Novel application of sodium manganese oxide in removing acidic gases in ambient conditions

Abstract

In this study, we have demonstrated the application of sodium manganese oxide for the chemisorption of toxic acidic gases at room temperature. The fabricated alkali ceramic has Na_0.4MnO₂, Na₂Mn₃O₇, and Na_xMnO₂ phases with a surface area of 2.6 m² g^-1. Na-Mn oxide was studied for oxidation of H₂S, SO₂, and NO₂ gases in the concentration range of 100-500 ppm. The material exhibited a high uptake capacity of 7.13, 0.75, and 0.53 mmol g^-1 for H₂S, SO₂, and NO₂ in wet conditions, respectively. The material was reusable when regenerated simply by soaking the spent oxide in a NaOH-H₂O₂ solution. While the H₂S chemisorption process was accompanied by sulfide, sulfur, and sulfate formation, the SO₂ chemisorption process yielded only sulfate ions. The NO₂ chemisorption process was accomplished by its conversion to nitrite and nitrate ions. Thus, the present work is one of the first reports on alkali ceramic utilization for room-temperature mineralization of acidic gases.