Oxidative-coupling reaction of TNT reduction products by manganese oxide

• Published in: Water research (Oxford) 2006-03, Vol.40 (5), p.903-910
• Main Authors: Kang, Ki-Hoon, Lim, Dong-Min, Shin, Hyunsang
• Format: Article
• Language: English
• Subjects: Applied sciences; Birnessite; chemical reactions; Decontamination. Miscellaneous; diaminonitrotoluenes; dinitroaminotoluenes; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Fe 0; Groundwaters; Iron - chemistry; Kinetics; manganese; Manganese Compounds - chemistry; Mn oxide; Natural water pollution; oxidation; Oxidation-Reduction; Oxidative-coupling reaction; oxidative-coupling reactions; oxides; Oxides - chemistry; Pollution; pollution control; Pollution, environment geology; reduction; reduction products; Soil and sediments pollution; Soil Pollutants; surface area; TNT; trinitrotoluene; Trinitrotoluene - chemistry; water pollution; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2005.12.036

Abiotic transformation of TNT reduction products via oxidative-coupling reaction was investigated using Mn oxide. In batch experiments, all the reduction products tested were completely transformed by birnessite, one of natural Mn oxides present in soil. Oxidative-coupling was the major transformation pathway, as confirmed by mass spectrometric analysis. Using observed pseudo-first-order rate constants with respect to birnessite loadings, surface area-normalized specific rate constants, k surf, were determined. As expected, k surf of diaminonitrotoluenes (DATs) (1.49–1.91 L/m 2 d) are greater about 2 orders than that of dinitroaminotoluenes (DNTs) (1.15×10 −2–2.09×10 −2 L/m 2 d) due to the increased number of amine group. In addition, by comparing the value of k surf between DNTs or DATs, amine group on ortho position is likely to be more preferred for the oxidation by birnessite. Although cross-coupling of TNT in the presence of various mediator compounds was found not to be feasible, transformation of TNT by reduction using Fe 0 followed by oxidative-coupling using Mn oxide was efficient, as evaluated by UV–visible spectrometry.