Removal of nitrite ions from aqueous solutions by cross-linked polymer of ethylenediamine with epichlorohydrin

We describe, for the first time, a polymeric sorbent which is specific for nitrite ions. We have demonstrated that an epoxy-amine resin obtained by suspension polycondensation of ethylenediamine with epichlorohydrin practically contains only secondary amino groups. The hydrochloride form of the resin is extremely efficient and highly selective in the removal of nitrite ions from aqueous solutions, even in very low concentrations. Nitrite binding occurs through formation of N-nitroso groups. The nitrite-loaded resin can essentially be regenerated by concentrated acid solutions, without losing its reactivity.