蛭石和蒙脱石对Sr的吸附性能

Adsorption of Strontium by Vermiculite and Montmorillonite

研究了蛭石、蒙脱石对Sr的吸附行为及各种实验条件对吸附的影响。结果表明,在室温下,pH=8,初始浓度C0=20 MBq/L的Sr2＋溶液,保持液固比为50∶1（mL∶g）不变时,蛭石和蒙脱石对Sr^2＋的去除率分别达96.8%和98.5%;在相同条件下,其适宜吸附的pH范围均为3-10,吸附平衡时间分别为2 h和15 min;Ca^2＋对蛭石和蒙脱石的吸附影响均较大;而2 mol/L HNO3能分别将82.7%和98.7%的Sr^2＋从蛭石和蒙脱石上解吸下来。蛭石经[Ag（NH3）2]^＋和1 mol/L HCl改性,吸附率有所提高,[Cu（NH3）4]^2＋的改性能提高蒙脱石的吸附性能;高温改性却使蛭石和蒙脱石的吸附性能变得更差。此外,还用X衍射分析谱（XRD）对改性前后的蛭石和蒙脱石进行了解析,并初步分析了改性后蛭石和蒙脱石吸附性能发生变化的原因。

The adsorption of Sr^2＋ by vermiculite and montmorillonite and the effects of experimental conditions were investigated. The results show that more than 96.8% and 98.5% of the total Sr^2＋ can be adsorbed by the vermiculite and montmorillonite from pH = 8 Sr^2＋ solution of 20 MBq/L （Co） at room temperature, respectively. The equilibrium of adsorption by vermiculite and montmorillonite was achieved within 2 h and 15 min severally, and the optimum pH both ranged from 3 to 10. More than 82.7% and 98.7% Sr^2＋ can be desorbed by 2 mol/L HNO3 solution from the vermiculite and montmorillonite. The adsorption rate of Sr^2＋ by vermiculite and montmorillonite will decrease in presence of coexistent Ca^2＋ , while modified by [Ag（NH3）2]^＋ and 1 mol/L HCl can improve the adsorption abilities of vermiculite for Sr^2＋ , but decreased by high temperature. As for montmorillonite, modified by [Cu（NH3）4]^2＋ can improve adsorption, however, by [Ag（NH3）2]^＋ and high temperature can decrease. Additionally, the modified vermiculite and montmorillonite were analyzed by X-ray diffractometer system （XRD）. The results show that the spectra of the modified vermiculite or montmorillonite are different from that of the original one.