Biosorption of Cr(III) and Pb(II) by Schoenoplectus californicus and insights into the binding mechanism

REARTE T.A.; BOZZANO P.; ANDRADE M.L.; IORIO A. F. DE

ISRN Chemical Engineering

Hindawi Publishing Corporation

Año: 2013 vol. 2013 p. 1 - 13

2090-861X

Biosorption and desorption of chromium and lead on shoots biomass of Schoenoplectus californicus was 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 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 pseudo-equilibrium 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 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.