蛭石和蒙脱石对Sr的吸附性能

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C_0=20 MBq/L的Sr~(2+)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 HNO_3 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(NH_3)_2]~+和1 mol/L HCl改性,吸附率有所提高,Cu(NH_3)_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.

Adsorption of Strontium by Vermiculite and Montmorillonite

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 (C_0) 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 HNO_3 solution from the vermiculite and montmorillonite.The adsorption rate of Sr~(2+) by vermiculite and montmorillonite will decrease in presence of coexistent Ca2+, while modified by Ag(NH_3)_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(NH_3)_4]~(2+) can improve adsorption, however, by Ag(NH_3)_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.