Construction of a dual-functional H2TiO3 composite featuring 12-Crown-4 ether side arm with ion-imprinting effects for enhancing extraction Li+ performance

Silane coupling agent (KH570) was grafted onto Li 2 TiO 3 @GO via its -OH group. • The 12-crown-4 functional group serves as a side arm for the Li + imprinting agent. • H 2 TiO 3 @GO-CR was engineered and exhibited a bifunction Li + capture effect. To enhance lithium-ion adsorption performance, we designed a novel ion-sieve (denoted as H 2 TiO 3 @GO-CR) that synergistically combines the ion-imprinting effect with the intrinsic lithium capture capability of H 2 TiO 3 . This ion-imprinted monomer containing 12-crown-4-ether groups was fabricated through a two-step reaction involving ring-opening and self-condensation. The abundant -OH functional groups on graphene oxide (GO) served as a bridge to graft this monomer onto H 2 TiO 3 . The successful incorporation of the crown ether into the composite was proved by the FT-IR band at 553 cm −1 , and the Raman shift at 154.2 cm −1 . Owing to its unique dual-adsorption structure and functional groups, H 2 TiO 3 @GO-CR exhibited an excellent adsorption capacity of 39.87 mg·g −1 , with XPS analysis verifying an elevated surface hydroxyl (OH) content of 65.68%. In selectivity tests using simulated salt lake brine, the separation factors ( α Li Me) of H 2 TiO 3 @GO-CR for Li + against competing ions (Na + , K + , Ca 2+ , Mg 2+ ) all exceeded 80, demonstrating exceptional selectivity toward Li + . The α Li Mg = 295.0 shows high selectivity in salt lake brine, which is further substantiated by density functional theory (DFT) calculations of adsorption energies. This work brings a novel strategy for developing bifunctional lithium ion-sieves. Download: Download high-res image (265KB) Download: Download full-size image