Phenol adsorbs in two ways on activated carbons: by physisorption and chemisorption. During the course of time and by raising the temperature, chemisorption is increased and part of the physisorbed phenol becomes chemisorbed. This phenol is impossible to remove as such. Upon heating to elevated temperatures it decomposes, depositing carbon, resulting in a decrease in the adsorption capacity of activated carbons. By studying this, we have been able to find adsorption conditions which prevent phenol chemisorption and yield a method of 100% regeneration of phenol-polluted activated carbons.