The phase behavior of microemulsions stabilized by a binary anionic–nonionic surfactant mixture of sodium dihexyl sulfosuccinate (SDHS) and C12-14 alcohol ethoxylate (C_{12 − 14}E_j) that contains an ethylene oxide (E_j) group number, j, of either 1, 5, or 9 was investigated for oil remediation. The oil–water interfacial tension (IFT) and optimal salinity of the microemulsion systems with different equivalent alkane carbon numbers (EACN) were examined. The anionic–nonionic surfactant ratio was found to play a pivotal role in the phase transition, IFT, and optimal salinity. The minimum IFT of mixed SDHS − C_{12 − 14}E_j systems were about three times lower than those of neat SDHS systems. A hydrophilic–lipophilic deviation (HLD) empirical model for the mixed anionic–nonionic surfactant system with the characteristic parameter was proposed, as represented in the excess free energy term . The results suggested that the mixed system of SDHS − C_{12 − 14}E₁ was more lipophilic, while SDHS − C_{12 − 14}E₉ was more hydrophilic than the ideal mixture (no excess free energy during the microemulsion formation), and the SDHS − C_{12 − 14}E₅ system was close to the ideal mixture. The findings from this work provide an understanding of how to formulate mixed anionic–nonionic microemulsion systems using the HLD model for oils that possess a wide range of EACN.

中文翻译：

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阴离子-非离子混合表面活性剂体系中环氧乙烷基团对微乳液相行为的影响

（C由二己磺基琥珀酸钠（SDHS）和C12-14醇乙氧基化物的二元阴离子-非离子表面活性剂混合物稳定微乳液的相行为_{- 14 12} Ë _Ĵ包含环氧乙烷（E）_Ĵ）组号，Ĵ的，对 1、5 或 9 进行了石油修复研究。研究了具有不同当量烷烃碳数 (EACN) 的微乳液体系的油水界面张力 (IFT) 和最佳盐度。发现阴离子-非离子表面活性剂比例在相变、IFT 和最佳盐度中起关键作用。混合 SDHS 的最小 IFT − C _{12 − 14} E _j系统大约比纯 SDHS 系统低三倍。提出了具有特征参数的混合阴离子-非离子表面活性剂体系的亲水-亲油偏差（HLD）经验模型，如过量自由能项所示。结果表明，SDHS − C _{12 − 14} E ₁的混合体系更亲油，而 SDHS − C _{12 − 14} E ₉比理想混合物（微乳液形成过程中没有过量的自由能）更亲水，而 SDHS − C _{12 − 14} E ₅体系接近于理想的混合物。这项工作的发现提供了对如何使用具有广泛 EACN 范围的油的 HLD 模型配制混合阴离子-非离子微乳液系统的理解。