Effect of temperature on equilibrium adsorption of phenols onto nonionic polymeric resins

The amounts of equilibrium adsorption of phenol and 4-chlorophenol from aqueous solutions on nonionic polymeric resins were measured in the 288-318 K temperature range. In general, these polymeric resins have a higher capacity for 4-chlorophenol at low solute concentrations but for phenol at higher solute concentrations. The adsorption data for both phenols were presented in terms of the number of adsorbed monolayers and the fraction of pore volume filled due to poor fit by the widely used Langmuir, Freundlich, and BET equations over the entire concentration range (100-3000 g/m³). Finally, the isosteric enthalpies of adsorption were determined. They decreased with increasing surface coverage.