COMPETITIVE ADSORPTION OF PHENOLS ON GAC .1. ADSORPTION EQUILIBRIUM

The impact of the presence of molecular oxygen on multicomponent adsor ption is evaluated in this study. Adsorption equilibria for binary mix tures of phenol/o-cresol and ternary mixtures of phenol/o-cresol/3-eth ylphenol on granular activated carbon (GAC) are determined at 23-degre es-C using three different initial-concentration combinations. Experim ents were conducted under conditions where molecular oxygen is present (oxic adsorption) and under conditions where oxygen was excluded from the adsorbate solution and the GAC particles (anoxic adsorption). The ideal adsorbed solution theory, using the Myers equation for correlat ing the single-solute anoxic isotherms, is found to accurately describ e the competitive adsorption behavior of these phenolic mixtures under anoxic conditions. When the Freundlich equation was used to describe the single solute behavior, increased deviations were observed. Poor m odel predictions for the oxic isotherms arc attributed to the presence of molecular oxygen, which promotes the polymerization of the adsorba tes on the surface of GAC.