The Activity of TiO_2 and Heteropolytungstate-Modified TiO_2 in the Photocatalytic Degradation of Aqueous Cyanide

摘要

Photocatalytic oxidation of cyanide in water was studied. In the presence of P25, cyanate was produced prior to the other products, and nitrate was mainly formed as the cyanate decomposed. Photo-oxidation of cyanide occurred even without dissolved oxygen suggesting that water molecule could be a source of oxygen. Tungstophosphoric acid-modified titania (TPA/TiO_2) showed better activity than the corresponding pure titania. In the presence of OH· scavenger such as isopropyl alcohol and bromide, the activity of TPA/TiO_2 was retarded less than that of pure titania suggesting that the possibility of another reaction mechanism, probably direct oxidation by electron transfer.