Liquid—liquid extraction drop formation: mass transfer and the influence of surfactant

✍ Scribed by T.-B. Liang; M.J. Slater

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 901 KB
• Volume: 45
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(90)87084-6

✦ Synopsis

The extent of mass transfer during drop formation has been measured using cumene drops containing acetic acid at about 0.25 M transferring to water. The effect of the addition of the surfactant sodium dodecyl sulphate has been investigated. A model of the behaviour is proposed, taking account of drop size, formation time and the effect of the surfactant. The presence of surfactant affects the drop mass transfer coefficient during the free rise of the drop; an empirical coefficient used to describe surfactant effects and to correlate free-rise mass transfer coefficients is also used to correlate the fraction of solute extracted during drop formation. Under the conditions used the extent of mass transfer is larger than predicted from many equations found in the literature; it is assumed that this is due to circulation-enhanced diffusion in the forming drop. An internal diffusivity reducing with time is used to correlate the data satisfactorily.