Impact of environmental conditions on the sorption behavior of radionuclide Sr-90(II) on Na-montmorillonite
Impact of environmental conditions on the sorption behavior of radionuclide Sr-90(II) on Na-montmorillonite
复制标题
环境条件对钠蒙脱土吸附放射性核素Sr-90(II)行为的影响
DOI：
10.1016/j.molliq.2014.12.041
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发表时间：
2015
影响因子：
6
通讯作者：
Wang Xiangke
中科院分区：
文献类型：
--
作者：
Yu Shujun;Mei Huiyang;Chen Xin;Tan Xiaoli;Ahmad Bashir;Alsaedi Ahmed;Hayat Tasawar;Wang Xiangke
粘土矿物对各种环境污染物具有很强的吸附和络合能力，因而被广泛研究。在这项研究中，90 Sr（II）的钠蒙脱石吸附作为各种环境条件，如pH值，离子强度，腐殖酸（HA）和温度的函数进行了研究。结果表明，90 Sr（II）在钠基蒙脱石上的吸附受pH和离子强度的强烈影响。利用Visual Minteq 3.0软件，采用扩散层模型（DLM）对90 Sr（II）的吸附实验数据进行了较好的模拟。低pH时，90 Sr（II）在钠基蒙脱石表面的吸附主要是外球表面络合和与Na+/H+的离子交换，而高pH时，内球表面络合是主要的吸附机制。HA的存在增强了90 Sr（II）在pH < 7.0时的吸附，但降低了90 Sr（II）在pH > 7.0时的吸附。采用Langmuir和Freundlich吸附等温线模型分别模拟了303、318和333 K三种温度下90 Sr（II）的吸附等温线。由吸附等温线计算的热力学参数（ΔH，ΔSand ΔG）表明，90 Sr（II）在钠基蒙脱石上的吸附是一个吸热的自发过程。由温度依赖性吸附数据计算的热力学参数对于理解90 Sr（II）与钠基蒙脱石的相互作用行为至关重要。
Clay minerals have been studied extensively due to their strong sorption and complexation ability toward various environmental pollutants. In this study, the sorption of90Sr(II) on Na-montmorillonite was studied as a function of various environmental conditions such as pH, ionic strength, humic acid (HA) and temperature. The results indicated that the sorption of90Sr(II) on Na-montmorillonite was strongly dependent on pH and ionic strength. The experimental data of90Sr(II) sorption was simulated by the diffuse-layer model (DLM) well with the aid of Visual Minteq 3.0. At low pH, the sorption of90Sr(II) was dominated by outer-sphere surface complexation and ion exchange with Na+/H+on Na-montmorillonite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The presence of HA enhanced90Sr(II) sorption at pH < 7.0 but decreased90Sr(II) sorption at pH > 7.0. Langmuir and Freundlich models were used to simulate the sorption isotherms of90Sr(II) at three different temperatures of 303, 318 and 333 K. The thermodynamic parameters (ΔH, ΔSand ΔG) calculated from the temperature-dependent sorption isotherms indicated that the sorption of90Sr(II) on Na-montmorillonite was an endothermic and spontaneous process. The thermodynamic parameters calculated from temperature-dependent sorption data were crucial to understand the interaction behavior of90Sr(II) with Na-montmorillonite.