Performance of functionalized UIO-66 and HKUST-1 for Li+ absorption and separation from aqueous solutions with Li+

For lithium extraction processes from liquid lithium resources, surmounting the interference of coexisting ions on the selective extraction of Li  +  − especially the selective separation of Mg 2+ and Li +  − presents a challenging task. UIO-66 and HKUST-1, both metal-organic frameworks (MOFs), are synthesized using organic ligands with benzene ring groups. To boost the Li + adsorption and recognition capabilities of these two materials, LiNO 3 was introduced as a template, which not only constructs a Li + -size-adapted microenvironment within the adsorbent framework but also functions as a mineralizer, facilitating the formation of more uniformly sized crystals. The modified Li/UIO-66 and Li/HKUST-1 achieved maximum Li + adsorption capacities ( Q ) of 35.57 and 26.33 mg/g, respectively, reaching adsorption equilibrium within approximately 3 h. Li/UIO-66 showcases excellent Mg 2+ /Li + separation performance and maintains certain separation factor even in mixed solutions containing multiple interfering ions. Although Li/HKUST-1 demonstrates a stronger tendency for selective adsorption of higher-valent ions, it holds promise for the removal of interfering ions from solutions, thereby contributing to the overall optimization of lithium extraction processes.