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 (3.0-7.0), biomass concentration (0.05-0.4 g dry biomass/100 mL), initial uranium concentration (10-500 mg/L) and contact time (30-1440 min). The results revealed that the optimum pH was 5.0 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 100mg/L uranium was increased significantly in comparison with live and dead biomass of  A. niger. The metal removal was rapid with 86.4% metal sorption (43.2 mgU/g dry biomass) taking place in 30 min and the equilibrium was achieved in 240 min. The maximum uranium removal was 98.43% (16.41 mgU/g dry biomass) in concentrations 0.3g dry biomass/100mL. Adsorption process could be well defined by Langmuir isotherm with R2 values 0.985. The kinetic data fitted through the pseudo-second-order kinetic model with the R2 value of 0.998.