Nitrogen-doped substrate material ion imprinting-capacitive deionization selective recovery of lithium ions from acidic solutions.

ABSTRACT

With the continuous development of global industry and the increasing demand for lithium resources, recycling valuable lithium from industrial solid waste is necessary for sustainable development and environmental friendliness. Herein, we employed ion imprinting and capacitive deionization to prepare a new electrode material for lithium-ion selective recovery. The material morphology and structure were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and other characterization methods, and the adsorption mechanism and water clusters were correlated using the density functional theory. The electrode material exhibited a maximum adsorption capacity of 36.94 mg/g at a Li+ concentration of 600 mg/L. The selective separation factors for Na+, K+, Mg2+, and Al3+ in complex solution environments were 2.07, 9.82, 1.80, and 8.45, respectively. After undergoing five regeneration cycles, the material retained 91.81% of the initial Li+ adsorption capacity. Meanwhile, the electrochemical adsorption capacity for Li+ was more than twice the corresponding conventional physical adsorption capacity because electrochemical adsorption provides the energy needed for deprotonation, enabling exposure of the cavities of the crown ether molecules to enrich the active sites. The proposed environment-friendly separation approach offers excellent selectivity for Li+ recovery and addresses the growing demand for Li+ resources.