Wu Jiaojiao, Li Bing, Liao Jiali, Feng Yue, Zhang Dong, Zhao Jun, Wen Wei, Yang Yuanyou, Liu Ning
Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, 29 WangJiang Road, Chengdu, P.R. China.
J Environ Radioact. 2009 Oct;100(10):914-20. doi: 10.1016/j.jenvrad.2009.06.024. Epub 2009 Aug 3.
The adsorption of Cs by montmorillonite and the effects of experimental conditions on adsorption were investigated by using (134)Cs as a radioactive tracer. Additionally, the Cs-adsorbed and the modified montmorillonite were analyzed by X-ray Diffractometer System (XRD) and Scanning Electron Microscopy (SEM). The results showed that the adsorption of Cs by montmorillonite was efficient in the initial concentration (C(0)) of 30 microg/L Cs nitrate solution with 20 g/L montmorillonite at room temperature. In this condition, more than 98% Cs(+) ions could be adsorbed at pH approximately 8. The adsorption equilibrium was achieved within 5 min and the relationship between the concentration of Cs(+) in aqueous solutions and adsorption capacities of Cs(+) can be described by the Langmuir adsorption isotherm. The adsorption rate would decrease when temperature increase from 0 degrees C to 50 degrees C or in presence of coexistent K(+), Na(+) and Ca(2+), while modification by (NH(4))(2)SO(4), Ag(NH(3))(2), Cu(NH(3))(4) or 450 degrees C could improve the adsorption abilities of montmorillonite for Cs(+). However, more than 89% of adsorbed Cs(+) on montmorillonite could be desorbed by 2 mol/L HNO(3) solutions. The XRD and SEM analysis further showed that the structure of the Cs-adsorbed or modified montmorillonite were different from that of the original one.
以¹³⁴Cs作为放射性示踪剂，研究了蒙脱石对Cs的吸附以及实验条件对吸附的影响。此外，采用X射线衍射仪系统（XRD）和扫描电子显微镜（SEM）对吸附Cs后的蒙脱石及改性蒙脱石进行了分析。结果表明，在室温下，20 g/L蒙脱石对初始浓度为30 μg/L硝酸铯溶液中的Cs具有高效吸附性能。在此条件下，在pH约为8时，超过98%的Cs⁺离子能够被吸附。吸附平衡在5分钟内达到，水溶液中Cs⁺浓度与Cs⁺吸附容量之间的关系可用Langmuir吸附等温线描述。当温度从0℃升高到50℃或存在共存的K⁺、Na⁺和Ca²⁺时，吸附速率会降低，而用(NH₄)₂SO₄、[Ag(NH₃)₂]⁺、[Cu(NH₃)₄]²⁺改性或在450℃处理可提高蒙脱石对Cs⁺的吸附能力。然而，蒙脱石上吸附的Cs⁺中有超过89%可被2 mol/L硝酸溶液解吸。XRD和SEM分析进一步表明，吸附Cs或改性后的蒙脱石结构与原始蒙脱石不同。
