介电泳增强吸附法去除饮用水中的氟离子

Removing fluoride ion from drinking water by dielectrophoresis-enhanced adsorption

高氟水的危害引起了人们的广泛关注。为减少饮用水中含量过高的氟离子(F-),基于介电泳技术建立了一种新的去除水体中F-的方法,组装了介电泳装置,将介电泳技术和吸附法结合,增强了对F-的去除效果。探讨了吸附剂种类、投加量和外加电压对于F-去除效果的影响,并用SEM对电极进行表征。结果表明,羟基磷灰石对F-具有最佳的吸附性能,其饱和吸附量为5.88 mg·g-1,Langmuir吸附等温方程能够很好地描述羟基磷灰石对F-的吸附热力学行为,说明吸附满足单分子层吸附模型。在优化的实验条件下(羟基磷灰石投加量6 g·L-1,外加电压15 V),F-去除率由单纯吸附法的67.02%提高到90.39%,达到了WHO饮用水水质标准,且无二次污染。SEM的表征结果表明,经过介电泳后,羟基磷灰石在电极上相互连接形成细长的线状结构。研究为减少高氟水中的氟离子提供了一种快速、高效的新方法。

The harm of high-fluorine water has attracted considerable attention.In order to reduce the highcontent fluoride(F-) ion in drinking water,a new approach,based on dielectrophoresis(DEP),was developed in this study for F- removal from water.The DEP apparatus was designed to improve F- removal by combining dielectrophoresis with adsorption,and the effects of the types and dosage of adsorbent,and applied voltage on Fremoval were discussed.The electrodes after dielectrophoresis was characterized by scanning electron microscopy(SEM).The experiment results showed that hydroxyapatite had the best perfromance for Fadsorption,and its saturated adsorption capacity was 5.88 mg·g-1.The thermodynamic behavior of F- adsorption on hydroxyapatite could be fitted by Langmuir adsorption isotherm equation which indicated that the adsorption belonged to the monolayer adsorption model.The F-removal efficiency was significantly improved from67.02% by adsorption alone to 90.39% by adsorption-DEP under optimal conditions:the dosage of hydroxyapatite was 6 g·L-1,the applied voltage was 15 V,and the residual F-concentration met the drinking water quality standards of WHO without secondary pollution.SEM indicated that after dielectrophoresis,a slender linear structure occurred on the electrode due to the connection of hydroxyapatite particles.This study provides a new,rapid and efficient method for reducing fluoride ions from high-fluorine water.