The -Nonane Preadsorption Method Applied to Activated Carbons

Abstract

The n -nonane preadsorption method has been applied to evaluate the microporosity of two series of activated carbons (prepared from olive stones and almond shells) reacted with air at 623 K to different degrees of burn-off. A detailed study of the experimental conditions needed for the successive removal of the n -nonane preadsorbed has been carried out, showing that the sample outgassed at 673 K is identical to the original. In general, the results obtained with the preadsorption of n-nonane are satisfactory only in carbons with a narrow microporosity. On the other hand, this method has been used to calculate the apparent surface area of the carbons from the n-nonane retained using an A m value of 0.844 nm 2 , the results being in good agreement with the N 2 BET values. An analysis of the evolution with burn-off of the parameters C(BET) and D(DR) has also been carried out and their relationship calculated; both parameters describe reasonably well the evolution of the microporosity of the carbons.