Removal of Zirconium from Aqueous Solution by Aspergillus niger

Removal of zirconium from its dilute aqueous solution by using Aspergillus niger as dried and living biomass was investigated. Through that, the effect of some operational parameters including pH, temperature, contact time, initial concentration of zirconium, and dose of biomass on biosorption 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 living biomass was obtained in 30 OC. 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 Freundlich model and uptake of dried biomass follows Langmuir model. Kinetic studies showed that both kinds of biomasses follow second order model of kinetic.