Hydrogen-Bond Anchored Channel-Microenvironment Engineering in Polymer Membranes for Efficient Lithium Extraction

Area of Science:

• Materials Science
• Separation Science
• Chemical Engineering

Background:

• Mimicking biological ion channels for synthetic membranes is challenging.
• Controlling the chemical microenvironment in sub-nanometer pores of polymers is difficult.

Purpose of the Study:

• To engineer the microenvironments of confined channels in polymers of intrinsic microporosity (PIMs).
• To enhance ion selectivity and flux for applications like lithium extraction.

Main Methods:

• Utilized hydrogen bonding to anchor oligoether chains onto PIM pore walls.
• Engineered pore microenvironments to control ion-channel interactions and transport pathways.

Main Results:

• Achieved high monovalent over divalent ion selectivity (Li+/Mg2+ >270) with significant Li+ flux (>0.6 mol m-2 h-1).
• Demonstrated effective lithium extraction from brine with high recovery rates (268 g m-2 day-1) and low energy consumption (7.26 Wh gLi-1).

Conclusions:

• The engineered PIM membranes offer a promising solution for selective ion separation and direct lithium extraction.
• This approach significantly improves upon existing polymeric membrane performance for lithium recovery.