Coupled Abiotic–Biotic Mineralization of 2,4,6‐Trinitrotoluene (TNT)

Abstract

Munitions wastes such as TNT are widespread contaminants in soils and ground waters. We investigated a coupled abiotic-biotic treatment scheme for remediation of aqueous solutions of TNT. Mineralization of aqueous TNT (0.22 mM) was initially optimized with minimum reactant use (Fe3+ and H2O2) in light-assisted and dark, modified Fenton reactions at acidic and neutral pH. Complete TNT degradation occurred under all reaction conditions within 24 h. Using the optimum reactant concentrations, coupled abiotic-biotic reactions showed an increase in TNT mineralization, from 47 to 80%, after biomass addition to the acidic, dark Fenton-like reaction. Comparable increases of TNT mineralization were observed under neutral pH with similar reaction conditions. In light-assisted Fenton-like reactions at neutral pH, no increase in cumulative TNT mineralization (66%) was seen in coupled abiotic-biotic reactions. Abiotic photo-Fenton-like reactions alone, at acidic pH, produced complete TNT mineralization and required no biotic assistance. While light-enhanced Fenton reactions alone can provide high levels of TNT mineralization, the dark abiotic-biotic reaction scheme has perhaps a wider use due to a similar extent of TNT mineralization in the absence of light, leading to possible applications in soil slurry and in situ processes in the subsurface.

Combined biological–chemical procedure for the mineralization of TNT

“…Combined degradation procedures have already been described in the literature Hess and Schrader 2002;Hwang et al 2000a, b;Kearney et al 1983;Schrader and Hess 2004), which, however, in contrast to our procedure all start with a photochemical treatment followed by a microbiological transformation. From a comparison of those results with the data presented here, the concept of a biological reduction of TNT prior to an oxidative photochemical treatment by advanced oxidation procedures (AOP) seems to be the most appropriate approach towards mineralization of TNT.…”

Combined chemical and biological oxidation of penicillin formulation effluent

“…However, integrated chemical-biological treatment of industrial effluents is generally found to derive both economic and technical advantages over chemical oxidation alone (Scott and Ollis, 1995). Studies have already been conducted successfully coupling biologicalC chemical oxidation for the treatment of originally refractory industrial pollutants in wastewater (Gulyas et al, 1995;Stockinger et al, 1995;Jochimsen et al, 1997;Benitez et al, 2001;Akmehmet Balcioglu and Arslan, 2001;Arslan-Alaton and Akmehmet Balcioglu, 2002;Hess and Schrader, 2002). To our knowledge, the integrated chemicalCbiological treatment of real antibiotic formulation wastewater has not been reported so far.…”

Studies on nitroaromatic compound degradation in modified Fenton reactions by electrospray ionization tandem mass spectrometry (ESI-MS-MS)

“…Research on advanced oxidation processes (AOPs) used to promote degradation of trinitrotoluene (TNT) and other nitroaromatic compounds, in soil or aqueous solutions, has included Fenton reactions [1][2][3] and, in aqueous solution, has used TiO 2 -mediated photocatalytic reactions. [4][5][6] In these studies, the authors reported that OH• was the active mechanism of destruction due to its nature as a nonspecific oxidant that reacted with many organic compounds at near diffusion controlled rates.…”