Effective toluene oxidation under ozone over mesoporous MnOx/γ-Al2O3 catalyst prepared by solvent deficient method: Effect of Mn precursors on catalytic activity

Kannapu Hari Prasad Reddy; Beom-Sik Kim; Su Shiung Lam; Sang-Chul Jung; JiHyeon Song; Young-Kwon Park

doi:10.1016/j.envres.2021.110876

Effective toluene oxidation under ozone over mesoporous MnO_x/γ-Al₂O₃ catalyst prepared by solvent deficient method: Effect of Mn precursors on catalytic activity

Environ Res. 2021 Apr:195:110876. doi: 10.1016/j.envres.2021.110876. Epub 2021 Feb 13.

Authors

Kannapu Hari Prasad Reddy¹, Beom-Sik Kim², Su Shiung Lam³, Sang-Chul Jung⁴, JiHyeon Song⁵, Young-Kwon Park⁶

Affiliations

¹ School of Environmental Engineering, University of Seoul, Seoul, 02504, Republic of Korea.
² Hydrogen Research Center, Research Institute of Industrial Science and Technology, Pohang, 37673, Republic of Korea.
³ Pyrolysis Technology Research Group, Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (Akuatrop), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia.
⁴ Department of Environmental Engineering, Sunchon National University, Suncheon, 57923, Republic of Korea.
⁵ Department of Civil and Environmental Engineering, Sejong University, Seoul, 05006, Republic of Korea.
⁶ School of Environmental Engineering, University of Seoul, Seoul, 02504, Republic of Korea. Electronic address: catalica@uos.ac.kr.

PMID: 33592225
DOI: 10.1016/j.envres.2021.110876

Abstract

In this study, the role of manganese precursors in mesoporous (meso) MnOx/γ-Al₂O₃ catalysts was examined systematically for toluene oxidation under ozone at ambient temperature (20 °C). The meso MnOx/γ-Al₂O₃ catalysts developed with Mn(CH₃COO)_2, MnCl₂, Mn(NO₃)₂.4H₂O and MnSO₄ were prepared by an innovative single step solvent-deficient method (SDM); the catalysts were labeled as MnO_x/Al₂O₃(A), MnO_x/Al₂O₃(C), MnO_x/Al₂O₃(N), and MnOx/Al₂O₃(S), respectively. Among all, MnO_x/Al₂O₃(C) showed superior performance both in toluene removal (95%) as well as ozone decomposition (88%) followed by acetate, nitrate and sulphated precursor MnO_x/Al₂O₃. The superior performance of MnO_x/Al₂O₃(C) in the oxidation of toluene to CO_x is associated with the ozone decomposition over highly dispersed MnO_x in which extremely active oxygen radicals (O^2-, O₂^2- and O^-) are generated to enhance the oxidation ability of the catalysts greatly. In addition, toluene adsorption over acid support played a vital role in this reaction. Hence, the properties such as optimum Mn³⁺/Mn⁴⁺ ratio, acidic sites, and smaller particle size (≤2 nm) examined by XPS, TPD of NH₃, and TEM results are playing vital role in the present study. In summary, the MnO_x/Al₂O₃ (C) catalyst has great potential in environmental applications particularly for the elimination of volatile organic compounds with low loading of manganese developed by SDM.

Keywords: Mn; Ozone; Precursor; Solvent deficient method; Toluene.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catalysis
Oxidation-Reduction
Ozone*
Solvents
Toluene

Substances

Solvents
Toluene
Ozone