PERGAMON Carbon 38 (2000) 1873–1878 Preparation of activated carbon from lignin by chemical activation a, a a b * Jun’ichi Hayashi , Atsuo Kazehaya , Katsuhiko Muroyama , A.Paul Watkinson a Department of Chemical Engineering, Kansai University,3-3-35 Yamate-cho, Suita, Osaka, 564-8680 Japan b Pulp and Paper Centre, Department of Chemical and Bio-Resource Engineering, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4 Received 30 September 1999; accepted 25 January 2000 Abstract Activated carbons were prepared from lignin by chemical activation with ZnCl , H PO and some alkali metal 2 3 4 compounds. The influence of carbonization and activating reagent on the pore structure of the activated carbon was investigated. It was found that the maximum surface areas were obtained at the carbonization temperature of 6008C in both ZnCl and H PO activation, and that the surface areas were as large as those of the commercial activated carbons. On the 2 3 4 other hand, in alkali metal activation it was found that the maximum surface areas were obtained at the carbonization temperature of 8008C. Except for Na CO maximum surface areas were much larger than those of the commercial activated 2 3 2 carbons. The activated carbon prepared by K CO activation showed a surface area of nearly 2000 m / g. It was shown that 2 3 ZnCl works effectively as dehydration reagent below 6008C. On the other hand, K CO works effectively in two 2 2 3 temperature ranges, below 5008C and above 6008C. Below 5008C, the carbonization behavior was modified by impregnation with K CO , but the pore structure changes little. Above 6008C, carbon was consumed by K CO reduction and then the 2 3 2 3 surface area was increased.  2000 Elsevier Science Ltd. All rights reserved. Keywords: A. Activated carbon; B. Activation; C. BET surface area; D. Surface areas 1. Introduction greatly desired and the production of activated carbons from wastes is an interesting possibility. Lignin is a waste Activated carbon is a high-porosity material which is which is generally used only for its fuel value. Therefore, useful in adsorption of both gases and solutes from it was of interest to prepare a higher value product such as aqueous solution. Therefore it has been widely used for the an activated carbon from lignin. separation of gases, the recovery of solvents, the removal There are basically two methods for preparing activated of organic pollutants from drinking water and as a catalyst carbon: physical and chemical activation. Physical activa- support. As environmental pollution is becoming a more tion consists of two steps: the carbonization of the starting serious problem, the need for activated carbon is growing. material, and the activation of the char by using carbon Coals and ligno-cellulosic materials are commonly used dioxide or steam. In chemical activation both the carboni- as the starting material for preparing activated carbon. zation and the activation step proceed simultaneously. Recently, numerous attempts to prepare activated carbon Many studies for preparing activated carbon by chemical from solid wastes have also been made [1–10]. The activation [1,4,5,9–16] have been done. Recently, acti- development of methods to re-use waste materials is vated carbons with very high surface area have been prepared by chemical activation [11–14]. Gas storage is a potential application for such high surface area materials. However, the purpose of most of these studies was to *Corresponding author. Tel.: 181-6-6368-0913; fax: 181-6- prepare the activated carbon, and little attention has been 6388-8869. E-mail address: hayashi7@kansai-u.ac.jp (J. Hayashi) given to the influence of the activating reagent on the pore 0008-6223 / 00 / $ – see front matter  2000 Elsevier Science Ltd. All rights reserved. PII: S0008-6223(00)00027-0