Microemulsion Formation with Chlorinated Hydrocarbons of Differing Polarity

Baran, Jimmie R.; Pope, Gary A.; Wade, William H.; Weerasooriya, V.; Yapa, A.

doi:10.1021/es00056a027

Cited by 61 publications

(60 citation statements)

References 10 publications

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“…As a general trend the solubilization parameter rises with increasing oil polarity (i.e., decreasing oil EACN) for systems with strong surfactants, in agreement with the UTCHEM model [33]. However, at sufficiently high oil polarity, when the linear EACN mixing rule fails and the tricritical point or another nonmicroemulsion surfactant-rich phase boundary is approached, the solubilization parameter is expected to change trends with further EACN decrease.…”

Section: Introductionsupporting

confidence: 75%

Preferential solubilization of dodecanol from dodecanol–limonene binary oil mixture in sodium dihexyl sulfosuccinate microemulsions: Effect on optimum salinity and oil solubilization capacity

Szekeres

Acosta

Sabatini

et al. 2005

Journal of Colloid and Interface Science

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Section: Introductionsupporting

confidence: 75%

Preferential solubilization of dodecanol from dodecanol–limonene binary oil mixture in sodium dihexyl sulfosuccinate microemulsions: Effect on optimum salinity and oil solubilization capacity

Szekeres

Acosta

Sabatini

et al. 2005

Journal of Colloid and Interface Science

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“…Surfactant-enhanced solubilization and mobilization of residual NAPL have been widely studied for environmental remediation (5,(18)(19)(20)(21)(22)(23). Mixed surfactant systems have been used to enhance subsurface remediation by increasing the solubility of, and forming middle-phase microemulsions with, the NAPL (19,22,24,25).…”

mentioning

confidence: 99%

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Doan¹,

Acosta²,

Sabatini³

2003

J Surfact & Detergents

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Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1:1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.Mixed anionic-cationic surfactant systems. Mixtures of anionic and cationic surfactants often exhibit synergistic effects. The synergism depends on the charge and molecular structure of the individual surfactant components and can be attributed to nonideal mixing effects, which can produce substantially lower critical micelle concentration CMC values and interfacial tensions (IFT) than otherwise possible (1). For anioniccationic surfactant mixtures, the mixed CMC can be two orders of magnitude below that expected if the surfactants have similar structure (2). The use of mixed anionic and cationic surfactants has been evaluated in washing and fabric softening, analytical chemistry, enhanced oil recovery, and pharmaceutical applications (3-5).In this project we are particularly interested in the use of anionic-cationic surfactant mixtures in the formulation of microemulsions. Microemulsions are optically transparent, thermodynamically stable phases containing oil and water stabilized by an interfacial film composed of surfactants and sometimes other molecules (e.g., cosurfactant, alcohols). Microemulsions are important in many applications such as enhanced oil recovery, remediation of oil-impacted aquifer, detergency,...

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“…Properly formulated surfactant systems can greatly facilitate contaminant extraction from the geologic subsurface (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Surfactant micelles increase contaminant solubility by micellar-enhanced contaminant solubility.…”

mentioning

confidence: 99%

Alcohol‐free diphenyl oxide disulfonate middle‐phase microemulsion systems

Harwell

Sabatini

et al. 2000

J Surfact & Detergents

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Diphenyl oxide disulfonate (DPDS) surfactants were successfully used to formulate Winsor Type III middlephase microemulsion systems with tetrachloroethylene (PCE) and decane. To our knowledge this is the first time that monochain DPDS surfactant phenyloxide monohexadecyl disulfonate surfactant (C16MADS) and commercially available DOWFAX 8390 were found to form middle-phase microemulsion systems with oils. Hydrophobic dioctyl sodium sulfosuccinate (Aerosol OT) was also used as a cosurfactant to lower the systems' hydropholic-liphophilic balance. Two organic acids (hydrophobic octanoic acid and hydrophilic L-tartaric acid) were used in place of the alcohol to formulate middle-phase microemulsion. The middle-phase microemulsion systems dramatically increased organic solubility when compared to micellar DPDS surfactant systems. Winsor Type I systems near the Type I-III boundary produced "super" solubilization for hydrophobic oils. Findings from this study enable us to improve DPDS solubilization enhancement of hydrophobic compounds.Properly formulated surfactant systems can greatly facilitate contaminant extraction from the geologic subsurface (1-11). Surfactant micelles increase contaminant solubility by micellar-enhanced contaminant solubility. Surfactants can also mobilize subsurface contaminants by forming middle-phase microemulsions (1).Twin-head diphenyl oxide disulfonate (DPDS) surfactants are desirable for environmental application because of high water solubility, low subsurface sorption and precipitation potential, and strong electrolyte resistance (i.e., their robustness). Numerous laboratory studies and several field tests have demonstrated the robust nature of these surfactants (12,13). Their classification as indirect food-grade additives is also advantageous when considering subsurface injection. However, the relatively low solubilization enhancement of DPDS surfactants limits their usefulness for hydrophobic nonaqueous phase liquids (NAPL) (13).The low solubilization capacity of DPDS surfactants can be attributed to their relatively high hydrophilicity. As very hydrophilic surfactants, they have high critical micelle concentration (CMC) values and the charge distribution is higher in their aggregates. This highly hydrophilic nature also makes it difficult for DPDS surfactants to form middlephase microemulsions with highly hydrophobic NAPL (14).Increasing the DPDS surfactants' solubilization capacity will increase their competitiveness with other surfactants, especially when considering their robust nature (e.g., low sorption, low viscosity, and high electrolyte resistance). In a previous study (13), we investigated several approaches for enhancing the solubilization potential of DPDS. We first tried to increase the compound's partitioning into micelles by adjusting micelle size and hydrophobicity. We attempted this by lengthening the hydrocarbon chain of the surfactant and by mixing DPDS surfactants with hydrophobic nonionic surfactants like alkyl phenyl ethoxylates. We next tried formulating middle-p...

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Microemulsion Formation with Chlorinated Hydrocarbons of Differing Polarity

Cited by 61 publications

References 10 publications

Preferential solubilization of dodecanol from dodecanol–limonene binary oil mixture in sodium dihexyl sulfosuccinate microemulsions: Effect on optimum salinity and oil solubilization capacity

Preferential solubilization of dodecanol from dodecanol–limonene binary oil mixture in sodium dihexyl sulfosuccinate microemulsions: Effect on optimum salinity and oil solubilization capacity

Formulating middle‐phase microemulsions using mixed anionic and cationic surfactant systems

Alcohol‐free diphenyl oxide disulfonate middle‐phase microemulsion systems

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