Photodecomposition of a nonylphenol polyethoxylate surfactant in a cylindrical photoreactor with TiO2 immobilized fiberglass cloth

The photodegradation of p-nonylphenol polyethoxylate (NPE-9) has been examined in a large-scale circulating photoreactor to assess a set of different procedures to construct hybrid TiO(2) films immobilized on a flexible fiberglass cloth (TiO(2)-FGC). The method consisted of pasting active TiO(2) particles onto the fiberglass cloth support (PA method; 0.24 nm thick; weight, 210 g m(-2)), followed by a number of dip-coatings in a titania sol-gel solution (SG method). Various TiO(2) particulates from different sources have been screened. The Degussa P-25 titania exhibited the greater photocatalytic activity. The hybrid TiO(2)-FGC specimens retained a greater quantity of the TiO(2) catalyst on the FGC support than did the corresponding PA and SG samples. Comparison of the photodegradation of NPE-9 taking place in the various hybrid TiO(2)-FGC specimens with processes occurring in TiO(2) aqueous dispersions, on PA TiO(2)-FGC and SG Ti02-FGC specimens reveals that the hybrid TiO(2)-FGC specimens were the more photocatalytically active. Formic and acetic acids are two of the photo-oxidation intermediates identified in the degradation of NPE-9. Experimental conditions used in the present study to assess the cylindrical photoreactor containing the hybrid TiO(2)-FGC specimens show that such a reactor can be useful in a large-scale treatment of wastewaters. (C) 2002 Elsevier Science B.V. All rights reserved.