MOLECULAR-OXYGEN AND THE ADSORPTION OF PHENOLS - EFFECT OF FUNCTIONAL-GROUPS

This study reveals that the presence of molecular oxygen (oxic conditi ons) has a significant impact on the exhibited adsorptive capacity of granular activated carbon (GAC) for several phenolic compounds. The in crease in the GAC adsorptive capacity under oxic conditions results fr om polymerization of these adsorbates on the carbon surface. The mecha nism of polymer formation is through oxidative coupling of phenolic mo lecules. The extent of an increase in the GAC adsorptive capacity is i n accordance with the ease of oxidation of these compounds. However, s ubstituting a nitro group on the parent phenol molecule suppressed pol ymerization reactions and no increase in the GAC adsorptive capacity w as observed under oxic conditions for these substituents.