“…However, no breakthrough experiment was conducted below 0.2 g. Since the material has a high density, loading adsorbent below 0.2 g led to a narrow bed length (since the tube diameter was 6 mm), which had a poor adsorbate-adsorbent interaction. The maximum adsorption capacity of 1.31 mmol g −1 achieved for the synthesized nanocomposite is similar to or higher than those reported for commercial ZnO (1.16 mmol g −1 ) 39 , CeO 2 -Mn 2 O 3 -Fe 2 O 3 (0.83 mmol g −1 ) 28 , Mn 2 O 3 -Fe 2 O 3 (0.35 mmol g −1 ) 27 , α-Fe 2 O 3 -Na 2 SO 4 (1.06 mmol g −1 ) 29 , and ZnFe 2 O 4 (0.05 mmol g −1 ) 40 in similar experimental conditions. Figure 4 H 2 S breakthrough curves for ( a ) dry/wet adsorbents; ( b ) wet adsorbent at different flowrate; ( c ) adsorbent loading.…”
Section: Resultssupporting
confidence: 77%
“…The nanocomposite possessed a BET surface area of 21.03 m 2 g −1 and a pore volume of 0.07 cm 3 g −1 . These values are higher than other nanocomposites like Mn 2 O 3 /Fe 2 O 3 (6.18 m 2 g −1 , 0.12 cm 3 g −1 ) 27 , CeO 2 /Mn 2 O 3 /Fe 2 O 3 (15.64 m 2 g −1 , 0.09 cm 3 g −1 ) 28 , and Fe 2 O 3 /Na 2 SO 4 (2.89 m 2 g −1 , 0.01 cm 3 g −1 ) 29 used for the same applications. The spectrum has a broad band centred at 621 cm −1 for the metal–oxygen stretching vibrations 30 , 31 .…”
A ternary Mn–Zn–Fe oxide nanocomposite was fabricated by a one-step coprecipitation method for the remotion of H2S and SO2 gases at room temperature. The nanocomposite has ZnO, MnO2, and ferrites with a surface area of 21.03 m2 g−1. The adsorbent was effective in mineralizing acidic sulfurous gases better in wet conditions. The material exhibited a maximum H2S and SO2 removal capacity of 1.31 and 0.49 mmol g−1, respectively, in the optimized experimental conditions. The spectroscopic analyses confirmed the formation of sulfide, sulfur, and sulfite as the mineralized products of H2S. Additionally, the nanocomposite could convert SO2 to sulfate as the sole oxidation by-product. The oxidation of these toxic gases was driven by the dissolution and dissociation of gas molecules in surface adsorbed water, followed by the redox behaviour of transition metal ions in the presence of molecular oxygen and water. Thus, the study presented a potential nanocomposite adsorbent for deep desulfurization applications.
“…However, no breakthrough experiment was conducted below 0.2 g. Since the material has a high density, loading adsorbent below 0.2 g led to a narrow bed length (since the tube diameter was 6 mm), which had a poor adsorbate-adsorbent interaction. The maximum adsorption capacity of 1.31 mmol g −1 achieved for the synthesized nanocomposite is similar to or higher than those reported for commercial ZnO (1.16 mmol g −1 ) 39 , CeO 2 -Mn 2 O 3 -Fe 2 O 3 (0.83 mmol g −1 ) 28 , Mn 2 O 3 -Fe 2 O 3 (0.35 mmol g −1 ) 27 , α-Fe 2 O 3 -Na 2 SO 4 (1.06 mmol g −1 ) 29 , and ZnFe 2 O 4 (0.05 mmol g −1 ) 40 in similar experimental conditions. Figure 4 H 2 S breakthrough curves for ( a ) dry/wet adsorbents; ( b ) wet adsorbent at different flowrate; ( c ) adsorbent loading.…”
Section: Resultssupporting
confidence: 77%
“…The nanocomposite possessed a BET surface area of 21.03 m 2 g −1 and a pore volume of 0.07 cm 3 g −1 . These values are higher than other nanocomposites like Mn 2 O 3 /Fe 2 O 3 (6.18 m 2 g −1 , 0.12 cm 3 g −1 ) 27 , CeO 2 /Mn 2 O 3 /Fe 2 O 3 (15.64 m 2 g −1 , 0.09 cm 3 g −1 ) 28 , and Fe 2 O 3 /Na 2 SO 4 (2.89 m 2 g −1 , 0.01 cm 3 g −1 ) 29 used for the same applications. The spectrum has a broad band centred at 621 cm −1 for the metal–oxygen stretching vibrations 30 , 31 .…”
A ternary Mn–Zn–Fe oxide nanocomposite was fabricated by a one-step coprecipitation method for the remotion of H2S and SO2 gases at room temperature. The nanocomposite has ZnO, MnO2, and ferrites with a surface area of 21.03 m2 g−1. The adsorbent was effective in mineralizing acidic sulfurous gases better in wet conditions. The material exhibited a maximum H2S and SO2 removal capacity of 1.31 and 0.49 mmol g−1, respectively, in the optimized experimental conditions. The spectroscopic analyses confirmed the formation of sulfide, sulfur, and sulfite as the mineralized products of H2S. Additionally, the nanocomposite could convert SO2 to sulfate as the sole oxidation by-product. The oxidation of these toxic gases was driven by the dissolution and dissociation of gas molecules in surface adsorbed water, followed by the redox behaviour of transition metal ions in the presence of molecular oxygen and water. Thus, the study presented a potential nanocomposite adsorbent for deep desulfurization applications.
“…One important thing to note here is that though the oxidation state variation is expected during these redox reactions, the proportional changes in the %Mn n+ ratio are not high. The possible reason for this is the role of adsorbed molecular O 2 , which could re-oxidize these low oxidation state Mn ions to a higher valency 36,59 . But, from the Mn 2p and Mn 3s analyses, it is confirmed that the Mn sites in NMO are the active sites for the adsorption and oxidation of acidic gas molecules.…”
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.
“…[37] Usually poisoned oxide catalysts with sulfur can be regenerated by using high-temperature calcination in an oxygen atmosphere and impregnation with an ammonium hydroxide solution. [61][62][63] The carbon-based catalysts can be regenerated by using washing, thermal sublimation, and a combination of the two. [64] For example, half of carbon-based catalysts' desulfurization performance can be restored by using Soxhlet washing (hot water) and deionized water washing followed by drying.…”
Section: Selective Oxidationmentioning
confidence: 99%
“…The formed sulfur can be removed by different methods: solution washing, thermal sublimation or both two [37] . Usually poisoned oxide catalysts with sulfur can be regenerated by using high‐temperature calcination in an oxygen atmosphere and impregnation with an ammonium hydroxide solution [61–63] . The carbon‐based catalysts can be regenerated by using washing, thermal sublimation, and a combination of the two [64] .…”
Section: Overview Of H2s Reaction Mechanismmentioning
Catalytic conversion of hydrogen sulfide (H2S) plays a vital role in environmental protection and safety production. In this review, recent theoretical advances for catalytic conversion of H2S are systemically summarized. Firstly, different mechanisms of catalytic conversion of H2S are elucidated. Secondly, theoretical studies of catalytic conversion of H2S on surfaces of metals, metal compounds, and single‐atom catalysts are systematically reviewed. In the meantime, various strategies which have been adopted to improve the catalytic performance of catalysts in the catalytic conversion of H2S are also reviewed, mainly including facet morphology control, doped heteroatoms, metal deposition, and defective engineering. Finally, new directions of catalytic conversion of H2S are proposed and potential strategies to further promote conversion of H2S are also suggested: including SACs, double atom catalysts (DACs), single cluster catalysts (SCCs), frustrated Lewis pairs (FLPs), etc. The present comprehensive review can provide an insight for the future development of new catalysts for the catalytic conversion of H2S.
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