Wang Guifang, Xiao Huizhen, Zhang Shuai, Qiu Jun, Li Hengjun, Yang Meijin, Ma Shaojian, Komarneni Sridhar
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials, Guangxi University, Nanning 530004, China.
Materials (Basel). 2018 Nov 19;11(11):2320. doi: 10.3390/ma11112320.
In this study, a novel dual-cation organomontmorillonites (OMt) nanocomposite was synthesized by two kinds of modifiers cetyltrimethylammonium chloride and cysteamine hydrochloride, and the adsorption behavior of modifiers into montmorillonite (Mt) has been investigated. The OMt were characterized by techniques, such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and thermogravimetric and differential thermal (TG-DTA) analyses. The effects of temperature, contact time, the order of addition and the concentration of organic modifiers on the amounts of organics adsorbed were investigated. The adsorption amount of cetyltrimethylammonium chloride (CTAC) and cysteamine hydrochloride (CSH) increased with the increase of the added CTAC amount and contact time, while the addition order of modifiers and modification temperature had no significant effect on the actual adsorption amount of CTAC and CSH on Mt, as confirmed by the XRD patterns. The experimentally determined isotherms showed a good fit with the Langmuir adsorption models. The adsorption kinetics demonstrated that the adsorption of CTAC and CSH by Mt followed the pseudo-second-order model, and CTAC adsorption rate on Mt was faster than that of CSH. FTIR spectrum clearly revealed the incorporation of surfactant ions into the interlayer region. The TG-DTA analyses showed that the total mass losses of OMt strongly depended on the molecular volume of modifiers.
在本研究中，通过十六烷基三甲基氯化铵和盐酸半胱胺两种改性剂合成了一种新型双阳离子有机蒙脱石（OMt）纳米复合材料，并研究了改性剂在蒙脱石（Mt）中的吸附行为。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱以及热重和差热（TG-DTA）分析等技术对OMt进行了表征。研究了温度、接触时间、添加顺序和有机改性剂浓度对有机物吸附量的影响。XRD图谱证实，十六烷基三甲基氯化铵（CTAC）和盐酸半胱胺（CSH）的吸附量随CTAC添加量和接触时间的增加而增加，而改性剂的添加顺序和改性温度对CTAC和CSH在Mt上的实际吸附量没有显著影响。实验测定的等温线与朗缪尔吸附模型拟合良好。吸附动力学表明，Mt对CTAC和CSH的吸附遵循准二级模型，且Mt对CTAC的吸附速率比CSH快。FTIR光谱清楚地显示了表面活性剂离子进入层间区域。TG-DTA分析表明，OMt的总质量损失强烈依赖于改性剂的分子体积。
