Seidel, J. and Wittrock, C. and Kohler, H.-H. (1996) Adsorption enthalpies of cationic and nonionic surfactants on silica gel .2. Microcalorimetric determination of adsorption enthalpies. LANGMUIR, 12 (23). pp. 5557-5562. ISSN 0743-7463
Full text not available from this repository.Abstract
There are two common methods for the experimental determination of adsorption enthalpies of surfactants on solid surfaces in aqueous solution, either directly by calorimetry or indirectly by using a Clausius-Clapeyron equation. The present paper is the second part of a two-part contribution dealing with a comparison of both methods. In this part calorimetric results on the adsorption of a nonionic (n-octyltetraoxyethylene) and a cationic (cetylpyridinium chloride) surfactant on a wide pore silica gel are presented for different temperatures between 25 and 40 degrees C. For the fast adsorbing nonionic surfactant good quantitative agreement between the isosteric and calorimetric differential molar heats of adsorption (13.5 +/- 1 kJ/mol) is found above a relative surface coverage of 0.1. For the cationic surfactant the agreement between the isosteric and the calorimetric enthalpy data is more qualitative. The reason is probably that the adsorption rate is too slow to reach equilibrium in the calorimetric experiments (flow calorimetry). The differential molar enthalpies of adsorption of the cationic surfactant are exothermic. Advantages and limitations of the calorimetric and isosteric method are discussed.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SOLID-LIQUID INTERFACE; IONIC SURFACTANTS; WATER INTERFACE; FLOW MICROCALORIMETRY; ANIONIC SURFACTANTS; AQUEOUS-SOLUTIONS; CHARGED SURFACES; OXIDE SURFACES; THERMODYNAMICS; MODEL |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 09 Jun 2023 12:48 |
| Last Modified: | 09 Jun 2023 12:48 |
| URI: | https://pred.uni-regensburg.de/id/eprint/51348 |
Actions (login required)
 |
View Item |
