Journal of Environmental Biology

Cr (VI) and Fe (III) removal using Cajanus cajan husk

N. Ahalya¹, R.D. Kanamadi² and T.V. Ramachandra*¹

*cestvr@ces.iisc.ernet.in

¹Energy and Wetlands Research Group, Centre for Ecological Sciences

  Indian Institute of Science, Bangalore-560 012, India

²Department of Zoology, Karnataka University, Dharwad-580 005, India

(Received: October 01, 2005 ; Revised received: March 15, 2006 ; Accepted: April 28, 2006)

Abstract: Husk of tur dal (Cajanus cajan) was investigated as a new biosorbent for the removal of Fe (III) and Cr (VI) ions from aqueous solutions. Parameters like agitation time, adsorbent dosage and pH were studied at different initial Fe (III) and Cr (VI) concentrations. The biosorptive capacity of the Tur dal husk was dependent on the pH of the chromium and iron  solution, with pH 2 and 2.5 respectively being optimal.  The adsorption data fit well with Langmuir and Freundlich isotherm models. The practical limiting adsorption capacity (q_max) calculated from the Langmuir isotherm was 96.05 mg of Cr(VI)/g of the biosorbent at an initial pH of 2.0 and 66.65 mg/g at pH 2.5 . The infrared spectra of the biomass revealed that hydroxyl, carboxyl and amide bonds are involved in the uptake of Cr (VI) and Fe (III) ions. Characterisation of tur dal husk has revealed that it is an excellent material for treating wastewaters containing low concentration of metal ions.

Key words:   Chromium biosorption, Iron biosorption, Agro-wastes, Tur dal husk, Cajanus cajan

Copyright © 2007 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any form without prior permission. Responsibility regarding the authenticity of the data, and the acceptability of the conclusions enforced or derived, rest completely with the author(s).