An activated carbon was modified by impregnating with various acids or bases. The effects of adsorption capacity and impregnated contents on the textural properties of the impregnated activated carbons (IACs) were investigated. Furthermore, VOC adsorption and desorption experiments were carried out to determine the relationship between the adsorption capacity and chemical properties of the adsorbents. The effects of various parameters such VOC concentration, aspect ratio, flow rate, and impregnated contents were investigated. High adsorption capacity for the selected VOCs was obtained over 1 wt.% H3PO4/AC (1 wt.% PA/AC). As a result, IAC was found to be effective for VOC removal by adsorption with the potential for repeated use through desorption by simple heat treatment. (c) 2005 Elsevier B.V. All rights reserved.