Adsorption Behavior of Mono-Cationic Pyridinium Salts on the Clay Surface

The adsorption behavior of cationic organic molecules was examined on a clay surface. Systematically chosen pyridinium salts and artificially synthesized anionic clay were used. The adsorption equilibrium constants and the free energy for adsorption (Delta G) values were obtained for each pyridinium salt. It was discovered that Delta G values were proportional to the cross-sectional area of the pyridinium salt. These results indicate that hydrophobic and/or van der Waals interactions play an important role for the adsorption process.