US EPA

1203997 

Journal Article 

An investigation of tio2 photocatalysis for the treatment of water contaminated with metals and organic-chemicals 

Prairie, MR; Evans, LR; Stange, BM; Martinez, SL 

1993 

1 

Environmental Science & Technology
ISSN: 0013-936X
EISSN: 1520-5851 

27 

9 

1776-1782 

English 

10.1021/es00046a003 

WOS:A1993LW24900014 

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Laboratory experiments were performed to investigate TiO2 photocatalysis for treating water contaminated with dissolved metals (Ag, Au, Cd, Cr, Cu, Hg, Ni, and Pt) and a variety of organics (e.g., methanol, formic acid, salicyclic acid, EDTA, phenol, and nitrobenzene). It was found that only those metals with half-reaction standard reduction potentials more positive than 0.3 V (vs normal hydrogen electrode) can be treated using TiO2 as the photocatalyst. Kinetic data illustrating the synergism between oxidation and reduction are presented. Experiments using singly substituted benzenes as electron donors show that the rate of reduction of Cr(VI) is correlated with Hammett sigma constants. Photoefficiencies approaching 85% were measured for the conversion of Cr(VI) to Cr(III) using citric acid as the reductant. In contrast, photoefficiency was only 4% when oxidizing salicyclic acid using O2 as the oxidant. It is concluded that efficient designs of photocatalytic systems 

Radiation-Radiation and Isotope Techniques; Biochemical Studies-General; Biochemical Studies-Minerals; External Effects-Light and Darkness; Toxicology-Environmental and Industrial Toxicology; Public Health: Environmental Health-Sewage Disposal and Sanitary Measures; Public Health: Environmental Health-Air