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The chemical physical precipitation it’s not usually adequate to satisfy the low regulation limits: in this case it becomes necessary a following water filtration stage before proceeding to the disposal.
This section, named “final polishing”, is usually carried on with a media filtration stage, followed by an absorbent filtration with activated carbon and a final filtration with two selective resins
columns.
The selective resins, characterized by functional chelating groups, form stable compounds with the heavy metals present in the solution, in both the ion or complex form.
The functional chelating group selectively captures only the heavy metals (copper, lead, etc.), while permits the passage, with no exchanges, the other non polluting ions (salinity) so they won’t
contribute to the exhaustion of the resin itself.
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