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Preparation of activated carbon from sawdust by zinc chloride activation Huiping Zhang · Ying Yan · Lichun Yang

Received: 3 March 2008 / Accepted: 28 April 2010 / Published online: 12 May 2010 © Springer Science+Business Media, LLC 2010

Abstract A series of activated carbons were prepared from sawdust by zinc chloride activation in different operation conditions. The effects of operation parameters such as impregnation ratio, activation temperature and time on the adsorption properties of activated carbons were measured and analyzed in order to optimize these operation conditions. The experimental results show that under the experimental circumstances studied, both the yield and the adsorption for iodine and methylene blue of activated carbon can reach a relatively higher value in the chemical activation process with the impregnation ratio of 100% ZnCl2 /sawdust in the activation temperature of 500 °C carbonized for 60– 90 minutes which are the optimum activation conditions in making wood activated carbon. The most important operation parameter in chemical activation with zinc chloride was found to be the impregnation ratio. Keywords Activated carbon · Activation · Carbonization · Adsorption

1 Introduction Activated carbons as porous adsorption materials with abundant micropores (0–2 nm), mesopores (2–50 nm) and H. Zhang () · Y. Yan The School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641, P.R. China e-mail: [email protected] L. Yang Department of Chemical Engineering, Xiamen University, Xiamen 361005, P.R. China

macropores (>50 nm) as well as high specific surface areas are widely used in gas purification and separation, water and wastewater treatment, chemical processing, etc. Activated carbons are also used as the support of catalysts in industries such as chemical, pharmaceutical, polymerization and environmental protection. In China the production of activated carbons is estimated to exceed 200,000 tons per year in which activated carbons of 40,000 tons are wooden activated carbons manufactured by different activation methods including chemical and physical activation methods. Most carbonaceous substances such as coal, coconut shell, wood and sawdust, etc. can be converted into activated carbons. The porous structures and final properties of activated carbons depend significantly on both the activation processes and the natures of raw materials. A lot of processes for preparing activated carbons have been developed over past century (Lua and Gua 2000; Lozano-Castello et al. 2001; Cooney 1999; Hayashi et al. 2000; Ahmadpour and Do 1996, 1997; Bernardo et al. 1997). Most processes can be divided into two different processes, the so-called physical and chemical activation. Physical activation comprises the pyrolysis (or carbonization) step followed by a stage of controlled oxidation to activate the carbon in the presence of a physical activating agent such as steam, carbon dioxide etc. Chemical activation includes that the raw material is impregnated with a given