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 Na0.4MnO2, Na2Mn3O7, and NaxMnO2 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.

Reactive adsorption of NO2 over the NaCoO2–Co3O4 nanocomposite: experimental study and first-principles calculations

“…Xi et al reported a NO 2 breakthrough capacity of 52.3 mg g −1 over porous amino-modified zirconia aerogels in similar experimental conditions, 42 which is lower when compared in terms of capacity-to-surface area ratio. Similar NO 2 removal capacities at room temperature have been reported for Ce 0.2 Zr 0.8 O 2 (40.0 mg g −1 , 12% NO release), 45 ordered mesoporous carbon (68.2 mg g −1 , 28% NO release), 46 Na x MnO 2 (24.4 mg g −1 ), 14 PCN-224 (62.6 mg g −1 , 25% NO release), 47 and UiO-66 (73.0 mg g −1 , 30% NO release). 48…”

“…In our previous study, we explored the room-temperature reactive adsorption of NO 2 over a Na x MnO 2 composite, where it was confirmed that an alkali ceramic-like Na x MnO 2 is capable of adsorbing and oxidizing NO 2 gas molecules into surface-bound nitrate ions. 14 However, the work was limited to exploring the potential of Na–Mn oxide and did not address other alkali ceramic materials, and experimental conditions like the role of operational parameters and humidity. In this study, we have aimed to explore Na–Co oxide fabricated from a bimetallic MOF precursor for the reactive adsorption of NO 2 in ambient conditions.…”

Reactive Adsorption of SO2 and NO2 Gases over Black Mass Derived from Discarded Alkaline Batteries

“…30,31 The dissolution and The decrease in the adsorption capacity with the increased flow rate is a consequence of decreasing gas retention time and poor adsorbate−adsorbent interactions. 32 Ene_R, when tested for NO 2 adsorption in similar experimental conditions, showed a NO 2 uptake capacity of 10.0 and 11.9 mg g −1 in dry and wet conditions, respectively (Figure 3b). The NO evolution during the NO 2 adsorption was minimal under both the studied conditions.…”

“…Besides, the SO 2 adsorption capacity of Ene_R decreased from 41.4 mg g –1 for a flow rate of 0.1 L min –1 to 27.2 mg g –1 for a flow rate of 0.2 L min –1 . The decrease in the adsorption capacity with the increased flow rate is a consequence of decreasing gas retention time and poor adsorbate–adsorbent interactions . Ene_R, when tested for NO 2 adsorption in similar experimental conditions, showed a NO 2 uptake capacity of 10.0 and 11.9 mg g –1 in dry and wet conditions, respectively (Figure b).…”

Probing room-temperature reactivity of H2S, SO2, and NO on the Li2MnO3 crystal surface by experimental and first-principles studies

“…The room-temperature oxidation of toxic gases over Li 2 MnO 3 has yet to be investigated. Unlike Li-Mn oxides, Na-analogues like Na x MnO 2 composites or phase pure oxides have shown exceptionally high adsorption capacity for acidic gases like H 2 S, SO 2 , NO 2 , 25,26 and CO 2 27 under certain experimental conditions at room temperature.…”