what is the role of NaOH during the synthesis of zinc nanoparticles? does it directly participate in the zinc reduction reaction? does OH compete with the plant extract in synthesizing zinc nanoparticles? any how do we raise the PH to 12 to accurately produce zinc nanoparticles and obtain the white percipitate?
The role of NaOH is to react with the zinc salt precursor (e.g. zinc chloride) to form the hydroxide, Zn(OH)2 which is heated to thermally decompose to the oxide. It is not a reducing agent - there is no change in oxidation state of the zinc (it remains in the +2 oxidation state). Note that if you get a precipitate, then your material cannot be nano (< 100 nm) - a simple Stokes' Law calculation will show this. You talk of 'zinc nanoparticles' on 3 occasions in your description. Surely you mean zinc oxide? pH (not PH, please!) can be raised to 12 relatively easily with NaOH or KOH.
Dear all, basic pH is essential for three reasons, two of them areinterconnected proprties. Basic pH hinder the formation of agglorates, thus, fine nanoparticles are obtained so. The third property that is governed by pH is the form/type of crystal structure of the ZnO NPs. My Regards
https://doi.org/10.1016/j.matpr.2015.11.123
https://www.researchgate.net/publication/236858721_Effect_of_pH_on_ZnO_nanoparticle_properties_synthesized_by_sol-gel_centrifugation#:~:text=The ZnO powders agglomerate when,was obtained at pH 9.
Abdul Nasir
I give an example of the synthesis of zinc oxide nanoparticles to answer the question more clearly. Alan F Rawle is right that NaOH is needed to obtain Zn(OH)2. Plant extract molecules play the role of a stabilizer and temperature reducer during the dehydration of Zn(OH)2.
"For the synthesis of zinc oxide nanoparticles, 50 cm3 of 0.5 M zinc acetate dihydrate solution was prepared using distilled water. 1 cm3 aqueous leaf extract of Ixora coccinea was introduced into the above solution after 10 minutes of stirring. In order to maintain the pH 12, 2.0 mol・dm−3 sodium hydroxide was used which resulted in a pale white aqueous solution. This was then placed in a magnetic stirrer for 2 hrs. The pale white precipitate was then taken out and washed over and over again with distilled water followed by ethanol to get free of the impurities. Then a pale white powder of zinc oxide nanoparticles was obtained after drying at 60˚C in oven over night to give yield of 96.7%"
Article Biosynthesis of Zinc Oxide Nanoparticles Using Ixora Coccine...
Dear scholar, if am using pure bioactive compound such luteolin, resveratrol e.t.c instead of plant extract. Can I still used the same method stated Yuri Mirgorod
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