Studies on the photodegradation of Rhodamine dyes on nanometer-sized zinc oxide.

The nanometer-sized ZnO was prepared through the sol-gel method. Its average particle diameter, determined by TEM, was 20-30 nm. The specific surface area was determined to be 22 m2 g(-1) by BET. The photodegradation mechanism of Rhodamine dyes on nanometer-sized ZnO was studied by dynamic molecular spectra, and the results showed that the photodegradation of Rhodamine dyes obeyed the rules of a pseudo first-order kinetic reaction. The rate constant k of the degradation of Rhodamine B (RB) and butyl-Rhodamine (BR) were 0.0128 and 0.0154 min(-1), respectively, and the half period t(1/2) were 60 and 52 min, respectively. The photodegradation reaction conditions were optimized. After intermixing with silver, the photodegradation efficiency was greatly improved. A life-span test showed that nanometer-sized ZnO had a long life-span.

[1]  Marc A. Anderson,et al.  Semiconductor clusters in the sol-gel process: quantized aggregation, gelation, and crystal growth in concentrated zinc oxide colloids , 1991 .

[2]  Gongxuan Lu,et al.  Adsorption and photo-induced reduction of Cr(VI) ion in Cr(VI)-4CP (4-chlorophenol) aqueous system in the presence of TiO2 as photocatalyst , 1998 .

[3]  G. Colón,et al.  Photocatalytic deactivation of commercial TiO2 samples during simultaneous photoreduction of Cr(VI) and photooxidation of salicylic acid , 2001 .

[4]  W. E. Mourad,et al.  Photocatalytic reduction of environmental pollutant Cr(VI) over some semiconductors under UV/visible light illumination , 1998 .

[5]  B. Ohtani,et al.  Role of platinum deposits on titanium(IV) oxide particles : structural and kinetic analyses of photocatalytic reaction in aqueous alcohol and amino acid solutions , 1997 .

[6]  P. Kamat.  Photoelectrochemistry in particulate systems. 9. Photosensitized reduction in a colloidal titania system using anthracene-9-carboxylate as the sensitizer , 1989 .

[7]  Prashant V. Kamat,et al.  Environmental Photochemistry on Semiconductor Surfaces: Photosensitized Degradation of a Textile Azo Dye, Acid Orange 7, on TiO2 Particles Using Visible Light , 1996 .

[8]  A. Sclafani,et al.  Effect of silver deposits on the photocatalytic activity of titanium dioxide samples for the dehydrogenation or oxidation of 2-propanol , 1991 .

[9]  T. Yoko,et al.  Sol—gel preparation and photoelectrochemical properties of TiO2 films containing Au and Ag metal particles , 1996 .

[10]  Detlef W. Bahnemann,et al.  Preparation and characterization of quantum size zinc oxide: a detailed spectroscopic study , 1987 .

[11]  P. Seybold,et al.  A spectroscopic/thermodynamic study of the rhodamine B lactone ⇌ zwitterion equilibrium , 1988 .

[12]  K. Honda,et al.  Photocatalysis through excitation of adsorbates. 1. Highly efficient N-deethylation of rhodamine B adsorbed to cadmium sulfide , 1977 .

[13]  S. Martin,et al.  Environmental Applications of Semiconductor Photocatalysis , 1995 .

[14]  A. Bard,et al.  Heterogeneous photocatalytic oxidation of hydrocarbons on platinized titanium dioxide powders , 1980 .

[15]  B. Viswanathan,et al.  Rhodium and rhodium sulfide coated cadmium sulfide as a photocatalyst for photochemical decomposition of aqueous sulfide , 1990 .

[16]  Horst Weller,et al.  Photochemistry and radiation chemistry of colloidal semiconductors. 23. Electron storage on zinc oxide particles and size quantization , 1988 .

[17]  J. Yates,et al.  Photocatalysis on TiO2 Surfaces: Principles, Mechanisms, and Selected Results , 1995 .

[18]  N. Serpone,et al.  Application of concept of relative photonic efficiencies and surface characterization of a new titania photocatalyst designed for environmental remediation , 1996 .