Poster Session

A novel method for zeta potential measurement of gas bubbles

Aref Seyyed Najafi, PhD student in Chemical Engineering

Supervisor - Dr. Xu and Dr. Masliyah

Accurate measurement of zeta potential of gas bubbles is a challenging task as it requires the generation an adequate number of very small gas bubbles. During zeta potential distribution measurements, using a micro-electrophoretic mobility method, these bubbles have to remain in suspension with a very limited upward movement under prevailing buoyancy force. In our laboratory, we developed a simple and reliable method to generate a stable nano-bubble suspension. Preparation of this suspension was based on the concept of bubble nucleation in a supersaturated solution. Zeta potential of nano-bubbles was measured by ZetaPals (Brookhaven Instruments Co.) using Uzgiris, Brookhaven electrodes coated with Palladium and He-Ne laser as the light source. The evaluation of the zeta potential was based on the Smoluchowski equation. Compared with other existing methods, the reproducibility of zeta potential measurement of bubbles using our method was improved significantly. Our developed technique was applied to measuring zeta potential of air bubbles in Aurora plant process water and synthetic process water. For comparison, the measurement was also performed in fractionated foam and residual water from the Aurora plant water. In all cases, the air bubbles are negatively charged. The absolute value for the measured zeta potential of the air bubbles in the Aurora process water was found to be lower than that in the foam fraction, but higher than in the residual and synthetic water. With the proposed technique, zeta potential measurements of gas bubbles can become routine. Such measurements would assist in a better understanding of air bubble-bitumen attachment as would occur in bitumen extraction.