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