| Feature | Nanobubbles (NBs) | Microbubbles (MBs) |
|---|---|---|
| Size | Typically < 1 µm (commonly 100–200 nm). | Typically 1–100 µm (definitions vary slightly but distinct from nano). |
| Buoyancy | Negligible buoyancy. Gravity and buoyancy forces are overcome by other forces. | Significant buoyancy. They rise steadily to the surface. |
| Behavior in Water | Exhibit Brownian motion, moving randomly and remaining suspended for weeks to months. Solutions appear transparent. | Rise vertically according to Stokes' law. Solutions appear milky or cloudy initially. |
| Collapse Dynamics | Shrink and dissolve into the liquid or collapse internally, often releasing free radicals and significant energy. | Rise to the surface and burst at the gas-liquid interface, or shrink into nanobubbles before collapsing. |
Citations for Table:
- Size/Buoyancy: Akshit et al., 2024; Alheshibri et al., 2016.
- Behavior: Ebina et al., 2013; Foudas et al., 2023.
- Collapse: Takahashi et al., 2007; Agarwal et al., 2011.