How to remove cadmium with ion exchange.
Cadmium can be found in potable water supplies as a result of the deterioration of galvanized plumbing, industrial waste contamination, or possibly the result of surface water contamination by certain fertilizers.
Although it is possible for trace cadmium to be chelated or sequestered as with any metal, it will generally be found in the dissolved ionic form. In this form, cadmium may be removed by standard, strong acid cation resin, such as ResinTech CG8 regenerated with sodium chloride (NaCl). It must be assured that the ten ppb MCL limit can be met by the ion exchange system at all operating conditions.
Actual operating tests to verify performance are recommended. The cadmium exchanged onto the resin can be effectively removed by a sodium chloride regeneration.
Cadmium can also be found in some industrial or metal finishing waste waters. Removal by cation exchange resin, Resintech CG8 is easily accomplished, but for streams that also include other cations, particularly hardness, a selective chelating resin, Resintech SIR-300, should be used.