Keywords: 
• defluoridation /
• hydroxyl zirconia /
• adsorption /
• interfering anions

Abstract: The adsorbents of granular hydroxyl zirconia (GHZ) were prepared from the hydroxyl zirconia powder， and their properties of defluoridation were studied. The results showed that the F- adsorption of GHZ fitted better with Freundlich isotherm model than Langmuir model， and the kinetic data showed that it fitted pseudo-second order model. The process of F- adsorption involved liquid membrane diffusion and intra-particle diffusion. The adsorption capacity of GHZ can reach the maximum value of 27.72 mg/g at pH from 3 to 4， which would decrease with the pH out of this range. Chloridion had no appreciable impact on the defluoridation process， but the F- adsorption was obviously influenced by sulfate ions and phosphate ions， and the higher the concentration the greater the effect. Scanning electron microscope and X-ray spectrometer showed that fluorine content gradually reduced along with the increase of depth of particles， which indicated that the mass transfer process of fluorinion inside the particle was blocked. SEM-EDS data also showed that the interference of sulfate ions and phosphate ions on defluoridation mainly occurred on the particle surface.