Removal of zirconium from aqueous solution by Aspergillus niger

Removal of zirconium from its dilute aqueous solution using Aspergillus niger as a dried and living biomass was investigated. Through that, the effect of some operational parameters on biosorption, including pH, temperature, contact time, initial concentration of zirconium and dose of biomass, were studied. Based on the results, it was concluded that the uptake of zirconium by both dried and living biomasses is pH dependent, and maximum uptake was observed in pH = 3.1 for both biomasses. The maximum uptake capacity of the living biomass was obtained at 30 degrees C. However, the biosorption of zirconium by dried biomass was not affected by temperature. The maximum uptake capacity for living and dried biomasses (78.8 mg/g and 142 mg/g, respectively) was obtained at equilibrium time of 120 min and 30 min, respectively. Equilibrium isotherms showed that adsorption of zirconium by living biomass follows the Freundlich model, and the uptake of dried biomass follows the Langmuir model. Kinetic studies showed that both kinds of biomass follow the second order kinetic model. (C) 2014 Sharif University of Technology. All rights reserved.