Method And Apparatus To Measure The-Potential Of Bubbles

Abstract

A method and an apparatus to measure the -potential of bubbles has been developed. The apparatus is of micro-electrophoresis type. Small bubbles of 20–40μm in diameter are generated by pressure reduction of a solution containing dissolved air and are introduced into an electrophoresis cell of 0.972 mm thickness. As the movement of the bubbles is followed over 4 seconds in this arrangement, the measurement error due to the rapid rising of the bubbles can be considerably decreased. The bubbles were positively charged in a cationic surfactant solution of cetyltrimethylammonium bromide (CTAB) and the charge decreased with increasing electrolyte concentration in the solution. In an anionic surfactant solution of sodium dodecyl sulfate (SDS), both the bubbles and oil particles were negatively charged. But, by the addition of A12(S04)3, the oil particles maintained their negative charge while the charge of the bubbles was changed to positive. The situation of the attaching of oil particles to bubbles was observed photographically. © 1987, The Society of Chemical Engineers, Japan. All rights reserved.