How to Selectively Reduce Fe(III) Without Affecting UO22+?

[Questions_14]

Hi All,

I have been searching the web for days now, trying to find a way to selectively reduce Fe(III) to Fe(II) without reducing the uranium oxide (UO₂²⁺) present, and was hoping someone with more of a chemistry background could give me some advice on what to try/do.


Cheers
Simon

 

[espen180]

Hi, and welcome to PF!

I did some searching on my own, and I think this works.

The reaction UO₂⁺ + e^- → U⁴⁺ + 2O^2- has a standard reduction potential of 0.38 V.

The reaction Fe³⁺ + e^- → Fe²⁺ has a standard reduction potential of 0.771 V.

Since the iron reaction has a higher potential, you can construct a cell where the anode reaction has a potential higher than 0.38 but lower than 0.771, which will then be spontaneous for the iron reaction but not for the uranium reaction.

http://www.webelements.com/uranium/compounds.html

 

[Borek]

The reaction UO₂⁺ + e^- → U⁴⁺ + 2O^2- has a standard reduction potential of 0.38 V.

O₂^- in water solution? That's not the reaction you will observe.

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[espen180]

No, I realize that. Each oxygen ion will immediately deprotinate a water molecule making OH^-.

All I really wanted from the reaction was the reduction potential, but you are right of course, it's not the right picture.