Polyamino succinic acids are effective chelants for use in photography and gas conditioning (both applications preferably involving the polyamino disuccinic acid in the form of a metal, preferably an iron complex).

The copper chelates are also useful in electroless copper plating. In photography, the invention includes a method of bleaching or bleach-fixing a photographic material which comprises contacting said material with a bleaching solution containing a bleaching agent comprising a ferric complex of a polyamino di-succinic acid(cas:110-15-6) and the solution so used. In electroless deposition, the invention includes a method of electroless deposition of copper upon a non-metallic surface receptive to the deposited copper including a step of contacting the non-metallic surface with an aqueous solution comprising a soluble copper salt and a polyamino di-succinic acid(cas:110-15-6) and plating baths appropriate for such use. Another aspect of the invention includes a method for removing iron oxide deposits from a surface including a step of contacting the deposits with a solution comprising an ammoniated polyamino disuccinic acid.

Yet another aspect of the invention involves gas conditioning including a process of removing H2 S from a fluid comprising contacting said fluid with an aqueous solution at a pH suitable for removing H2 S wherein said solution contains at least one higher valence polyvalent metal chelate of a polyamino disuccinic acid and a process of removing NOx from a fluid comprising contacting the fluid with an aqueous solution of at least one lower valence state polyvalent metal chelate of a polyamino disuccinic acid.