Photocatalytic Oxidation Decomposition of Cyanide Ion Using Suspended TiO₂ Catalysts

Abstract

Photocatalytic oxidation of cyanide ion was investigated using two type of TiO₂ catalysts; Sample A, fine powder of anatase and rutile, and Sample B, pure anatase ultrafine powder. Cyanide ion was oxidized to CNO^-, and subsequently to NO₃^- and CO₃^2- ions with both catalysts. With Sample A, CN^- oxidation proceeded faster at higher initial concentration of CN^- and at lower initial concentration of KOH. In contrast, with Sample B, CN^- oxidation was faster when initial concentration of CN-, but KOH initial concentration effect appeared reversely. From there finding the authors proposed the different routes for sample A and B. On the other hand, the oxidation of CNO^- was faster despite of type of catalyst was used when initial KOH concentration was low. In the experimental range of present work, suitable range of quantity of photocatalyst used exists, and UV intensity affect linearly for oxidation of CN^- to CNO^-.