ULTRASONIC MONITORING OF OIL-IN-WATER EMULSIONS UNDERGOING DEPLETION FLOCCULATION

The paper describes a three-part experiment on flocculating emulsions in order to determine whether ultrasonic spectroscopy could be used to detect and characterize the flocculation process. Three emulsions whi ch represented unflocculated, partially flocculated, and fully floccul ated systems were prepared, They were characterized independently usin g direct microscopic examination and their creaming behavior. Ultrason ic spectroscopic measurements of the flocculating emulsions showed lar ge changes during the flocculation process, which were not readily mod eled using single particle scattering theory, The ultrasonic propertie s of the unflocculated emulsion did not change during the measurement period. The results demonstrate that ultrasonic techniques are capable of detecting the flocculation process. There is clear potential to us e ultrasonic techniques to characterize flocculated structures, but mo re work is needed on the theoretical analysis of the interaction of ul trasound with particle aggregates. (C) 1997 Academic Press.