Experimental and Simulation Study of n-Heptane Adsorption on Rutile
The adsorption of n-heptane on microcrystalline rutile has been studied experimentally by thermodynamic techniques (adsorption isotherms and microcalorimetry) over a wide range of coverage at 303 K and complemented by Grand Canonical Monte Carlo simulations. The differential heat of adsorption exhib...
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| Format: | Article |
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SAGE Publishing
2007-09-01
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| Series: | Adsorption Science & Technology |
| Online Access: | https://doi.org/10.1260/0263-6174.25.7.517 |
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| author | G.U. Rakhmatkariev A.J. Palace Carvalho J.P. Prates Ramalho |
| author_facet | G.U. Rakhmatkariev A.J. Palace Carvalho J.P. Prates Ramalho |
| author_sort | G.U. Rakhmatkariev |
| collection | DOAJ |
| description | The adsorption of n-heptane on microcrystalline rutile has been studied experimentally by thermodynamic techniques (adsorption isotherms and microcalorimetry) over a wide range of coverage at 303 K and complemented by Grand Canonical Monte Carlo simulations. The differential heat of adsorption exhibited three descending segments corresponding to the adsorption of n-heptane on three types of surfaces. The mean molar adsorption entropy of n-heptane in the monolayer was less than the entropy of the bulk liquid by ca. −23 J/(mol K), thus revealing a hindered state of motion for the n-heptane molecules on the surface of rutile. Simulations of the adsorption of n-heptane were performed on the three most abundant crystallographic faces of rutile. The adsorption isotherm obtained from the combination of the isotherm for each face weighted by the respective abundance was found to be in good agreement with experimental data. A structural characterization of n-heptane near the surface was also conducted which indicated that the substrate strongly perturbed the distribution of the n-heptane conformations relative to the situation found for the gaseous phase. Adsorbed molecules are predominantly orientated with their long axes, with the zig-zag planes of their backbones parallel to the surface and preferentially aligned along the five-fold cus Ti 4+ ions of the faces. Fewer gauche conformations were observed for molecules near the surface than was characteristic of the bulk phase. |
| format | Article |
| id | doaj-art-9ab9c3bb0595493f8b682e5ab73c7fd5 |
| institution | Kabale University |
| issn | 0263-6174 2048-4038 |
| language | English |
| publishDate | 2007-09-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Adsorption Science & Technology |
| spelling | doaj-art-9ab9c3bb0595493f8b682e5ab73c7fd52025-01-02T22:37:57ZengSAGE PublishingAdsorption Science & Technology0263-61742048-40382007-09-012510.1260/0263-6174.25.7.517Experimental and Simulation Study of n-Heptane Adsorption on RutileG.U. Rakhmatkariev0A.J. Palace Carvalho1J.P. Prates Ramalho2 Institute of General and Inorganic Chemistry, Academy of Sciences of Uzbekistan, 700170 Tashkent, Uzbekistan Centro de Quimica de Evora, University of Evora, 7000-671 Evora, Portugal Centro de Quimica de Evora, University of Evora, 7000-671 Evora, PortugalThe adsorption of n-heptane on microcrystalline rutile has been studied experimentally by thermodynamic techniques (adsorption isotherms and microcalorimetry) over a wide range of coverage at 303 K and complemented by Grand Canonical Monte Carlo simulations. The differential heat of adsorption exhibited three descending segments corresponding to the adsorption of n-heptane on three types of surfaces. The mean molar adsorption entropy of n-heptane in the monolayer was less than the entropy of the bulk liquid by ca. −23 J/(mol K), thus revealing a hindered state of motion for the n-heptane molecules on the surface of rutile. Simulations of the adsorption of n-heptane were performed on the three most abundant crystallographic faces of rutile. The adsorption isotherm obtained from the combination of the isotherm for each face weighted by the respective abundance was found to be in good agreement with experimental data. A structural characterization of n-heptane near the surface was also conducted which indicated that the substrate strongly perturbed the distribution of the n-heptane conformations relative to the situation found for the gaseous phase. Adsorbed molecules are predominantly orientated with their long axes, with the zig-zag planes of their backbones parallel to the surface and preferentially aligned along the five-fold cus Ti 4+ ions of the faces. Fewer gauche conformations were observed for molecules near the surface than was characteristic of the bulk phase.https://doi.org/10.1260/0263-6174.25.7.517 |
| spellingShingle | G.U. Rakhmatkariev A.J. Palace Carvalho J.P. Prates Ramalho Experimental and Simulation Study of n-Heptane Adsorption on Rutile Adsorption Science & Technology |
| title | Experimental and Simulation Study of n-Heptane Adsorption on Rutile |
| title_full | Experimental and Simulation Study of n-Heptane Adsorption on Rutile |
| title_fullStr | Experimental and Simulation Study of n-Heptane Adsorption on Rutile |
| title_full_unstemmed | Experimental and Simulation Study of n-Heptane Adsorption on Rutile |
| title_short | Experimental and Simulation Study of n-Heptane Adsorption on Rutile |
| title_sort | experimental and simulation study of n heptane adsorption on rutile |
| url | https://doi.org/10.1260/0263-6174.25.7.517 |
| work_keys_str_mv | AT gurakhmatkariev experimentalandsimulationstudyofnheptaneadsorptiononrutile AT ajpalacecarvalho experimentalandsimulationstudyofnheptaneadsorptiononrutile AT jppratesramalho experimentalandsimulationstudyofnheptaneadsorptiononrutile |