Sediments are important sinks for hydrophobic compounds discharged to surface waters. Hydrophobic compounds tend to associate strongly with black carbon, which is thought to comprise a few percent of total organic carbon in aquatic sediments. Sorption to black carbon has been assumed to hinder degradation by pathways that occur in the aqueous phase. However, recent studies indicate that black carbon can mediate abiotic reduction and nucleophilic substitution reactions of nitrated organic compounds with hydrogen sulfide. In this study, we extended the applicability of black carbon-mediated reactions to a wider variety of contaminant structures, including nitrated and halogenated aromatic compounds, heterocyclic aromatic compounds, and halogenated alkanes. While both nitro- and halonitroaromatic compounds underwent black carbon mediate reaction with hydrogen sulfide, product analysis indicated that the nitro group was the primary site of attack.  We have also demonstrated that the reactivity of nitrated aromatics correlated with the calculated energy of the lowest unoccupied molecular orbital.

Use of pyrogenic carbonaceous materials for the in situ, abiotic destruction of sediment-associated hydrophobic organic compounds with hydrogen sulfide

248th National Meeting (2014)

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