Mechanism of biosurfactant adsorption to oil/water interfaces from millisecond scale tensiometry measurements

Kong, Lingling; Saar, Kadi L.; Jacquat, Raphaël P. B.; Hong, Liu; Levin, Aviad; Gang, Hong‐Ze; Ye, Ru‐Qiang; Mu, Bo‐Zhong; Knowles, Tuomas P. J.

doi:10.1098/rsfs.2017.0013

Cited by 18 publications

(19 citation statements)

References 34 publications

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“…This could be due to the adsorption of surfactant AOT molecules at the interface of the oil–NFs system (Figure b). As the surfactant molecules enter the oil–water interface, they apply an expanding force against the normal interfacial tension leading to a decrease in the IFT. , Moreover, the impact of NPs (kaolinite, silica) with a surfactant for the IFT reduction of the oil–NFs system is found to be insignificant in the presence of surfactant AOT (Table ). This could be due to the presence of the same surface charged NPs and surfactant molecules in the aqueous medium .…”

Section: Mechanismmentioning

confidence: 99%

Nanofluids of Kaolinite and Silica in Low Saline Seawater (LowSal) with and without Surfactant: Interfacial Tension and Wettability Alteration of Oil–Water–Rock System for Low Salinity-Enhanced Oil Recovery

Behera

Sangwai

2020

Ind. Eng. Chem. Res.

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Low salinity water injection (LSWI) has gained popularity recently as a potential enhanced oil recovery (EOR) method. The efficiency of LSWI can be improved with the advent of nanotechnology. Nanofluids can alter the wettability of the solid surface from intermediate-wet to water-wet, a condition most favorable to enhance the oil displacement efficiency. Studies have been reported in the literature on the use of nanoparticles and surfactants with LSWI mainly for carbonate rock and synthesized saline water containing mainly sodium salt; however, not much information is available for sandstone rock and the use of low saline seawater (LowSal). Also, a comparative study on the use of silica and kaolinite nanofluids in LowSal has not yet been explored in detail to understand their impact on the wettability alteration and interfacial tension (IFT) of the oil−nanofluid−rock system. Thus, in this work, silica and kaolinite nanofluids have been prepared in LowSal with varying concentrations (0−2000 ppm) without and with an anionic surfactant, dioctyl sodium sulfosuccinate (AOT), to assess their impact on the IFT and wettability alternation (through contact angle measurements) of the oil−nanofluid−rock system. Three different oil samples, viz., model oil A, model oil B, and light crude oil to represent acidic, basic, and weakly basic oil systems, respectively, have been considered. An intermediate-wet quartz plate is used to mimic the properties of the sandstone rock. A detailed mechanism has been highlighted to ascertain the impact of nanofluids on the IFT and wettability alteration of the representative rock sample from an intermediate-wet to water-wet condition based on the Gibbs adsorption isotherm, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDXA/EDS/EDX) studies. The results are outlined to understand the possible future applications of silica and kaolinite nanofluids for enhanced oil recovery processes.

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Section: Mechanismmentioning

confidence: 99%

Nanofluids of Kaolinite and Silica in Low Saline Seawater (LowSal) with and without Surfactant: Interfacial Tension and Wettability Alteration of Oil–Water–Rock System for Low Salinity-Enhanced Oil Recovery

Behera

Sangwai

2020

Ind. Eng. Chem. Res.

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“…Microfluidic setups and the experimental protocols were similar to those discussed in our previous work . Surfactin solution and n -hexadecane were separately introduced into the microfluidic device using a plastic syringe, and the flow rates were controlled by syringe pumps (longer) with flow rates of 400 and 10 μL/h, respectively.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…Faster adsorption and desorption of C15-surfactin relative to sodium cetyl benzene sulfonate was observed previously. The equilibration time of C15-surfactin (1 × 10 −4 mol/L, 10 mM PB buffer) at the n-hexadecane/aqueous solution interface was ∼300 ms, and the equilibration time of sodium cetyl benzene sulfonate was far beyond the upper limit time of the microfluidic method, 3500 ms. 4 Moreover, surfactin was found to lower the interfacial tension of the dodecane/water interface rapidly, compared with the synthetic surfactant, sodium dodecyl sulfate, using the conventional drop volume tensiometer, even faster than other lipopeptides, such as iturin A and fengycin. 38 At concentrations above CMC, the balance between monomers and micelles is the other factor affecting the adsorption dynamics of surfactin.…”

Section: Adsorption Dynamicsmentioning

confidence: 99%

Adsorption Kinetics of Biosurfactant Surfactin at the n-Hexadecane/Aqueous Solution Interface

Gang

Yang

et al. 2023

J. Phys. Chem. B

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Surfactin is a typical kind of biosurfactant with a large diversity of structure, and its molecular structure is expected to play a crucial role in its adsorption dynamics. Adsorption kinetics of surfactin homologues at the n-hexadecane/aqueous solution interface is studied using a droplet-based microfluidic method. Molecular dynamics simulations are performed to illustrate the dependence of adsorption energy on the surfactin structure. Rapid reduction of dynamic interfacial tensions is obtained. The best fit to experimental results reveals that surfactin with shorter aliphatic chains, C13-surfactin and C14-surfactin, has larger rate constants of adsorption and desorption. Interfacial tensions are rapidly reduced in the case of the oil/water interface which is freshly formed, and the equilibrium adsorption is rapidly established approximately in 100–350 ms at concentrations above the critical micelle concentration. C15-surfactin that has a longer aliphatic chain adsorbs and desorbs slower, and the equilibration time of adsorption is slightly longer. Moreover, C15-surfactin has a strong tendency for adsorbing at the interface, which is in accordance with the larger adsorption energy obtained by molecular dynamics simulation, and aggregating behavior in solution. The present study provides insights on the surfactin structure and the dynamics of adsorption at the liquid/liquid interface.

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“…Penetration of lipopeptides into phospholipids had been investigated using sum frequency generation spectroscopy . Ultrafast adsorption of lipopeptides onto the hexadecane/aqueous solution were analyzed by a microfluidic technique . Alternatively, coarse-grained (CG) molecular dynamics simulation was a powerful method to perform long-time and large-scale simulations, which had provided better understanding for surfactant self-assembly − and aggregate deformation. − However, no related work has been conducted for microbial lipopeptides.…”

Section: Introductionmentioning

confidence: 99%

A Coarse-Grained Model for Microbial Lipopeptide Surfactin and Its Application in Self-Assembly

Gang

et al. 2020

J. Phys. Chem. B

Self Cite

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Biosurfactants exhibit outstanding interfacial properties and unique biological activities that fairly related to their self-assembly in solutions and at interfaces. Computational simulations provide structural details of biosurfactant aggregates at the molecular level relevant to thermodynamic properties, but the understanding of kinetics of self-assembly remains limited due to lower simulation efficiency. In this work, a coarse-grained model has been developed for microbial lipopeptide surfactin, and surfactin monolayer at the octane/water interface and micelle in aqueous solution were studied using molecular dynamics simulations. Interaction parameters were optimized and validated by comparing with results obtained from experiments and atomistic molecular dynamics simulations. In particular, self-assembly of surfactin in aqueous solution was studied using the optimized parameters. Results showed that coarse-grained simulations well reproduced structural properties of surfactin monolayer and micelle and the molecular behavior such as surfactin orientation and conformation. Self-assembly features of surfactin in different stages have been captured, and the aggregation numbers of dominant clusters were in accordance with experimental data. This report suggested that the present coarse-grained model and interaction parameters allowed surfactin simulations over longer timescales and larger systems, which provide insights into characterizing both the kinetics of surfactin self-assembly and the adsorption of surfactin onto varying interfaces.

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Mechanism of biosurfactant adsorption to oil/water interfaces from millisecond scale tensiometry measurements

Cited by 18 publications

References 34 publications

Nanofluids of Kaolinite and Silica in Low Saline Seawater (LowSal) with and without Surfactant: Interfacial Tension and Wettability Alteration of Oil–Water–Rock System for Low Salinity-Enhanced Oil Recovery

Nanofluids of Kaolinite and Silica in Low Saline Seawater (LowSal) with and without Surfactant: Interfacial Tension and Wettability Alteration of Oil–Water–Rock System for Low Salinity-Enhanced Oil Recovery

Adsorption Kinetics of Biosurfactant Surfactin at the n-Hexadecane/Aqueous Solution Interface

A Coarse-Grained Model for Microbial Lipopeptide Surfactin and Its Application in Self-Assembly

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