Colloidal gas aphrons (CGA): Dispersion and structural features

Jauregi, Paula; Mitchell, Geoffrey R.; Varley, Julie

doi:10.1002/aic.690460105

Cited by 62 publications

(31 citation statements)

References 23 publications

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“…Bredwell and Worden [17] estimated the shell thickness to be 200-300 nm for nonionic surfactant Tween 20, based on the study of gas diffusion from the CGA bubble to the liquid bulk, assuming that the mass transfer is limited by the rate of diffusion across the shell. More recently, Jauregi et al [15] employed freeze fracture with TEM and X-ray diffraction to study the structure of the soapy shell. They imaged and measured the thickness of a surfactant shell to be 96 nm.…”

Section: Introductionmentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams)

Larmignat

Vanderpool

Lai

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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This paper reports on the effect of surfactant concentration and pipe shape and size on the rheological properties of colloidal gas aphrons (CGA) or microfoams. CGA consists of closely packed spherical gas bubbles with diameter ranging from 10 to 100 microns surrounded by a surfactant shell. It is produced by stirring an aqueous surfactant solution at high speed in a baffled beaker. Pipe flow experiments were performed in cylindrical pipes with diameter ranging from 1.0 to 3.0 mm under adiabatic laminar flow conditions. The porosity, bubble size distribution, surface tension, and pH were systematically measured. First, it is established that there was no slip velocity at the wall and CGA did not change morphology and porosity between the inlet and outlet of the pipes less than 2 mm in diameter. Compressibility effects were accounted for through the volume equalization approach. Then, pipe shape and diameter have no

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Section: Introductionmentioning

confidence: 99%

Rheology of colloidal gas aphrons (microfoams)

Larmignat

Vanderpool

Lai

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…The microbubbles (10±100 lm), consisting of a gaseous inner core surrounded by a thin, multilayered surfactant ®lm (Jauregi et al, 2000;Sebba, 1987), provide a high interfacial area for adsorption of molecules, and their high buoyancy leads to a quick and simple separation from the bulk solution . Moreover, involving the use of very low concentration of only one chemical, aphrons provide an extremely economical separation tool.…”

Section: Introductionmentioning

confidence: 99%

Selective recovery of lactate dehydrogenase using affinity foam

Fernandes

Hatti‐Kaul

Mattìasson

2002

Biotech & Bioengineering

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Selective isolation of lactate dehydrogenase (LDH) from porcine muscle extract was studied using foam generated from the vigorous stirring of a non-ionic surfactant, Triton X-114 derivatized with Cibacron blue. The cloud point of the surfactant-dye conjugate was higher than that of the native Triton X-114, and also the foam prepared from the affinity surfactant was more rigid taking a longer time to collapse. The equilibrium dissociation constant between pure LDH and surfactant-dye conjugate was 5.0 microM as compared to the value of 2.2 microM for the enzyme and free dye as measured by differential spectroscopy. The isolation procedure involved mixing of the porcine muscle extract with the affinity foam, separating and collapsing the foam, and warming the solution formed to 37 degrees C to yield the surfactant-dye phase and an aqueous phase containing the enzyme. The effect of surfactant concentration and protein load on enzyme recovery and purification was investigated. Under optimal conditions, LDH was quantitatively recovered with high purification factor in a very short time. Both recovery and purification were higher when foam prepared from an equivalent mixture of surfactant-dye conjugate and unmodified surfactant was used. The selectivity of interaction between LDH and detergent-dye conjugate was confirmed by lowered recovery when NADH was included during the binding step.

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“…Aphrons multi-layered surfactant structure proposed by Sebba [1,2], responsible for aphrons stability, could not be directly verified, although some studies about this structure thickness have already been conducted [22,23,39]. Moreover, there are no studies correlating aphrons layers with the EO/PO surfactants used in this work.…”

Section: Configuration Proposal For Surfactants On Microbubblesmentioning

confidence: 56%

Aphrons Obtained From Different Nonionic Surfactants: Properties and Filtration Loss Evaluation

Gomes¹,

Alves²,

Nunes³

et al. 2017

ChChT

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Abstract.1 Aphrons were produced using nonionic surfactants by applying a differential pressure. Bubble size distribution was obtained from optical microscopy using FIJI-ImageJ2 program. The aim of this work was to correlate surfactants structures with aphrons properties (density and viscosity), size distribution and the number of bubbles. API fluid loss tests were based on standard proceedings specifications for water-based drilling fluids of Petrobras/Brazil. The structure of the nonionic surfactants showed a great influence on the fluid properties and the performance of the fluid contributing with a filtrate reduction up to 31% with the systems that were presented between 1088 and 1850 bubbles with diameters ranging from 33 to 104µm. These systems were produced by poly(ethylene oxide) with 7 ethylene oxide units, a poly(ethylene oxide)-b-poly(propylene oxide) with 6 ethylene oxide units and 3 propylene oxide units.

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Colloidal gas aphrons (CGA): Dispersion and structural features

Cited by 62 publications

References 23 publications

Rheology of colloidal gas aphrons (microfoams)

Rheology of colloidal gas aphrons (microfoams)

Selective recovery of lactate dehydrogenase using affinity foam

Aphrons Obtained From Different Nonionic Surfactants: Properties and Filtration Loss Evaluation

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