Specialty Chemistry Forums > Nuclear Chemistry and Radiochemistry Forum

Polonium instant deposition on Cu disc

(1/3) > >>

Jotaro:
Dear all,

I am new to this forum and really glad this forum exists!
I am working with radiochemistry, with no chemistry background. Not the best introduction, but I have to be honest. Still, I manage to do my job.

I have a question regarding the Polonium instant deposition (plating) on Cu discs (also applicable on Ni and Ag discs).
The procedure I work with (after liquid-liquid extraction with TBP and Xylene) I dry the 8M HNO3 fraction that contains the Po. Change the media to about 2M HCL, my question is why is HCL used? I understand that HNO3 would eat away Cu and other metal discs, but does the HCL help to plate the Po on the Cu disc?

Thank you for your time

Borek:
Hard to tell not knowing more details, but in general HCl is much more volatile so it is often used when we need strong acid that will be easy to remove by drying.

Corribus:
Based on the information you provide, it's probably mostly due to the activity of nitric acid. Nitric acid reacts strongly with copper, but hydrochloric acid does not.

Jotaro:
Thank you both for replying!


--- Quote from: Borek on October 24, 2018, 03:07:04 AM ---Hard to tell not knowing more details, but in general HCl is much more volatile so it is often used when we need strong acid that will be easy to remove by drying.

--- End quote ---

I can give you as many details as you need.

Actually, the solution is maintained in 2M HCL throughout the plating process, leading to my understanding that HCL (or acids in generals) "helps" plating the Po, but we can not use any acid, due to it dissolving the disc itself.
But I am not sure why or how this is. Maybe someone knows this detail? I could be completely wrong too. Could be to prevent something else to plate, like lead.

Borek:
Apart from what Corribus has mentioned, Cl- often shows complexing properties, which help maintain right concentration of the cations involved and help plate them at right potentials.

In my experience some of the recipes used for plating are partially magic - that is, it is "easy" to "explain" why the work once you experimentally find the right conditions, but these "explanations" have no predictive power that would make it easier to deal with other cases. No idea if that's the case.

Navigation

[0] Message Index

[#] Next page