The reduction of 2,4,6-trinitrotoluene (TNT) in aqueous solution using nanoscale zero-valent iron (nZVI) was investigated. The results showed that the pseudo-first order reaction law fit the reduction of TNT. The measured apparent rate constant (K-abs) of TNT on nZVI (0.761 h(-1)) was 7.8-fold than on conventional iron powders (0.0979 h(-1)) at 303 K. The apparent activation energy (E-a) of nZVI reducing TNT was found to be 24.85 KJ/mol, which was decreased by 60% compared to employing conventional iron powders. The apparent rate constant of TNT reduction on nZVI also can be improved by an increase in nZVI concentration, reaction temperature and a decrease of pH. (C) 2008 Elsevier B.V. All rights reserved.