Phase inversion in agitated liquid–liquid dispersions: Anomalous effect of electrolyte

Deshpande, Kiran B.; Kumar, Sanjeev

doi:10.1016/j.ces.2012.04.039

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…The largest drops were formed in FC‐40/D‐PBS system which can be explained by the highest interfacial tension and also by the presence of substantial amounts of different salts (in total approximately 0.2 mol L ‐1 of KCl, KH 2 PO 4 , NaCl, Na 2 HPO 4 ‐7H 2 O) in the continuous phase. This explanation is in agreement with the results reported by Deshpande and Kumar, who found that the presence of salts drastically changes the dynamics of oil/water dispersions and leads to an increase in the average drop size.…”

Section: Resultssupporting

confidence: 93%

Engineering considerations on the use of liquid/liquid two-phase systems as a cell culture platform

Murasiewicz

Nienow

Hanga

et al. 2017

J. Chem. Technol. Biotechnol

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Section: Resultssupporting

confidence: 93%

Engineering considerations on the use of liquid/liquid two-phase systems as a cell culture platform

Murasiewicz

Nienow

Hanga

et al. 2017

J. Chem. Technol. Biotechnol

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“…The density dependence on the concentration of KI is shown in Figure A2 in the Supporting Information and fits the data published by MacInnes et al and Pawar et al for very diluted concentrations and at saturation, respectively. , The linear concentration dependency of the aqueous phase density is equal to the trend observed for aqueous solutions of sodium chloride and potassium chloride . The effect of the KI concentration on the interfacial tension of water and n-heptane is low for KI concentrations below 10 mM . The weight percentage of KI in n-heptane was measured by mixing an aqueous KI-solution with n-heptane and subsequently drying the n-heptane and found to be less than 0.01 wt %.…”

Section: Methodssupporting

confidence: 81%

“…25 The effect of the KI concentration on the interfacial tension of water and n-heptane is low for KI concentrations below 10 mM. 26 The weight percentage of KI in n-heptane was measured by mixing an aqueous KI-solution with n-heptane and subsequently drying the n-heptane and found to be less than 0.01 wt %. GC-MS analysis showed that there is no ink dissolved in the n-heptane.…”

Section: Tomography Setupmentioning

confidence: 99%

Water and n-Heptane Volume Fractions in a Rotor-Stator Spinning Disc Reactor

Visscher

Bieberle

Schubert

et al. 2012

Ind. Eng. Chem. Res.

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This paper presents the volume fractions of n-heptane and water measured in a rotor-stator spinning disc reactor. The volume fractions were measured using γ-ray tomography and photographic image analysis. The volume fractions were determined as a function of rotational disc speed, flow ratio, position in the reactor, and rotor material. In addition, the effect of the density difference between water and n-heptane was determined by dissolving potassium iodide in the water phase. Below a rotational disc speed of 75 rpm the volume fraction measured by tomography and photographic image analysis are within 10% deviation. For low rotational disc speeds, the n-heptane volume fraction decreases slightly with increasing rotational disc speed: the centrifugal force accelerates the larger n-heptane droplets to the center. At higher rotational disc speeds the droplets become smaller accordingly, the friction between the phases determines the flow, and the n-heptane volume fraction becomes equal to the n-heptane to total flow ratio. An increase in density difference from 0.31 to 0.79 kg dm–3 did not influence the volume fractions.

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“…The large-scale operations are therefore carried out in safe range, away from the critical conditions. Because the critical dispersed phase fraction for intensely agitated dispersions depends only on the physical properties of a liquid−liquid system, 4 it can be increased advantageously only by altering the nature of the liquids used, for example by adding surfactants or electrolytes, 5 both of which can adversely impact the downstream processing.…”

Section: ■ Introductionmentioning

confidence: 99%

Phase Inversion of Agitated Liquid–Liquid Dispersions in the Presence of Micrometer-Sized Particles

Reddy

Prakash

Kumar

2015

Ind. Eng. Chem. Res.

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We have investigated the impact of partially wetting particles of tens of micrometers on inversion instability of agitated liquid−liquid dispersions. Particles of this size can be easily separated from the exit streams to avoid downstream processing-related issues. The results show that the presence of hydrophilic particles in small quantities (volume fraction range of 2 × 10 −4 to 1.25 × 10 −2 ) significantly decreases the dispersed phase fraction at which water-in-oil (w/o) dispersions invert but leaves the inversion of oil-in-water (o/w) dispersions nearly unaffected. The addition of the same particles after they are hydrophobized decreases the dispersed phase fraction at which o/w dispersions invert but leaves the inversion of w/o dispersions unaffected. These findings suggest an increased rate of coalescence of drops when particles wet drops preferentially and a marginal decrease when they wet the continuous phase preferentially. High-speed conductivity measurements on w/o dispersion show transient conduction of a few hundred milliseconds duration through voltage pulses. Close to the inversion point, voltage pulses appear at high frequency for even 7 cm separation between the electrodes. The presence of hydrophilic particles produces a nearly identical signal at a significantly lower dispersed phase fraction itself, close to the new lowered inversion point in the presence of particles. We propose formation of elongated domains of the conducting dispersed phase through a rapid coalescence−deformation−breakup process to explain the new observations. The voltage signal appears as a forerunner of inversion instability.

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Phase inversion in agitated liquid–liquid dispersions: Anomalous effect of electrolyte

Cited by 6 publications

References 25 publications

Engineering considerations on the use of liquid/liquid two-phase systems as a cell culture platform

Engineering considerations on the use of liquid/liquid two-phase systems as a cell culture platform

Water and n-Heptane Volume Fractions in a Rotor-Stator Spinning Disc Reactor

Phase Inversion of Agitated Liquid–Liquid Dispersions in the Presence of Micrometer-Sized Particles

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