TiO(sub 2) photocatalysis for the destruction of organics and the reduction of heavy metals.

摘要

This paper describes laboratory work that investigates the applicability of TiO(sub 2) photocatalysis to the treatment of water contaminated with heavy metals and organics. It was found that Ag(I), Cr(VI), Hg(II), and PT(IV) are easily treated while Cd(II), Cu(II), and Ni(II) are not. The importance of the entire photocatalytic redox cycle is demonstrated by showing that the rates of oxidation (of organics) and reduction (of metals) are intrinsically interrelated. As a result, very efficient photocatalytic decontamination can be realized by applying the technology to water contaminated with the right mixtures of organic compounds and reducible, toxic metals. Data are presented showing how photoefficiencies decrease as light intensity increases in the range of 0 to 20 suns UV. For solar applications, this result suggests that one-sun systems are more efficient than those using concentrated solar radiation. It is also shown that photocatalysis is effective for treating the compound phenylmercuric chloride, suggesting that photocatalysis may find a niche for handling hard-to-treat organometallic complexes.