Synthesis of porous fiber-supported lithium ion-sieve adsorbent for lithium recovery from geothermal water

The recovery of lithium has received widespread attention. Adsorption is one of the most promising methods, but the synthesis of adsorbents with high adsorption performance and stability is still a huge challenge. Herein, a novel porous fiber using H2TiO3 (HTO) as the core material was developed for lithium recovery from geothermal water. HTO was successfully coated and uniformly distributed in the polysulfone (PSF) fiber by a commercialized spinning apparatus combined with the wet spinning technology. When the percentage of HTO in PSF/HTO was 50%, the material showed high adsorption performance, even close to that of powdery HTO. The stability and adsorption capacity of PSF/HTO were further improved using hyperfine H2TiO3 synthesized by a modified solid-state method. Compared with other composite adsorbents reported at present, the maximum adsorption capacity and adsorption rate were obtained, and even the adsorption capacity for 25.78 mg·L−1Li+ in geothermal water reached 22.66 mg·g−1 after only 60 min with a recovery rate of 88.68%. The distribution coefficient of Li+ was 2 ∼ 3 orders of magnitude higher than other coexisting ions, and the average dissolution loss rate of Ti did not exceed 0.6% during cyclic tests. Because of the excellent adsorption properties of PSF/HTO, especially the feasibility of large-scale preparation using commercialized spinning apparatus, the material developed in this work can be used as a potential adsorbent for lithium recovery from geothermal water or other liquid lithium resources.