The Inhibition of Foaming. II. A Mechanism for the Rupture of Liquid Films by Anti-foaming Agents.

Ross, Sydney

doi:10.1021/j150477a018

Cited by 88 publications

(42 citation statements)

References 6 publications

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“…They found better correlation of the antifoam activity with the entering coefficient than the spreading coefficient. Several workers have made similar studies and found many materials that spread without antifoaming action and vice versa (17,(26)(27)(28)(29). This has led Garrett (13) and later Denkov et al (15) to conclude that spreading is not a necessary condition for antifoaming, although it may operate in some types of antifoams.…”

mentioning

confidence: 90%

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Chaisalee

Soontravanich

Yanumet

2003

J Surfact & Detergents

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Aqueous solutions of nonionic surfactants exhibit low foaming above their cloud point, a temperature above which the homogeneous solution separates into two phases: a dilute phase containing a low surfactant concentration and a coacervate phase containing a very high surfactant concentration (e.g., 20 wt% surfactant). In this work, foam formation was measured for the dilute phase, the coacervate, and the mixed solution using the Ross-Miles method for nonylphenol polyethoxylates with 8, 9, or 10 ethylene oxide moieties per molecule. The dilute phase showed no antifoam effect above the cloud point if the coacervate phase was not present, and the coacervate phase foamed little in the absence of the dilute phase. The coacervate phase acts as an oil droplet antifoam to the dilute phase. From surface and interfacial tension data, entering, spreading, and bridging coefficients for this system make it appear probable that the coacervate phase is forming bridges across the film lamellae of the dilute-phase foam and acting to suppress foam formation through the bridging mechanism.

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mentioning

confidence: 90%

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Chaisalee

Soontravanich

Yanumet

2003

J Surfact & Detergents

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“…The important parameters defining foam-oil interaction are the spreading coefficient S () σf -σof -σo) and the entering coefficient E () σf + σof -σo). Based on these parameters, the foam-oil interaction can be classified into three categories (17). If E is negative, then S must be negative, and oil would neither be drawn into the foam lamellae nor spread at the foam liquid-gas interface; thus, the presence of oil is not expected to destabilize the foam in this case.…”

Section: Foam Formulation and Stabilitymentioning

confidence: 99%

Novel Aqueous Foams for Suppressing VOC Emission

Gautam

Mohanty

2004

Environ. Sci. Technol.

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Reducing volatile organic compound (VOC) emissions from crude oil/gasoline distribution and storage facilities is important in controlling environmental pollution and enhancing workplace safety. Stable aqueous foam formulations are developed to provide a mass transfer barrier to the emission of VOCs during loading of gasoline. Experiments are carried out in a bench-scale foam cell using liquid hexane as oil. The foam columns of 32 cm in height were able to suppress the plateau concentration of hexane vapors in the effluent by 87% under experimental conditions tested. Vapor suppression increased with foam height but was almost insensitive to liquid viscosity. These experiments are then upscaled from bench-scale to a vessel having an exposed surface area of roughly 2 orders of magnitude higher. Gasoline is used as oil in the upscaled experiments, and the concentrations of volatile hydrocarbons in the effluent are measured during oil loading. A 40-cm-thick foam column is found to reduce the emissions by 96% for foams prepared with deionized water and by 93.8% for foams prepared with 3.5 wt % NaCl brine for 10 h of oil loading.

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“…The important parameters defining foam-oil interaction are spreading coefficient S (= σ f − σ of − σ o ) and entering coefficient E (= σ f + σ of − σ o ). The presence of oil is not expected to destabilize foam when the entering coefficient is negative [33].…”

Section: Foam Collapsementioning

confidence: 99%

“…At the oil layer-foam interface, the diffusing hydrocarbon species is at its equilibrium vapor pressure or (33) …”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

Mass transfer of volatile organic carbons through aqueous foams

Gautam

Mohanty

2004

Journal of Colloid and Interface Science

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The Inhibition of Foaming. II. A Mechanism for the Rupture of Liquid Films by Anti-foaming Agents.

Cited by 88 publications

References 6 publications

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point

Novel Aqueous Foams for Suppressing VOC Emission

Mass transfer of volatile organic carbons through aqueous foams

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