Chromium adsorption in olive stone activated carbon
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Chromium adsorption in olive stone activated carbon Milton Rog´erio Pereira · Pedro Augusto Arroyo · Maria Ang´elica Sim˜oes Dornellas de Barros · Viviane Monteiro Sanches · Edson Antonio da Silva · Isabel Maria Fonseca · Rafael Garc´ıa Lovera
Received: 2 August 2005 / Revised: 11 August 2006 / Accepted: 5 September 2006 C Springer Science + Business Media, LLC 2006
Abstract In this work, Cr(III) adsorption on activated carbon obtained from olive stones in an upflow fixed-bed column at 30◦ C was studied. The flow rate influence on the breakthrough curves at a feed concentration of 0.87 meq/L was investigated in an attempt to minimize the diffusional resistances. Breakthrough curves for a flow range of 2–8 mL/min were obtained at 10.5 cm bed height and inlet diameter of 0.9 cm. The mass transfer parameters indicated that the bed minimal resistance was attained at 2 mL/min. Therefore, the data equilibrium was carried out until the bed was saturated at 2 mL/min. The dynamic system generated a favorable isotherm with a maximum chromium uptakeof
M. R. Pereira . P. A. Arroyo . M. A. S. D. de Barros () . V. M. Sanches Universidade Estadual de Maring´a, Departamento de Engenharia Qu´ımica, Av. Colombo 5790 Bl. D-90, CEP 87020-900, Maring´a - Pr - Brazil e-mail: [email protected] E. A. da Silva Universidade do Oeste do Paran´a, Departamento de Engenharia Qu´ımica, Rua Faculdade, 645 Jardim La Salle, C.P. 520, CEP 85903-000, Toledo - Pr - Brazil e-mail: [email protected] I. M. Fonseca Universidade Nova de Lisboa, Centro de Qu´ımica Fina e Biotecnologia, 2829-516, Caparica, Portugal R. G. Lovera Universidad de Concepci´on, Facultad de Ciencias Qu´ımicas, Casilla 160-C, Concepci´on, Chile
0.45 meq/g. A column sorption mathematical model was created considering the axial dispersion in the column and the intraparticle diffusion rate-controlling steps. The isotherm was successfully modeled by the Langmuir equation and the mathematical model described the experimental dynamic data adequately for feed concentrations from 0.26 to 3.29 meq/L. Keywords Chromium . Activated carbon . Olive stones . Adsorption . Breakthrough
1 Introduction Industrial wastewater is one of the major sources of aquatic pollution. Heavy metals stand out among the aquatic pollutants due to their persistence and toxicity. Aqueous industrial wastes from several activities, such as metal plating, mining, tanning, etc. cause contamination by heavy metals. Treatment processes for removing metals from wastewaters include operations such as precipitation and filtration. The clarified solution still contains deleterious amounts of heavy metal ions. Chromium is one of the major trace metals in water effluents due to its capacity to form very stable complexes in solution (Barros, 2003). In order to remove very low concentrations of chromium, an adsorption step can be added to the conventional wastewater treatment process. Adsorption of Cr (III) ions in low-cost carbons has been gaining importance through the years. It is Springer
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