Needle-like PVP@Ce/Zr-MOFs for the highly efficient selective of fluoride and phosphate from aqueous solution

Polyvinylpyrrolidone (PVP) dispersant was added to Ce/Zr metal–organic frameworks (MOFs), forming needle-like PVP@Ce/Zr-MOFs adsorbents via the hydrothermal method. The effects of solution pH, co-existing ions, reaction temperature, and PVP dosage on the performance of fluoride and phosphate elimination from aqueous solution were examined in batch adsorption experiments. The sorption behaviors were also revealed through adsorption thermodynamic and kinetic studies. The PVP@Ce/Zr-MOFs have an outstanding selectivity over a wide pH range. In addition, they selectively adsorbed phosphate and fluoride ions co-existing with common ions in simulated and real wastewater and maintained high efficiency in the existence of other anions. The sorption procedure was depicted with the pseudo-second order model and the Langmuir model. A mechanistic analysis revealed that fluoride and phosphorus were eliminated by PVP@Ce/Zr-MOFs via exchange interaction with hydroxide ions, electrostatic interactions with charged particles on the adsorbent surface, and the formation of strong inner-sphere complexes of Zr and Ce ions with the target phosphate and fluoride ions.