TY - JOUR
T1 - Photochemical transformation of the insensitive munitions compound 2,4-dinitroanisole
AU - Rao, Balaji
AU - Wang, Wei
AU - Cai, Qingsong
AU - Anderson, Todd
AU - Gu, Baohua
N1 - Funding Information:
We thank Donna Kridelbaugh of ORNL for her technical editing of the manuscript. We also thank Xiangping Yin and Prasesh Sharma of ORNL for their help with the HPLC analysis. This research was supported in part by the Strategic Environmental Research and Development Program (SERDP) of the U.S. Department of Defense . Oak Ridge National Laboratory is managed by UT-Battelle, LLC for the U.S. Department of Energy under contract DE-AC05-00OR22725 .
PY - 2013/1/5
Y1 - 2013/1/5
N2 - The insensitive munitions compound 2,4-dinitroanisole (DNAN) is increasingly being used as a replacement for traditional, sensitive munitions compounds (e.g., trinitrotoluene [TNT]), but the environmental fate and photo-transformation of DNAN in natural water systems are currently unknown. In this study, we investigated the photo-transformation rates of DNAN with both ultraviolet (UV) and sunlight irradiation under different environmentally relevant conditions. Sunlight photo-transformation of DNAN in water was found to follow predominantly pseudo-first-order decay kinetics with an average half-life (t1/2) of approximately 0.70d and activation energy (Ea) of 53kJmol-1. Photo-transformation rates of DNAN were dependent on the wavelength of the light source: irradiation with UV-B light (280-315nm) resulted in a greater quantum yield of transformation (φUV-B=3.7×10-4) than rates obtained with UV-A light (φUV-A=2.9×10-4 at 316-400nm) and sunlight (φsun=1.1×10-4). Photo-oxidation was the dominant mechanism for DNAN photo-transformation, based on the formation of nitrite (NO2-) and nitrate (NO3-) as major N species and 2,4-dinitrophenol as the minor species. Environmental factors (e.g., temperature, pH, and the presence or absence of naturally dissolved organic matter) displayed modest to little effects on the rate of DNAN photo-transformation. These observations indicate that sunlight-induced photo-transformation of DNAN may represent a significant abiotic degradation pathway in surface water, which may have important implications in evaluating the potential impacts and risks of DNAN in the environment.
AB - The insensitive munitions compound 2,4-dinitroanisole (DNAN) is increasingly being used as a replacement for traditional, sensitive munitions compounds (e.g., trinitrotoluene [TNT]), but the environmental fate and photo-transformation of DNAN in natural water systems are currently unknown. In this study, we investigated the photo-transformation rates of DNAN with both ultraviolet (UV) and sunlight irradiation under different environmentally relevant conditions. Sunlight photo-transformation of DNAN in water was found to follow predominantly pseudo-first-order decay kinetics with an average half-life (t1/2) of approximately 0.70d and activation energy (Ea) of 53kJmol-1. Photo-transformation rates of DNAN were dependent on the wavelength of the light source: irradiation with UV-B light (280-315nm) resulted in a greater quantum yield of transformation (φUV-B=3.7×10-4) than rates obtained with UV-A light (φUV-A=2.9×10-4 at 316-400nm) and sunlight (φsun=1.1×10-4). Photo-oxidation was the dominant mechanism for DNAN photo-transformation, based on the formation of nitrite (NO2-) and nitrate (NO3-) as major N species and 2,4-dinitrophenol as the minor species. Environmental factors (e.g., temperature, pH, and the presence or absence of naturally dissolved organic matter) displayed modest to little effects on the rate of DNAN photo-transformation. These observations indicate that sunlight-induced photo-transformation of DNAN may represent a significant abiotic degradation pathway in surface water, which may have important implications in evaluating the potential impacts and risks of DNAN in the environment.
KW - 2,4-Dinitroanisole
KW - 2,4-Dinitrophenol
KW - Insensitive munitions
KW - Nitrate
KW - Photo-transformation
KW - Sunlight
UR - http://www.scopus.com/inward/record.url?scp=84870715235&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2012.11.033
DO - 10.1016/j.scitotenv.2012.11.033
M3 - Article
C2 - 23228715
AN - SCOPUS:84870715235
VL - 443
SP - 692
EP - 699
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -