Dead Fungal Biomass of Rhizopus Arrhizus for Decontamination of Hexavalent Chromium: Biosorption Kinetics, Equilibrium Modelling and Recovery
Kshama A. Shroff and Varsha K. Vaidya
Journal Title:Nature Environment and Pollution Technology
The kinetics and equilibrium of biosorption of hexavalent chromium from aqueous solution was carried out using the dead physico-chemically treated biomass of Rhizopus arrhizus in a batch system. The biosorption characteristics of Cr(VI) ions were studied with respect to well-established parameters including pH, temperature, rotational speed, biosorbent dosage, initial metal ion concentration and contact time. The uptake of Cr(VI) decreased with an increase in pH and biomass concentration whereas it increased with an increase in the Cr(VI) concentration, temperature and rotational speed. Biosorption equilibrium was established in about 180 min. The adsorption data were analysed using the first and the second-order kinetic models as well as intra-particular rate expressions. The first-order equation was the most appropriate equation to predict the biosorption capacities of the fungal biosorbent. The sorption data obtained at pH 2.0 conformed well to both the Langmuir and Freundlich isotherm models. The reusability of the biosorbent was tested in five consecutive adsorption-desorption cycles and the regeneration efficiency was above 95%. From the practical viewpoint, the abundant and inexpensive dead fungal biomass of Rhizopus arrhizus could be used as an effective, low cost and environmental friendly biosorbent for the detoxification of Cr(VI).