Equilibrium and kinetic studies on biosorption of CR (VI) by Aspergillus Oryzae isolated from tannery effluent

The present work is concerned to remove Cr (VI) using the biosorption potential of the chromium resistant fungal biomass Aspergillus oryzae isolated from tannery effluent was studied. 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 carried out. A maximum of 90.1% Cr (VI) removal was observed in 25 mg/L initial Cr (VI) metal ion concentration using dry Aspergillus oryzae biomass. A maximum of 96 % Cr (VI) removal was observed in 25 mg/L initial Cr (VI) metal ion concentration using nitric acid doped A. oryzae biomass at 37 degree C, pH 2.0 and 150 rpm. Further equilibrium modeling was carried out using Langmuir and Freundlich adsorption isotherm and the data were fitted. Kinetic studies have been evaluated with respect to first order and second order kinetic equations and arranged based on its adsorption capacity. The characterization studies were carried out using SEM. Desorption studies were carried out and the desorbed fungi was recycled effectively using 0.1M HCl and was found to remove 88.2% of Hexavalent chromium.