NMR Study of Phase Transitions in Pure Water and Binary H(2)O/HNO(3) Films Adsorbed on Surface of Pyrogenic Silica
| Autor: | Markku Kulmala, Boris Gorbunov, Anatoli Bogdan, Alexander Kruppa |
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| Rok vydání: | 1996 |
| Předmět: |
Phase transition
Molar concentration Chromatography Chemistry Analytical chemistry 02 engineering and technology Nuclear magnetic resonance spectroscopy 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 6. Clean water 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials chemistry.chemical_compound Colloid and Surface Chemistry Adsorption Nitric acid Binary system Surface layer 0210 nano-technology Fumed silica |
| Zdroj: | Journal of colloid and interface science. 177(1) |
| ISSN: | 1095-7103 |
| Popis: | Pyrogenic silica (aerosil) was employed as host within which the phase transitions in the adsorbed pure water and binary H2O/HNO3films have been studied with NMR spectroscopy. The median freezing temperature and freezing temperature region were shown to be highly sensitive both to the average thickness of the adsorbed films and to the amount of adsorbed nitric acid. The molar concentration of nitric acid in the adsorbed films was found to be very small, on the order of 10−3–10−2(M/liter). The concentration was found to be greater in the layers adjacent to the surface of silica and sharply decreases with distance from the surface. The difference between the median freezing temperatures for adsorbed pure water and for the binary system was found to be about 9 K for films of equal thickness. This is about 150 times greater than the difference between the freezing temperatures of bulk pure water and a solution with the same concentration of nitric acid. |
| Databáze: | OpenAIRE |
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