Introducing porous organic molecules into advanced membrane for the extraction of lithium ions

It is predicted that the continuously increasing demand for the energy-critical element of lithium will soon exceed its availability, rendering it a geopolitically significant resource. Lithium (Li+) extraction from salt lake brines is an effective way to circumvent the lithium supply shortage. Given the close hydrated radius of Mg2+ (4.3 Å) and Li+ (3.8 Å) ions, a facile membrane synthesis method is needed to fabricate membranes for efficient Li extraction from high Mg2+/Li+ ratio brines. Porous organic molecules (POMs) with inner cavity diameter from 3.2 to 4.3 Å, such as cyclodextrin, calixarene, cucurbituril, and pillararene, will be used as main building blocks to construct NF membranes with uniform sub-nanometer pores for precise ion-ion separation. Furthermore, the fundamental mechanisms underlying cations transport and selectivity in subnanometer pores will be elucidated to provide the scientific base for the design of NF membranes with high Li+ selectivity.

Keywords:Nanofiltration, Lithium extraction, Porous organic molecules, Precise separation, cations transport mechanisms

Disciplines:Membrane technologies, Separation technologies