Macroporous Lithium Adsorbent Monolith Prepared via High Internal Phase Emulsion Technique

A facile strategy to fabricate macroporous polymeric loam composites with uniformly distributed lithium-ion sieves (LIS) was fabricated toward lithium ion (Li+) selective recovery. With LiMn2O4 nanoparticles as stabilizers, oil-in-water (o/w) high internal phase emulsions (HIPEs) were prepared, and then a series of porous hydrophilic materials containing LIS (LNP@polyHIPEs) was obtained by the polymerization of water-soluble monomers in the Pickering HIPEs and followed by acid pickling. Lithium-ion adsorption was conducted by flowing lab made seawater through a LIS@polyHIPEs monolith. The LIS@polyHIPE exhibited a high adsorption capacity (similar to 35.6 mg/g (LiMn2O4)) and fast adsorption kinetics (the equilibrium time was similar to 3.0 h). The kinetics data and fitting them by a pseudo-first-order model showed that the loading of LIS onto polyHIPE had little influence on the adsorption rate, and the uptake of Li+ onto LIS@polyHIPE was an ion exchange or chemical adsorption control process. After the Li+ was extracted by washing the foam with a 0.5 mol/L HCl aqueous solution, the LIS@polyHIPE could be reused for recovery of Li+ from seawater. Its adsorption capacity and Li+ extraction rate were more than 31 mg/g (LiMn2O4) and 90% in four cycles, respectively.