Magnetic graphene oxide surface lithium ion-imprinted material towards lithium extraction from salt lake

Abstract

In order to effectively extract lithium from salt lake brine, a novel magnetic graphene oxide-based lithium ion-imprinted polymer (IIP-GO/Fe3O4@C) was developed by combining magnetic separation technology with surface ion imprinting technology. GO/Fe3O4@C, which is composed of graphene oxide (GO) and Fe3O4@C, was modified by silane coupling agent KH570 and then grafted with methacrylic acid (MAA). The IIP-GO/Fe3O4@C achieved excellent Li+ separation performance, including an adsorption capacity of 31.24 mg/g, good regeneration performance (91% of the initial value after six adsorption–desorption cycles), a moderate equilibrium time of about 2 h, and relatively high selectivity against Na+, K+, and Mg2+ of 14.31, 12.05, and 10.9, respectively. These excellent properties are due to the synergistic effect between the construction of adsorption sites brought by the high specific surface area (225.8 m2/g) of GO/Fe3O4@C skeleton and the particular recognition of Li+ by 2-hydroxymethyl-12-crown ether-4. Therefore, IIP-GO/Fe3O4@C can be used as a prominent candidate for extracting lithium from salt lake brine.