Adsorption of oleic acid dissolved in isopropanol–water mixtures on hydrotalcite

Fatty acids are an interesting class of educts for chemical processes as they are available from renewable resources. For obtaining high-purity fatty acids, efficient separation techniques are needed. An interesting option is adsorption. In the present work, therefore, the adsorption of oleic acid on hydrotalcite, a readily available adsorbent, is studied. The focus is on studying the influence of the composition of the solvent on the adsorption. Adsorption isotherms are reported for oleic acid in pure isopropanol and mixtures of isopropanol and water at temperatures between 278 and 308 K. Even though the solubility of oleic acid in isopropanol is higher than in mixtures of isopropanol and water, the highest capacity of the adsorber is found for pure isopropanol. The reasons are discussed. No significant influence of the temperature was observed.