Comment on “Aqueous dispersions of nanobubbles: Generation, properties and features“ by A. Azevedo, R. Etchepare, S. Calgaroto, J. Rubio [Miner. Eng. 94 (2016) 29-37]

- Much smaller critical bubble diameter by air supersaturation than prediction.
- Nanobubble population from air supersaturation is <1% of that from the theoretical prediction.
- Spontaneous bubble nucleation on hydrophobic solids is fastest for particle-bubble attachment.