高温下高矿化度对泡沫性能的影响

Effect of salinity on foaming properties at high temperature

考察了一价阳离子Na^+和二价阳离子Ca^(2+),Mg^(2+)对非离子起泡剂烷基糖苷(WT)、两性离子起泡剂甜菜碱(YX)泡沫性能的影响,测定了WT和YX的临界胶束浓度(CMC)及YX在含Ca^(2+),Mg^(2+)溶液中的透射率,采用SEM表征了泡沫微观结构,分析了矿化度对泡沫稳定性的影响机理。表征结果显示,随矿化度增大,形成的泡沫液膜厚度和黏弹性均增加。实验结果表明,矿化度大于3×104 mg/L时,随矿化度的增大,CMC降低,泡沫液膜厚度增加,包裹在液膜上的无机盐增多,泡沫稳定性增强,表现出一定的盐增效性;Na^+主要通过改变泡沫体系的CMC和电荷作用来影响泡沫的稳定性,而Ca^(2+)与Mg^(2+)则是通过离子与离子之间的化学反应、水化作用及电荷作用共同影响泡沫的稳定性,Ca^(2+)将与YX中阴离子基团反应生成不溶物,降低泡沫的起泡性与稳定性;Mg^(2+)则对YX泡沫性能影响不大。

The effects of Na^＋, Ca^2＋ and Mg^2＋ on the foaming properties of nonionic foaming agent alkyl glycoside（WT） and zwitterionic foaming agent betaine（YX） were studied. The critical micelle concentration（CMC） of WT and YX, and the transmittance of YX in the solution containing Ca^2＋ or Mg^2＋ were determined. The foam microstructures were characterized by means of SEM and the effect of salinity on the foam stability was analyzed. It was showed that the liquid film thickness and viscoelasticity of formed foam increased with increasing the salinity. The experimental results indicated that, when the salinity was higher than 3 × 104 mg/L, with increasing the salinity, CMC of the foam systems decreased, and the liquid film thickness of the foam and the inorganic salts on the liquid film increased, so the stability of the foam increased, which showed some salt synergistic effect. Na＋ influenced the stability of the foam system mainly by changing CMC and the electric charge effect of the foam systems. Ca^2＋ and Mg^2＋ affected the stability of the foam systems through the chemical reactions between ions, hydration and electric charge effect. Ca^2＋ could react with the anionic groups of YX to form insolubles which would decrease the foaming properties and the form stability, but the effect of Mg^2＋ was little.