Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition
Methyl iodide, a common methylation intermediate used in the production of pesticides and pharmaceuticals, is characterized by both acute and chronic toxicity. In the nuclear industry, some of the radio-iodine release occurs in the form of methyl iodide, exacerbating the hazard posed by the chemical...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-05-01
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| Series: | Chemical Engineering Journal Advances |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666821122000515 |
| _version_ | 1818262331190149120 |
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| author | Heinrik Goettsche Krishnan Raja Piyush Sabharwall Vivek Utgikar |
| author_facet | Heinrik Goettsche Krishnan Raja Piyush Sabharwall Vivek Utgikar |
| author_sort | Heinrik Goettsche |
| collection | DOAJ |
| description | Methyl iodide, a common methylation intermediate used in the production of pesticides and pharmaceuticals, is characterized by both acute and chronic toxicity. In the nuclear industry, some of the radio-iodine release occurs in the form of methyl iodide, exacerbating the hazard posed by the chemical. Sorbents containing silver, particularly silver mordenites, have been preferentially investigated for capturing radio-iodine emissions including those of methyl iodide. Literature reports suggest that methyl iodide is catalytically decomposed by silver mordenite into diatomic iodine and hydrocarbons/hydrocarbon derivatives. Continuous column studies utilizing silver mordenite pellets have experienced difficulties obtaining consistent results within a reasonable time when dealing with air streams containing organoiodides at low (∼100 ppb) concentrations. An alternate approach based on utilizing a thin coating of reduced silver mordenite on an inert honeycomb cordierite matrix is described in the present study. This dynamic sorption study was conducted at 170°C with air streams containing methyl iodide at 110-140 ppb concentrations in absence of moisture. The reduction in the silver mordenite mass needed to conduct the investigations resulted in reduced runtimes and successful quantification of the catalytic decomposition of methyl iodide. Kinetics of this decomposition was determined by varying gas residence time and monitoring the methyl iodide conversion. Data analysis using the integral method revealed the reaction rate had a likely first order dependence on methyl iodide concentration with a rate constant of 0.1202 L/g sorbent/s at the operating temperature. Control experiments revealed that sodium mordenite did not exhibit a similar catalytic decomposition behavior. |
| first_indexed | 2024-12-12T19:01:25Z |
| format | Article |
| id | doaj.art-1407e90315bc4f8d9bfc51ad12f33fcd |
| institution | Directory Open Access Journal |
| issn | 2666-8211 |
| language | English |
| last_indexed | 2024-12-12T19:01:25Z |
| publishDate | 2022-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Chemical Engineering Journal Advances |
| spelling | doaj.art-1407e90315bc4f8d9bfc51ad12f33fcd2022-12-22T00:15:05ZengElsevierChemical Engineering Journal Advances2666-82112022-05-0110100290Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide DecompositionHeinrik Goettsche0Krishnan Raja1Piyush Sabharwall2Vivek Utgikar3University of Idaho, 875 Perimeter Drive, Moscow, Idaho 83844University of Idaho, 875 Perimeter Drive, Moscow, Idaho 83844Idaho National Laboratory, Idaho Falls, Idaho 83415University of Idaho, 875 Perimeter Drive, Moscow, Idaho 83844; Corresponding author.Methyl iodide, a common methylation intermediate used in the production of pesticides and pharmaceuticals, is characterized by both acute and chronic toxicity. In the nuclear industry, some of the radio-iodine release occurs in the form of methyl iodide, exacerbating the hazard posed by the chemical. Sorbents containing silver, particularly silver mordenites, have been preferentially investigated for capturing radio-iodine emissions including those of methyl iodide. Literature reports suggest that methyl iodide is catalytically decomposed by silver mordenite into diatomic iodine and hydrocarbons/hydrocarbon derivatives. Continuous column studies utilizing silver mordenite pellets have experienced difficulties obtaining consistent results within a reasonable time when dealing with air streams containing organoiodides at low (∼100 ppb) concentrations. An alternate approach based on utilizing a thin coating of reduced silver mordenite on an inert honeycomb cordierite matrix is described in the present study. This dynamic sorption study was conducted at 170°C with air streams containing methyl iodide at 110-140 ppb concentrations in absence of moisture. The reduction in the silver mordenite mass needed to conduct the investigations resulted in reduced runtimes and successful quantification of the catalytic decomposition of methyl iodide. Kinetics of this decomposition was determined by varying gas residence time and monitoring the methyl iodide conversion. Data analysis using the integral method revealed the reaction rate had a likely first order dependence on methyl iodide concentration with a rate constant of 0.1202 L/g sorbent/s at the operating temperature. Control experiments revealed that sodium mordenite did not exhibit a similar catalytic decomposition behavior.http://www.sciencedirect.com/science/article/pii/S2666821122000515 |
| spellingShingle | Heinrik Goettsche Krishnan Raja Piyush Sabharwall Vivek Utgikar Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition Chemical Engineering Journal Advances |
| title | Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition |
| title_full | Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition |
| title_fullStr | Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition |
| title_full_unstemmed | Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition |
| title_short | Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition |
| title_sort | treatment of off gas emissions kinetics of silver mordenite catalyzed methyl iodide decomposition |
| url | http://www.sciencedirect.com/science/article/pii/S2666821122000515 |
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