Characteristics of Pore Structures and Surface Chemistry of Activated Carbons by Physisorption, Ftir And Boehm Methods

Abstract

Highly-porous structures of activated carbon were prepared from oil palm shell. Their adsorptive characteristics and surface chemistry were investigated. Five series of activated carbons were obtained at different temperatures using chemical activation with potassium hydroxide. The results show that the activated carbon produced from 500-700 o C exhibit Type I isotherm, characteristics of microporous structure. The activated carbon prepared from 800-900 o C show a combination Type I and IV isotherm with wide hysteresis loop indicating mesoporous structures. The BET surface area and total pore volume increased almost linearly with increasing activation temperatures resulting 2301 m 2 g-1 and 0.55 cm 3 g-1 , respectively. Modification of surface chemistry of the activated carbon using chemical treatment with nitrit acid have increased the number of total acid groups. Reaction between nitric acid and activated carbons sharply increased the total acid groups containing of carboxylic, lactonic and phenolic groups as oxygen-surface functional groups. Reaction urea and ammonia with activated carbon provided a numbers of the total basic groups as N-H and NH 2 groups, indicating the presences of nitrogen-surface functional groups.