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

Cheng Qian; Mianping Zheng; Yongsheng Zhang; Enyuan Xing; Baoling Gui

doi:10.3389/fchem.2023.1265290

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

Front Chem. 2023 Oct 25:11:1265290. doi: 10.3389/fchem.2023.1265290. eCollection 2023.

Authors

Cheng Qian^{1

2}, Mianping Zheng^{1

2}, Yongsheng Zhang^{1

2}, Enyuan Xing^{1

2}, Baoling Gui^{1

2}

Affiliations

¹ Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, China.
² Key Laboratory of Saline Lake Resources and Environment, Ministry of Land and Resources, Beijing, China.

Abstract

A combined method of solid-phase alkali activation and surface precipitation was used to prepare the lithium/aluminum layered double hydroxides-SiO₂ 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⁺, Ca²⁺, and Mg²⁺), 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.

Keywords: LDH-Si-BX; Li + adsorption behavior; brines; mechanism; regeneration.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by Geological Survey Project of China Geological Survey (DD20230037).