title: 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.
authors.affiliation: Center for Hazardous Waste Remediation and Research, Univ. of Idaho, Moscow 83844-0904, USA. tfhess@uidaho.edu
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Hess
authors.forename: Paul S
authors.initials: PS
authors.lastname: Schrader
mesh_terms: D001673:Biodegradation, Environmental; D002384:Catalysis; D006256:Hazardous Waste / Q000032:analysis*; D006801:Humans; D006861:Hydrogen Peroxide; D007477:Ions; D007501:Iron; D014303:Trinitrotoluene / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: C045076:Fenton's reagent; D006256:Hazardous Waste; D007477:Ions; D014874:Water Pollutants, Chemical; D014303:Trinitrotoluene; D006861:Hydrogen Peroxide; D007501:Iron