Research on Pb²⁺ desorption and Pb recovery from halloysite adsorbent materials by electrochemical precipitation method

Research results on the adsorption process of halloysite material in Thach Khoan, Phu Tho area for Pb2+ showed that this halloysite material has good Pb2+ adsorption ability with an adsorption efficiency of 90.75% under optimal conditions. The process of desorption of Pb2+ from Pb-adsorbed halloysite material and also recovery of metallic Pb by electrochemical precipitation method has been studied. The electrolysis process was carried out under constant current mode in 0.01M HCl electrolyte with an electrochemical system including a working electrode as an Au electrode (geometric area of 1 cm2), a reference electrode as a silver/silver chloride electrode, and a counter electrode as a Pt grid. The effects of current intensity, mass of adsorbed halloysite material, and electrolysis time on Pb2+ desorption and Pb recovery were evaluated. The obtained results show that, under electrolysis conditions: current density 5 mA/cm2, material mass 0.3 g, electrolysis time 5 h, temperature 25oC, Pb recovery efficiency reached 93.67%. The result shown that the electrochemical precipitation method is effective in desorbing Pb2+ and recovering metallic Pb.