Evidence for the presence of cyanide during carbon activation by KOH Original Research Article

The observation that carbon activation by KOH gives rise to a significant formation of cyanide moieties is confirmed. However, contrary to what has been reported, our results show that the N2 used as an atmosphere during the activation process has little to do with the formation of such cyanide moieties. The main source of cyanides is ascribed to structural nitrogen already present in the precursors. Reducing species (H2 and metallic K) formed during the KOH carbon activation process might promote the transformation of that structural nitrogen to cyanides. In order to minimise cyanide formation (and related environmental concerns), materials with low nitrogen content should be selected as precursors for the preparation of KOH-activated carbons.