Abstract
We show that the mixing of organic solvents with pure water leads to the spontaneous formation of suspended nano-entities which exhibit long-term stability on the scale of months. A wide range of solvents representing different functional groups are studied: methanol, ethanol, propanol, acetone, DMSO and formamide. We use various physical and chemical analytical techniques to provide compounded evidence that the nano-entities observed in all these aqueous solvent solutions must be gas-filled nanobubbles as they cannot be attributed to solvent nanodroplets, impurities or contamination. The nanobubble suspensions are characterized in terms of their bubble size distribution, bubble number density and zeta potential. The bubble number density achieved is a function of the type of solvent. It increases sharply with solvent content, reaching a maximum at an intermediate solvent concentration, before falling off to zero. We show that, whilst bulk nanobubbles can exist in pure water, they cannot exist in pure organic solvents and they disappear at some organic solvent-water ratio depending on the type of solvent. The gas solubility of the solvent relative to water as well as the molecular structure of the solvent are determining factors in the formation and stability of bulk nanobubbles. These phenomena are discussed and interpreted in the light of the experimental results obtained.
Highlights
Bulk nanobubbles (BNBs) are an emerging field which is attracting much attention from researchers and industrial practitioners alike
The various physical and chemical analytical techniques used above have produced multiple evidence which, taken together, provides conclusive proof that the nano-entities spontaneously formed by water–solvent mixing cannot be attributed to solvent nanodroplets or any type of common impurities or contamination as speculated in some literature reports[8,9,10,11,12,13,14,15] and, must be gas-filled BNBs
Multiple evidence has been provided which shows that the nano-entities formed by water–solvent mixing cannot be attributed to solvent nanodroplets, impurities or contamination and must be gas-filled
Summary
Bulk nanobubbles (BNBs) are an emerging field which is attracting much attention from researchers and industrial practitioners alike. It is still not understood how they can be produced in an efficient, consistent and controlled fashion, especially in large volumes, and how they can be efficiently exploited in all the pertinent technologies
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
