Adsorption performance and mechanism of TiO2/PVDF-based lithium-ion imprinted membrane in leaching solution of spent lithium-ion batteries

Efficient recycling of spent lithium-ion batteries (LIBs) is particularly important for the sustainable development of energy metal resources. A lithium ion-imprinted membranes (LIIMs) was synthesized by environmentally friendly hydrolysis polymerization. Its adsorption performance and mechanism in a simulated spent LIBs leaching solution was investigated. The Li+ adsorption of the LIIMs conformed to a pseudo-second-order kinetic model and occurred with a fast adsorption rate. The activation energy was associated with chemical adsorption. Thermodynamic results confirmed that Li+ adsorption was exhibited by the LIIMs as spontaneous exothermic behavior. The LIIMs showed a satisfactory affinity for lithium in simulated leaching solution (SLS), and the selective separation factors of Li+ for Fe2+, Cu2+, Ca2+, Zn2+, Mn2+, K+, and Na+ were 10.93, 19.30, 22.66, 23.49, 26.14, 27.57 and 39.00, respectively. The selective adsorption mechanism of LIIMs mainly occurred through coordination between Li+ and the oxygen on the crown ether at the surface active adsorption sites. The results proved that the LIIMs as a highly selective green adsorbent material has a broad application prospect in the recycling of spent LIBs. Importantly, the elucidation of the adsorption performance and the revelation of the adsorption mechanism provide the theoretical support for the future commercialization of LIIMs.