Solubility of ionic surfactants below their Krafft point in mixed micellar solutions: Phase diagrams for methyl ester sulfonates and nonionic cosurfactants

Danov, Krassimir D.; Stanimirova, Rumyana D.; Kralchevsky, Peter A.; Slavova, Tatiana G.; Yavrukova, Veronika I.; Ung, Yee Wei; Tan, Emily; Xu, Hui; Petkov, Jordan T.

doi:10.1016/j.jcis.2021.05.147

Cited by 8 publications

(1 citation statement)

References 31 publications

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“…Krafft Point (K t ) is an important property of ionic surfactants. The solubility of this type of surfactant does not change significantly with the increase of temperature in the lower temperature range, but when the temperature rises to a certain value, its solubility increases rapidly with the increase of temperature, and the temperature at this time is called the Clough characteristic [55]. The specific test method is as follows: first, the surfactant is prepared into a 1 wt% aqueous solution, and then placed in the refrigerator (<0 • C) for 24 h to ensure that the clear and transparent aqueous solution becomes turbid.…”

Section: Surface Tension Testmentioning

confidence: 99%

Study on the Synthesis, Surface Activity, and Self-Assembly Behavior of Anionic Non-Ionic Gemini Surfactants

Man,

2024

Molecules

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The use of surfactants in oil recovery can effectively improve crude oil recovery rate. Due to the enhanced salt and temperature resistance of surfactant molecules by non-ionic chain segments, anionic groups have good emulsifying stability. Currently, there are many studies on anionic non-ionic surfactants for oil recovery in China, but there is relatively little systematic research on introducing EOs into hydrophobic alkyl chains, especially on their self-assembly behavior. This article proposes a simple and effective synthesis method, using 3-aminopropane sulfonic acid, fatty alcohol polyoxyethylene ether, and epichlorohydrin as raw materials, to insert EO into hydrophobic alkyl chains and synthesize a series of new anionic non-ionic Gemini surfactants (CnEO-5, n = 8, 12, 16). The surface activity, thermodynamic properties, and self-assembly behavior of these surfactants were systematically studied through surface tension, conductivity, steady-state fluorescence probes, transmission electron microscopy, and molecular dynamics simulations. The surface tension test results show that CnEO-5 has high surface activity and is higher than traditional single chain surfactants and structurally similar anionic non-ionic Gemini surfactants. Additionally, thermodynamic parameters (e.g., ΔG°mic ΔH°mic ΔS°mic et al. indicate that CnEO-5 molecules are exothermic and spontaneous during the micellization process. DLS, p-values, and TEM results indicate that anionic non-ionic Gemini surfactants with shorter hydrophobic chains (such as C8EO-5) tend to form larger vesicles in aqueous solutions, which are formed in a tail to tail and staggered manner; Negative non-ionic Gemini surfactants with longer hydrophobic chains (such as C12EO-5, C16EO-5) tend to form small micelles. The test results indicate that CnEO-5 anionic non-ionic Gemini surfactants have certain application prospects in improving crude oil recovery.

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Section: Surface Tension Testmentioning

confidence: 99%

Study on the Synthesis, Surface Activity, and Self-Assembly Behavior of Anionic Non-Ionic Gemini Surfactants

Man,

2024

Molecules

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Characterization of a biosurfactant produced by Peruvian strain Pseudomonas aeruginosa 6K‐11

Obregon‐Maldonado,

Merino‐Rafael,

Gutiérrez‐Moreno

2024

J of Chemical Tech & Biotech

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BACKGROUNDThe oil industry has a big impact on the environment by itself and by using chemically synthesized surfactants. Biosurfactants are an ecofriendly alternative, especially rhamnolipids produced by Pseudomonas aeruginosa. Rhamnolipids in a determined concentration decrease the liquid surface tension, and this allows access oil hydrocarbon to be degraded. The objective of this research is to characterize the biosurfactant produced by the native strain P. aeruginosa 6K‐11 by determining its critical micelle concentration (CMC), Krafft point, and emulsifying activity.RESULTSExperiments were initially performed with rhamnolipid produced by P. aeruginosa 6K‐11 growing on Siegmund‐Wagner medium with 1% of waste oil as carbon source and at 31.26 °C, 186 rpm after 42 h of incubation. After that, the biosurfactant was purified according to acid precipitation methodology. The first conductivity measurement, 34 μS/cm, was obtained with 12.5 g/L of rhamnolipid by using an APERA conductivity meter. The rhamnolipid CMC was 5.86 g/L due to the conductivity measurements graph and 0.49 was the dissociation degree. The equations of both lines were found by the method of least squares. The rhamnolipid has produced 1.97 Units of Emulsifying Activity (UEA) and 50% stability was observed based on the E24 Index. The highest conductivity achieved under 39 °C, as calculated from a conductivity against temperature graph, was the Krafft point.CONCLUSIONThese findings give important parameters to characterize the P. aeruginosa 6K‐11 biosurfactant activity that can be used to accelerate oil biodegradation in bioremediation processes. © 2024 Society of Chemical Industry (SCI).

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Nanoscopic microheterogeneities or pseudo-phase separations in non-conventional liquids

Blahnik

Müller

Braun

et al. 2022

Current Opinion in Colloid & Interface Science

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Solubility of ionic surfactants below their Krafft point in mixed micellar solutions: Phase diagrams for methyl ester sulfonates and nonionic cosurfactants

Cited by 8 publications

References 31 publications

Study on the Synthesis, Surface Activity, and Self-Assembly Behavior of Anionic Non-Ionic Gemini Surfactants

Study on the Synthesis, Surface Activity, and Self-Assembly Behavior of Anionic Non-Ionic Gemini Surfactants

Characterization of a biosurfactant produced by Peruvian strain Pseudomonas aeruginosa 6K‐11

Nanoscopic microheterogeneities or pseudo-phase separations in non-conventional liquids

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