关键词: 羟基磷灰石;磁性;除氟

Abstract: Fluoride above a permissible level (>1.0 mg/L) in drinking water has serious health effects on human beings.Ferroferric oxide/hydroxyapatite composites nanoparticles (magnetic hydroxyapatite) were prepared by the in-situ co-precipitation method mixed with ferroferric oxide.The magnetic HAP had magnetism, which can separate and recycle by the ordinary magnets.Current results show that the optimal experimental conditions are happened in 60 ℃ of reaction temperature, 1 h of reaction time, 25 ℃ of aging temperature and 12 h of aging time, 0.08 g dosages of ferroferric oxide.Magnetic hydroxyapatite is used to remove fluoride under different conditions and its defluoridation performance is compared with that of hydroxyapatite.The adsorption process is fitted better by the Langmuir model with a maximum fluoride adsorption capacity (13.70 mg/g), indicating that the interaction between fluoride and magnetic HAP is monolayer absorption process.The negative values of ΔG0 and positive values of ΔH0 revealed that the adsorption is a spontaneous and endothermic reaction.The pseudo-second-order kinetic model fitted better for fluoride adsorption by magnetic HAP.The adsorption efficiency of magnetic HAP can still maintain above 85％ after recycling four times.High adsorption and recycling performance suggest that magnetic HAP can be used as an effective and reusable defluoridation adsorbent.

Key words: hydroxyapatite;magnetic;defluoridation