Removing copper from etchant solution?

[earthtonesaudio]

The only thing I've found so far (just started looking) was to use spruce sawdust  to remove copper from an aqueous solution.  Anyone know of a way to remove copper from used etchant (either ferric chloride or cupric chloride)?

[oskar]

with electrolysis?
Two electrodes, really low voltage <1V and good ventilation. The Cu⁺² ions should be heading for the minus pole ( a cu-plate/rod ), and the negative ions (Cl^-...) will head for the positive ( carbon/platina... something is less ( or more, don't remember) electronegative than Cu )

EDIT! I don't know how safe this is. I've only done electrolysis with known solutions in classroom situation. Also, you could have other ions that will make a run for the negative pole before the Cu...

[oskar]

Or better still, just go for the electrolysis...
http://www3.telus.net/chemelec/Projects/Etching/Etching.htm

[David]

The only thing I've found so far (just started looking) was to use spruce sawdust  to remove copper from an aqueous solution.  Anyone know of a way to remove copper from used etchant (either ferric chloride or cupric chloride)?

This question caused a flashback from a college chemistry class.  Thanks a lot!  I hated that class...   
However, the thought might be sound.  I seem to recall something about a substance called a "chelate" that might be a step in the right direction.

[MarcoMike]

regarding Cu2Cl2 electrolysis works just fine... you can use a graphite electrode as + and copper (or more noble) for -
this way you recover the Cu at the cathode and have a couple of reactions at the anode: evolution of Cl2 and oxidation of Cu1+ to Cu2+.... of course the evolution of Cl2 is bad, as: 1- it is toxic. 2- the solution after the process will lack Cl2, which is part of the etching power of CuCl2 and FeCl3. 3-chlorine is in a oxidized state, so you are wasting energy... the best would be working in a sealed "cell", so the produced Cl2 can chemically oxidize Cu1+ to Cu2+, but back to point 1, this is kind of dangerous.

cheap solution: in the "environment" the stable form of Cu is 2+, cu1+ will turn to 2+ just by air-oxidation... this results in the increase of cu2+ so you should diluite ir at one point. and add H+ (HCl) both because the total volume is increased and because the air oxidation "eats" H+...

sorry I wrote in a hurry, but funnily I have to go and give private lessons of chemistry now

[earthtonesaudio]

Thanks for the ideas so far!  I should say I'm much more interested in the non-toxic and less dangerous methods... 

[Paul Perry (Frostwave)]

Surely adding an excess of sodium carbonate (washing soda) or sodium bicarbonate (baking soda) will precipitate the copper as the insoluble carbonate. (add the carb/bicarb slowly, it will fizz.)

[MarcoMike]

yes, but it will also spoil the etching solution...