Lead removal from electrolytic aqueous solutions using nanofiltration process equipped with a commercial polyamide membrane

Development of enormous industries has resulted in the entrance of dangerous and toxic compounds such as heavy metals into the environment polluting water bodies. Lead, which exists in most of industrial effluents, has a high contamination potential. In the present work, performance of nanofilteration (NF) membrane (NF 90) has been studied to separate lead from synthetic wastewater.
The present research was conducted experimentally in a batch reactor. All of the parameters including Pb concentration (10-90 mg/L), pressure (6-18 bar) and ionic power (50-150 mg/L of NaCl) were optimized by the one at a time in 15 times and within a fixed temperature (25± 2 °C) and pH (5.4± 0.1). Also, the removal efficiency of Pb and permeate flux were detected.
The findings showed that the removal efficiency went up dramatically when pressure was raised from 6 to 9 bar. But 1% increase was observed in efficiency with increasing pressure from 9 to 18 bar. Besides, the efficiency decreased by 5.5% with increasing initial lead concentration. It was also found that the efficiency increased in the presence of NaCl. The highest removal efficiency (over 99%) was achieved at initial lead concentration of 10 mg/L, pressure of 18 bar and NaCl concentration of 150 mg/L.
Since this technique can remove Pb, it can be applied in industrial applications. Of course, in the case of real wastewaters, operating parameters are required to be optimized.