The aim of this work was to compare the effect of different activating atmospheres on the final properties and
adsorption performance of activated carbons. Almond shell based activated carbons have been obtained by
chemical activation with phosphoric acid. Two sets of activated carbons were prepared. First set was prepared
under inert atmosphere at different impregnation ratios, temperatures and times of activation. Second set of
activated carbons was prepared at the same activating conditions except the activating atmosphere using an
oxidant one. Activated carbons prepared under both activation atmospheres were characterized by elemental
analysis (EA), thermogravimetry (TGA), temperature programmed desorption (TPD), point zero charge (PZC),
Boehm titration and N2 physisorption. To study the adsorption performance of the activated carbons toluene
adsorption–desorption isotherms were determined gravimetrically. The results obtained confirm that the
activating atmosphere has a strong influence on the final characteristics of the activated carbons. Activated
carbons with higher oxygen content and more negative surface charge have been obtained by changing the
activating atmosphere by an oxidant one. Surface area is also higher for activated carbons prepared under oxidant
atmosphere. However toluene adsorption capacity is lower for activated carbons prepared under oxidant atmosphere
due to their surface chemistry.