Table of Contents
ISRN Chemical Engineering
Volume 2013 (2013), Article ID 851602, 13 pages
http://dx.doi.org/10.1155/2013/851602
Research Article

Biosorption of Cr(III) and Pb(II) by Schoenoplectus californicus and Insights into the Binding Mechanism

1Laboratory of Analytical Chemistry, Department of Natural Resources and Environment, Faculty of Agronomy, University of Buenos Aires, C1417DSE Buenos Aires, Argentina
2Laboratory of Electron Microscopy, Atomic Center Constituyentes, National Atomic Energy Commission, B1650 Buenos Aires, Argentina
3Department of Plant Biology and Soil Science, Faculty of Biology, University of Vigo, 36310 Pontevedra, Spain

Received 8 May 2013; Accepted 13 June 2013

Academic Editors: C. Chen, C. B. Coldeira, C.-T. Hsieh, J. J. Rodriguez, and C. Xu

Copyright © 2013 Tomás Agustín Rearte et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Biosorption and desorption of chromium and lead on shoots biomass of Schoenoplectus californicus were investigated by performing batch sorption tests in different conditions of pH, biosorbent dose, and initial concentration in simple and binary solutions. Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models were employed to describe sorption equilibrium. Filters and biomass were characterized before and after treatments by environmental scanning electron microscopy and X-ray energy-dispersive spectrometry. The optimal conditions for biosorption were found to be pH 5 for both metals. The contact time to reach pseudoequilibrium changed as a function of pH and the metal studied. The highest optimisation of biosorbent dose was 5 g L−1 at pH 7 and 15 g L−1 at pH 5 for both metals. The most effective extracting agents for lead and chromium proved to be HNO3 and NaOH, respectively. The recovery of lead was greater than of chromium because the Cr(III) sorption mechanisms involve a stronger binding energy than the mechanisms for Pb(II), such as in intern sphere complexes. Both metals accounted for a high % removal (>90%) under the best sorption conditions. The use of Schoenoplectus californicus proved to be an efficient and economical alternative for the treatment of effluents contaminated with lead and chromium.