Hexavalent chromium sorption by biomass of chromium tolerant Pythium sp.

The removal of Cr(VI) from aqueous solutions by live and pretreated fungal biomass of Pythium sp was investigated in a batch mode. The influence of biomass dose, solution pH, initial metal ion concentration, temperature and pretreatment of biomass on biosorption efficiency was studied. The acid pretreated biomass adsorbed 1.7 times more hexavalent chromium in comparison to untreated biomass. The chromium removal rate increased with decrease in pH and increase in Cr(VI) concentration, biomass dose and temperature. The adsorption data was described well by Freundlich isotherm model. Evaluation of biosorption mechanism using infrared spectroscopy showed the involvement of positively charged amino groups in Cr(VI) biosorption. The biosorption of Cr(VI) by Pythium sp. followed second order kinetics, the biosorption process was found to be spontaneous and endothermic with high affinity of biomass for Cr(VI).