Cobalt oxide-alumina catalysts for the methane-assisted selective catalytic reduction of SO2 to sulfur

Masoud Khani; Seyyed Ebrahim Mousavi; Reza Khalighi; Saeed Abbasizadeh; Hassan Pahlavanzadeh; Habib Ale Ebrahim; Abbas Mozaffari

doi:10.1016/j.heliyon.2023.e21269

Cobalt oxide-alumina catalysts for the methane-assisted selective catalytic reduction of SO₂ to sulfur

Heliyon. 2023 Oct 27;9(11):e21269. doi: 10.1016/j.heliyon.2023.e21269. eCollection 2023 Nov.

Authors

Masoud Khani¹, Seyyed Ebrahim Mousavi², Reza Khalighi³, Saeed Abbasizadeh², Hassan Pahlavanzadeh², Habib Ale Ebrahim¹, Abbas Mozaffari⁴

Affiliations

¹ Faculty of Chemical Engineering, Petrochemical center of Excellency, Amirkabir University of Technology, Tehran, Iran.
² Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.
³ School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
⁴ Research and Development Unit, Sarcheshmeh Copper Complex, Kerman, Iran.

Abstract

Preventing emission of pollutants in any kind, is a way to protect global environment. The objective of this study is to develop cobalt catalysts supported on alumina for the conversion of the toxic gas SO₂ into elemental sulfur using methane. Although several useful catalysts have been proposed, there is still a need to synthesize a catalyst with a high sulfur yield that is also persistent during on-stream stability. To this end, four different catalysts were prepared using the wet impregnation technique, with Co₃O₄ content ranging from 0 to 15 wt%. Catalytic activity tests were carried out at atmospheric pressure and temperatures ranging from 550 to 800 °C. The Al₂O₃-Co (15 %) catalyst exhibited superior performance, with a sulfur yield of 98.1 % at 750 °C. The catalytic stability of the best catalyst was examined using a 20 h on-stream stability test under the optimized conditions including an SO₂/CH₄ molar feed ratio of 2 at 750 °C. The structural changes of the used catalyst after the stability test were investigated using XRD and TPO analyses. It was revealed that sulfidation of Co₃O₄ after a short while, results in decreasing the sulfur yield from 98.1 % to 89.8 %.

Keywords: Alumina; Catalyst; Cobalt oxide; Methane; SO2; Selective catalytic reduction.