Abstract
Optimal condition-based microemulsion is key to achieving great efficiency in oil removal. One useful empirical equation to predict an optimal condition is a hydrophilic–lipophilic deviation (HLD). However, the K constants of each surfactant should be the same to combine the HLD equations for the mixed surfactant. Recently, a normalized hydrophilic-lipophilic deviation (HLDN) was presented to avoid this limitation. This work sought to determine the phase behaviors and predict the optimal salt concentrations, using HLDN for the mixed surfactant. Sodium dihexyl sulfosuccinate (SDHS) as an anionic surfactant, and alcohol alkyl polyglycol ether (AAE(6EO4PO)) as a nonionic surfactant, were both investigated. Alkanes and diesel were used as a model oil. The results showed that AAE(6EO4PO) enforced both the hydrophilic and the hydrophobic characteristics. The Winsor Type I-III transition was influenced by the ethylene oxide, while the propylene oxide presence affected the Winsor Type III-II inversion. For the HLDN equation, the average interaction term was 1.82 ± 0.86, which markedly showed a strong correlation with the fraction of nonionic surfactant in the mixed systems. The predicted optimal salt concentrations using HLDN of SDHS-AAE(6EO4PO) in the diesel systems were close to the experimental results, with an error of <10% that is significantly beneficial due to the shorter time required for optimal determination.
Highlights
Published: 1 October 2021The rapid growth of both industries and population leads to environmental concerns.Oil cleaning and decontamination applications have been receiving increased attention due to enhancing resource recovery potentials, such as oil-contaminated materials and waste.For many years, microemulsion formulation has been an attractive method and is applied for cleaning products and for other applications, e.g., enhanced oil recovery (EOR) and soil remediation [1,2]
We investigated the characteristics of the mixed anionic-nonionic system by a phase behavior study, determined the hydrophilic-lipophilic deviation (HLDN) equations for both single and mixed systems, and predicted the optimal condition in the diesel system via the HLDN equations
The mixed surfactant systems of anionic and extended nonionic surfactants containing ethylene oxide (EO) and polypropylene oxide (PO) groups were analyzed to enhance the solubilization of the n-alkane oils with different EACNs
Summary
Microemulsion formulation has been an attractive method and is applied for cleaning products and for other applications, e.g., enhanced oil recovery (EOR) and soil remediation [1,2]. Extended surfactants are a novel classification that has been widely used to formulate microemulsions They contain intermediate polarity groups between a head and a tail part of the surfactant structure [11,12,13,14,15]. Intermediate polarity molecules, for Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
