Effect of salt on the mechanism of adsorption of aromatics on activated carbon

The effect of KCl on the adsorption of phenol, toluene, and benzene on acti vated carbon, with different degrees of surface oxygenation, was investigat ed. Different trends of salt effect were observed for each compound. The ob served KCl effects were interpreted on the basis of electrical charge neutr alization on the carbon surface and the adsorbate molecules, water adsorpti on, and the "salt out" effect. In particular, water adsorption was found to be crucial in reducing the adsorption capacity of the activated carbon. Th e influence of water adsorption was more pronounced on carbon surfaces with higher amounts of oxygen-containing groups. This was additionally confirme d by measurements using flow microcalorimetry.