Emulsification by ultrasound: drop size distribution and stability

Area of Science:

• Colloid and Surface Science
• Chemical Engineering
• Materials Science

Background:

• Oil-in-water emulsions are crucial in various industries.
• Efficient emulsion production requires optimizing droplet size and stability.
• Mechanical agitation and power ultrasound are common emulsification methods.

Purpose of the Study:

• To compare the efficacy of mechanical agitation versus power ultrasound in producing oil-in-water emulsions.
• To investigate the impact of emulsification parameters on emulsion characteristics.
• To determine the optimal method for achieving stable emulsions with minimal surfactant.

Main Methods:

• Emulsification of a water/kerosene/polyethoxylated (20 EO) sorbitan monostearate system.
• Comparison of Ultra-Turrax mechanical agitation (10,000 rpm, 170 W) and power ultrasound (20 kHz, 130 W).
• Variation of emulsification time, surfactant concentration, consumed power, and oil volume fraction.

Main Results:

• Power ultrasound produced significantly smaller droplet sizes (Sauter diameter, d32) than mechanical agitation.
• Emulsions produced by ultrasound exhibited enhanced stability.
• Less surfactant was required to achieve a specific droplet size when using ultrasound.

Conclusions:

• Power ultrasound is a more effective method for producing stable oil-in-water emulsions compared to mechanical agitation.
• Ultrasound-mediated emulsification offers advantages in terms of droplet size reduction and surfactant efficiency.
• The findings suggest potential for improved emulsion formulations and reduced processing costs.