The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30-60 min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600, 700 and 800 degrees C. Of the three chemical reagents under evaluation only ZnCl2 produced activated carbons with high surface areas. BET surface areas for rice husk were up to 750 m(2)/g for 1:1 ZnCl2:rice husk ratio. BET surface areas for bagasse were Lip to 674 m(2)/g for 0.75:1 ZnCl2:bagasse ratio. Results were compared to regular two-stage physical activation methods. (C) 2008 Elsevier Ltd. All rights reserved.