A unified kinetic model for adsorption and desorption – Applied to water on zeolite

Gaulke, Marco; Guschin, Viktor; Knapp, Sebastian; Pappert, Sandra; Eckl, Wilhelm

doi:10.1016/j.micromeso.2016.06.034

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…Concerning the adsorption and desorption processes, only NH 3 and H 2 O were considered because of their competitive interactions with the active sites in the current model; the basic NH 3 molecule has high affinity with the acid zeolite support, and there can be spontaneous adsorption of water . Consequently, NH 3 and H 2 O adsorption on S1, S2, S3, and S4 was assumed to be a nonactivated process ( ). , Indeed, the consideration of large amounts of water within the reaction mechanistic path is crucial to represent the catalyst behavior, as has been shown by various studies on several zeolite-based catalysts. , …”

Section: Methodsmentioning

confidence: 99%

“…39,54 Indeed, the consideration of large amounts of water within the reaction mechanistic path is crucial to represent the catalyst behavior, as has been shown by various studies on several zeolite-based catalysts. 54,78 In addition, several studies using zeolite-based catalyst as catalytic SCR system 54,78 have shown that an excess of water vapour could impact SCR performance, principally at low temperatures. Although the detailed mechanism for interaction of redox sites with water is still under investigation, 79,80 several studies highlight the possible hydroxylation of copper sites into ZCu(OH) + species, which further interact with NH 3 to form a complex with monomeric copper species such as [Cu(OH)-(NH 3 ) x ] + or dimeric Cu.…”

Section: Nrmentioning

confidence: 99%

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Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

Pétaud

Gil

Giroir‐Fendler

et al. 2020

Ind. Eng. Chem. Res.

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A multisite kinetic model has been developed to represent ammonia selective catalytic reduction (NH 3 -SCR) behavior. The performance of copper-based chabazite catalyst Cu-SAPO-34 synthetized by ionic exchange method is studied under different dynamic operating conditions, characteristic to the DeNOx process. The model has the distinction of considering four active sites of different nature, allowing specific interpretation of the catalyst active phase function and, also, estimation of the relevant kinetic parameters. The adsorption/desorption of species on each site is described by a nonequilibrium model. The proposed optimized reaction mechanism includes the key reaction pathways found in standard catalytic SCR behavior: competitive adsorption of ammonia and water molecules on each site, the impact of low temperature water and corresponding hydroxyl intermediate formation on copper species, and the nitrite intermediary route. This multisite model enables the nonequilibrium representation of catalytic Cu-SAPO-34 behavior under different operating profiles, including fast and slow temperature modification in accordance with the different site configurations.

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Section: Methodsmentioning

confidence: 99%

Section: Nrmentioning

confidence: 99%

Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

Pétaud

Gil

Giroir‐Fendler

et al. 2020

Ind. Eng. Chem. Res.

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“…In the previous multi-component adsorption kinetic models [26][27][28][29][30][31] in Table S1), there is no the rate equation on the adsorbent, the adsorbent fraction that should be occupied by each adsorbate was only considered.…”

Section: The Comparison Of Kinetic Parameters On Competitive Adsorptionmentioning

confidence: 99%

A New Adsorption Rate Equation in Batch Systems

Hong¹,

Sin²,

Pak³

et al. 2018

Preprint

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In this paper, the deficiencies and cause of previous adsorption kinetic models were revealed, ne w adsorption rate equation has been proposed and its validities were verified by kinetic analysis of various experimental data. This work is a new vie w on the adsorption kinetics rather than a comment on the previous adsorption papers.Many adsorption kinetic models had been proposed and used during about 120 years. The frequently used and recently established 28 models 1-31 were listed in Table S1. The development of adsorption kinetic model has been conducted to obtain the specific models that agree better with the experimental data, as the result, dozens of kinetic models were established. The most of them were based on the Lagergren model 1 (in 1898) and Langmuir kinetic model 24 (in 1918), there were no innovative development. The Deficiencies and Cause of Previous Adsorption Kinetic ModelsCan those be used for the calculation of activation e nergy? One of the important objectives of kinetic study is to evaluate activation energy. Activation energy is the energy which must be available to a chemical system with potential reactants to result in a reaction. Activation energy is obtained by Arrhenius equation and the rate constants of different temperature.Activation energy can't be evaluated by the many of previous adsorption kinetic models, such as the pseudo-order models [1][2][3][4][12][13][14][15] and its changed types [5][6][7][8][20][21][22][23] . These models involve the adsorption amount q e (No. 1-9 and No. 13-21 in Table S1). When Arrhenius equation is used to calculate activation energy, the rate constants must be a constant at given temperature. However, not only the

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“…In [9], a unified model of kinetic adsorption was proposed. Adsorption is described as the interaction between water and surface centers.…”

Section: Introductionmentioning

confidence: 99%

“…Adsorption is described as the interaction between water and surface centers. However, the authors of [9] note deviations in the calculation of the outer water layer and equilibrium states. It has been suggested that not all elementary reactions were examined in detail, and the data are not very reliable in this area.…”

Section: Introductionmentioning

confidence: 99%

Water vapor adsorption/desorption on granulated binder-free low-module zeolites

et al. 2021

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A characteristic of granulated LTA and SOD zeolites is given. It was determined that LTA zeolite particles have a cube shape with a size of ~2 μm; SOD particles have an irregular shape with a size of 0.5–1 μm. The dimension of the coherent scattering region was calculated to be 760 nm for LTA and 453 nm for SOD. The specific surface area of LTA is 115 m2·g–1 and SOD is 141 m2·g–1. Static tests of granulated zeolite showed that the maximum quantity of absorbed water vapor for LTA was ~30 wt.%, and for SOD ~20 wt.%. It was found LTA zeolite to provide adsorption of water from the gas to a dew point of –50 °C, and SOD zeolite of –9 °C. The apparent activation energies for the desorption of water on zeolites were calculated using isoconversional analysis of Friedman, Ozawa–Flynn–Wall, and Kissinger–Akahira–Sunose.

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A unified kinetic model for adsorption and desorption – Applied to water on zeolite

Cited by 12 publications

References 14 publications

Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

A New Adsorption Rate Equation in Batch Systems

Water vapor adsorption/desorption on granulated binder-free low-module zeolites

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A unified kinetic model for adsorption and desorption – Applied to water on zeolite

Cited by 12 publications

References 14 publications

Development of a Nonequilibrium Multisite Kinetic Model for NH3-SCR of NOx on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

Development of a Nonequilibrium Multisite Kinetic Model for NH3-SCR of NOx on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

A New Adsorption Rate Equation in Batch Systems

Water vapor adsorption/desorption on granulated binder-free low-module zeolites

Contact Info

Product

Resources

About

Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations

Development of a Nonequilibrium Multisite Kinetic Model for NH₃-SCR of NO_x on CHA Cu-SAPO-34: Impact of Active Site Configurations and Locations