Biosorption of Uranium (VI) from Aqueous Solution by Pretreated Aspergillus niger Using Sodium Hydroxide

The removal of uranium and any other heavy metals from wastewater might be achieved via several chemical or physical treatment techniques. Biosorption process has been considered as a potential alternative way to remove contaminants from industrial effluents. Moreover the surface of biosorbent was characterized by SEM. The biosorption characteristics of uranium (VI) on pretreated A. niger were evaluated as a function of pH (۳.۰-۷.۰), biomass concentration (۰.۰۵-۰.۴ g dry biomass/۱۰۰ mL), initial uranium concentration (۱۰-۵۰۰ mg/L) and contact time (۳۰-۱۴۴۰ min). The results revealed that the optimum pH was ۵.۰ for the adsorption of U(VI) by pretreated  A. niger. The maximum adsorption capacity of U (VI) by pretreated A. niger in concentration less than ۱۰۰mg/L uranium was increased significantly in comparison with live and dead biomass of  A. niger. The metal removal was rapid with ۸۶.۴% metal sorption (۴۳.۲ mgU/g dry biomass) taking place in ۳۰ min and the equilibrium was achieved in ۲۴۰ min. The maximum uranium removal was ۹۸.۴۳% (۱۶.۴۱ mgU/g dry biomass) in concentrations ۰.۳g dry biomass/۱۰۰mL. Adsorption process could be well defined by Langmuir isotherm with R۲ values ۰.۹۸۵. The kinetic data fitted through the pseudo-second-order kinetic model with the R۲ value of ۰.۹۹۸.

کلیدواژه ها:

Biosorption ، Uranium ، Pretreate d aspergillus niger ، kinetic model