blogfast25
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Easy wet reduction of PbO2?
There may be some answers to this question in the lead salts thread but I didn’t find a great deal.
I’ve quite a bit of old PbO2 from various car batteries, accumulated over some years. I’d like to convert it to more useful Pb salts like
Pb(NO3)2, or any Pb [+II] salt, preferably in watery medium and using quite OTC materials. I was thinking of reducing the PbO2 to lead (II) acetate
with Fe (II) acetate. At first glance this is thermodynamically possible:
PbO2 + 4 H+ + 2e --- > Pb2+ +2 H2O ….. E = +1.455 V
2 x (Fe2+ --- > Fe3+ + e) ….. E = -0.771 V
PbO2 + 4 H+ + 2 Fe2+ --- > Pb2+ + 2 H2O + 2 Fe3+ ….. ΔE = +0.684 V
The lead and iron would then still have to be separated. Instead of using Fe (II) acetate, Mohr’s Salt could be used but that would give PbSO4, not
highly useful either…
I’m pretty confident some here will have reduced PbO2 before, so any ideas are welcome…
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hissingnoise
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Lead nitrate ---suitable for a few things . . .
2PbO<sub>2</sub> +4HNO<sub>3</sub>--->2Pb(NO<sub>3</sub> <sub>2</sub> +H<sub>2</sub>O + O<sub>2</sub>
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blogfast25
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That simple, huh? I didn't think of HNO3 because it's an oxidiser, usually... But here it's oxygen that's being oxidised. Nifty...
I wonder if a reduction with oxalic acid works, it does for the analogous:
MnO2 + 4 H+ + 2e --- > Mn2+ +2 H2O ….. E = +1.224 V
H2C2O4 --- > 2 CO2 + 2 H+ + 2e ….. E = +0.49 V
ΔE = 1.71 V
[Edited on 3-3-2011 by blogfast25]
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