Surfactant Adsorption and Rheological Behavior of Surface-Modified Sepiolite
A. Alvarez, J. Santarén, R. Pérez-Castells, B. Casal, E. Ruiz-Hitzky, P. Levitz, J. J. Fripiat, 1985. "Surfactant Adsorption and Rheological Behavior of Surface-Modified Sepiolite", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
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Adsorption isotherms of a non-ionic surfactant (Triton X-100) and a quaternary cationic surfactant (Sanisol TPR) by aqueous dispersions of sepiolite gels have been measured at 25°C. The adsorption mechanisms of these two surfactants were different. Triton X-100 was adsorbed by hydrophyllic interaction, whereas the cationic surfactant was adsorbed in two stages. The first stage, to about 10 meq/ 100 g in the adsorption isotherm, involved cation exchange, as shown by a correlation between the amount of Mg extracted and the amount of adsorbed surfactant. The mechanism of adsorption in the second stage is not clear and was more complicated than that for smectite-quaternary systems.
The Brookfield viscosity and sediment volume of surface-modified sepiolite dispersions were found to depend on the nature and the amount of adsorbed surfactants and on the chemical nature of the solvent. Stable and highly viscous suspensions of Sanisol-modified sepiolite were obtained in organic solvents of low polarity (e.g., xylene), whereas Triton-modified sepiolite suspensions of high viscosity were obtained in polar organic solvents, such as triethanol amine.
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Proceedings of the International Clay Conference Denver, 1985
The papers included in this proceedings volume are representative of the research on clays being conducted in all parts of the world at the time of publication. Many of the subjects treated are controversial, and although some ideas expressed may not necessarily represent the views of the editors, the referees, or the publisher, they deserve to be brought to the attention of the international clay community.