| Abstract | The UV-induced photocatalytic degradation of two azo dyes, Methyl Red and Methyl Orange, has been carried out in aqueous media in the
presence of oleic acid (OLEA)- and tri-n-octylphosphine oxide (TOPO)-capped anatase TiO2 nanocrystal powders (mean particle size: 6 nm)
deposited onto a quartz substrate. The progress of photodegradation was followed by combining UVvis absorption measurements with
HPLCMS analysis. The abatement efficiency for the two organic compounds was compared with that obtained with commercial TiO2 P25
Degussa by evaluating a few significant variables, such as the dye chemical structure, pH of the solution, and catalyst surface status.
Identification of several by-products by HPLCMS analysis has allowed to propose a reasonable degradation pathway for both target
molecules. Significantly, although all titania catalysts were effective in removing both parent dyes and their related derivatives, the
degradation rate by the OLEA-capped TiO2 nanocrystals was double as that obtained with both its TOPO-capped analogous and TiO2 P25
Degussa. It is suggested that efficient catalysis strictly depends on microscopic mechanisms that occur at the catalyst surface, basically
involving specific dye adsorption and local density of terminal OH moieties. |
| Text | 39496 2005 Photocatalytic degradation of azo dyes by organic capped anatase TiO2 nanocrystals immobilized onto substrates R. Comparelli, E. Fanizza, M.L. Curri, P.D. Cozzoli, G. Mascolo, R. Passino, A. Agostiano aDipartimento di Chimica, Universita` di Bari, via Orabona 4, I 70126 Bari, Italy bCNR IPCF, Sez Bari c/o Dip. di Chimica, Universita` di Bari, via Orabona 4, I 70126 Bari, Italy cCNR IRSA, Sez. Bari, Via F. De Blasio 5, I 70123 Bari, Italy The UV induced photocatalytic degradation of two azo dyes, Methyl Red and Methyl Orange, has been carried out in aqueous media in the presence of oleic acid OLEA and tri n octylphosphine oxide TOPO capped anatase TiO2 nanocrystal powders mean particle size 6 nm deposited onto a quartz substrate. The progress of photodegradation was followed by combining UVvis absorption measurements with HPLCMS analysis. The abatement efficiency for the two organic compounds was compared with that obtained with commercial TiO2 P25 Degussa by evaluating a few significant variables, such as the dye chemical structure, pH of the solution, and catalyst surface status. Identification of several by products by HPLCMS analysis has allowed to propose a reasonable degradation pathway for both target molecules. Significantly, although all titania catalysts were effective in removing both parent dyes and their related derivatives, the degradation rate by the OLEA capped TiO2 nanocrystals was double as that obtained with both its TOPO capped analogous and TiO2 P25 Degussa. It is suggested that efficient catalysis strictly depends on microscopic mechanisms that occur at the catalyst surface, basically involving specific dye adsorption and local density of terminal OH moieties. 55 R. Comparelli, E. Fanizza, M. L. Curri, P. D. Cozzoli, G. Mascolo, R. Passino, A. Agostiano Applied Catalysis B Environmental, 2005, 55 2 , 81 91. 2005_Appl_Cat_B_Env_TiO2nano_.pdf Articolo in rivista Elsevier 0926 3373 Applied catalysis. B, Environmental Print Applied catalysis. B, Environmental Print Appl. catal., B Environ. Print Applied catalysis. Print FANIZZA ELISABETTA pantaleodavidecozzoli COZZOLI DAVIDE angela.agostiano AGOSTIANO ANGELA marialucia.curri CURRI MARIA LUCIA roberto.comparelli COMPARELLI ROBERTO giuseppe.mascolo MASCOLO GIUSEPPE |
