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 TiO2 films immobilized on a flexible fiberglass cloth (TiO2–FGC). The method consisted of pasting active TiO2 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 TiO2 particulates from different sources have been screened. The Degussa P-25 titania exhibited the greater photocatalytic activity. The hybrid TiO2–FGC specimens retained a greater quantity of the TiO2 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 TiO2–FGC specimens with processes occurring in TiO2 aqueous dispersions, on PA TiO2–FGC and SG TiO2–FGC specimens reveals that the hybrid TiO2–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 TiO2–FGC specimens show that such a reactor can be useful in a large-scale treatment of wastewaters.