A comparison of trimeric surfactant intercalated montmorillonite with its gemini modified one: Characterization and application in methyl orange removal
A comparison of trimeric surfactant intercalated montmorillonite with its gemini modified one: Characterization and application in methyl orange removal
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DOI：
10.1016/j.molliq.2016.11.104
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发表时间：
2017-02
影响因子：
6
通讯作者：
Ya-qin Liang;Hui Li
中科院分区：
文献类型：
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作者：
Ya-qin Liang;Hui Li
采用三聚表面活性剂甲基十二烷基双[2-（十二烷基二甲基铵基）乙基]三溴化铵（3RenQ）和相应的二聚表面活性剂1.2-双（十二烷基二甲基铵基）乙烷二溴化铵（2 RenQ）对钠基蒙脱土进行改性。采用X射线衍射（XRD）、傅里叶变换红外（FTIR）、N2吸附等温线、热重分析（TG）、扫描电镜（SEM）和X射线衍射（XRD）等手段对有机蒙脱土3RenQ-Mt和2 RenQ-Mt进行了表征。结果表明，3RenQ和2 RenQ成功地插入到钠基蒙脱土片层中，随着表面活性剂阳离子交换容量（CEC）和聚合度的增加，有机蒙脱土的层间距和亲水性增加。采用间歇法研究了3RenQ-Mt和2 RenQ-Mt对橙子（MO）的吸附性能，考察了表面活性剂浓度、接触时间、pH值和温度对吸附性能的影响。3RenQ-Mt和2 RenQ-Mt对MO的最佳吸附条件为：表面活性剂浓度为1.0 CEC，接触时间为6 h，自然pH为3，温度为20 °C，3RenQ-Mt和2 RenQ-Mt的平衡吸附容量分别达到85.97和98.07 mg g− 1;在相同的实验条件下，3RenQ-Mt与MO的相互作用强于2 RenQ-Mt。动力学数据符合准二级动力学模型。吸附等温线符合Langmuir模型。热力学参数如吉布斯自由能ΔGθ、标准焓ΔHθ和标准熵ΔSθ表明，MO吸附过程是自发的、放热的、物理吸附的和随机性降低的。
Trimeric surfactant methyldodecylbis [2-(dimethyldodecylammonio)ethyl] ammonium tribromide (3RenQ) and the corresponding dimer 1.2-bis(dodecyldimethylammonio)ethane dibromide (2RenQ), were used to modify sodium montmorillonite. Organo-montmorillonites 3RenQ-Mt and 2RenQ-Mt were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, N2adsorption isotherms, thermogravimetric analysis (TG), scanning electron microscopy (SEM) and dispersibility measurement. The results showed that 3RenQ and 2RenQ had inserted into the lamella of sodium montmorillonite successfully, the interlayer spacer and the hydrophilicity of organoclays increased with the increasing of the cationic exchange capacity (CEC) of surfactants and polymerization degree. The adsorption experiments of methyl orange (MO) on 3RenQ-Mt and 2RenQ-Mt were studied using batch method as a function of the concentration of surfactants, contact time, pH and temperature. The optimal conditions for MO on 3RenQ-Mt and 2RenQ-Mt were as follows: 1.0 CEC of the concentration of surfactants, contact time of 6 h, natural pH of 3, the temperature of 20 °C, the equilibrium adsorption capacity of 3RenQ-Mt and 2RenQ-Mt reached to 85.97 and 98.07 mg g− 1, respectively; at the same experimental condition, 3RenQ-Mt exhibited the stronger interaction with MO than 2RenQ-Mt. The kinetic data were better described by the pseudo-second order kinetics model. The adsorption isotherm was in good agreement with the Langmuir model. Thermodynamic parameters such as the Gibbs free energy ΔGθ, the standard enthalpy ΔHθand the standard entropy ΔSθconfirmed that the process of MO adsorption was spontaneous, exothermic, physisorption and randomness decreasing.