| The unique photoelectrochemical properties of titanium dioxide semiconductor materials (particles or wire electrodes) were exploited in order to decompose and detect a variety of organic compounds in aqueous and acetonitrile solutions.; A detailed investigation of a dark and illuminated photoelectrochemical detection system was completed as a function of solvent system, electrochemical and TiO{dollar}sb2{dollar} production variables. Detection limits of 10 ng and linearity over two orders of magnitude were demonstrated for p-aminoacetanilide and diethyl amine in acetonitrile. The photoelectrochemical detector is nonselective, responding to a variety of organic analytes including amines, aromatic alcohols, hydroquinones, aldehydes, and furans with redox potentials less positive than the valence band edge of the titanium dioxide semiconductor.; The photocatalytic destruction of a simulated exhausted copper plating bath (CPB) and its individual components in a bulk titanium dioxide slurry photoreactor was characterized with respect to pH, titanium dioxide photocatalyst concentration, oxygen purge, and the initial concentration and the type of compound decomposed. Reaction rates for each separate component were determined at pH 6 to be 154, 52, and 14 ppm/hr for sodium formate, EDTA, and SDS, respectively. In addition, a proprietary surfactant was decomposed at a rate of 12 ppm/hr at pH 2. The overall reaction rate for the complete simulated exhausted CPB at pH 2 was determined to be 51 ppm/hr. In general, the reaction rate and quantum efficiency increased with pH, oxygen and (TiO{dollar}sb2{dollar}).; Characterization of an aqueous particulate titanium dioxide photoelectrochemical slurry cell was undertaken with respect to cell and solution parameters, electrochemical variables, and quenching reactions using the rotating optical disk ring (RODRE) electrode. Analysis of the light-induced current transient data suggests that (1) the TiO{dollar}sb2{dollar} particles adsorb onto the electrode, (2) intermediates are generated in the light and dark, and (3) improved photocatalysis may occur at high mass transfer rates. |
