(1. 中南大学 冶金与环境学院，长沙 410083；
2. 湖南城市学院 市政与测绘工程学院，益阳 413000)
摘 要: 采用双滴共沉淀法制备MgO-LDH水滑石去除溶液中氟，并采用静态实验系统地讨论溶液初始pH值、氟初始浓度和吸附时间等因素对MgO-LDH吸附性能影响。结果表明：吸附条件对氟的吸附能力影响较大，适宜的MgO-LDH投加量为10 g/L，溶液初始pH为6.40；随着温度的升高，MgO-LDH的吸附量也随之增加。在较佳的实验条件下，MgO-LDH对氟的最大吸附量为16.60 mg/g。动力学数据分析显示，准二级动力学方程(R2=0.9314~ 0.9907)比准一级动力学方程(R2=0.7941~0.9919)能更好地描述吸附动力学特征。颗粒内扩散方程拟合结果发现，氟在MgO-LDH吸附过程包括表面吸附和颗粒内扩散两个过程。吸附等温数据拟合发现，Langmuir吸附等温式(R2=0.9982~0.9992)比Freundlich吸附等温式(R2=0.6904~0.9453)更好地描述氟在MgO-LDH上的等温吸附行为。
关键字: MgO-LDH；含氟废水；吸附等温线；吸附动力学
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China）
Abstract:The magnesium oxide layer double hydrotalcite (MgO-LDH) was prepared by double drop co-precipitation using magnesium oxide as magnesium source. And it was applied for the treatment of wastewater containing fluoride. The influences of initial fluoride concentration, pH and adsorption time on fluoride adsorption using MgO-LDH were investigated by the batch experiments. The experimental results show that the adsorption capacity for fluoride is affected by the adsorption conditions. The suitable adsorbent dosage is 10 g/L, the suitable pH of MgO-LDH fluorine adsorption is 6.40. The amount of adsorption increase with increasing the temperature. The adsorption capacity of the adsorbent for Fluoride is 16.60 mg/g at optimal conditions. The kinetic data show that the pseudo-second-order model (R2=0.9314-0.9907) can better describe the characteristic of the adsorption kinetic than the pseudo-first-order model (R2=0.7941-0.9919). The results from the Intra-particle model also show that there exist two separate stages in sorption process, which are external diffusion and the diffusion of inter-particle. Langmuir and Freundlich isotherms were used to fit the adsorption equilibrium data, and it is found that the adsorption process follows preferably the Langmuir isotherm adsorption model, which indicates that the adsorption mainly occurs in active region on the surface of MgO-LDH and belong to the monolayer adsorption.
Key words: MgO-LDH; wastewater containing fluoride; adsorption isotherm; adsorption kinetic
