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A B S T R A C TWe report on the photoelectrocatalytic degradation of the endocrine disruptor propyl paraben (PPB) using a TiO 2 nanotube (TiO 2 -NT) electrode prepared via chemical anodization, and a TiO 2 -NT electrode modified with WO 3 by electrodeposition. Solutions containing 50 mg L − 1 PPB were subjected to the photoelectrocatalytic process in a 0.2 L one-compartment electrochemical cell under UV/VIS irradiation, and the effects of bias potential (+ 0.5, + 1.0 and +1.5 V) and solution pH (3.0, 7.0 and 10) on the performances of the unmodified and modified electrodes were investigated. Scanning electron micrographs (SEM) showed that the nanotubes were highly organized and perpendicularly aligned with a mean length of 800 nm. According to energy dispersive X-ray and SEM analyses, the concentration of W in the TiO 2 -NT/WO 3 electrode was~0.75% and the distribution of the modifier was continuous and homogeneous on the surface, with pores uncovered and decorated with WO 3 . The photocurrent of the TiO 2 -NT/WO 3 electrode was improved by more than 20% in relation to its unmodified counterpart. The maximum degradation efficiencies were achieved at higher applied potentials and under acidic conditions for both electrodes. However, best results were obtained using the TiO 2 -NT/WO 3 electrode with an applied potential of + 1.50 V and at pH 3. Under these conditions, more than 99% of PPB was removed in 30 min and 94% mineralization was achieved in 60 min. The photoactivity of the electrode was highly stable even after exhaustive application, indicating that WO 3 deposition is an important method for improving the properties of TiO 2 -NT electrodes as applied to organic oxidation.

In the present work, the hybrid catalyst films of TiO 2 /CuO containing up to 10% in mol of copper were deposited onto glass surface. Precursor solutions were obtained by citrate precursor method. Films were porous and the average particle size was 20 nm determined by FEG-SEM analysis. The photocatalytic activities of these films were studied using Rhodamine B as a target compound in a fixed bed reactor developed in our laboratory and UV lamp. It was observed that the addition of copper to TiO 2 increased significantly its photocatalytic activity during the oxidation of Rhodamine B. The degradation exceeded 90% within 48 hours of irradiation compared to 38% when pure TiO 2 was used. Moreover, there was a reduction in the particles band gap energy when compared to that of pure TiO 2. These results indicate that the TiO 2 /CuO films are promising catalysts for the development of fixed bed reactors to be used to treat effluents containing azo dyes.

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The present work describes a suitable method for treatment of water contaminated with nitrate by using a photo-electrochemical method. A Cu/Cu

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