Adsorption of an anionic surfactant at air-liquid and different solid-liquid interfaces from solutions containing high counter-ion concentration

Onaizi, Sagheer A.; Nasser, Mustafa S.; Al-Lagtah, Nasir

doi:10.1007/s00396-015-3694-5

Cited by 10 publications

(5 citation statements)

References 44 publications

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“…the solution [22][23][24]. When ionic surfactants co-exist with a relatively higher concentration of the counter-ion(s), as it is the case in this study, the value of n approaches unity [10,19,25]. The simplicity of Eq.…”

Section: Methodsmentioning

confidence: 61%

“…Although the Langmuir-Szyszkowski model has been widely used to estimate C 1 , it does not take into account the interaction between the adsorbed molecules at the interface, which is an obvious limitation, particularly for ionic surfactants. Such a limitation is addressed by the Frumkin model [10,32,33] which accounts for the lateral interaction between the adsorbed molecules, shown in the coupled Eqs. 3 and 4:…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the aim of this study is to investigate the adsorption of surfactin, which is an interesting lipopeptide biosurfactant, at liquid-air interface; the adsorption of this biosurfactant will be compared to those of SDBS (anionic) and C 14 E 8 (nonionic) synthetic surfactants. Unlike the limited number of published studies on biosurfactant adsorption, the adsorption of synthetic surfactants at different interfaces has been widely studied (see for examples [6][7][8][9][10][11][12]). Adsorption from synthetic surfactants [7,13,14] or protein-surfactant [15,16] mixtures has been also addressed in some of the previously published studies.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Benchmarking the Self‐Assembly of Surfactin Biosurfactant at the Liquid–Air Interface to those of Synthetic Surfactants

Onaizi

Nasser

Al-Lagtah

2016

J Surfact & Detergents

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The adsorption of surfactin, a lipopeptide biosurfactant, at the liquid–air interface has been investigated in this work. The maximum adsorption density and the nature and the extent of lateral interaction between the adsorbed surfactin molecules at the interface were estimated from surface tension data using the Frumkin model. The quantitative information obtained using the Frumkin model was also compared to those obtained using the Gibbs equation and the Langmuir–Szyszkowski model. Error analysis showed a better agreement between the experimental and the calculated values using the Frumkin model relative to the other two models. The adsorption of surfactin at the liquid–air interface was also compared to those of synthetic anionic, sodium dodecylbenzenesulphonate (SDBS), and nonionic, octaethylene glycol monotetradecyl ether (C14E8), surfactants. It has been estimated that the area occupied by a surfactin molecule at the interface is about 3- and 2.5-fold higher than those occupied by SDBS and C14E8 molecules, respectively. The interaction between the adsorbed molecules of the anionic biosurfactant (surfactin) was estimated to be attractive, unlike the mild repulsive interaction between the adsorbed SDBS molecules.

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Section: Methodsmentioning

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Benchmarking the Self‐Assembly of Surfactin Biosurfactant at the Liquid–Air Interface to those of Synthetic Surfactants

Onaizi

Nasser

Al-Lagtah

2016

J Surfact & Detergents

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“…Looking again at Figure 3 reveals the continuous decrease in the IFT between diesel and the nanoemulsions. This is an interesting observation since it is commonly known that the decrease in the interfacial/surface tension usually levels off when the surfactant concentration exceeds its critical micelle concentration (CMC) [ 48 , 49 ]. Since the CMC of SDBS is below 0.1 wt% [ 49 , 50 ], it would be intuitively expected that increasing SDBS concentration in the studied range (0.1–4 wt%) should not result in a significant change in the IFT of the diesel/emulsion interface, which is not the case.…”

Section: Resultsmentioning

confidence: 99%

“…This is an interesting observation since it is commonly known that the decrease in the interfacial/surface tension usually levels off when the surfactant concentration exceeds its critical micelle concentration (CMC) [ 48 , 49 ]. Since the CMC of SDBS is below 0.1 wt% [ 49 , 50 ], it would be intuitively expected that increasing SDBS concentration in the studied range (0.1–4 wt%) should not result in a significant change in the IFT of the diesel/emulsion interface, which is not the case. Therefore, it seems that an increase in SDBS adsorption at the diesel/emulsion interface still occurs with increasing its concentration at least up to 4 wt% as can be inferred from the IFT results shown in Figure 3 .…”

Section: Resultsmentioning

confidence: 99%

Characteristics and pH-Responsiveness of SDBS–Stabilized Crude Oil/Water Nanoemulsions

Onaizi

2022

Nanomaterials

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Nanoemulsions are colloidal systems with a wide spectrum of applications in several industrial fields. In this study, crude oil-in-water (O/W) nanoemulsions were formulated using different dosages of the anionic sodium dodecylbenzenesulfonate (SDBS) surfactant. The formulated nanoemulsions were characterized in terms of emulsion droplet size, zeta potential, and interfacial tension (IFT). Additionally, the rheological behavior, long-term stability, and on-demand breakdown of the nanoemulsions via a pH-responsive mechanism were evaluated. The obtained results revealed the formation of as low as 63.5 nm average droplet size with a narrow distribution (33–142 nm). Additionally, highly negative zeta potential (i.e., −62.2 mV) and reasonably low IFT (0.45 mN/m) were obtained at 4% SDBS. The flow-ability of the nanoemulsions was also investigated and the obtained results revealed an increase in the nanoemulsion viscosity with increasing the emulsifier content. Nonetheless, even at the highest SDBS dosage of 4%, the nanoemulsion viscosity at ambient conditions never exceeded 2.5 mPa·s. A significant reduction in viscosity was obtained with increasing the nanoemulsion temperature. The formulated nanoemulsions displayed extreme stability with no demulsification signs irrespective of the emulsifier dosage even after one-month shelf-life. Another interesting and, yet, surprising observation reported herein is the pH-induced demulsification despite SDBS not possessing a pH-responsive character. This behavior enabled the on-demand breakdown of the nanoemulsions by simply altering their pH via the addition of HCl or NaOH; a complete and quick oil separation can be achieved using this simple and cheap demulsification method. The obtained results reveal the potential utilization of the formulated nanoemulsions in oilfield-related applications such as enhanced oil recovery (EOR), well stimulation and remediation, well-bore cleaning, and formation fracturing.

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Self-assembly of a surfactin nanolayer at solid–liquid and air–liquid interfaces

2015

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Surfactin, a sustainable and environmentally friendly surface active agent, is used as a model to study the adsorption of biosurfactants at hydrophobic and hydrophilic solid-liquid interfaces as well as the air-liquid interface. Surfactin adsorption was monitored as a function of time and concentration using surface plasmon resonance (SPR) technique in the case of the solid-liquid interfaces or the drop shape analysis (DSA) technique in the case of the air-liquid interface. The results obtained in this study showed that surfactin adsorption at the "hard" hydrophobic (functionalized with octadecanethiol) solid-liquid and the "soft" air-liquid interface were 1.12 ± 0.01 mg m(-2) (area per molecule of 157 ± 2 Å(2)) and 1.11 ± 0.05 mg m(-2) (area per molecule of 159 ± 7 Å(2)), respectively, demonstrating the negligible effect of the interface "hardness" on surfactin adsorption. The adsorption of surfactin at the hydrophilic (functionalized with β-mercaptoethanol) solid-liquid interface was about threefold lower than its adsorption at the hydrophobic-liquid interfaces, revealing the importance of hydrophobic interaction in surfactin adsorption process. The affinity constant of surfactin for the investigated interfaces follows the following order: air > octadecanethiol > β-mercaptoethanol. Biosurfactants, such as surfactin, are expected to replace the conventional fossil-based surfactants in several applications, and therefore the current study is a contribution towards the fundamental understanding of biosurfactant behavior, on a molecular level, at hydrophobic and hydrophilic solid-liquid interfaces in addition to the air-liquid interface. Such understanding might aid further optimization of the utilization of surfactin in a number of industrial applications such as enhanced oil recovery, bioremediation, and detergency.

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Adsorption of an anionic surfactant at air-liquid and different solid-liquid interfaces from solutions containing high counter-ion concentration

Cited by 10 publications

References 44 publications

Benchmarking the Self‐Assembly of Surfactin Biosurfactant at the Liquid–Air Interface to those of Synthetic Surfactants

Benchmarking the Self‐Assembly of Surfactin Biosurfactant at the Liquid–Air Interface to those of Synthetic Surfactants

Characteristics and pH-Responsiveness of SDBS–Stabilized Crude Oil/Water Nanoemulsions

Self-assembly of a surfactin nanolayer at solid–liquid and air–liquid interfaces

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