ζ Potential of Microbubbles in Aqueous Solutions:  Electrical Properties of the Gas−Water Interface

Abstract

Microbubbles are very fine bubbles and appropriate for the investigation of the gas-water interface electrical charge, because of their long stagnation, due to slow buoyancy, in the electrophoresis cell observation area. This study investigated the zeta potential of microbubbles in aqueous solutions and revealed that the bubbles were negatively charged under a wide range of pH conditions. The potential was positive under strong acidic conditions, and the inorganic electrolytes decrease the potential by increasing the amount of counterions within the slipping plane. OH(-) and H(+) are crucial factors for the charging mechanism of the gas-water interface, while other anions and cations have secondary effects on the zeta potential, because counterions are attracted by the interface charge. The addition of a small amount of propanol and butanol provided significant information for considering the mechanism of the gas-water interface charge. Even though these alcohols did not have any electrical charge, they had a strong effect on the gas-water interface charge and dispersed the zeta potential of the microbubbles in the aqueous solution. These alcohols tended to adsorb to the interface and affect the hydrogen-bonding network at the interface, so that it was concluded that the gas-water interface electrical charge must be related to the difference of the construction of the hydrogen-bonding network between the bulk water and the gas-water interface.

Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry

“…According to the Stokes' law, the rising speed of bubbles which determines their retention time in the water is mainly related to the bubble size [27]. In the current study, the Stokes' law was applied to roughly calculate the rising velocity of bubbles, of the former was much greater than that of the later, which can explain why the difference between these two ozonation processes in gas holdup significantly increased with dissolved ozone concentration.…”

“…The pH in aqueous solutions also influences the zeta potential of microbubbles. The results of previous researchers [11,27] revealed that zeta potential of microbubbles of ozone is negative over a wide range of pH conditions [32]. In general, the bubbles' zeta potentials are positive in the highly acidic solutions.…”

Role of Collectors and Depressants in Mineral Flotation: A Theoretical Analysis Based on Extended DLVO Theory

“…Using Derjaguin approximation, the total double-layer energy, E T e , between the hemisphericalasperity-coated silica sphere and air bubble surface becomes [26]: [29][30][31][32][33]. It should be noted that Equation (4) works best when the closest distance (i.e., h − r) is greater than several Debye lengths due to the linear approximation treatment [26].…”

A study for biofilm removing and antimicrobial effects by microbubbled tap water and other functional water, electrolyzed hypochlorite water and ozonated water

“…Recently, microbubbled water has been used in several technical applications, including the decomposition of organic chemicals, wastewater treatment, medical technology and food processing [1][2][3][4][5][6][7] , however, it has not yet been applied in the fi eld of dentistry.…”