Oxidation mechanisms of H2S by oxygen and oxygen-containing functional groups on activated carbon

Li, Yuran; Lin, Yu‐Ting; Xu, Zhicheng; Wang, Bin; Zhu, Tong

doi:10.1016/j.fuproc.2019.03.006

Cited by 63 publications

(20 citation statements)

References 27 publications

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“…Activated carbons are amorphous carbon materials with a surface area up to thousands of square meters per gram and a well-developed microporosity [2]. They are widely used for processing industrial gases [3][4][5], air [6][7][8], and waste water purification [9] due to their versatile nature as adsorbents or catalysts and their multi-pollutant removal capability [10]. Other than surface area, pore volume, and pore size distribution, it is known that altering the surface functional groups present on the carbon, for example by changing the pH, greatly affect the adsorption or reaction mechanism of H 2 S and thus the removal performance [11].…”

Section: Introductionmentioning

confidence: 99%

“…The relatively low cost of activated carbons compared to other desulfurization adsorbents, such as inorganic materials (e.g., metal oxides), makes it an attractive adsorbent candidate. In dry and oxygen lacking conditions, only weak and reversible physical adsorption of H 2 S has been demonstrated to occur [10,12,13]. Therefore, methods to facilitate faster reactions between the surface and the adsorbate have generated much research interest.…”

Section: Introductionmentioning

confidence: 99%

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Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

2021

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Its relatively low cost and high surface area makes activated carbon an ideal adsorbent candidate for H2S removal. However, physical adsorption of H2S is not very effective; therefore, methods to facilitate reactive H2S oxidation on carbons are of interest. The performance of H2S removal of non-impregnated, impregnated, and doped activated carbon in low-temperature syngas was evaluated in fixed-bed breakthrough tests. The importance of oxygen content and relative humidity was established for reactive H2S removal. Impregnates especially improved the adsorption rate compared to non-impregnated carbons. Non-impregnated carbons could however retain a high capture capacity with sufficient contact time. In a relative performance test, the best performance was achieved by doped activated carbon, 320 mg g−1. Ammonia in syngas was found to significantly improve the adsorption rate of non-impregnated activated carbon. A small quantity of ammonia was consumed by the carbon bed, suggesting that ammonia is a reactant. Finally, to validate ammonia-enhanced desulfurization, bench-scale experiments were performed in biomass-based gasification syngas. The results show that when the ammonia concentration in syngas was in the tens of ppm range, 40–160 ppm H2S oxidation proceeded rapidly. Ammonia-enhanced oxidation allows utilization of cheaper non-impregnated activated carbons by in situ improvement of the adsorption kinetics. Ammonia enhancement is therefore established as a viable method for achieving high-capacity H2S removal with unmodified activated carbons.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

2021

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“…However, studies on the adsorption of gaseous CH 3 COOH on activated carbon have hardly been reported. Relatively few studies have been reported on the adsorption of gaseous H 2 S using activated carbon . Li et al conducted the adsorption of H 2 S gas using activated carbon with oxygen‐containing functional groups in the presence of oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…Relatively few studies have been reported on the adsorption of gaseous H 2 S using activated carbon . Li et al conducted the adsorption of H 2 S gas using activated carbon with oxygen‐containing functional groups in the presence of oxygen. Both H 2 S and O 2 were adsorbed on the active sites of activated carbon, and then the catalytic reaction produced elemental sulfur.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of acetic acid and hydrogen sulfide using NaOH impregnated activated carbon for indoor air purification

Wang

Nam

Gebreegziabher

et al. 2020

Engineering Reports

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Excessive exposure to hydrogen sulfide (H 2 S) and acetic acid (CH 3 COOH) gases is extremely dangerous in a confined space. An effective indoor air pollutant removal porous carbon filter was developed using NaOH impregnated on activated carbon (NaOH/AC) for the adsorption of H 2 S and CH 3 COOH. Activated carbon (NaOH/AC) filter was characterized using various methods, indicating good physical and chemical properties (especially -OH functional groups) for the adsorption of air pollutants. The prepared NaOH/AC filter was cured at different curing temperatures and residence times to understand the effect of the curing conditions on the adsorption performance. The best results were obtained with NaOH/AC filter cured at 100 • C for 20 minutes as it eliminated the initial concentration of 400 ppm of CH 3 COOH in 15 minutes and H 2 S in 30 minutes at 20 • C and 60% relative humidity. Isotherm and kinetic models were used to analyze the adsorption process. Langmuir isotherm and pseudo-second order kinetic models provided the best fit to the adsorption of CH 3 COOH and H 2 S on NaOH/AC filter. The adsorption mechanism was controlled by the intraparticle diffusion combined with film diffusion. The maximum adsorption capacity of NaOH/AC filter was 473 mg/g for H 2 S adsorption, and 550 mg/g for CH 3 COOH adsorption. In addition, the spent NaOH/AC filter was regenerated for reuse.This study is expected to develop low-cost and effective porous carbon filter using NaOH-modified activated carbon for indoor air purification.

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“…In industry, H 2 S is usually removed by the Claus process, in which it is partially oxidized to produce water and elemental sulfur [8]. Additionally, Li et al [9] studied the oxidation process of H 2 S on activated carbon (AC) to simultaneously capture H 2 S and SO 2 . The results indicate that H 2 S was adsorbed on the AC surface and combined with oxygen-containing functional groups to form sulfate (SO 4 2− ) in the absence of O 2 .…”

Section: Introductionmentioning

confidence: 99%

Ni-Mo Sulfide Semiconductor Catalyst with High Catalytic Activity for One-Step Conversion of CO2 and H2S to Syngas in Non-Thermal Plasma

et al. 2019

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Carbon dioxide (CO2) and hydrogen sulfide (H2S) ordinarily coexist in many industries, being considered as harmful waste gases. Simultaneously converting CO2 and H2S into syngas (a mixture of CO and H2) will be a promising economic strategy for enhancing their recycling value. Herein, a novel one-step conversion of CO2 and H2S to syngas induced by non-thermal plasma with the aid of Ni-Mo sulfide/Al2O3 catalyst under ambient conditions was designed. The as-synthesized catalysts were characterized by using XRD, nitrogen sorption, UV-vis, TEM, SEM, ICP, and XPS techniques. Ni-Mo sulfide/Al2O3 catalysts with various Ni/Mo molar ratios possessed significantly improved catalytic performances, compared to the single-component catalysts. Based on the modifications of the physical and chemical properties of the Ni-Mo sulfide/Al2O3 catalysts, the variations in catalytic activity are carefully discussed. In particular, among all the catalysts, the 5Ni-3Mo/Al2O3 catalyst exhibited the best catalytic behavior with high CO2 and H2S conversion at reasonably low-energy input in non-thermal plasma. This method provides an alternative route for syngas production with added environmental and economic benefits.

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Oxidation mechanisms of H2S by oxygen and oxygen-containing functional groups on activated carbon

Cited by 63 publications

References 27 publications

Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

Adsorption of acetic acid and hydrogen sulfide using NaOH impregnated activated carbon for indoor air purification

Ni-Mo Sulfide Semiconductor Catalyst with High Catalytic Activity for One-Step Conversion of CO2 and H2S to Syngas in Non-Thermal Plasma

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