DOI: 10.5593/SGEM2014/B52/S20.015


S. Sabo, T. Bakalar,M. Bugel, H. Pavolova
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-18-6 / ISSN 1314-2704, June 19-25, 2014, Book 5, Vol. 2, 109-116 pp

Biosorption of Cu(II) ions from aqueous solutions has been studied and the adsorption capacity of eggshell has been determined. The experimental data obtained from batch equilibrium tests have been analysed by two- and three-parameter isotherm models (Freundlich, Langmuir, Redlich-Peterson) and the data obtained from kinetics experiments have been analysed by the model of Urano-Tachikawa. The eggshell was cleaned and dried at room temperature. The material was washed and oven dried at 50°C for 72 hours. The shell was ground and sieved under 71 μm of particle size. The suspensions of eggshell were treated to reach the pH of 6. The equilibrium experiments were carried out by varying concentrations of initial Cu(II) solution. In all experiments, the flasks were shaken on orbital shaker at 200 rpm and at 25˚C for 6 hours to ensure ion-exchange equilibrium. The suspensions were then filtered through a micro filter of pore size 0.8 μm and filtrates were analysed using flame AAS in order to determine the final Cu(II) concentration in solution. The kinetics experiments were performed with initial metal concentrations 100 mg/L. The aqueous samples were taken at different time intervals (1-90 min) and then filtered through a micro filter. The concentration of biosorbent was 0.1 g/L. According to the results of the experiments the adsorption equilibrium of Cu(II) on eggshell was best described by Freundlich and Redlich- Peterson isotherms (almost identically). The maximum sorption capacity was 100 mg/g. The effective diffusion coefficient was in the order of magnitude 10-18 m2/s estimated by the model of Urano-Tachikawa. The kinetics of adsorption is fast. The Cu(II) concentration decreased markedly during the first 2-3 minutes. The actual concentration decreased from 103 mg/L to 16, 19, and 18 mg/L at 150, 250, and 350 rpm, respectively, after ten minutes. Further on the Cu(II) concentration did not change significantly with time. The experimental results of this study demonstrate that eggshell is suitable for adsorption of copper from aqueous solutions at low concentrations.

Keywords: biosorption, eggshell, copper, equilibrium, kinetics