Abstract:Variety of oxygen pressure leaching residues of spent lithium iron phosphate were obtained by changing reaction conditions. Through adsorption experiment of Pb2+, Cu2+, Zn2+ and Ni2+, material with the best comprehensive performance was determined. Subsequently, this material was used as adsorbent to study effect of initial concentration of solution and initial pH value of solution on adsorption performance of adsorbent for Pb2+, Cu2+, Zn2+ and Ni2+, and the optimal conditions for different heavy metal ions were obtained. Finally, samples before and after adsorption were characterized and analyzed to further study adsorption mechanism. The results show that FPOH-ML leaching residue obtained at 120 ℃, 0.5 MPa, and adding mannitol (ML) has the best comprehensive adsorption performance. When concentration of all heavy metal ions are 10 mg/L, pH value of Pb2+ bearing solution is 5, and pH value of Cu2+, Zn2+ and Ni2+ bearing solutions are 6, adsorption capacities of FPOH-ML for Pb2+, Cu2+, Zn2+ and Ni2+ are 18.26, 17.53, 9.60, and 6.24 mg/g, respectively. The characterization analysis results show that main structure of FPOH-ML has not changed significantly before and after adsorption, and no new substances are produced, indicating that adsorption process belongs to physical adsorption.