Selective recovery of Li+ in acidic environment based on one novel electroactive Li+-imprinted graphene-based hybrid aerogel

Abstract To meet the requirements of industrial lithium extraction from the simulated acidic leaching solution of fly ash, one novel ion-imprinted graphene-based hybrid aerogel (LIIP@N-CMS/GA) has been developed by a combination of pulse electropolymerization and surface ion imprinting technique. The imprinted film consists of polypyrrole (PPy), graphene oxide (GO), benzo-12-crown 4-ether (B12C4) and nitrogen-doped carbon microspheres/graphene aerogel (N-CMS/GA). By integrating the electric field driving and specific recognition of B12C4 towards Li+, the LIIP@N-CMS/GA electrode achieves excellent ionic separation performance, including high adsorption capacity of 41.05 mg g−1 with superior retention ratio (keeping 91.7% of the initial value even experiencing 10 cycles of electrochemical adsorption–desorption), short equilibration time less than 2 h, and relatively high selectivity separation factor of 51.99, 19.66, 14.37 and 12.40 against Na+, K+, Mg2+ and Al3+, respectively. These performances originate from the synergistic effects of the porous structure of N-CMS/GA with excellent conductivity, specific recognition of B12C4 towards Li+, and electric field driving which accelerates ion transport as well as electron transfer. Therefore, LIIP@N-CMS/GA can act as an outstanding candidate for lithium extraction in acidic environment.