Selective removal of copper or nickel from complexing agents in aqueous solution

In an improved process for electroless deposition of copper which facilitates waste treatment or recovery of complexed copper ions from plating or rinse solutions or effluents thereof, wherein a workpiece is contacted with a copper plating bath, containing complexed copper ions and complexing agent selected from the group consisting of alkanolamines or carboxylic acids or salts thereof, and subsequently contacted with one or more aqueous rinse solutions in which said complexed copper ions and said complexing agent accumulate, the improvement which comprises the steps of:

• (a) providing a bed of chelating ion-exchange resin having an iminodiacetic acid functionality,
• (b) passing the aqueous solution containing said complexed copper ions and said complexing agent through said resin bed, whereby copper ions are removed from said aqueous solution and retained in said resin bed and the effluent passing out of said resin bed contains said complexing agent, but is substantially free of complexed copper ions, and
• (c) eluting said retained copper ions from said resin bed by passage therethrough of an aqueous acid solution, whereby the eluate contains copper ions and is substantially free of said complexing agent, and whereby said resin bed is regenerated for reuse.

In an improved process for electroless deposition of nickel which facilitates waste treatment or recovery of complexed nickel ions from plating or rinse solutions or effluents thereof, wherein a workpiece is contacted with a nickel plating bath, containing complexed nickel ions and complexing agent selected from the group consisting of alkanolamines or carboxylic acids or salts thereof, and subsequently contacted with one or more aqueous rinse solutions in which said complexed nickel ions and said complexing agent accumulate, the improvement which comprises the steps of:

• (a) providing a bed of chelating ion-exchange resin having an iminodiacetic acid functionality,
• (b) passing the aqueous solution containing said complexed nickel ions and said complexing agent through said resin bed, whereby nickel ions are removed from said aqueous solution and retained in said resin bed and the effluent passing out of said resin bed contains said complexing agent, but is substantially free of complexed nickel ions, and
• (c) eluting said retained nickel ions from said resin bed by passage therethrough of an aqueous acid solution, whereby the eluate contains nickel ions and is substantially free of said complexing agent, and whereby said resin bed is regenerated for reuse.