Fabrication of Na_0.4MnO₂ Microrods for Room-Temperature Oxidation of Sulfurous Gases

Abstract

Phase pure Na0.4MnO2 microrods crystallized in the orthorhombic symmetry were fabricated for the wet oxidation of H2S and SO2 gases at room temperature. The material was found highly effective for the mineralization of low concentrations of acidic gases. The material was fully regenerable after soaking in a basic H2O2 solution.

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

“…Even in previously reported work on SO 2 adsorption over Na 0.4 MnO 2 , we have observed sulphate as the sole S species. 25 Here, the S 2p peak is fitted with a single 2p 3/2 –2p 1/2 doublet with 2p 3/2 peak at 168.8 eV for sulphate species, which agrees with the literature (Fig. 10a).…”

“…28 Previously, H 2 S oxidation to sulphur and sulphate has been reported for Na 0.4 MnO 2 , where all three species were confirmed after H 2 S adsorption. 25 Thus, dissociative H 2 S adsorption over the Mn-sites of Li 2 MnO 3 is accompanied by the transfer of electrons to the oxide surface, which is confirmed by a decrease in the Mn 4+ / (Mn 3+ + Mn 2+ ) ratio from 1.08 (for Li 2 MnO 3 ) to 0.81 (for Li 2 M-nO 3 _H 2 S). This ratio decrement further confirmed that H 2 S chemisorption is accompanied by the transfer of electrons from H 2 S molecules over the Li 2 MnO 3 surface (Fig.…”

“…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.…”

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

“…Ene_R, after SO 2 or NO 2 adsorption, was regenerated by soaking in a binary NaOH-H 2 O 2 solution. 14 The PXRD analysis showed an insignificant change in the material composition after the regeneration process (Figure S8). For the three regeneration cycles, Ene_R exhibited an average SO 2 and NO 2 adsorption capacity of 30.2 and 13.8 mg g −1 , respectively (Figures 3c, 3d), showing an excellent potential of the battery waste material as a regenerable adsorbent for toxic gas removal.…”

“…Subsequently, these extracted materials were evaluated in column configurations to determine their SO 2 and NO 2 gas adsorption capacities. Moreover, the material’s reusability performance was evaluated after regenerating the spent adsorbent with the NaOH-H 2 O 2 solution . Additionally, spectroscopic analysis and theoretical calculations were conducted to understand the underlying adsorption mechanisms.…”