Lead Removal from Mine Tailings with Multiple Metallic Ions

This study investigates the ionic effects of Cu2+, Fe3+, Ni2+ and Zn2+on the sorption of the target metal ion Pb2+ by natural zeolite in the form of clinoptilolite. The batch testing configuration consists of a synthetic nitrate salt solution maintained at 10 meq/L system total concentration, acidified to a pH of 2 by HNO3 acid, with an adsorbent dosage of 40 g/L. The aqueous solution is agitated within a contact period of 5 to 180 minutes by means of a triple-eccentric drive orbital shaker operating at 400 r/min. The objective is to determine the overall sorption of the target metal lead and the selectivity of clinoptilolite to the various heavy metallic ions (HMIs) combined in aqueous phase. Elemental analysis concludes that after 3 contact hours, the lead ion is removed by 76.8% in the single-lead system. In the dual-lead system, Pb2+ is removed by 88.3%, 79.5%, 89.1%, and 88.5% when combined with copper, iron, nickel, and zinc, respectively. Finally, Pb2+ is removed by 90.2% and 94.0% in the triple-(lead-copper-iron) and multi-component systems, respectively. As the HMIs are introduced to the system with a 10 meq/L total concentration, the uptake of the Pb2+ ion in the single-system of 7.68 meq/L is decreased by 75.6% to 1.88 meq/L in the multi-component system. Overall, the total HMIs removed decreases from 7.68 meq/L in the single-system to 3.95 meq/L with the subsequent addition of ions in the multi-component system.