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15N NMR investigation of the reduction and binding of TNT in an aerobic bench scale reactor simulating windrow composting

Environmental Science and Technology

By:
, , and
DOI: 10.1021/es011382r

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Abstract

T15NT was added to a soil of low organic carbon content and composted for 20 days in an aerobic bench scale reactor. The finished whole compost and fulvic acid, humic acid, humin, and lignocellulose fractions extracted from the compost were analyzed by solid-state CP/MAS and DP/MAS 15N NMR. 15N NMR spectra provided direct spectroscopic evidence for reduction of TNT followed by covalent binding of the reduced metabolites to organic matter of the composted soil, with the majority of metabolite found in the lignocellulose fraction, by mass also the major fraction of the compost. In general, the types of bonds formed between soil organic matter and reduced TNT amines in controlled laboratory reactions were observed in the spectra of the whole compost and fractions, confirming that during composting TNT is reduced to amines that form covalent bonds with organic matter through aminohydroquinone, aminoquinone, heterocyclic, and imine linkages, among others. Concentrations of imine nitrogens in the compost spectra suggestthat covalent binding bythe diamines 2,4DANT and 2,6DANT is a significant process in the transformation of TNT into bound residues. Liquid-phase 15N NMR spectra of the fulvic acid and humin fractions provided possible evidence for involvement of phenoloxidase enzymes in covalent bond formation.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
15N NMR investigation of the reduction and binding of TNT in an aerobic bench scale reactor simulating windrow composting
Series title:
Environmental Science and Technology
DOI:
10.1021/es011382r
Volume
36
Issue:
17
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Science and Technology
First page:
3797
Last page:
3805