Role of Naphthenic Acids in Stabilizing Water-in-Diluted Model Oil Emulsions

Gao, Song; Moran, Kevin; Xu, Zhenghe; Masliyah, Jacob H.

doi:10.1021/jp910855q

Cited by 69 publications

(79 citation statements)

References 26 publications

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“…To study the effect of concentration, the number of VO-79 molecules was then increased to 32, corresponding to simulations 5 to 8 in Table 1. These 4 simulations are of bulk concentrations > 28000 ppm (2.8 wt%), which is far above those in our experimental studies as well as those usually employed in other experimental studies 8,30 . where VO-79 are packed on the interface between water and organic solvent.…”

Section: Simulation Systems Simulatedmentioning

confidence: 45%

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Reduction of Water/Oil Interfacial Tension by Model Asphaltenes: The Governing Role of Surface Concentration

Jian¹,

Poopari²,

Liu³

et al. 2016

J. Phys. Chem. B

118

139

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In this work, pendant drop techniques and molecular dynamics (MD) simulations were employed to investigate the effect of asphaltene concentrations on the interfacial tension (IFT) of the oil/water interface. Here, oil and asphaltene were represented by, respectively, common organic solvents and Violanthrone-79, and two types of concentration, i.e., bulk concentration and surface concentration, were examined. Correlations between the IFTs from experiments and MD simulations revealed that surface concentration, rather than the commonly used bulk concentration, determines the reduction of oil/water IFTs. Through analyzing the hydrogen bonding, the underlying mechanism for the IFT reduction was proposed. Our discussions here not only enable the direct comparison between experiments and MD simulations on the IFTs but also help with future interfacial studies using combined experimental and simulation approaches. The methodologies used in this work can be extended to many other oil/water interfaces in the presence of interfacially active compounds.

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Section: Simulation Systems Simulatedmentioning

confidence: 45%

“…In contrast, experiments reported that IFT can be decreased by asphaltenes at very low bulk concentrations. For instance, for heptol/water interface, IFT reduction was reported by Gao et al 8 (toluene-heptane volume ratio 4:1) at 0.1 wt % of asphaltenes, and by Fan et al 30 (toluene-heptane volume ratio 6:4) at 2~5 g/L of asphaltenes.…”

Section: Introductionmentioning

confidence: 91%

Reduction of Water/Oil Interfacial Tension by Model Asphaltenes: The Governing Role of Surface Concentration

Jian¹,

Poopari²,

Liu³

et al. 2016

J. Phys. Chem. B

118

139

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“…[1][2][3][4][5][6][7][8][9][10][11][12]21,22,26,27] However, the lack of molecular structures of asphaltenes that actually stabilize the emulsions hindered the progress in understanding the role of their aggregation and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 28 interfacial behavior in emulsion stabilization. Asphaltenes do not have well defined amphiphilic structure as in conventional surfactants [48,49] to explain their affinity to adsorb at the oil/water interface.…”

Section: Discussionmentioning

confidence: 99%

“…These compounds include resins, natural surfactants and asphaltenes compounded with fine solids. [1][2][3][4][5][6][7][8][9] As a major stabilizer among these compounds, asphaltenes were found to form 'skin-like' layer at the oil/water interface. This interface prevents coalescence between water droplets by providing mechanical strength.…”

Section: Introductionmentioning

confidence: 99%

Asphaltene Subfractions Responsible for Stabilizing Water-in-Crude Oil Emulsions. Part 2: Molecular Representations and Molecular Dynamics Simulations

et al. 2015

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After successful isolation of the most interfacially active subfraction of asphaltenes (IAA) reported in part one of this series of publications, comprehensive chemical analyses including ES-MS, elemental analysis, FTIR and NMR were used to determine how the molecular fingerprint features of IAA are different from those of the remaining asphaltenes (RA).Compared with RA, the IAA molecules were shown to have higher molecular weight and higher contents of heteroatoms (e.g., three times higher oxygen content). The analysis on the elemental content and FTIR spectroscopy suggested that IAA contained a higher content of high polarity sulfoxide groups which were not present in the RA. The results of ES-MS, NMR, FTIR and elemental analysis were used to construct average molecular representations of IAA and RA molecules. These structures were used in molecular dynamic (MD) simulation to study interfacial and aggregation behaviors of the proposed representative molecules. MD simulation study showed little affinity of representative RA molecules to the oil/water interface while the representative IAA molecules had a much higher interfacial activity, which corresponds to the extraction method. The aggregation of IAA molecules in the bulk oil phase and their adsorption at oil/water interface were not directly related to the ring system but rather to the associations between or including sulfoxide groups. The IAA molecules self-assembled in solvent, forming supramolecular structures and a porous network at the oil/water interface as suggested in our previous work. The results obtained in this study provide a better understanding of the role of asphaltenes in stabilizing petroleum emulsions.

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“…The salts within the water and the solids that remain with the bitumen subsequently causes corrosion related problems in downstream unit operations and fouling in unexpected regions of the upgrading facility [7][8][9][10][11][12]. Therefore it is critical that water in oil emulsions found in rag layers are prevented, and that water is removed from the oil well before the upgrading steps.…”

Section: Introductionmentioning

confidence: 99%