Abstract: The interfacial tensions (IFTs) between zwitterionic surfactant, hexadecyl diethyl2hydroxy1proply sulfobetaine and Shengli crude oil were investigated using spinning drop method. The influences of salinity, concentration of divalent ions and weak base NaHCO3 on IFT were discussed. The experimental results show the mixed adsorption of betaine molecules and the active components present in the crude oil at the interface and the synergism of them together determine the IFT of oilwater. The betaine surfactant with electroneutrality permits closer packing at the interface. An increase in the concentration of Na+ and Mg2+ with less ion radii appears to decrease the IFT gradually, however, the value of IFT remain at higher level with increase in the concentration of Ca2+ with larger ion radius. NaHCO3 can react with the active components present in the crude oil, which reduces IFT to ultralow value. In this case, one can find that total salinity is the key factor that determines the IFT, while ionic type has little effect on the IFT.

Key words: Betaine,    ,  Crude oil,    ,  Interfacial tension,   , Calcium and magnesiumion

摘要： 采用旋转滴法测定了两性离子表面活性剂十六烷基二乙基羟丙基磺基甜菜碱与胜利原油间界面张力,并考察了矿化度、二价离子浓度及弱碱NaHCO3 对界面张力的影响。结果表明,甜菜碱分子与原油活性组分在界面上混合吸附、协同作用,共同决定油水界面张力。电中性的甜菜碱表面活性剂在界面上排列较为紧密,随着离子半径较小的Na+ 和Mg2+ 质量分数增大,界面张力呈缓慢下降的趋势;而随着离子半径较大的Ca2+ 质量分数增大,界面张力始终较高;NaHCO3 与原油活性组分反应,能将油水界面张力降至超低,此时总矿化度起决定作用,离子类型影响不大。

关键词: 甜菜碱 , 原油 , 界面张力 , 钙镁离子