Carbon dioxide/water, water/carbon dioxide emulsions and double emulsions stabilized with a nonionic biocompatible surfactant

Torino, Enza; Reverchon, Ernesto; Johnston, Keith P.

doi:10.1016/j.jcis.2010.04.027

Cited by 36 publications

(22 citation statements)

References 33 publications

(48 reference statements)

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“…Thus, the interfacial tension is in the order of 50 mJ/m 2 [24], and the width of the interface loaded by macromolecules is in the order of δ 0 ≈ 0.1 µm [25]. The molecular weight of macromolecular surfactants is typically in the order of 1000g/mol, while the density is considered to be approximately 1 g/cm 3 [26,27], yielding the average density of the system ρ ≈ 1000 kg/m 3 .…”

Section: B Parametersmentioning

confidence: 99%

Analysis of Ginzburg-Landau-type models of surfactant-assisted liquid phase separation

Tóth

Kvamme

2015

Phys. Rev. E

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Citation: TOTH, G. and KVAMME, B., 2015 In this paper the diffuse interface models of surfactant assisted liquid-liquid phase separation are addressed. We start from the generalized version of the Ginzburg-Landau free energy functional based model of van der Sman and van der Graaf. First we analyze the model in the constant surfactant approximation and show the presence of a critical point, at which the interfacial tension vanishes. Then we determine the adsorption isotherms and investigate the validity range of previous result. As a key point of the work, we propose a new model of the van der Sman / van der Graaf type designed for avoiding both unwanted unphysical effects and numerical difficulties being present in previous models. In oder to make the model suitable to describe real systems, we determine the interfacial tension analytically more precisely, and analyze it on the entire accessible surfactant load range. Emerging formulas are then validated by calculating the interfacial tension from the numerical solution of the Euler-Lagrange equations. Time dependent simulations are also performed to illustrate the slowdown of the phase separation near the critical point, and to prove that the dynamics of the phase separation is driven by the interfacial tension.

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Section: B Parametersmentioning

confidence: 99%

Analysis of Ginzburg-Landau-type models of surfactant-assisted liquid phase separation

Tóth

Kvamme

2015

Phys. Rev. E

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“…The team of Dow Oil & Gas and University of Texas at Austin also described a new, nonionic, glycerin-based, twin-tailed, water-soluble, ethoxylated surfactant for stabilizing CO 2 -in-water emulsions used for CO 2 -flooding sweep improvement (Sanders et al 2010). Johnston and coworkers also studied the use of a biocompatible, water-soluble, nonionic, ethoxylated surfactant-polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80)-for stabilizing CO 2 -in-water and water-in-CO 2 emulsions and double emulsions (Torino et al 2010).…”

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confidence: 99%

CO2-Soluble, Nonionic, Water-Soluble Surfactants That Stabilize CO2-in-Brine Foams

et al. 2012

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Several commercially available and a few experimental, nonionic surfactants were identified that are capable of dissolving in carbon dioxide (CO 2 ) in dilute concentration at typical minimum-miscibility-pressure (MMP) conditions and, upon mixing with brine in a high-pressure windowed cell, stabilizing CO 2 -in-brine foams. These slightly CO 2 -soluble, water-soluble surfactants include branched alkylphenol ethoxylates, branched alkyl ethoxylates, a fatty-acid-based surfactant, and a predominantly linear ethoxylated alcohol. Many of the surfactants were between 0.02 to 0.06 wt% soluble in CO 2 at 1,500 psia and 25 C, and most demonstrated some capacity to stabilize foam. The most-stable foams observed in a high-pressure windowed cell were attained with branched alkylphenol ethoxylates, several of which were studied in highpressure small-angle-neutron-scattering (HP SANS) tests, transient mobility tests using Berea sandstone cores, and high-pressure computed-tomography (CT)-imaging tests using polystyrene cores. HP SANS analysis of foams residing in a small windowed cell demonstrated that the nonylphenol ethoxylate SURFONIC V R N-150 [15 ethylene oxide (EO) groups] generated emulsions with a greater concentration of droplets and a broader distribution of droplet sizes than the shorter-chain analogs with 9-12 ethoxylates. The in-situ formation of weak foams was verified during transient mobility tests by measuring the pressure drop across a Berea sandstone core as a CO 2 /surfactant solution was injected into a Berea sandstone core initially saturated with brine; the pressure-drop values when surfactant was dissolved in the CO 2 were at least twice those attained when pure CO 2 was injected into the same brine-saturated core. The greatest mobility reduction was achieved when surfactant was added both to the brine initially in the core and to the injected CO 2 . CT imaging of CO 2 invading a polystyrene core initially saturated with 5 wt% KI brine indicated that despite the oilwet nature of this medium, a sharp foam front propagated through the core, and CO 2 fingers that formed in the absence of a surfactant were completely suppressed by foams formed because of the addition of nonylphenol ethoxylate surfactant to the CO 2 or the brine.

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“…Various techniques have been used for the investigation of the microstructure of microemulsions in supercritical fluids. Among them are the time-resolved fluorescence spectroscopy using coumarin 480 (Pramanik et al, 2010), pyridine N-oxide (Simón de Dios & Díaz-García, 2010, Yazdi et al, 1990, Zhang & Bright, 1992a, 1992b, López-Quintela et al, 2004, pyrene (Nazar et al, 2009) or Ti(IV) complexes (Chem et al, 2009) as fluorescence probe, FT-IR spectroscopy (Yee et al, 1991, Takebayashi et al, 2011, small-angle neutron scattering (SANS) measurements (Eastoe et al, 1996, Zielinski et al, 1997, Cummings et al, 2012, Torino et al, 2010, Frielinghaus et al, 2006, electron paramagnetic resonance (EPR) spectroscopy (Johnston et al, 1996), small-angle X-ray scattering (SAXS) (Fulton et al, 1995, Kometani et al, 2008, Akutsu et al, 2007, nearinfrared spectroscopy (Takebayashi et al, 2011), and high-pressure NMR (Thurecht et al, 2006), which have been extensively employed for investigation of these systems.…”

Section: Microemulsions In Non-conventional Systemsmentioning

confidence: 99%

Microemulsions - A Brief Introduction

Najjar¹

2012

Microemulsions - An Introduction to Properties and Applications

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Carbon dioxide/water, water/carbon dioxide emulsions and double emulsions stabilized with a nonionic biocompatible surfactant

Cited by 36 publications

References 33 publications

Analysis of Ginzburg-Landau-type models of surfactant-assisted liquid phase separation

Analysis of Ginzburg-Landau-type models of surfactant-assisted liquid phase separation

CO2-Soluble, Nonionic, Water-Soluble Surfactants That Stabilize CO2-in-Brine Foams

Microemulsions - A Brief Introduction

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