Dear Hem C Joshi, dissolve or disperse ? My Regards

Hi;

ZnO is soluble in strong acids, such as hydrochloric acid, and strong bases such as ammonia, ammonium carbonate, ammonium chloride as well as NaOH and KOH but in dry and molten states. Also the ZnO nanoparticles readily dispersed in alcohol such as methanol or ethanol by using a sonicator, though it depends on the size of your nanoparticles.

With my best regards

Dear Hem C. Joshi if you dissolve nanoparticles, you don't have nanoparticles any more. As mentioned by Abdelkader BOUAZIZ and Doufnoune RACHIDA Rachida you can of course prepare a dispersion of your nanoparticles in various solvents.

Dear Hem C Joshi,

Do you want to 'dissolve' or 'disperse'?

Stable and uniform dispersion of ZnO nanoparticles can be achieved in ethanol. Additionally, short-chain-acid-modified reactive crystalline nanoparticles can form transparent and clear dispersion in polar solvents like acrylic ester.

The following article seems to provide additional information:

Nanoscale, 2015, 7, 9532–9544

Dear Hem C Joshi;

As confirmed by Frank T. Edelmann and Kamal Prasad Sapkota, you can obtain ZnO dispersions by making surface modifications using, for example, certain types of polymers. ZnO disperses well in DMSO, toluene, isopropanol and chlorobenzene. Surfactants can also be used to stabilize dispersions.

With my best regards

Dear all, nothing is said about TiO2 which Can be dispersed in H2O. Please check the following documents. My Regards

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003191/

https://doi.org/10.1155/2012/718214

https://www.researchgate.net/post/How_to_disperse_Titanium_dioxide_Ti02_nano_particles_in_water

https://doi.org/10.1179/1432891715Z.0000000001351

https://doi.org/10.1016/j.jeurceramsoc.2011.01.026

https://doi.org/10.1016/j.porgcoat.2016.12.006

Dear all, I would like to add a remark which I consider as an error that was repeated so many times in different RG threads by many authors.

Metal oxides in acid/base media react chemically to lead to other molecules. By definition, solubility is a physical process in which a solute molecules are separated by the action of a solvent which overcomes the cohesion induced by the intermolecular forces, the molecular structure of the solute keeps its integrity. Please check the attached files. My Regards

Dear Hem C. Joshi in addition to the excellent previous answers, you can easily find various articles on this topic on RG. Here are some examples for ZnO nanoparticles:

Article Stabilization and Dispersion of ZnO Nanoparticles in PVA Matrix

Article Preparation and Characterisation of ZnO Nanoparticles

Article A study of ZnO nanoparticles and ZnO-EG nanofluid

Article Synthesis and characterization of ZnO nanoparticles

There are many more!

Dear Hem C. Joshi here are a few articles on the dispersion of TiO2 nanoparticles which are available on RG:

Article Dispersion of TiO2 Nanoparticles in Aqueous Solution

Article Ultrasonic Dispersion of TiO2 Nanoparticles in Aqueous Suspension

Article The effect of dispersion of TiO2 nanoparticles on preparatio...

Article Preparation of water-dispersible TiO2 nanoparticles

Hi;

Here are some references on the solubility of ZnO:

1- Insoluble in water and soluble in dilute acid

[1] Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 4-100.

[2] Goodwin FE; Zinc Compounds. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2013). New York, NY: John Wiley & Sons. Online Posting Date: 17 Feb 2006.

2- Soluble in acids and alkalies; insoluble in alcohol

[3] Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007. p. 1347.

With my best regards

Hem C. Joshi and Doufnoune RACHIDA Rachida we should not forget that once the ZnO (or TiO2) dissolves, it isn't ZnO any more!

Thank you Everyone for your excellent suggestions regarding ZnO and TiO2 Nanoparticles. thank you very much

Hi;

I totally agree with you Frank T. Edelmann. But I would like to know if Hem C Joshi wants to dissolve or disperse the metal oxides.

With my best regards

Dear Hem C. Joshi you're very welcome. I hope our answers were helpful.