Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites
The sorption properties of samples of H-ZSM-5 zeolite and their forms modified with P, B and Mg were determined by the physical adsorption of nitrogen and evaluated by BET isotherm and t-plot methods. The diffusivities of the samples were measured using a new flow gravimetric method involving the so...
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| Format: | Article |
| Language: | English |
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SAGE Publications
1996-12-01
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| Series: | Adsorption Science & Technology |
| Online Access: | https://doi.org/10.1177/026361749601300606 |
| _version_ | 1797283286227091456 |
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| author | P. Hudek D. Bobok A. Smiešková Z. Židek |
| author_facet | P. Hudek D. Bobok A. Smiešková Z. Židek |
| author_sort | P. Hudek |
| collection | DOAJ |
| description | The sorption properties of samples of H-ZSM-5 zeolite and their forms modified with P, B and Mg were determined by the physical adsorption of nitrogen and evaluated by BET isotherm and t-plot methods. The diffusivities of the samples were measured using a new flow gravimetric method involving the sorption of p- and o -xylenes. The BET specific surface area decreased from 358 m 2 /g to 35–90 m 2 /g mainly because of a decrease in micropore volume as determined by the t-plot method. The rate of sorption of p -xylene on all the samples investigated followed Fick's second law of diffusion, leading to an effective diffusivity of ca. 1.7 × 10 −11 m 2 /s, irrespective of whether the H-form or the modified forms were investigated. The sorption isotherms for o -xylene showed some unusual steps. Values for the effective diffusivities decreased from 2.6 × 10 −12 m 2 /s for the H-form to 2.0–2.3 × 10 −12 m 2 /s for the modified forms. The equilibrium concentration of o -xylene at P/P 0 = 0.1 was only 0.38–0.68 mol/unit cell, while that of p -xylene was 4.40–5.98 mol/unit cell. |
| first_indexed | 2024-03-07T17:28:57Z |
| format | Article |
| id | doaj.art-2c4e1ab6c62e441383aeb3e4ece49c62 |
| institution | Directory Open Access Journal |
| issn | 0263-6174 2048-4038 |
| language | English |
| last_indexed | 2024-03-07T17:28:57Z |
| publishDate | 1996-12-01 |
| publisher | SAGE Publications |
| record_format | Article |
| series | Adsorption Science & Technology |
| spelling | doaj.art-2c4e1ab6c62e441383aeb3e4ece49c622024-03-02T18:28:50ZengSAGE PublicationsAdsorption Science & Technology0263-61742048-40381996-12-011310.1177/026361749601300606Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 ZeolitesP. Hudek0D. Bobok1A. Smiešková2Z. Židek3 Department of Petroleum Chemistry and Technology, Faculty of Chemical Technology, Slovak Technology University, Radlinskeho 9, 812 37 Bratislava, Slovak Republic Department of Chemical Engineering, Faculty of Chemical Technology, Slovak Technical University, Radlinskeho 9, 812 37 Bratislava, Slovak Republic Department of Petroleum Chemistry and Technology, Faculty of Chemical Technology, Slovak Technology University, Radlinskeho 9, 812 37 Bratislava, Slovak Republic Department of Petroleum Chemistry and Technology, Faculty of Chemical Technology, Slovak Technology University, Radlinskeho 9, 812 37 Bratislava, Slovak RepublicThe sorption properties of samples of H-ZSM-5 zeolite and their forms modified with P, B and Mg were determined by the physical adsorption of nitrogen and evaluated by BET isotherm and t-plot methods. The diffusivities of the samples were measured using a new flow gravimetric method involving the sorption of p- and o -xylenes. The BET specific surface area decreased from 358 m 2 /g to 35–90 m 2 /g mainly because of a decrease in micropore volume as determined by the t-plot method. The rate of sorption of p -xylene on all the samples investigated followed Fick's second law of diffusion, leading to an effective diffusivity of ca. 1.7 × 10 −11 m 2 /s, irrespective of whether the H-form or the modified forms were investigated. The sorption isotherms for o -xylene showed some unusual steps. Values for the effective diffusivities decreased from 2.6 × 10 −12 m 2 /s for the H-form to 2.0–2.3 × 10 −12 m 2 /s for the modified forms. The equilibrium concentration of o -xylene at P/P 0 = 0.1 was only 0.38–0.68 mol/unit cell, while that of p -xylene was 4.40–5.98 mol/unit cell.https://doi.org/10.1177/026361749601300606 |
| spellingShingle | P. Hudek D. Bobok A. Smiešková Z. Židek Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites Adsorption Science & Technology |
| title | Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites |
| title_full | Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites |
| title_fullStr | Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites |
| title_full_unstemmed | Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites |
| title_short | Sorption and Diffusion Properties of H- and Modified Forms of ZSM-5 Zeolites |
| title_sort | sorption and diffusion properties of h and modified forms of zsm 5 zeolites |
| url | https://doi.org/10.1177/026361749601300606 |
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