Drop Sizes in Liquid Membrane Dispersions

Abstract

The effect of hydrodynamic conditions and physical properties on the characteristics of an emulsion dispersion in a stirred tank was studied in the presence of mass transfer, in an attempt to identify the parameters for Sauter mean diameter data correlation in emulsion liquid membranes. The organic phase of the water-in-oil emulsion contained the cadmium extractant Cyanex 302 and an emulsion stabilizer, and the dispersion continuous phase was an aqueous solution of phosphoric acid containing cadmium. Variations in emulsion viscosity and interfacial tension were achieved by changing the extractant and surfactant concentrations. The dispersion drop size distribution was measured from photographs taken with a high-speed video camera system attached to an endoscope. It was found that the emulsion physical properties, emulsion swelling, and operating conditions were interrelated in a complex way. However, emulsion swelling seemed to lump together the effect of some of the parameters on globule size, which made possible the development of a simple correlation for the Sauter mean diameter in terms of We -0.6 , emulsion swelling percentage, and empirical correction factors for emulsion viscosity and dispersed-phase holdup. A modified Rosin-Rammler probability distribution function fitted well the globule size distribution data.

Study on removal of cadmium from wastewater by emulsion liquid membrane

“…Such a behavior is in accordance with the experimental correlation [25], in which d 32 ∝ We −0.6 . Since the Weber number is increased by decreasing interfacial tension, it is expected that Sauter mean diameter, d 32 , will be decreased by increasing interfacial tension due to adding more surfactant.…”

Synthesis of micrometer to nanometer CaCO3 particles via mass restriction method in an emulsion liquid membrane process

“…The large differences between real and calculated particle size at raised temperature may suggest a multiple nucleation mechanism within a droplet instead of one-particle-in-one-droplet as seen at room temperature. In addition, the existence of large agglomerates accommodating tens of PCC particles inside may imply a reorganization of thermodynamically instable droplets in the system due to the coalescence and fusion of the droplets [17,18] at raised temperature.…”

Drop size distribution in highly concentrated liquid–liquid dispersions using a light back scattering method

“…Gal‐Or and Hoelscher17 proposed a Gamma‐type function that relates drop size distribution directly to the rotational speed of the impeller and the dispersed phase fraction. Gallego‐Linzon and Perez de Ortis18 applied a modified Rosin–Rammler function to fit their data in emulsion liquid membrane systems using flat blade turbines with different diameters.…”

“…Pacek et al 14 studied the area close to the wall using an internal light source and reported results for mixtures with dispersed phase fractions up to 70%. The recent use of endoscopes has allowed recording at different locations within the container, overcoming the problem of dense dispersions (up to 30%18) but in an intrusive way. The introduction of lasers resulted in a number of drop‐size measuring techniques, where the amount of light scattered by the drops is related to their size.…”