Abstract
Abstract Experimental studies of solute adsorption from dilute solutions, especially from aqueous dilute solutions, are carried out in many laboratories, yet the theoretical foundations of this phenomenon are still insufficiently solved (1). Adsorption of phenols on carbons is an important subject especially due to ecological aspects. Therefore, an enormous number of papers has been published in this field. The most important reviews dealing with this problem were recently published by Radovic and co‐workers (2) and by Moreno ‐ Castilla (3). The authors consider the changes in the surface chemistry of carbons with changes in pH, and discuss different mechanisms of adsorption proposed in the literature. The main regularities associated with adsorption of phenol on carbons are as follows (2): (usually observed) a decrease in adsorption with a rise in surface acidity (as measured by Boehm titration) and with surface oxidation, problems in determining real equilibrium; chemisorption is inhibited by the presence of oxygen surface complexes; therefore, the sites responsible for phenol chemisorption are carbon sites of the active surface area, that is, oxygen free sites located at the edges of graphene layers whereas physisorption occurs all over the surface; irreversible adsorption is caused by oxidative coupling in the presence of molecular oxygen.
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