Inverse gas chromatography of chromia. Part I. Zero surface coverage
The surface properties of the solid obtained from colloidal chromiawere investigated by inverse gas chromatography (IGC), at zero surface coverage conditions. The solid samples I dried at 423 K and II heated at 1073 K in the amorphous and crystalline form, respectively, were studied in the...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Serbian Chemical Society
2001-01-01
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| Series: | Journal of the Serbian Chemical Society |
| Subjects: | |
| Online Access: | http://www.doiserbia.nb.rs/img/doi/0352-5139/2001/0352-51390104259O.pdf |
| Summary: | The surface properties of the solid obtained from colloidal chromiawere
investigated by inverse gas chromatography (IGC), at zero surface coverage
conditions. The solid samples I dried at 423 K and II heated at 1073 K in
the amorphous and crystalline form, respectively, were studied in the
temperature range 383-423 K. The dispersive components of the surface free
energies, enthalpies, entropies, and the acid/base constants for the
solidswere calculated from the IGCmeasurements and compared with the data
for a commercially available chromia (III). Significantly lower enthalpies
and entropies were obtained for cyclohexane on solid II and chloroform,
highly polar organic, on solid I. The dispersive contributions to the
surface energy of solid II and III were similar, but much greater in the
case of solid I. All the sorbents had a basic character, with the KD/KA
ratio decreasing in the order I > II > III. The retention and resolution in
the separation of a vapour mixture of C5-C8 n-alkanes on the three
substrates were different.Arapid separationwas observed on solid II and an
enhanced retention on solid I. Generally, the heated chromia (II) exhibited
diminished adsorption capacity, and enhanced homogeneity of the surface. |
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| ISSN: | 0352-5139 1820-7421 |