A redox copolymer having N-chlorosulfonamide groups for cyanide ion decomposition in dilute aqueous solutions

Abstract

A redox copolymer, macroporous poly(S/DVB) resin having N-chlorosulfonamide groups was used for removal of cyanide ions from aqueous solutions. This resin contains active chlorine in functional groups (2.3 mmoUg, i.e., 4.6 meq/g) and shows oxidative properties. The possibility of using this resin for oxidation of cyanide ions to less toxic or non-toxic compounds was investigated in aqueous media containing different amounts of these ions (26–2600 mg CN −/dm 3) and at different pH values. Examples of the use of the macromolecular chloramine as a polymer supported reagent for oxidation of cyanides in static and dynamic conditions are given. The data showed that the oxidative properties of the N-chlorosulfonamide resin in contact with cyanide ions are remarkable. Active chlorine easily oxidized cyanides forming cyanates (1000-times less toxic than cyanides). In contact with the resin the concentration of cyanides in the majority of tested solutions dropped below 0.05 mg CN −/dm 3. During oxidation processes the -S0 2NCINa groups transform to −SO 2NH 2 groups. They can be regenerated by the use of hypochlorite solutions.