Kinetics and mechanism of TNT degradation in TiO2 photocatalysis.

The photocatalytic degradation of TNT in a circular photocatalytic reactor, using a UV lamp as a light source and TiO(2) as a photocatalyst, was investigated. The effects of various parameters such as the initial TNT concentration, and the initial pH on the TNT degradation rate of TiO(2) photocatalysis were examined. In the presence of both UV light illumination and TiO(2) catalyst, TNT was more effectively degraded than with either UV or TiO(2) alone. The reaction rate was found to obey pseudo first-order kinetics represented by the Langmuir-Hinshelwood model. In the mineralization study, TNT (30 mg/l) photocatalytic degradation resulted in an approximately 80% TOC decrease after 150 min, and 10% of acetate and 57% of formate were produced as the organic intermediates, and were further degraded. NO(-)(3) NO(-)(2), and NH(+)(4) were detected as the nitrogen byproducts from photocatalysis and photolysis, and more than 50% of the total nitrogen was converted mainly to NO(-)(3)in the photocatalysis. However, NO(-)(3) did not adsorbed on the TiO(2) surface. TNT showed higher photocatalytic degradation efficiency at neutral and basic pH.

[1]  R. Faure,et al.  Photocatalysed degradation of cyromazine in aqueous titanium dioxide suspensions: comparison with photolysis. , 2001 .

[2]  W. Lowe,et al.  Granular activated carbon pilot treatment studies for explosives removal from contaminated groundwater , 1992 .

[3]  G. Low,et al.  Effects of common inorganic anions on rates of photocatalytic oxidation of organic carbon over illuminated titanium dioxide , 1990 .

[4]  M. Hoffmann,et al.  Photocatalytic degradation of pentachlorophenol on titanium dioxide particles: identification of intermediates and mechanism of reaction , 1993 .

[5]  C. Minero,et al.  Photocatalytic interconversion of nitrogen-containing benzene derivatives , 1997 .

[6]  Dingwang Chen,et al.  Photodegradation kinetics of 4-nitrophenol in TiO2 suspension , 1998 .

[7]  James R. Clark,et al.  The toxic effects of trinitrotoluene (TNT) and its primary degradation products on two species of algae and the fathead minnow , 1976 .

[8]  L. Disalvo,et al.  Toxicity and mutagenicity of 2,4,-6-trinitrotoluene and its microbial metabolites , 1976, Applied and environmental microbiology.

[9]  J. Turner,et al.  Mechanistic studies of the photocatalytic behavior of titania: particles in a photoelectrochemical slurry cell and the relevance to photodetoxification reactions , 1991 .

[10]  G. Roam,et al.  Factors affecting the photocatalytic degradation of dichlorvos over titanium dioxide supported on glass , 1993 .

[11]  R. W. Matthews.  Kinetics of photocatalytic oxidation of organic solutes over titanium dioxide , 1988 .

[12]  M. Hoffmann,et al.  Photocatalytic oxidation of organic acids on quantum-sized semiconductor colloids. , 1994, Environmental science & technology.

[13]  Kimberly A. Gray,et al.  Photocatalytic transformation and mineralization of 2,4,6-trinitrotoluene (TNT) in TiO2 slurries , 1995 .

[14]  D. Kaplan,et al.  Mutagenicity of 2,4,6-trinitrotoluene-surfactant complexes , 1982, Bulletin of environmental contamination and toxicology.

[15]  F. Feeherry,et al.  Microbial transformation of 2,4,6-trinitrotoluene and other nitroaromatic compounds , 1976, Applied and environmental microbiology.

[16]  J. Yinon.  Toxicity and metabolism of explosives , 1990 .

[17]  Patrick J Shea,et al.  TNT transport and fate in contaminated soil , 1995 .

[18]  S. McEvoy,et al.  Formation of nitrate and ammonium ions in titanium dioxide mediated photocatalytic degradation of organic compounds containing nitrogen atoms , 1991 .

[19]  P. Pichat,et al.  Photocatalytic destruction of hazardous chlorine‐ or nitrogen‐containing aromatics in water , 1993 .

[20]  I. Poulios,et al.  Photodegradation of the textile dye Reactive Black 5 in the presence of semiconducting oxides , 1999 .

[21]  Michael K Stenstrom,et al.  Fenton oxidation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). , 2002, Water research.

[22]  A. Akgerman,et al.  Catalytic wet oxidation of phenol over a Pt/TiO catalyst , 1997 .

[23]  John L. Falconer,et al.  Mechanism of the Photocatalytic Oxidation of Ethanol on TiO2 , 1998 .

[24]  R. Spalding,et al.  Groundwater munition residues and nitrate near Grand Island, Nebraska, U.S.A. , 1988 .