An Ion Adsorption Model Related to the Change in the Standard Chemical Potential of Adsorption Reactions

• Main Author: Xiaofu Wu
• Format: Article
• Language: English
• Published: Hindawi - SAGE Publishing 2011-08-01
• Series: Adsorption Science & Technology
• Online Access: https://doi.org/10.1260/0263-6174.29.8.747

A simple model is proposed for the prediction of equilibrium ion adsorption in liquid/solid systems. The establishment of the model was based on the assumption that the change in the standard chemical potential of the adsorption system should be zero if ion adsorption taking place spontaneously at a constant temperature is purely a thermodynamic process in which, driven by the electrochemical potentials, the ions move between liquid and solid phases without changing their chemical nature. Experiments have been conducted to test this assumption using the adsorption of Zn 2+ , Cd 2+ and K + ions from aqueous solutions onto swelling vermiculite, natural zeolite and synthetic zeolite. The results showed that the proposed model fitted the experimental data well. This study provides evidence that, under the conditions employed, ion adsorption reactions are essentially physical processes and the change in the standard chemical potential of the adsorption reaction is negligible.