Facile fabrication of photochromic microspheres with multimodal hierarchically porous for selective extraction of lithium ions

Abstract Salt lake brine with a high Mg/Li ratio remains one of major sources for lithium recovery. In this work, one kind of sensitive photochromic microspheres (SP-C/PVDF) with multimodal hierarchically porous structure was prepared via a facile phase inversion method. The SP-C in the microspheres was still stable and active resulting in stable reversible color switch of SP-C/PVDF. The SP-C/PVDF microspheres presented high selective adsorption for Li+ compared with that of Mg2+ under UV light irradiation. The pseudo-second-order model and chemical monolayer isotherm model can describe the adsorption kinetics and binding way with Li+, respectively. This work developed an available idea and method for selective extraction of trace Li+ from salt lake brine, which can provide references for the separation of other valuable ions from complex systems.