Fe 2 O 3 ‐Functionalized Magnetic Adsorbent Derived From Salt Lake Bischofite‐Based CaMgAl LDO for Aqueous Fluoride Capture

ABSTRACT The bischofite produced from the Chaka Salt Lake was selected as the magnesium source, and a urea‐assisted hydrothermal process was used to synthesize Fe 2 O 3 @CaMgAl LDO. The structure of the generated material was characterized by XRD, FTIR, and BET, which proved that Fe 2 O 3 had been successfully incorporated into the CaMgAl LDH‐derived material, the specific surface area of the composite was measured to be 33.39 m 2 /g. The Fe 2 O 3 @CaMgAl LDO exhibited efficient performance in removing fluoride, with a maximum adsorption capacity of 47.5 mg/g. Based on the kinetics and thermodynamics experiments, it was confirmed that the adsorption process was endothermic and mainly involved chemical‐controlled adsorption. The equilibrium data were highly consistent with the Langmuir model, suggesting monolayer adsorption onto energetically homogeneous active sites. Fluoride are mainly adsorbed through ligand exchange, electrostatic attraction, and LDO structural reconstruction. Additionally, the incorporated Fe 2 O 3 endowed the composite with sufficient magnetic response properties. Under the action of an external magnetic field, solid‐liquid rapid separation could be achieved in just 10 s. This performance enhanced the practical treatment quality and recyclability of the material. Fe 2 O 3 @CaMgAl LDO exhibited fluoride‑removal capacity, confirming the feasibility of preparing the adsorbent from salt‑lake bischofite.