I galvanised a nail by putting it in a zinc sulfate solution with a piece of zinc and putting a voltage over them.

 

For the sake of experimentation, I reversed the polarity to see what happens, but now the solution is brown. My best guess is that now I also have iron ions in it.

 

I was wondering whether there was a quick and easy way to get the iron out again, while leaving the zinc in. It is not terribly important, but would satisfy my curiosity.

 

One thing I found was waiting for the oxygen in the air to oxidise the iron to form an iron oxide precipitation that can be filtered out. Would that work in a zinc sulfate solution? Does that take a long time?

 

Is there something else I could throw in the solution to form a precipitation with the iron, but not with the zinc?

A simple answer would be to add some more galvanised nails.

Zn + FeSO4 --> Fe + ZnSO4

That is indeed very simple

Thanks.

 

Wouldn't it take a long time? Would it help to heat up the solution?

To conclude this: leaving it rest for a week resulted in a rusty brown precipitation that I could filter out, leaving a pretty clear solution.