Ultrasonic Separation of Particulate Fluids in Small and Large Scale Systems: A Review

Abstract

This review details recent developments in nondestructive ultrasound separation techniques that can be used to separate, trap, or fractionate particles or emulsified droplets from bulk phase liquids. Whereas most previous reviews have focused on small scales or specific applications, this review groups different aspects of the acoustic separation technique and directs it at an audience with interests in separation technologies. The process has potential as an attractive alternative to common separation processes such as centrifugation, membrane filtration, sedimentation, or fluorescence activated cell sorting (FACS). The technology can achieve precise, gentle, and label-free separation in a system that involves no moving parts. The fundamental concepts are presented in detail and previous studies covering a range of different applications are reviewed. The challenges and opportunities for addressing large-scale industrial applications are evaluated.

Acoustic separation of oil droplets, colloidal particles and their mixtures in a microfluidic cell

“…The use of ultrasonic waves to separate particulates from solutions is a promising alternative to established separation processes, such as distillation, filtration or centrifugation, with a range of potential applications in food processing, pharmaceutical, oil production and biomedicine industries [1][2][3][4]. Some of the advantages of the high frequencies acoustic separation compared to traditional separation methods are the fast action, robustness of the process and low mechanical impact on the particulates to be separated.…”

Microfluidic bio-particle manipulation for biotechnology

“…Several of those methods are reviewed within this paper. Stand-alone review papers are present for each of these methods [6][7][8][9][10][11][12][13][14] since there has been a vast amount of research effort on these techniques for microfluidic platforms for the last two decades. In this review, our objective is to give the basics of each method.…”

Ultrasonic Processing for Dairy Applications: Recent Advances

“…These larger entities then rise more rapidly to the surface of the container according to Stokes' Law [64], resulting in faster creaming. The acoustic and buoyancy forces influencing the separation are dependent on the size of the fat globules [68]. The acoustic forces can be manipulated by adjusting the applied frequency and energy density.…”

“…Examples of suitable applications include emulsification and homogenisation. In contrast, high-frequency low-power ultrasound uses intensities below 1 W/cm 2 where the physical effects are comparatively gentle and as such can be utilised for processes such as non-invasive analysis and monitoring food materials, and non-destructive separations of multi-component mixtures [68]. The intermediate frequency range is characterised by peak sonochemical effects and as such can be selected to initiate chemical modifications in food systems.…”