Biosorption of Hexavalent Chromium and its Kinetic Studies

The present work is concerned to remove Cr (VI) using the biosorption potential of the chromium resistant fungal biomass Aspergillus fumigatus isolated from tannery effluent. The dry fungal biomass was used to optimize various parameters such as contact time, initial metal ion concentration, pH, biomass loading etc. The percentage removal of chromium using various chemical pre-treatments was studied. A maximum of 92.48% Cr (VI) removal was observed in 25 mg/L initial Cr (VI) metal ion concentration using dry Aspergillus fumigatus biomass. A maximum Cr (VI) removal of 96.99% was obtained using Nitric acid doped chemically modified fungal biomass followed by 94.78% removal using alkali pre-treated chemically modified fungal biomass and followed by 92.98% removal using Sulphuric acid doped chemically modified fungal biomass at 37ºC, pH 2.0 and 150 rpm. Further equilibrium modeling was carried out using Langmuir, Freundlich, Dubnin Radushkevich and Tempkin adsorption isotherm and the datäs were fitted. Freundlich isotherm showed the best fit with a correlation coefficient of 0.9992.