Effect of Bulk Viscosity and Emulsion Droplet Size on the Separation Efficiency of Model Mineral Oil-in-Water (O/W) Emulsions under Ultrasonic Standing Wave Fields: A Theoretical and Experimental Investigation

Abstract

Ultrasound standing waves can be used to separate emulsions. So far, they have been applied to oil-in-water emulsions with low continuous phase viscosity. This technique has the potential to be used for novel applications such as separating lipids from algal biomass; however, this requires the methodology to be optimized to process viscous emulsions. We have addressed this issue by studying the effects of bulk phase viscosity (1–23 mPa·s), emulsion droplet size (4.5–20 μm), power (10–54 W/L), and frequency (1 and 2 MHz) of ultrasound on the separation efficiency of model mineral oil-in-water–glycerol-mixture emulsions. For the small droplet size (4.5 μm) emulsion in water, the maximum separa..