Investigation and modeling of oxidative TNT degradation using Fe(II)-EDTA in conjunction with K2S2O8 and H2O2

Since 2,4,6-trinitrotoluene (TNT) is one of the most used explosives for military purposes or different industries such as mining and construction, it is highly probable to cause environmental pollution. Exposure to TNT can cause serious health problems in humans; therefore, its degradation is important. Two advanced oxidation processes (AOPs) were thoroughly investigated for TNT degradation in the presence of 0.04 M Fe(II)-EDTA complex at circumneutral pH (pH 6). In order to produce two different powerful oxidative radicals, namely, •OH and •SO4−, 100 mM H2O2 and K2S2O8 were used, respectively. Interferences of different radical scavengers possibly present in water and soil were also tested in detail. In order to determine TNT concentrations before and after AOP degradation, an existing colorimetric method was modified, depending on the formation of Meisenheimer anion of TNT. The optimal degradation conditions were experimentally determined and analyzed using face-centered composite design (FCCD) program. Both approaches showed that the most important parameters were the concentrations of Fe-EDTA and oxidant for TNT decomposition. The optimal degradation percentages were determined as 84 and 88