Nitroaromatic compounds degrading

Hess, T.F., Renn, T.S., Watts, R.J., Paszczynski, A.J. (2(X)3) Studies on Nitroaromatic Compound Degradation in Modified Fenton Reactions by Electrospray Ionization Tandem Mass Spectrometry (ESI-MS-MS). Analyst 128 156-160. 

Klupinski et al. (2004) conclude that the reduction of nitroaromatic compounds is a surface-mediated process and suggest that, with lack of an iron mineral, reductive transformation induced only by Fe(II) does not occur. However, when C Cl NO degradation was investigated in reaction media containing Fe(II) with no mineral phase added, a slow reductive transformation of the contaminant was observed. Because the loss of C Cl NO in this case was not described by a first-order kinetic model, as in the case of high concentration of Fe(II), but better by a zero-order kinetic description, Klupinski et al. (2004) suggest that degradation in these systems in fact is a surface-mediated reaction. They note that, in the reaction system, trace amounts of oxidize Fe(II), which form in situ suspended iron oxide... 

Higson FK. 1992. Microbial degradation of nitroaromatic compounds. Adv AppI Microbiol 37 1-19 Hine J, Mookerjee PK. 1975. The intrinsic hydrophilic character of organic compounds Correlations... 

The Simplot Anaerobic Biological Remediation (SABRE ) process is a patented, ex situ technology used to treat soils contaminated with nitroaromatic compounds. Researchers isolated a selection of anaerobic bacteria based on their ability to degrade nitroaromatic compounds with the total destruction of intermediate compounds by the completion of treatment. These bacteria are the basis of the SABRE process. 

Degradation of nitroaromatic compounds is possible at temperatures much lower than optimal for most bioremedial technologies. 

Until very recently, explosives-contaminated soils have been remediated by incineration, a process whose high cost has stimulated the search for a more economical cleanup method (Roberts et al., 1993). Microbially mediated degradation of explosives is a promising technology. Many researchers have studied microbial consortia and various pure cultures for their ability to degrade TNT and other nitroaromatic compounds (for a review see Crawford, 1995), bringing about the development of bioremediation processes that can remove TNT and other explosives from contaminated soil and water (Funk etal., 1995 Williams a/., 1992). 

Degradation of nitroaromatic compounds by UV/1i02. (From Dillert, R., Brant, M., Siebers, U., and Bahnemann, D., Chemosphere, 30(12), 2333, 1995. With permission.)... 

Photosensitization for the removal of certain pollutants in photolytic processes can contribute significantly to the degradation rate. Thus, Simmons and Zepp [88] observed increases of up to 26 times of the photodegradation rates of nitroaromatic compounds due to the action of natural or commercial humic substances with solar irradiation. In another work [89], the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) was irradiated in water with 300 nm light in the presence of different photosensitizers. This compound, which does not photolyze directly at this wavelength, could be degraded more than 95% in 5 hr when riboflavin was used as photosensitizer. 

Fritsche W et al., Fungal degradation of explosives TNT and related nitroaromatic compounds, in Biodegradation of Nitroaromatic Compounds and Explosives, Spain JC, Hughes JB, and Knackmuss H-J, Eds., CRC Press, Boca Raton, FL, 2000, 213. 

Binding of molecules of TNT or any one of a suite of related nitroaromatic compounds commonly associated with the presence of TNT (for example, 2,4-dinitrotoluene), or photochemical or microbial degradation products of TNT (1,3-dinitrobenzene or amino-dinitrotoluenes) results in a dramatic reduction in the emission intensity of films of AFP. The reduction in emission intensity is proportional to the mass of quencher adsorbed by the films and is measured by the sensor system. A schematic of an early Fido prototype is shown in Figure 4. 

Nishino SF, Spain JC, He Z. (2000). Strategies for the aerobic degradation of nitroaromatic compounds by bacteria Process discovery to field application. In Biodegradation of Nitroaromatic Compounds and Explosives (eds. JC Spain, JB Hnghes, H Knackmnss). Boca Raton, FL Lewis Publishers, pp. 1 7. 

Figure 1. Microbial degradation of nitroaromatic compounds [23]. —, steps...

Nitroaromatic compounds (NACs) are widely used as pesticides, explosives, solvents, and intermediates in chemical syntheses. NACs and their degradation products pose a potential threat to ecological and human health because they are toxic environmental contaminants commonly found in soil and subsurface environments at elevated concentrations. At a site in Texas, for example, soil concentrations of NAC contaminants in excess of 75,000 mg/kg have been reported and have been detected at depths of greater than 30 meters at concentrations above human health exposure limits (1). In general, NACs degrade relatively slowly in the environment (2,3). Recent evidence has shown that certain NACs have a high affinity for certain types of clay minerals, and this may contribute to their recalcitrant behavior (4-11). This chapter will examine the chemical mechanisms that govern NAC-clay interactions from two perspectives. First, we will examine... 

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