Latent photocatalytic behavior of semi-conducting poly(1-naphthylamine) nanotubes in the degradation of Comassie Brilliant Blue RG-250

TiO2 and ZnO have been extensively used as low price photocatalysts for the degradation of dyes. To enhance the photocatalytic activity of these inorganic oxides under the visible light irradiation, conducting polymers such as polyaniline (PANI) and its derivatives are generally used as photosensitizers. The present preliminary study explores, for the first time, the latent photocatalytic behavior of pure polymeric organic semiconductor - poly(1-naphthylamine) (PNA) nanotubes in the degradation of Comassie Blue (CB) dye under solar irradiation. Pristine PNA has band gap energy of 2.11 eV which can facilitate the excitation of electrons from its valence band to conduction band under visible light irradiation. In order to enhance the e(-)/h(+) separation and to prevent their recombination, simultaneous ultrasonic irradiation was used. Ultrasonic irradiation was found to accelerate the photodegradation and mineralization of CB dye. Sonophotocatalysis and sonolysis exhibited pseudo first order rate kinetics which was found to be in agreement with Langmuir Hinshelwood equation. The mechanism of sonophotocatalytic degradation and tentative photodegradation pathways have been proposed. (C) 2012 Elsevier B.V. All rights reserved.