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采用共沉淀法合成Mg-Al-Fe类水滑石,并通过不同焙烧温度制得焙烧类水滑石。采用XRD,FT-IR,SEM等方法进行了吸附材料表征。研究了焙烧温度,吸附剂投加量,吸附时间,吸附初始p H值,吸附动力学,吸附等温线、吸附热力学等因素对Mg-Al-Fe类水滑石及其焙烧产物吸附F-的效果。研究表明,500℃焙烧类水滑石吸附效果最好,0.2 g吸附剂是最佳投加量值,在p H变化范围为3~8内吸附量基本无变化。研究结果表明,焙烧水滑石吸附符合准二级动力学曲线,反应活化能为E_a=14.63 k J/mol。反应基本符合Langmuir吸附等温模型。△G~0为负值表明该反应是一自发进行过程。高温有利于吸附反应进行。
Synthesis of Mg-Al-Fe hydrotalcite by coprecipitation method, and calcined hydrotalcite obtained by different calcination temperature. The XRD, FT-IR, SEM and other methods were used to characterize the adsorbent. The effects of calcination temperature, adsorbent dosage, adsorption time, initial pH of adsorption, adsorption kinetics, adsorption isotherm and adsorption thermodynamics on the adsorption of F- on Mg-Al-Fe hydrotalcite and its calcined product were studied . The results show that calcined hydrotalcite has the best adsorption capacity at 500 ℃, and 0.2 g adsorbent is the best dosing value. There is almost no change in the amount of adsorbed Hg from 3 to 8 in the range of p H. The results show that the adsorption of hydrotalcite accords with the quasi-second-order kinetic curve, and the activation energy is Ea = 14.63 kJ / mol. The reaction is basically consistent with Langmuir adsorption isotherm model. △ G ~ 0 is a negative value indicates that the reaction is a spontaneous process. High temperature is conducive to the adsorption reaction.