Comment on "Bulk Nanobubbles or Not Nanobubbles: That is the Question".

Area of Science:

• Colloid and Surface Chemistry
• Physical Chemistry
• Nanotechnology

Background:

• Recent research by Jadhav and Barigou (Langmuir 2020) reported stable bulk nanobubbles in water.
• These nanobubbles were purportedly generated via hydrodynamic cavitation, ultrasound cavitation, or ethanol addition.
• Previous studies have contested the nanobubble nature of such observed nanoentities.

Purpose of the Study:

• To critically analyze the findings of Jadhav and Barigou regarding stable bulk nanobubbles.
• To re-evaluate the experimental evidence and conclusions presented in the aforementioned study.
• To demonstrate the incorrectness of attributing observed nanoentities to stable bulk nanobubbles.

Main Methods:

• Detailed analysis of the experimental techniques employed by Jadhav and Barigou.
• Identification of limitations in the sensitivity and application of experimental methods.
• Review of the interpretation of experimental outcomes and data.

Main Results:

• The study identifies significant issues with the experimental techniques used, including low sensitivity.
• Methodical problems in the application of otherwise appropriate techniques were found.
• Ambiguous experimental results were misinterpreted as evidence for nanobubbles.

Conclusions:

• The conclusions drawn by Jadhav and Barigou regarding stable bulk nanobubbles are incorrect.
• The observed nanoentities are not stable bulk nanobubbles due to experimental limitations and methodological flaws.
• Further research with more sensitive and appropriate techniques is needed to clarify the nature of these nanoentities.