摘要：以蛭石、蒙脱石和膨润土为吸附剂, 采用静态吸附试验研究3种黏土矿物对Cr⁶⁺的吸附影响因素及规律、最佳吸附条件和吸附行为特性, 并采用红外线光谱、扫描电镜、能谱和X射线衍射对3种黏土矿物的活性基团构成、微观形貌和化学元素组成等进行表征与分析。结果表明, 3种黏土矿物对Cr⁶⁺的吸附基本在60 min内达到平衡, 在p H为5.0时有较好的吸附效果。蛭石、沸石和膨润土对Cr⁶⁺的吸附过程更符合二级反应动力学, 以Langmuir方程拟合得到理论最大吸附量分别为19.959、8.3963、15.432 mg·g^-1, 正交实验结果表明, 在吸附剂的质量浓度为1.0 g·L^-1, 吸附质质量浓度为300 mg·L^-1, p H为5.0, 温度为25℃, 时间为120 min的条件下, 3种黏土矿物的吸附量达到最大, 其中蛭石对Cr⁶⁺的吸附效果最好。

关键词：蛭石；蒙脱石；膨润土；吸附

Abstract：Adsorption of heavy metal ions such as Cr⁶⁺on vermiculite, montmorillonite and bentonite was studied.With the static experimental method, the adsorption factors, rules, optimum adsorption condition and adsorption properties of the three kinds of clay minerals were obtained. The active group structure, morphology and chemical elements were examined by fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive spectrometer and X-ray diffraction.The results indicate that the adsorption equilibriums are achieved in 60 minutes. The uptake of Cr⁶⁺ by the three kinds of clay minerals maintaines high efficiencies in the p H of 5. The adsorption of Cr⁶⁺ onto vermiculite, montmorillonite and bentonite could be well described by pseudo-second-order model. The theoretical maximum adsorption amount fitted by Langmuir isothermal are 19.959, 8.3963, 15.432 mg·g^-1. As the results of optimization test show, optimal condition for adsorption of Cr⁶⁺ on vermiculite, montmorillonite and bentonite are adsorbent concentration 1.0 g·L^-1, adsorbate concentration 300 mg·L^-1, p H5.0, reaction temperature 25 ℃, adsorption time 120 min. Among the three, vermiculite has the best adsorption effect on Cr⁶⁺.

Keywords: vermiculite；montmorillonite；bentonite；adsorption