磁性羟基磷灰石的制备及其除氟性能研究

氟离子在饮用水中浓度超过1.0mg/L,将对人体健康造成极大危害.通过原位共沉淀法将具有磁性的四氧化三铁掺入羟基磷灰石(HAP)中制备磁性HAP.磁性HAP可通过普通磁体将其吸附并分离回收.实验结果表明,最佳的制备条件为反应温度和时间为60℃和1h,陈化温度和陈化时间为25℃和12h,四氧化三铁用量为0.08g.比较了HAP和磁性HAP对水溶液中氟离子的去除效果.Langmuir模型更适合于该体系,拟合得到最大吸附容量为13.70mg/g,说明磁性HAP对氟离子的吸附属于单层吸附.ΔG0<0和ΔH0>0表明该吸附过程为自发的吸热过程.吸附过程符合拟二级动力学.磁性HAP循环再生使用4次以上,仍能保持85％以上的除氟效率.高吸附容量和优异的循环使用性能表明磁性HAP是一种有效的、可重复使用的除氟吸附剂.

Fabrication of Magnetic Hydroxyapatite and Its Property for Defluoidation

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.