Nanobubbles are defined as: “Nanoscopic gas cavities in aqueous solutions which diameter is smaller that 1 micron (d<1μm).”
- Taking into consideration the classical thermodynamics, a paradox seems to appear in systems containing nanobubbles.
- According to the Young-Laplace Law, the pressure in the interior of gas bubbles is inversely proportional to their diameter, with excess pressure:
Obviously, since the pressure inside gas bubbles is inversely proportional to their diameter, microscopic bubbles have large internal pressure.
- Nanobubbles demonstrate an extended lifetime compared to larger size bubbles.
- Over the last few years, nanobubbles have drawn great attention due to their exotic properties.
- It would be expected that bubbles which their diameter is in the nanoscale (<1 μm), dissolve immediately, within a few microseconds. However, it is observed that nano-bubbles remain stable for extended periods of time and still exist even after several months!