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Publication . Article . 2019

Adsorption of volatile organic and iodine compounds over silver-exchanged mordenites A comparative periodic DFT study for several silver loadings

Hicham Jabraoui; Etienne Paul Hessou; Siwar Chibani; Laurent Cantrel; Sébastien Lebègue; Michael Badawi;
Open Access
English
Published: 15 Aug 2019
Publisher: HAL CCSD
Country: France
Abstract

International audience; The ability of Ag-exchanged mordenite (Ag-MOR)to capture iodine species such as I2 and CH3I as released for instance during a nuclear accident could be severely limited by the presence of volatile organic compounds (VOCs)that can disrupt their adsorption in the zeolite. Here, using density functional theory (DFT), we investigate in detail the adsorption process of several hydrocarbons (methane, cyclohexane, benzene, and 1,3-dimethylbenzene)and oxygenated compounds (methanol, ethanol, propan-2-ol and propanone)and compare it with the adsorption of I2 and CH3I for different values of the Si/Al ratio of the Ag-exchanged mordenite. It is found that the adsorption process of the iodine species becomes favorable as the Si/Al ratio is decreased. Indeed at high Si/Al ratio, some VOCs such as benzene, 1, 3-dimethylbenzene and propan-2-ol exhibit strong inhibiting effects, while at low Si/Al ratio, only the adsorption of CH3I is limited by the presence of aromatic hydrocarbons. Also, in addition to the elongation of the I[sbnd]I bond upon the adsorption of the iodine molecule in Ag-MOR with a high silver content, we found that there is a significant electron transfer between the Ag and I atoms. Thus, our results indicate that the I[sbnd]I bond becomes weaker during the adsorption and therefore the formation of AgI precipitates is favored. © 2019 Elsevier B.V.

Subjects by Vocabulary

Microsoft Academic Graph classification: Mordenite Benzene chemistry.chemical_compound chemistry Electron transfer Cyclohexane Absorption (chemistry) Adsorption Inorganic chemistry Zeolite Methanol

Subjects

[CHIM]Chemical Sciences, Surfaces, Coatings and Films, Condensed Matter Physics, Surfaces and Interfaces, General Physics and Astronomy, General Chemistry

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