天然铝硅酸盐矿物对氟离子的吸附性能研究

含氟工业废水对环境和人体具有较大的危害，以三种天然铝硅酸盐矿物一水硬铝石、三水铝石以及高岭石为吸附剂，探究其对氟离子吸附的可行性并对除氟的机理进行探讨。单因素条件试验表明，高岭石对氟离子的吸附效率最高。在高岭石粒度-18 μm、用量10 g/L、pH=1.5、反应时间t=10 min、反应温度25 ℃的最佳反应条件下，氟离子去除率可达83.69%，废水中氟离子浓度由150 mg/L降低至24.47 mg/L。动力学拟合结果表明，高岭石对氟离子的去除符合准二级动力学，理论吸附容量Q_e=8.0244 mg/g。吸附等温线研究表明，该反应符合Freundlich模型，属于单层吸附。FTIR、XPS等检测结果表明高岭石中的羟基脱离后与氟离子发生离子交换，并在高岭石表面生成Al-F键，从而实现含氟废水的净化。 

Adsorption of Fluoride by Natural Aluminosilicate Minerals

The fluorine-containing wastewater discharged from industrial production has great harm to the environment and human body. In this study, three kinds of natural aluminosilicate minerals, diaspore, gibbsite and kaolinite, are used as adsorbents to explore the feasibility of their adsorption of fluorine ions and the mechanism of defluorination. The single factor condition test showed that kaolinite had the best adsorption efficiency for fluoride ion. The removal rate of fluoride ion can reach 82.44% and the concentration of fluoride ion can be reduced from 150 mg/L to 26.34 mg/L under the optimum reaction conditions of granularity of Kaolinite -18 μm, dosage of 10 g/L, pH = 13, reaction time = 10 min and reaction temperature 25 ℃. Kinetic fitting showed that the removal of fluoride ion by kaolinite accorded with quasi-second-order kinetics with theoretical capacity value Q_e=8.0244 mg/g. The adsorption isotherms show that the reaction conforms to Freundlich model and belongs to single layer adsorption. XPS analysis shows that fluoride ion exchanges with hydroxyl groups in kaolinite, and Al-F bonds are formed on the surface of kaolinite, thus achieving the purification of fluoride-containing wastewater.