Surfactant Aggregation in CO2/Heptane Solvent Mixtures

详细信息    查看全文

• 作者：Martin J. Hollamby ; Kieran Trickett ; Azmi Mohamed ; Julian Eastoe ; Sarah E. Rogers ; Richard K. Heenan
• 刊名：Langmuir
• 出版年：2009
• 出版时间：November 17, 2009
• 年：2009
• 卷：25
• 期：22
• 页码：12909-12913
• 全文大小：762K
• 年卷期：v.25,no.22(November 17, 2009)
• ISSN：1520-5827

文摘

The effect of improving “solvent quality” of pure liquid CO₂ with a heptane cosolvent on the phase behavior and micellization of commercially available surfactants has been explored using high-pressure small-angle neutron scattering (HP-SANS). The nonionic C₁₂E₅ was found to be highly soluble in both pure CO₂ and the solvent blends, but no aggregation was detected by HP-SANS for any of the compositions studied, even up to 12 vol % surfactant. On the other hand, improving CO₂ solvent quality by adding heptane above 30 vol % promoted solubility and aggregate formation with normal sodium bis(ethylhexyl)sulfosuccinate (AOT). The solvent quality index Hildebrand solubility parameter, used to predict surfactant aggregation in pure hydrocarbon solvents (Langmuir, 2008, 24 (21), 12235−12240) has been tested here for CO₂−heptane mixtures. The results show how solubility and efficiency of AOT, a commercially viable, well-known, and commonly used surfactant, can be boosted in alkane-containing CO₂-rich fluids compared to pure CO₂ alone.