Performance enhancement of hollow-structured H2TiO3 lithium ion sieve induced by Nb doping modification: High structural stability and superior adsorption capability

In this study, a high valence Nb-doped H 2 TiO 3 (Nb-HTO) lithium ion adsorption material was synthesized via high-temperature calcination, employing hollow structured anatase TiO 2 as the titanium source. The structure and adsorption behavior of Nb-HTO were systematically investigated using multiple characterization techniques. Results indicate that the Nb-HTO material processes a high specific surface area, which alleviates nanoparticle agglomeration typically induced by calcination and improves dispersion. The 2% Nb-doped sample exhibited a much lower water contact angle of 14.8°, compared to 34.5° for the pristine HTO, indicating a substantial improvement in surface hydrophilicity. At 25 °C, the Li + adsorption capacity of Nb-HTO reached 48.6 mg g −1 , substantially exceeding that of pure H 2 TiO 3 (36.7 mg g −1 ). After five consecutive adsorption-desorption cycles, the capacity decreased only from 51.8 mg g −1 to 46.1 mg g −1 , with titanium dissolution loss below 0.01%, demonstrating excellent cycling stability. Moreover, Nb-HTO exhibited a high adsorption capacity (22.3 mg g −1 ) and excellent selectivity toward Li + in real Xitaijinaier Salt Lake brine. Electrostatic attraction, coordination interaction and ion exchange serve as the probable adsorption mechanisms. In summary, Nb-HTO shows great potential as a high-performance lithium ion adsorbents in the future.