Study of effective factors on biological removal of uranium by live microalgae Chlorella vulgaris

Today bioremediation by microalga is an effective method to remove radionuclides and heavy metals from wastewater. Bioremediation of radionuclides and heavy metals is an efficient method of treating heavy metal contaminated effluents. In this study, the bioremediation of uranium from aqueous solutions was evaluated using live microalgae Chlorella vulgaris in a batch system. The Plackett-Burman method by Minitab statistical software was used to screen for effective factors such as initial uranium concentration, temperature, time, pH and amount of biomass on the removal of uranium by C. vulgaris. The results showed that the initial uranium concentration and pH factors were statistically effective by software. Optimization of effective factors in uranium bioremediation was evaluated by the response surface methodology (RSM). To determine the main effects and interaction of factors affecting uranium removal by C. vulgaris, central composite design (CCD) was used. The experimental data were then processed and the equation was evaluated to match the experimental data, and then the optimal removal values were determined. Finally, the results showed that C. vulgaris in optimal conditions proposed by Design-Expert software can remove 99.63% of existing uranium from aqueous solutions containing 7.1 mg / l uranium with pH 4.3.