Adsorption and desorption of lead using synthetic hydroxyapatite material

The adsorption of Pb2+ ions in solution by synthetic hydroxyapatite material has been researched. Investigations were conducted into the effects of adsorption time, adsorbent mass, solution pH, and Pb2+ ion concentration. The material's adsorption efficiency to Pb2+ can reach 98.7%. Two adsorption isotherm models, Freunlich and Langmuir, were used to evaluate adsorption isotherms. The pseudo-first-order and pseudo-second-order adsorption kinetic models were used to assess the adsorption process's kinetics. Using the electrolysis approach, Pb2+ ions were successfully desorbed from the adsorbed HAp material while recovering metallic Pb on the cathode surface. Pb recovery efficiency can be as high as 93.84%. After desorption, the HAp material retains its original characteristics and still can adsorb Pb2+ ions with a high efficiency of 95.96%.