Fine Bubbles

Fine Bubble Technology consists in enriching liquids with gas bubbles of a diameter of a single micron or lower.

Such a degree of fragmentation of the bubbles causes many unusual physical properties. Unlike larger bubbles, which either float to the surface of the liquid and burst, or dissolve into the volume, the nanobubbles can remain stable for as long as a few weeks.

As one can see in the figure above, bubbles in macroscale are rising to the surface of the liquid with elapsed time, where they burst. Microbubbles are shrinking due to dissolution and collapse to smaller bubbles. Nanobubbles remain stable and their size is constant in time.

Such small bubbles are able to accumulate electric charge on their surface, what creates the repelling force which keeps bubbles separate and unable to dissolve in liquid. It is also the reason of their homogenous distribution in whole volume of liquid. Due to the tendency of equal dispersion of the bubbles in the entirety of the volume of the liquid medium, the fine bubbles reach every nook of the vessel or the object submerged in it.

Nanobubbles are perfectly spherical thanks to surface tension and overpressure inside the bubble. Overpressure level is directly linked to the size of the bubble – the smaller the diameter the higher the overpressure. For example the bubble with a diameter of 50 nm has a pressure of around 60 bars.

Mass bursting of such bubbles, for example due to hitting the surface of a solid mass or caused by an acoustic wave results in:

  • a rapid expansion of the interphase surface
  • local temperature rise to thousdands of degrees
  • an occurrence of a high concentration of *OH hydroxyl radicals (if the liquid is water)
  • creation of an ultrasound wave.

Research on fine bubbles and their multiple uses is lead by Japan. Fine Bubble Industries Association(FBIA), with widely recognised multi-industry companies and industrial groups such as Hitachi, Kyocera, Mitsubishi, Panasonic, Sharp and Toshiba as members, was founded in 2012.​

Outside of Japan, the fastest development of fine bubble technologies and their uses can be observed in South Korea, Taiwan, Singapore, China, and USA, and recently in Canada. The ever growing number of various implementations of fine bubble technology increases the knowledge of the possibility of their use and causes increased activity from device producers.