Bulk micro-nanobubbles (BMNB) have potential advantages in various fields. However, systematic investigation under various parameters remains lacking. In this work, not only the properties of microbubbles were analyzed, but also the characters of nanobubbles. First, the dissolved oxygen concentration of water was determined for various parameters while micro-nanobubbles were being prepared. Then the size and number/concentration of microbubbles and nanobubbles were detected by focused bean reflectance measurement and nanoparticle tracer analysis respectively. Finally, the zeta potential of bulk nanobubbles and surface tension of aqueous solutions containing bulk nanobubbles were determined under a variety of operating settings. The results indicated that the characters of microbubbles (number, particle size) and nanobubbles (concentration, particle size and zeta potential) will be affected by the aeration rates and preparation time. The behavior of two distinct scale bubbles to operational conditions, on the other hand, is quite diverse. Additionally, the surface tension of an aqueous solution containing bulk nanobubbles was lower than that of pure water.
 

Bulk nanobubbles (BNBs); Bulk microbubbles (BMBs); Preparation time; Aeration rate; Dissolved oxygen (DO) content; Bubble concentration and size