Removal of fluoride and lead in wastewater with iron-bioflocculant

Fluoride and lead in the wastewater were removed with self-prepared iron-bioflocculant. The effects of the iron-bioflocculant dosage, pH, reaction time on the removal rate of fluoride and lead were also studied. The results show that the removal rates of F- and Pb2+ increase with the increase of dosage of iron-bioflocculant. F- can be removed more effectively under acidic condition, while alkaline iron solution is good for removing Pb2+. When the reaction time increases, the removal efficiency of F- and Pb2+ rise at the beginning then declines. In addition, the optimum treatment efficiency of the F- and Pb2+ is obtained when dosage is 7.5% (volume fraction), pH value is 6 and reaction time is 20 min. Under these conditions, the removal rates of F- and Pb2+ are 69.75% and 99.89%, respectively, and the residual concentrations of F- and Pb2+ are 6.05 mg/L and 0.226 mg/L, respectively, which are both lower than the emission standards of pollutants for lead and zinc industry at the same time.