Removal of Cr(VI) from aqueous solution by adsorption onto activated carbon

Activated carbon (AC) prepared from coconut tree sawdust was used as an ads orbent for the removal of Cr(VI) from aqueous solution. Batch mode adsorpti on studies were carried out by varying agitation time, initial Cr(VI) conce ntration, carbon concentration and pH. Langmuir and Freundlich adsorption i sotherms were applied to model the adsorption data. Adsorption capacity was calculated from the Langmuir isotherm and was 3.46 mg/g at an initial pH o f 3.0 for the particle size 125-250 mum. The adsorption of Cr(VI) was pH de pendent and maximum removal was observed in the acidic pH range. Desorption studies were carried out using 0.01-1 M NaOH solutions. (C) 2001 Elsevier Science Ltd. All rights reserved.