H2S adsorption by Ag and Cu ion exchanged faujasites

Kumar, Parveen; Sung, Chun Yi; Muraza, Oki; Cococcioni, Matteo; Hashimi, Saleh Al; McCormick, Alon V.; Tsapatsis, Michael

doi:10.1016/j.micromeso.2011.05.014

Cited by 76 publications

(64 citation statements)

References 37 publications

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“…Kumar et al [46] performed Au and Cu modified faujasites for the removal of H 2 S from streams including N 2 , CO, CO 2 and water vapor. The adsorption properties of H 2 S were also investigated on Cu(I)Y, Ag(I)Y, NaY and Cu(II) by using Density Functional Theory (DFT).…”

Section: Zeolite a Mfi And Zeolites X And Y Exchanged By Namentioning

confidence: 99%

Use of zeolites for the removal of H 2 S: A mini-review

Ozekmekci

Salkic

Fellah

2015

Fuel Processing Technology

196

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Section: Zeolite a Mfi And Zeolites X And Y Exchanged By Namentioning

confidence: 99%

Use of zeolites for the removal of H 2 S: A mini-review

Ozekmekci

Salkic

Fellah

2015

Fuel Processing Technology

196

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“…In contrast to studies on removal of H 2 S and SO 2 individually, technologies for simultaneous removal of H 2 S and SO 2 by activated carbon have rarely been reported, and the underlying mechanisms for the adsorption of H 2 S and SO 2 have not yet been fully elucidated. In this study, a coconut-shellbased activated carbon, ACS-1, was employed to simultaneously remove H 2 S and SO 2 from simulated Claus tail gas, and the breakthrough sulfur capacity of the ACS-1 sorbent was determined.…”

Section: ■ Introductionmentioning

confidence: 97%

Characterization and Mechanisms of H₂S and SO₂ Adsorption by Activated Carbon

et al. 2015

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Coconut-shell-based activated carbon (ACS-1) was used as a sorbent to simultaneously remove H 2 S and SO 2 from simulated Claus tail gas. Adsorption and regeneration tests were performed to systematically investigate the desulfurization performance, regenerability, and stability of the ACS-1 sorbent. The physicochemical properties of ACS-1 before and after adsorption were characterized by nitrogen adsorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The experimental results revealed that the ACS-1 sorbent exhibited good desulfurization performance under a feed gas of H 2 S (20 000 ppmv), SO 2 (10 000 ppmv), and N 2 (balance), and the concentrations of H 2 S and SO 2 in the simulated Claus tail gas could be reduced to less than 10 mg/m 3 by ACS-1. The breakthrough sulfur capacity of ACS-1 is 64.27 mg of S/g of sorbent at an adsorption temperature of 30°C and a gas hourly space velocity of 237.7 h −1 . The micropores with sizes of around 0.5 nm in ACS-1 are the main active centers for adsorption of H 2 S and SO 2 , whereas mesopores have little desulfurization activity for deep removal of H 2 S and SO 2 . Both physical adsorption and chemical adsorption coexisted in the process of desulfurization. The majority of sulfides were removed by physical adsorption, and 11% of the sulfur compounds existing in the form of elemental sulfur (ca. 20 atom %) and sulfate (ca. 80 atom %) were derived from the chemical adsorption. The mechanism of H 2 S and SO 2 adsorption on the ACS-1 sorbent is also discussed. H 2 S and SO 2 are first adsorbed on ACS-1 by physical adsorption and then partially oxidized to elemental sulfur and sulfate, respectively, by the oxygen adsorbed on ACS-1. At the same time, the Claus reaction between H 2 S and SO 2 occurs. In addition, the ACS-1 sorbent can be completely regenerated using water vapor at 450°C with a stable breakthrough sulfur capacity during five adsorption−regeneration cycles. ■ INTRODUCTIONAt present, the Claus tail gas still contains 1−4% sulfur species and other gaseous components such as CO, H 2 , CO 2 , water vapor, and N 2 because of the thermodynamic limitations of the Claus equilibrium reaction. The sulfur species consist mainly of H 2 S, SO 2 , COS, CS 2 , and sulfur vapor. The volume fractions of H 2 S and SO 2 in Claus tail gas are in the range of 0.3−1.99% and 0.15−0.89%, respectively. 1,2The Shell Claus off-gas treatment (SCOT) process is the most common tail gas treatment unit of the Claus process. 3 In the SCOT process, all of the sulfur compounds and elemental sulfur are first reduced to hydrogen sulfide at 300°C using typical hydrogenation catalysts such as cobalt−nickel or cobalt−molybdenum. The consequent reducing gas is composed of CO and H 2 . 4,5 H 2 S is absorbed by a selective absorbent such as N-methyldiethanolamine (MDEA) and then stripped from the amine-rich solvent and recycled to the Claus unit. 6 The tail gas of the SCOT unit contains rare H 2 S, which can be treated by a burner. This approach...

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“…The strongly enhanced coordination of H 2 O by Na + cation is due to water's higher dipole moment and oxygen's smaller van der Waals diameter. Previous experimental data and computations also demonstrated preferential adsorption of H 2 O over H 2 S on Na‐exchanged faujasites …”

Section: Resultsmentioning

confidence: 75%

“…Recently, ionic liquids and deep eutectic solvents have been suggested as more sustainable physical solvents for H 2 S/CO 2 capture; however, the costs of such absorption‐based separations still remain relatively high. Adsorption using molecular sieves, such as cation‐exchanged zeolites, has been a promising alternative for gas sweetening in general and selective H 2 S (over CO 2 ) removal in particular …”

Section: Introductionmentioning

confidence: 99%

Understanding the Reactive Adsorption of H₂S and CO₂ in Sodium‐Exchanged Zeolites

et al. 2018

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Purifying sour natural gas streams containing hydrogen sulfide and carbon dioxide has been a long-standing environmental and economic challenge. In the presence of cation-exchanged zeolites, these two acid gases can react to form carbonyl sulfide and water (H S+CO ⇌H O+COS), but this reaction is rarely accounted for. In this work, we carry out reactive first-principles Monte Carlo (RxFPMC) simulations for mixtures of H S and CO in all-silica and Na-exchanged forms of zeolite beta to understand the governing principles driving the enhanced conversion. The RxFPMC simulations show that the presence of Na cations can change the equilibrium constant by several orders of magnitude compared to the gas phase or in all-silica beta. The shift in the reaction equilibrium is caused by very strong interactions of H O with Na that reduce the reaction enthalpy by about 20 kJ mol . The simulations also demonstrate that the siting of Al atoms in the framework plays an important role. The RxFPMC method presented here is applicable to any chemical conversion in any confined environment, where strong interactions of guest molecules with the host framework and high activation energies limit the use of other computational approaches to study reaction equilibria.

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H2S adsorption by Ag and Cu ion exchanged faujasites

Cited by 76 publications

References 37 publications

Use of zeolites for the removal of H 2 S: A mini-review

Use of zeolites for the removal of H 2 S: A mini-review

Characterization and Mechanisms of H₂S and SO₂ Adsorption by Activated Carbon

Understanding the Reactive Adsorption of H₂S and CO₂ in Sodium‐Exchanged Zeolites

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H2S adsorption by Ag and Cu ion exchanged faujasites

Cited by 76 publications

References 37 publications

Use of zeolites for the removal of H 2 S: A mini-review

Use of zeolites for the removal of H 2 S: A mini-review

Characterization and Mechanisms of H2S and SO2 Adsorption by Activated Carbon

Understanding the Reactive Adsorption of H2S and CO2 in Sodium‐Exchanged Zeolites

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Characterization and Mechanisms of H₂S and SO₂ Adsorption by Activated Carbon

Understanding the Reactive Adsorption of H₂S and CO₂ in Sodium‐Exchanged Zeolites