摘要
采用分子模拟和电导率试验相结合的手段,研究了十二烷基苯磺酸钠(SDBS)和十八烷基三甲基氯化铵(STAC)在酸性集料主要化学成分(SiO2)和碱性集料主要化学成分(CaCO3)表面的吸附行为。模拟结果表明:两类乳化剂周围均有两层水化层,STAC的亲水基第一水化层内的水分子个数约为SDBS的两倍,其亲水性强于SDBS;通过界面能分析,对两类乳化剂而言,STAC在集料主要化学成分表面的吸附能力大于SDBS,对于两种集料来说CaCO3对两类乳化剂的吸附能力较SiO2强。电导率试验结果表明:不同集料比(乳化剂的质量与集料化学成分的质量比)下,乳化剂在CaCO3表面的吸附量大于SiO2,且随集料比的增加,不同集料化学成分对乳化剂的吸附量也增加;CaCO3和SiO2对两类乳化剂的吸附曲线近似为S型,且对STAC的吸附曲线离散性小于SDBS;SDBS和STAC在CaCO3上表面浓度(Γ1)最大,另STAC的最大吸附量约为SDBS的3.2倍;模拟参数中的配位数与试验参数中的最大吸附量和乳化剂吸附系数之间的灰色关联度良好,通过配位数可分析乳化剂的亲水性,最大吸附量和吸附系数可用来判断集料对乳化剂的吸附量大小。模拟结果与试验结果一致,表明分子动力学可以准确描述乳化剂在集料主要化学成分表面的吸附行为。
The adsorption behavior of sodium dodecyl benzene sulfonate(SDBS) and octadecyl trimethylammonium chloride(STAC) on the surface of the main chemical components of acidic aggregate(SiO2) and basic aggregate(CaCO3) was studied by means of molecular simulation and conductivity test.The simulation results show that there are two hydration layers around the two types of emulsifiers.The number of water molecules in the first hydration layer of the hydrophilic group of STAC is about twice that of SDBS,which is more hydrophilic than SDBS.According to the analysis of interface energy,for two types of emulsifiers,the adsorption capacity of STAC on the surface of the main chemical components of the aggregate is greater than SDBS.For both types of aggregates,the adsorption capacity of CaCO3 for the two types of emulsifiers is stronger than that of SiO2.The conductivity test results show that:under different aggregate ratios(mass ratio of emulsifier to aggregate chemical composition),the adsorption amount of emulsifier on the surface of CaCO3 is greater than SiO2,and with the increase of aggregate ratio,the chemical composition of different aggregates adsorption of emulsifiers also increased.The adsorption curves of CaCO3 and SiO2 for the two types of emulsifiers are approximately S-type,and the dispersion of the adsorption curves for STAC is less than SDBS.SDBS and STAC have the highest surface concentration(Γ1) on CaCO3,and the maximum adsorption capacity of STAC is about 3.2 times that of SDBS.The gray correlation between the coordination number of simulation parameters and the maximum adsorption amount and the adsorption coefficient of emulsifier is good.The coordination number can be used to analyze the hydrophilicity of the emulsifier,and the maximum adsorption capacity and adsorption coefficient can be used to judge the amount of the emulsifier adsorbed by the aggregate.The simulation results are consistent with the experimental results,indicating that molecular dynamics can accurately describe the adsorption behavior of emulsifier on the surface of main chemical components of the aggregate.
作者
孔令云
全秀洁
李朝波
余苗
KONG Lingyun;QUAN Xiujie;LI Chaobo;YU Miao(National and Local Joint Engineering Laboratory of Transportation Civil Engineering Materials,Chongqing Jiaotong University,Chongqing 400000,China;China Machine Engineering Corporation Limited,Chongqing 400039,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2020年第8期3196-3204,共9页
Chemical Industry and Engineering Progress
基金
国家自然科学基金(51608085,51708071)
重庆市基础科学与前沿技术研究项目(cstc2017jcyjAX0367)。
关键词
分子模拟
相对浓度
界面能
电导率
吸附系数
吸附等温线
molecular simulation
relative concentration
interfacial energy
conductivity
adsorption coefficient
adsorption isotherm
