Adsorption of thorium from aqueous solution by HDTMA+-pillared bentonite
Adsorption of thorium from aqueous solution by HDTMA+-pillared bentonite
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DOI：
10.1007/s10967-012-1793-z
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发表时间：
2012-04
影响因子：
1.6
通讯作者：
Youqun Wang;Zhi-Bin Zhang;Q. Li;Yunhai Liu
中科院分区：
文献类型：
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作者：
Youqun Wang;Zhi-Bin Zhang;Q. Li;Yunhai Liu
研究了十六烷基三甲基铵阳离子柱撑膨润土（HDTMA+-膨润土）对钍的去除和回收能力。采用小角X射线衍射、高分辨透射电子显微镜和傅里叶变换红外光谱对吸附剂进行了表征。 考察了溶液pH值、初始钍浓度、接触时间和温度等实验参数对吸附的影响。HDTMA+-膨润土在初始pH为3.5、接触时间为60 min时表现出最高的钍吸附容量。吸附动力学符合准二级动力学模型，吸附过程符合Langmuir等温式。 热力学参数Δ G°（298 K）、Δ H°和Δ S°分别为−31.78、−23.71 kJ/mol和27.10 J/mol K，表明HDTMA+-膨润土对Th（VI）的吸附过程是可行的、自发的、放热的。HDTMA+柱撑膨润土比钠基膨润土更有利于吸附，且298 K时饱和单分子层吸附量从17.88 mg/g提高到31.20 mg/g。吸附后的HDTMA+-膨润土用0.1mol/LHCl溶液可有效再生，用于Th（VI）的去除和回收。用7.0 g HDTMA+-膨润土处理1.0 L含16.8 mg Th（VI）离子的工业废水，Th（VI）的去除率可达99.9%.
The ability of hexadecyltrimethylammonium cation pillared bentonite (HDTMA+-bentonite) has been explored for the removal and recovery of thorium from aqueous solutions. The adsorbent was characterized using small-angle X-ray diffraction, high resolution transmission electron microscopy and Fourier transform infrared spectroscopy. The influences of different experimental parameters such as solution pH, initial thorium concentration, contact time and temperature on adsorption were investigated. The HDTMA+-bentonite showed the highest thorium sorption capacity at initial pH of 3.5 and contact time of 60 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir isotherm. The thermodynamic parameters, ∆G° (298 K), ∆H° and ∆S° were determined to be −31.78, −23.71 kJ/mol and 27.10 J/mol K, respectively, which demonstrated the sorption process of HDTMA+-bentonite towards Th(VI) was feasible, spontaneous and exothermic in nature. The adsorption on HDTMA+-bentonite was more favor than Na-bentonite, in addition the saturated monolayer sorption capacity increased from 17.88 to 31.20 mg/g at 298 K after HDTMA+pillaring. The adsorbed HDTMA+-bentonite could be effectively regenerated by 0.1 mol/L HCl solution for the removal and recovery of Th(VI). Complete removal (99.9 %) of Th(VI) from 1.0 L industry wastewater containing 16.8 mg Th(VI) ions was possible with 7.0 g HDTMA+-bentonite.