A novel high-performance IIP@PPy/rGO@PVDF composite membrane for the selective recovery of lithium-ion via an external-voltage-driven process

A novel lithium (Li) ion-imprinted composite membrane (IIP@PPy/rGO@PVDF) was developed for the selective recovery of Li + through an external-voltage-driven process. This membrane was synthesized by integrating ion-imprinting technology with electrochemically switched ion exchange technology, presenting a highly promising technique for the efficient extraction of Li from brine. The IIP@PPy/rGO@PVDF membrane consisted of polypyrrole (PPy), reduced graphene oxide (rGO), 12-crown 4-ether (12C4), and ethylene dimethacrylate (EDGMA). Furthermore, leveraging the electric field and specific recognition of 12C4 toward Li + , the membrane exhibited excellent ionic adsorption performance, including a high adsorption capacity of 214 mg.g −1 , a superior retention ratio (Maintaining the initial value even after 10 cycles of electrochemical adsorption–desorption), a short equilibration time of <25 min, and an adsorption capacity of 98 mg.g −1 at pH = 1. Subsequently, variations in the average heat of adsorption indicated that the electric field enhanced the adsorption performance. These performances were attributable to the synergistic effects of rGO with PPy. Therefore, IIP@PPy/rGO@PVDF serves as an outstanding candidate for Li extraction in environments with high applied voltages and strong acidity.