Phosphate and fluoride ions are common water pollutants whose presence and excessive discharge cause potential hazards to the environment and human health. MOF materials commonly used to remove phosphate and fluoride ions are usually in powder form, with low recovery during regeneration. Herein, to address these issues, Fe₃O₄@La-Zr-MOFs magnetic composites for phosphate and fluoride removal were fabricated by means of the hydrothermal method. The adsorption properties of the adsorbent were systematically assessed by means of adsorption experiments. The magnetic Fe₃O₄@La-Zr-MOFs exhibited a magnetic recovery efficiency of 93%, and they could maintain outstanding adsorption performance at a broad range of pH values and superior selectivity for phosphate and fluoride ions. The adsorption process conformed to the Langmuir isotherm and pseudo-second-order models, indicating that it was dominated by monomolecular chemisorption. Further characterization of the Fe₃O₄@La-Zr-MOFs before and after adsorption and kinetic thermodynamic investigation revealed that the elimination mechanism of phosphate and fluoride ions by Fe₃O₄@La-Zr-MOFs includes ion exchange, electrostatic interactions, and surface complexation. This study demonstrates that magnetic reusable Fe₃O₄@La-Zr-MOFs composites have great promise for phosphate and fluoride removal and recovery.

Fe–Ce-MOFs with a rice-grain-like morphology were successfully obtained via hydrothermal synthesis, where ferric chloride (FeCl₃) and cerium nitrate [Ce(NO₃)₃] served as the metal precursors and terephthalic acid (PTA) acted as the organic coordinating ligand. The effects of the Fe:Ce molar ratio, (Fe/Ce):PTA ratio, reaction duration, and synthesis temperature on adsorption performance of the Fe–Ce-MOFs were systematically studied. A comprehensive evaluation was conducted on the removal of fluoride and phosphate ions from aqueous solution. Under optimized conditions, the maximum adsorption capacities of Fe–Ce-MOFs for fluoride and phosphate reached 183.82 mg g⁻¹ and 110.74 mg g⁻¹, respectively. Adsorption data correlated strongly with the Langmuir isotherm, were best represented by the pseudo-second-order kinetic model, and were identified as a spontaneous and endothermic reaction. After three regeneration cycles, the adsorbent still maintained high removal efficiencies for fluoride (85.17%) and phosphate (47.34%) removal. In practical wastewater treatment, removal efficiencies of 92.04% for fluoride and 93.87% for phosphate were achieved. Mechanistic studies revealed that fluoride removal was dominated by electrostatic attraction and hydroxyl–fluoride ion exchange, whereas phosphate removal was attributed to the generation of inner-sphere complexes involving PO₄³⁻ and Fe/Ce active sites. This study not only elucidates the synergistic mechanism of fluoride and phosphate elimination by Fe–Ce-MOFs but also provides theoretical guidance and application prospects for the development of highly efficient and stable bimetallic MOF-based adsorbents for environmental remediation.

Ribbon-like porous cellulose acetate (CA) ultrafine fibers with diameter of 0.94 ± 0.36 μm and pore size of 52 × 98 nm were prepared by electrospinning. The adsorption properties of Cu²⁺ on porous CA ultrafine fibers were studied. The maximum removal efficiencies of Cu²⁺ on CA membrane (MCA), CA ultrafine fibers (FCA), and porous CA ultrafine fibers (PFCA) were 19.1, 70.8, and 88.6%, respectively. This was attributed to the formation of nanoporous structure on the fibers surfaces, which increased the special surface area from 4.33 to 56.57 m²/g. The adsorption data followed the Langmuir and Freundlich models. But the Langmuir model had better correlation at different temperatures. Based on the thermodynamic parameters, including ΔG^°, ΔH^°, and ΔS^° calculated, the negative values of ΔG^° indicated that the adsorption of Cu²⁺ on PFCA was spontaneous and thermodynamically favorable. The positive values of ΔH^° demonstrate that the adsorption process belonged to endothermic nature, and revealed that high temperature is more beneficial for adsorption than low temperature. The positive value of ΔS^° indicated that the randomness at the solid/solution interface with some structural changes in both the adsorbates and adsorbents during the adsorption process increased.