Effect of pH on adsorption equilibria for dissolved organic electrolytes and activated carbon

The influence of pH on the adsorption equilibria of ?-picolin and phenol from aqueous solution on activated carbon is studied experimentally for the single solutes and their mixtures. For these weak bases and weak acids the effect of pH on adsorption capacity is contrary, thus allowing an efficient separation by adsorption. A model based on the concept of competitive adsorption of ionic and molecular forms of the organic electrolytes represents the experimental data qualitatively. Deviations between theoretical and experimental results are discussed on the basis of possible interactions of the organic solutes and the activated carbon with components of the buffer used in the experiments