Synergistic Effect of Hydrophilic Surface and Porous Structure on Lithium Extraction by Titanium Ion Sieves

The H2TiO3 ion sieves have demonstrated as a promising adsorbent for lithium extraction from liquid lithium resources. However, it is still challenging to simultaneously manipulate the surface hydrophilicity and micro-structure of ion sieves for efficient lithium extraction. Here, we have grafted sodium dodecyl sulfate (SDS) on H2TiO3 ion sieves to enhance its hydrophilicity, and simultaneously promoted the formation of porous structure for the ion sieves with the addition of aluminum chloride (AlCl3⋅6H2O) through the solid-phase method. The effects of SDS and Al co-modification on the hydrophilicity, morphology, structure, and adsorption properties of the H2TiO3 ion sieve have been systematically investigated. The modified ion sieve features a uniform and dense mesoporous structure with improved surface hydrophilicity, enhancing its lithium extraction capability and increasing its contact sites with Li+ in solution. As a result, the modified H2TiO3 ion sieves demonstrated efficient lithium extraction performance with the maximum adsorption capacity reached 64.4 mg/g, significantly outperforming the unmodified ion sieves (56.3 mg/g). Furthermore, the adsorption isotherms of Li+ on the SDS and Al co-modified titanium lithium ion sieve follow the Langmuir model, and the adsorption kinetics fit the pseudo-second-order model.