物理化学学报 >> 2016, Vol. 32 >> Issue (8): 1933-1940.doi: 10.3866/PKU.WHXB201604212

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联苯甲酰桥联β-环糊精吸附U(VI)的动力学和热力学

荆鹏飞,刘慧君*(),张勤,胡胜勇,雷兰林,冯志远   

  • 收稿日期:2016-01-04 发布日期:2016-07-29
  • 通讯作者: 刘慧君 E-mail:liuhuijun@usc.edu.cn
  • 基金资助:
    国家自然科学基金(11375084);湖南省研究生科研创新项目(CX2015B399)

Kinetics and Thermodynamics of Adsorption of Benzil-Bridged β-Cyclodextrin on Uranium(VI)

Peng-Fei JING,Hui-Jun LIU*(),Qin ZHANG,Sheng-Yong HU,Lan-Lin LEI,Zhi-Yuan FENG   

  • Received:2016-01-04 Published:2016-07-29
  • Contact: Hui-Jun LIU E-mail:liuhuijun@usc.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(11375084);Hunan Provincial Innovation Foundation for Postgraduate, China(CX2015B399)

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摘要：

β-环糊精与对甲苯磺酰氯在低温碱性溶液中反应合成6-对甲苯磺酰酯-β-环糊精，并利用红外光谱和核磁共振氢谱对其进行表征；联苯甲酰与6-对甲苯磺酰酯-β-环糊精以摩尔比为1: 2反应合成一种新型的联苯甲酰桥联β-环糊精(BB β-CD)材料，并采用紫外可见分光光度法对其合成机理以及BB β-CD和联苯甲酰对U(VI)的吸附行为进行研究；同时采用扫描电镜对材料吸附U(VI)前后的外貌形态进行表征。通过间歇吸附法考察pH、反应时间、温度以及干扰离子等因素对吸附过程的影响。结果表明，相比联苯甲酰，BB β-CD能更有效地吸附U(VI)，在pH=4.5，反应时间为60 min条件下，最大吸附量为12.16 mg·g-1，吸附率高达91.2%。动力学和热力学拟合结果表明，吸附过程更符合准二级动力学速率方程，Langmuir等温吸附模型比Freundlich等温吸附模型更适合模拟吸附过程，且吸附是自发吸热的过程。

关键词: 联苯甲酰桥联β-环糊精, 铀(VI)吸附, 动力学, 平衡, 热力学

Abstract:

Sulfated β-cyclodextrin (β-CD) was prepared by the reaction of β-CD with p-toluenesulfonyl chloride at low temperature in aqueous sodium hydroxide. The product was analyzed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR). The novel benzil-bridged β-CD (BB β-CD) was acquired by the reaction of benzil with sulfated β-CD at a molar ratio of 1: 2. UV spectrophotometry was used to study the synthetic mechanism of BB β-CD and benzil and their adsorption onto U(VI). Scanning electron microscopy (SEM) was used to analyze the surface properties of the materials. The adsorption of BB β-CD onto U(VI) was investigated as a function of pH, contact time, temperature, and interfering ions using the batch adsorption technique. It was found that the adsorption equilibrium of BB β-CD was reached faster than that of benzil. The optimum experimental conditions were pH=4.5 and shaking for 60 min, achieving the maximum adsorption capacity of 12.16 mg·g-1 and a U(VI) removal ratio of 91.2%. Kinetic studies revealed that the adsorption reached equilibrium within 60 min for U(VI) and followed a pseudo-second-order rate equation. The isothermal data correlated with the Langmuir model better than with the Freundlich model. The thermodynamic data indicated the spontaneous and endothermic nature of the process.

Key words: BB β-CD, Uranium(VI) adsorption, Kinetics, Equilibrium, Thermodynamics 1933