摘要 |
Ferric ions may be removed very selectively from aqueous solutions by means of a metal-chelating resin consisting of the acid-quaternized form of a cross-linked polymer produced by the condensation of a phenolic component comprising one or more phenols, formaldehyde, and a diamino component comprising one or more di-(secondary amino) compounds under neutral conditions. The resin is prepared by treating the cross-linked polymer with an aqueous solution of a strong mineral acid. |