Inorganic porous carbon as the supporter of H2TiO3 via in-situ polymerization synchronous conversion for lithium recovery from aqueous solutions

Abstract

The extraction of lithium from liquid minerals, such as salt lake brines and underground brines, has garnered extensive interest due to its eco-friendly and cost-effective properties. However, the effectiveness of this method is constrained by the stability and capacity of the materials. Herein, a new-type inorganic carbon-supported H₂TiO₃ adsorbent was developed by a novel in-situ polymerization synchronous conversion strategy. It was found that when resorcinol and formaldehyde containing Li₂CO₃ and TiO₂ were polymerized in-situ and then calcined at 973.15 K, the resin was successfully carbonized to obtain the carbon supporter with a low degree of disorder, and the Li₂CO₃ and TiO₂ in the supporter were synchronously converted into Li₂TiO₃ and uniformly dispersed in the carbon matrix. Because of the large specific surface area and strong hydrophilicity of the carbon supporter, the material exhibited a maximum Li⁺ adsorption capacity of 52.14 mg·g⁻¹, which was far higher than that of inorganic composite materials reported at present. Even the equilibrium adsorption capacity for Li⁺ at a low concentration of 29.26 mg·L⁻¹ reached 28.51 mg·g⁻¹. Following adsorption, the Li⁺ in the material was easily eluted by 0.25 mol·L⁻¹ HCl, and the elution rate was more than 90 % within 2 h. Dynamic adsorption using a fixed-bed was also performed at 298.15 and 343.15 K, and the adsorption capacity for the same concentration of Li⁺ was 7.08 and 9.44 mg·g⁻¹, respectively. Because of the high capacity for low-concentration Li⁺ and the promoting effect of temperature on adsorption, the material is well-suited for recovering Li⁺ from liquid resources, particularly from geothermal water with high temperatures and low Li⁺ concentrations.