Shaping layered double hydroxides in geopolymer for selective lithium extraction in fixed-bed process

This study presents a method to shape Li/Al layered double hydroxides (Li/Al LDHs) adsorbent in a mesoporous potassium-based geopolymer binder, for the selective extraction of lithium in a fixed-bed process. After synthesis, the Li/Al LDHs powder is well dispersed into the binder, favorable for lithium adsorption kinetics. Batch and column extraction experiments in a brine with high magnesium content demonstrate effective lithium extraction with high selectivity. The geopolymer matrix traps Mg 2+ via cation exchange with K + improving lithium purity in the eluate. Overall, this composite is a promising material for scalable and selective direct lithium extraction from saline effluents. • A Li/Al layered double hydroxides powder was shaped using a geopolymer binder. • Layered double hydroxides-geopolymer composite exhibit a fast Li adsorption kinetic. • Layered double hydroxides-geopolymer composite exhibit a high selectivity for Li. • Layered double hydroxides-geopolymer is promising for Li extraction from brines.