Adsorption performance and mechanism of Li+ from brines using lithium/aluminum layered double hydroxides-SiO2 bauxite composite adsorbents

• Published in: Frontiers in chemistry Vol. 11; p. 1265290
• Main Authors: Qian, Cheng, Zheng, Mianping, Zhang, Yongsheng, Xing, Enyuan, Gui, Baoling
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 25.10.2023
• Subjects: brines; Chemistry; LDH-Si-BX; Li + adsorption behavior; mechanism; regeneration
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2023.1265290

A combined method of solid-phase alkali activation and surface precipitation was used to prepare the lithium/aluminum layered double hydroxides-SiO 2 loaded bauxite (LDH-Si-BX) and applied to adsorb Li + in brines. In the study, various characterization techniques such as SEM, XRD, BET, Zeta potential, and x-ray photoelectron spectroscopy (XPS) were applied to characterize and analyze the adsorbents. The adsorption-desorption performance of LDH-Si-BX for Li + in brines was systematically investigated, including adsorption temperature, adsorption time, Li + concentration, and regeneration properties. The results indicated that the adsorption kinetics were better fitted by the pseudo-second-order model, whereas the Langmuir model could match the adsorption isotherm data and the maximum Li + capacity of 1.70 mg/g at 298K. In addition, in the presence of coexisting ions (Na + , K + , Ca 2+ , and Mg 2+ ), LDH-Si-BX showed good selective adsorption of Li + , and the pH studies demonstrated that the adsorbents had better Li + adsorption capacity in neutral environments. In the adsorption process of real brines, LDH-Si-BX had a relatively stable adsorption capacity, and after 10 cycles of adsorption and regeneration, the adsorption capacity decreased by 16.8%. It could be seen that the LDH-Si-BX adsorbents prepared in this report have the potential for Li + adsorption in brines.