Gas–liquid mass transfer to single bubbles: Effect of surface contamination

Vasconcelos, Jorge; Orvalho, Sandra; Alves, Sebastião S.

doi:10.1002/aic.690480603

Cited by 109 publications

(90 citation statements)

References 34 publications

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“…Several mass transfer models utilized the stagnant-cap hypothesis with success (e.g. Griffith, 1960;Weber, 1975;Sadhal and Johnson, 1983;Vasconcelos et al, 2002). In case of surfaces moving at high shear rates in highly contaminated liquids or with interfacial temperature gradients, surface concentration gradients are established, leading to countercurrent interfacial liquid circulation, known as the Marangoni effect (Marangoni, 1871).…”

Section: Introductioncontrasting

confidence: 40%

Effects of interfacial surfactant contamination on bubble gas transfer

Rosso

Huo

Stenstrom

2006

Chemical Engineering Science

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Surface active agents depress gas transfer at gas-liquid interfaces. They are present as measurable trace contaminants at all environmental and at most industrial interfaces. An experimental apparatus to concurrently measure dynamic surface tension and mass transfer was constructed and tested for single-bubble and multi-bubble experiments. In this work, the parameters describing time-dependent bubble surface contamination were characterized. The application of a Ward-Tordai transient model and of a Langmuir saturation model showed that for fine-bubbles in low molecular weight surfactant solutions the interfacial surfactant accumulation equilibrates before bubble detachment. This is reflected in the bubbles behaving as solid-spheres, which is shown in our dimensionless results.For a given contamination, interfaces with higher renewal rates have higher mass transfer. At higher renewal rates, the variation due to different contamination is smaller than the variation at lower renewal rates, concluding that higher interfacial flow regimes can offset contamination. Our experimental evidence shows a gas transfer reduction of 30-70% of pure water values in surfactant solutions, which confirms full-scale field measurements. Results are consistent with expectations and correct previous Frössling-like dimensionless correlations for pure water systems. Our results offer a tool for mass transfer prediction from flow regime and surfactant properties. ᭧

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Section: Introductioncontrasting

confidence: 40%

Effects of interfacial surfactant contamination on bubble gas transfer

Rosso

Huo

Stenstrom

2006

Chemical Engineering Science

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“…At high wind speeds, breaking waves generate spray and bubbles. Gas transfer due to single bubbles is well studied experimentally (see for instance Mori et al, 2002, andVasconcelos et al, 2002) as well as in models (see Memery and Merlivat, 1985). The impact of spray on the gas exchange velocity, however, has not been well studied.…”

Section: Air-sea Gas Transfermentioning

confidence: 99%

First laboratory study of air–sea gas exchange at hurricane wind speeds

Krall

Jähne

2014

Ocean Sci.

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Abstract. In a pilot study conducted in October and November 2011, air-sea gas transfer velocities of the two sparingly soluble trace gases hexafluorobenzene and 1,4-difluorobenzene were measured in the unique high-speed wind-wave tank at Kyoto University, Japan. This air-sea interaction facility is capable of producing hurricane strength wind speeds of up to u 10 = 67 m s −1 . This constitutes the first lab study of gas transfer at such high wind speeds. The measured transfer velocities k 600 spanned two orders of magnitude, lying between 11 cm h −1 and 1180 cm h −1 with the latter being the highest ever measured wind-induced gas transfer velocity. The measured gas transfer velocities are in agreement with the only available data set at hurricane wind speeds (McNeil and D'Asaro, 2007). The disproportionately large increase of the transfer velocities found at highest wind speeds indicates a new regime of air-sea gas transfer, which is characterized by strong wave breaking, enhanced turbulence and bubble cloud entrainment.

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“…Further experiments to investigate this change in mass transfer have been undertaken with single bubbles held stationary by a downflow of water, Schulze and Schlünder (1985a,b);Vasconcelos et al (2002Vasconcelos et al ( , 2003; Alves et al (2004Alves et al ( , 2005. From these experiments a sharp transition in mass transfer rates was detected for a variety of different gases absorbing from single bubbles.…”

Section: Introductionmentioning

confidence: 99%

“…From these experiments a sharp transition in mass transfer rates was detected for a variety of different gases absorbing from single bubbles. The initial mass transfer rate was measured as 3 − 5 times larger than the latter rate, Vasconcelos et al (2002). In such cases…”

Section: Introductionmentioning

confidence: 99%

Mass transfer and gas–liquid interface properties of single CO2 bubbles rising in tap water

Nock

Heaven

Banks

2016

Chemical Engineering Science

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To improve the mass transfer efficiency in many industrial applications better understanding of the mass transfer rate is required. High speed images of single CO 2 bubbles rising in tap water were analysed to investigate the relationship between the mass transfer and properties of single bubbles. Transition to a lower mass transfer rate was shown to correspond with the transition from a mobile to an immobile bubble surface. This was indicated by the change in bubble rise velocity, bubble rise path and bubble shape. The presence of surfactants in untreated tap water appear to effect the transition point, particularly for bubbles with a smaller initial diameter and lower rise velocity.

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Gas–liquid mass transfer to single bubbles: Effect of surface contamination

Abstract: The dissolution of single bubbles of gases of low solubility kept stationary in a downward stream of water was studied. In ''clean'' water, two

Cited by 109 publications

References 34 publications

Effects of interfacial surfactant contamination on bubble gas transfer

Effects of interfacial surfactant contamination on bubble gas transfer

First laboratory study of air–sea gas exchange at hurricane wind speeds

Mass transfer and gas–liquid interface properties of single CO2 bubbles rising in tap water

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