Environmental Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 8 No. 3, Issue of December 15, 2005
© 2005 by Pontificia Universidad Católica de Valparaíso -- Chile Received March 16 , 2005 / Accepted July 4, 2005
DOI: 10.2225/vol8-issue3-fulltext-10  
RESEARCH ARTICLE

Biosorption of chromium (VI) from aqueous solutions by the husk of Bengal gram (Cicer arientinum)

N. Ahalya
Energy and Wetlands Research Group
Centre for Ecological Sciences
Indian Institute of Science
Bangalore 560 012, India
Tel: 91 080 23600985/22932506
Fax: 91-08023601428
E-mail: Ahalya@ces.iisc.ernet.in

R.D. Kanamadi
Department of Zoology
Karnataka
University, Dharwad, India
Tel: 91 836 2215225 /2215355
Fax 91-836-2747884 / 2741928
E-mail: ravishankar_kanamadi@yahoo.com

 T.V. Ramachandra*
Energy and Wetlands Research Group
Centre for Ecological Sciences
Indian Institute of Science
Bangalore 560 012, India
Tel: 91 080 22933099/23600985/22932506/22932786
Fax: 91 080 23601428/23600085/23500683
E-mail: cestvr@ces.iisc.ernet.in

*Corresponding author


Financial support: This research has been carried out with the financial assistance from the Ministry of Environment and Forests, Government of India and Indian Institute of Science.

Keywords: agro-wastes, Bengal gram husk (bgh), Cicer arientinum, chromium biosorption, isotherms, fourier transform infrared spectroscopy (FTIR).

Abbreviations:

bgh: Bengal gram husk
FTIR: fourier transform infrared spectroscopy


Abstract
Full Text

The potential to remove Cr (VI) from aqueous solutions through biosorption using the husk of Bengal gram (Cicer arientinum), was investigated in batch experiments. The results showed removal of 99.9% of chromium in the 10 mgl-1 chromium solution, the biomass required at saturation was 1 g mg-1. Kinetic experiments revealed that the dilute chromium solutions reached equilibrium within 180 min. The biosorptive capacity of the (bgh) was dependent on the pH of the chromium solution, with pH 2 being optimal. The adsorption data fit well with the Langmuir and Freundlich isotherm models. The adsorption capacity calculated from the Langmuir isotherm was 91.64 mg Cr (VI)/g at pH 2. The adsorption capacity increased with increase in agitation speed and an optimum was achieved at 120 rpm. The biosorption of Cr (VI) was studied by Fourier transform infrared spectroscopy (FTIR), which suggested that the presence of Cr (VI) ions in the biomass affects the bands corresponding to hydroxyl  and carboxyl groups. Comprehensive characterisation of parameters indicates bgh to be an excellent material for biosorption of Cr (VI) to treat wastewaters containing low concentration of the metal.

Supported by UNESCO / MIRCEN network