【作者】 邵月华；

【导师】 李英；

【作者基本信息】 山东大学 ， 物理化学， 2008， 硕士

【摘要】 本文系统研究了阴离子型表面活性剂SDBS（十二烷基苯磺酸钠）、非离子型表面活性剂TX-100（辛基酚基聚氧乙烯醚）和阳离子表面活性剂CTAB在石英表面的吸附规律,考察了在较大的表面活性剂浓度范围内,多价无机阳离子对不同类型表面活性剂吸附规律的影响。运用QCM（石英晶体微天平）、MD（分子动力学模拟）、FAAS（原子吸收光谱法）、AFM（原子力显微镜）等手段分析了其吸附机制及作用原理。（1）利用石英晶体微天平QCM研究阴离子表面活性剂SDBS在模拟矿化水条件下在石英表面的吸附行为,并用原子吸收光谱法验证了矿化水条件下SDBS的吸附机制。实验结果表明:①在纯水介质中阴离子表面活性剂SDBS在固体表面因晶格缺陷或氢键缺损产生的正电位以电性作用发生吸附是主要的吸附机制。②在矿化水中,金属阳离子在固体表面吸附作为“结构离子”促进了胶团排斥作用,胶团排斥作用是表面活性剂随浓度增大解吸附的主要原因。③Na⁺与表面的相互作用强于阴离子表面活性剂,在阴离子表面活性剂存在时可成为结构离子。（2）采用石英晶体微天平法研究了TX-100在石英表面的吸附动力学和热力学特性,并用分子动力学模拟以及原子吸收光谱法验证了所得结果。同时考察了多种因素（多价无机阳离子、电解质类型和pH值的变化）对吸附的影响。实验结果表明:①在矿化水介质中TX-100在石英表面的吸附量较大,在表面活性剂浓度到达一定程度后出现脱附现象;②采用分子动力学模拟和原子吸收光谱法验证了脱附现象的发生;③Ca²⁺、Mg²⁺与相同浓度Na⁺比较,更能促进TX-100的吸附。采用AFM（原子力显微镜）验证了当TX-100溶液中含有多价无机阳离子时,所形成的吸附层是一个非常松散的结构,附着力不是很强,因此多价无机阳离子在固体表面吸附是导致表面活性剂与固体之间的氢键相互作用减弱,使表面活性剂在较高浓度后发生脱附现象。（3）采用石英晶体微天平（QCM）法和分子模拟技术研究了阳表面活性剂CTAB在石英表面的吸附等温线,并考察矿化度、pH等条件对吸附等温线的影响,分析吸附机制。研究表明:多价无机阳离子存在时,CTAB在石英表面的吸附量减小。（4）运用QCM法研究了不同类型表面活性剂在地层水测量介质中的吸附动力学,并与非地层水情况作了对比,同时对吸附动力学参数进行了估算,与实验值有着很好的对应。实验结果表明,电解质对于不同类型表面活性剂吸附速率的大小具有一定的影响,在地层水的情况下会使得阴离子表面活性剂比阳离子表面活性剂反而更易在石英砂上发生吸附。本论文主要创新点:（1）在矿化水介质中,金属阳离子在固体表面吸附作为“结构离子”促进了胶团排斥作用,胶团排斥作用是阴离子表面活性剂随浓度增大解吸附的主要原因。且Na⁺与表面的相互作用强于阴离子表面活性剂,在阴离子表面活性剂存在时可成为结构离子。（2）利用分子动力学模拟以及原子吸收光谱法验证了在较大浓度时TX-100在石英表面脱附现象的发生,进一步分析其脱附机制。（3）多价无机阳离子存在时,由于金属阳离子在固体表面吸附,从而使CTAB在石英表面的吸附量较小。更多还原

【Abstract】 The adsorption laws of ionic surfactant SDBS,nonionic surfactant TX-100 and cation surfactant CTAB on silica are systematically studied in the paper.In a large scale of surfactant concentration,the effect of Ca²⁺,Mg²⁺and Na⁺ on the adsorption isotherm and kinetics of surfactants on silica are investigated.The adsorption mechanism and principle are studied by quartz crystal microbalance（QCM）, molecular dynamics simulations（MD）,flame atomic absorption spectrometry（FAAS） and atomic force microscopy（AFM）methods.The experimental results are analysed synthetically and the corresponding isothermal adsorption equation and adsorption kinetics parameters have been got.（1）The electrode-separated piezoelectric sensor（ESPS）,an improved setup of quartz crystal microbalance（QCM）,has been employed to investigate the adsorption behavior of SDBS at the hydrophilic quartz-solution interface in mineralized water medium in situ.The adsorption of positive ions on the silica surface has been verified by FAAS measurement.The experimental results show that in pure water medium. absorption of anionic surfactants SDBS on the solid surface because of lattice defects or defects of the hydrogen bond is the main absorption mechanism.Metal cations adsorbed onto the quartz surface as "structure ions" not only promote the adsorption of surfactants onto the silica surface at low concentration but also promote micelle rejection interaction,which is the main reason for desorption of surfactants with the increasing of surfactant concentration.Interaction between Na⁺ and silica surface is stronger than that between the head group of anionic surfactants SDBS and silica,and Na⁺ can be "structure ion" in the presence of anionic surfactants.（2）The electrode-separated piezoelectric sensor（ESPS）,an improved setup of quartz crystal microbalance（QCM）,has been employed to investigate the adsorption behavior of nonionic surfactant Triton X-100 at the hydrophilic quartz-solution interface in mineralized water medium in situ,in which the total salinity equal to 23171mg/L,containing CaCl₂ 1.3819g/L,MgCl₂ 1.0544g/L,NaCl 20.7347g/L.In a large scale of surfactant concentration,the effect of Ca²⁺,Mg²⁺and Na⁺ on the adsorption isotherm and kinetics are obviously different and a peculiar desorption of Triton X-100 at high concentration is investigated which might be important in practical process.The results get by solution depletion method are in good agreement with that obtained by ESPS.The effect of inorganic positive ions on the adsorption and desorption mechanism of Triton X-100 at the quartz-solution interface is discussed by molecular dynamics simulations（MD）,flame atomic absorption spectrometry（FAAS）and atomic force microscopy（AFM）methods.（3）Quartz crystal microbalance and molecular dynamics simulation method are used in the paper to discuss the mechanism of the effect of inorganic positive ions on the adsorption of CTAB at the hydrophilic silica-solution interface.Effect of salinity,pH on adsorption mechanism of CTAB on quartz surface has been investigated.The experimental results show that in the presence of inorganic positive ions,the adsorption densities of CTAB on the silica surface decrese.（4）The adsorption kinetic of different types of surfactants in mineralized water medium has been studied in situ by QCM,both in non-mineralized and mineralized water medium,the adsorption kinetic parameters have been obtained.The results are in good agreement with the experimental value.Experimental results show that ionic surfactant SDBS adsorb onto the quartz surface more easily than cation surfactant CTAB in mineralized water medium.The innovations in the thesis are as follows:（1）Metal cations adsorbed onto the quartz surface as "structure ions" not only promote the adsorption of surfactants onto the silica surface at low concentration but also promote micelle rejection interaction,which is the main reason for desorption of surfactants with the increasing of surfactant concentration.Interaction between Na⁺ and silica surface is stronger than that between the head group of anionic surfactants SDBS and silica,and Na⁺ can be "structure ion" in the presence of anionic surfactants.（2）The effect of inorganic positive ions on the adsorption and desorption mechanism of Triton X-100 at the quartz-solution interface is discussed by molecular dynamics simulations（MD）,flame atomic absorption spectrometry（FAAS）.And we discuss the effect of inorganic positive ions on the adsorption mechanism.（3）In the presence of inorganic positive ions,the adsorption densities of CTAB on the silica surface decrese.更多还原