRTEM, α-Mn2O3α-MnO2-500 consisted of a well mixed phase structure of tetragonal α-MnO2 and cubic α-Mn2O3 with high crystalline quality. XPS and the inhibition effect by phosphate confirmed the existence of surface hydroxyl groups (0.926 mmol g-1) on α-Mn2O3α-MnO2-500, while FTIR, Raman and ionic strength experiments further demonstrated that the formation inner-sphere interaction was the key step in PMS activation. Supported by XPS and CV, the mixed valence states in the α-Mn2O3α-MnO2-500 nanocomposite exhibited a more effective redox property, which favored electron transfer between Mn species (MnIV ↔ MnIII), and generated SO4-, OH and even 1O2 for the degradation of various hydrocarbon contaminants. Also, the activation energy of α-Mn2O3α-MnO2-500/PMS for phenol degradation was only 24.7 kJ mol-1, much lower than that of α-MnO2 (38.7 kJ mol-1) and α-Mn2O3 (44.9 kJ mol-1). This Mn catalyst with much lower toxicity can be considered as a green approach in environmental remediation.

Original languageEnglish
Pages (from-to)1590-1600
Number of pages11
JournalJournal of Materials Chemistry A
Volume6
Issue number4
DOIs
Publication statusPublished - 2018
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

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