Acoustic - Electroacoustic Spectrometer (AES) for colloids characterization

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The requested acoustic-electroacoustic spectrometer (AES) is an instrument that will be primarily utilized in determining the size and charge of particles and drops in suspensions and emulsions. Charge and size are important at the time of determining the estability of suspensions and emulsions. There are several methods to measure size and charge of colloids, most of them use the interaction of particles and drops with light (light scattering). However, these techniques are not suitable when the suspension is dark or turbit (as in the case of bitumen emulsions and concentrated suspensions of particles). In those cases, electroacoustic spectroscopy is the best option as it uses the attenuation of sound waves at different frequencies to determine the size and charge of particles. An additional advantage of this method is that it works best with relatively concentrated suspensions (volume fractions from 0.1 to 40%), which means that it is not necessary to dilute the sample. Other methods, common in a number of laboratories at the University of Toronto and other Universities, require the sample to be diluted in water or other suitable solvent. The necessary sampling and dilution methods interfere with the stability of the suspension or emulsion itself, thus creating systematic errors in the measurement. The applicants are well aware of these limitations as it has become clear in previous studies of bitumen emulsion stability, stability of clays and clay-rich material, stability of mineral suspensions, stability of particles carried over in kraft chemical recovery cycles used in the pulp and paper industry. Having access to a proper methodolgy of determining the size and charge of colloids will help the applicants and other colleagues improve methods of particle destabilization in settling ponds commonly used in the mineral extraction industry, improve methods of oil-particle-water separation in the processing of crude oils, improve the efficiency of chemical recovery cycles, and the design of nanoparticles for environmental and energy-related applications, understand and improve the formulation of creams and other topical products as well as emulsion-based food products and aqueous extraction of oils from seeds and other biomass.