Optimization of conditions for the preparation of activated carbons from olive-waste cakes

An experimental design (Doehlert matrix) has been drawn up to optimize the experimental conditions of the preparation of activated carbon from olive-w aste cakes. A series of activated carbons have been prepared by physical ac tivation with steam. Adsorption of N-2 (77 K), CO2 (273 K) and mercury poro simetry experiments have been carried out to determine the characteristics of all carbons prepared. Adsorption of iodine and methylene blue was used a s a primary indicator of the adsorption capacity of these carbons. The expe rimental response varied between: 13-27% for the total yield (Y-1), 115-490 mg/g for the adsorption or methylene blue (Y-2). 741-1495 mg/g for the ads orption of iodine (Y-3), 514-1271 m(2)/g for the BET surface area (Y-4), 0. 225-0.377 cm(3)/g for the micropore volume (Y-5), 0.217-0.557 cm(3)/g for t he volume of pores with a diameter greater than 3.7 nm (Y-6) and 31.3-132 m (2)/g for the external surface area (Y-7). The results obtained were exploi ted using response surface methodology. These responses have been represent ed and studied in all experimental regions of activation time and activatio n temperature, the most influential factors in activated carbon preparation . Optimization to obtain activated carbons with textural characteristics su itable to use in water treatment has been carried out. The optimal activate d carbon is obtained when using 68 min as activation time and 1095 K as act ivation temperature. (C) 2001 Elsevier Science Ltd. All rights reserved.