Preparation of high-surface-area activated carbons from coconut shell

High-surface-area activated carbons were prepared by chemical activation of coconut shell with KOH as active agent. The influence of activation parameters on the final products was studied by varying the KOH-to-shell ratio, activation temperature and pre-heat temperatures. The samples were characterized by nitrogen adsorption isotherms at 77 K. The surface area and pore volume of the carbons were estimated by BET, the Langmuir equation and the t-plot method. Pre-treatment at 600 degrees C favored the product with good yield, high surface area and granular form. The BET surface area and pore volume were as high as 2451 m(2)/g and 1.21 cm(3)/g, respectively The activated carbons exhibited a much higher adsorption capacity for phenol, 4-chlorophenol and it-nitrophenol from aqueous solution than did a commercial activated carbon. (C) 1999 Elsevier Science B.V. All rights reserved.