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.

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

Separation of suspensions and emulsions via ultrasonic standing waves - a review.

Ultrasound and acoustic cavitation enable ergonomic and eco-friendly treatment of complex liquids with outstanding performance in cleaning, separation and recycling of resources. A key element of ultrasonic-based technology is the high speed of mixing by streams, flows and jets (or shock waves), which is accompanied by sonochemical reactions. Mass transfer across the phase boundary with a great variety of catalytic processes is substantially enhanced through acoustic emulsification. Encapsulation, separation and recovery of liquids are fast with high production yield if applied by ultrasound. Here we discuss the state of knowledge of these processes by ultrasound and acoustic cavitation from a perspective of a physico-chemical model in order to predict and control the outcome. We focus on the physical interpretation and quantification of ultrasonic parameters and properties of liquids to understand the chemistry of liquid/liquid interfaces in acoustic fields. The roles of thermodynamic enthalpy and entropy (incl. Laplace and osmotic pressure) in the context of sonochemical reactions (separation, catalysis, degradation, cross-linking, ion exchange and phase transfer) are outlined. The synergy of ultrasound and electric fields or continuous flow chemistry for cleaning and separation via emulsification is highlighted by specific strategies involving polymers and ultrasonic membranes.

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

Provided herein are systems and methods for separation of particulate from water using ultrasonically generated acoustic standing waves.

Ultrasound and acoustophoresis for water purification

Creaming enhancement in a liter scale ultrasonic reactor at selected transducer configurations and frequencies.

This paper explores the use of acoustics for the recovery of oil in oil-water emulsions. A series of experimental studies were conducted using acoustic standing waves in resonant cavities as means of trapping oil droplets and enhancing oil separation. Several cavity configurations were explored and the frequency range used was between 1 MHz-2 MHz. Oil-water emulsions studied were made using mineral oil and motor oil.

/pdf/enhanced-acoustic-separation-of-oil-water-emulsion-in-4wrlw7uuk2.pdf

D.N. Sinha

Papers

Enhanced Acoustic Separation of Oil-Water Emulsion in Resonant Cavities