Heterometallic doping enhanced highly stable Ce-MOFs for efficient phosphate removal

Heterometallic regulation stabilizes Ce-MOFs for phosphate removal. • Al/Ce-MOF shows high phosphate capacity (313 mg g −1 ). • Dual-metal sites enable synergistic adsorption of phosphate. Excessive phosphate in aquatic environments poses serious ecological risks, and adsorptive removal is considered an effective strategy to mitigate this issue. Despite cerium-based metal-organic frameworks (Ce-MOFs) exhibit strong affinity toward phosphate, their practical application is often limited by insufficient stability in aqueous environments. In this study, a heterometallic regulation strategy was employed to enhance the structural stability of Ce-MOFs by incorporating Al 3 + into the framework. The resulting Al/Ce-BDC-NH 2 exhibited significantly improved structural properties, with the specific surface area increasing by more than 23-fold compared with pristine Ce-BDC-NH 2 . Adsorption experiments showed that Ce-BDC-NH 2 and Al/Ce-BDC-NH 2 achieved maximum phosphate adsorption capacities of 327 and 313 mg g −1 , respectively. The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetic models, indicating monolayer chemisorption behavior. To further explore practical applicability, Al/Ce-BDC-NH 2 was immobilized onto microcrystalline cellulose to fabricate MCC@Al/Ce-BDC-NH 2 microspheres, which achieved a breakthrough point after treating 430 bed volumes in dynamic column experiments. Mechanistic analysis revealed that phosphate removal mainly proceeds through ligand exchange, electrostatic interaction, and metal-phosphate complexation. This work demonstrates that heterometallic regulation is an effective strategy to simultaneously enhance the stability and adsorption performance of Ce-based MOFs, providing guidance for the design of robust MOF adsorbents for phosphate remediation. Download: Download high-res image (216KB) Download: Download full-size image