Sorption of substituted phenols by clay-based subsoils

Sorption isotherms of eleven substituted phenols with a typical clay-based southern Italy subsoil (Lucera-clay) have been carried out with the aim to find, if any, a correlation between sorption extent and selected phenols properties. Equilibrium isotherms, obtained at neutral pH, T=200C, in a concentration range between 0-50 ppmm, have been described by the Freundlich equation (S=K·C1/n) and the resulting K values have been tentatively correlated to four phenols properties: water solubility, dipole moment, polarizability, Hammett constant. Differently than previous results indicating H-bondings formation as responsible for sorption phenomena in similar systems, in the present investigation is the phenols polarizability that seems to play the most relevant role in determining sorption extent