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


Uzunboy S., BENER M., Demirci-Çekiç S., APAK M. R.

International Journal of Environmental Science and Technology, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2024
  • Doi Number: 10.1007/s13762-024-05600-0
  • Journal Name: International Journal of Environmental Science and Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Agricultural & Environmental Science Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, CAB Abstracts, Compendex, Environment Index, Geobase, INSPEC, Pollution Abstracts, Veterinary Science Database
  • Keywords: Face-centered composite design, Fenton oxidation, Hydroxyl radicals, Sulfate radicals, TNT degradation
  • Istanbul University Affiliated: Yes

Abstract

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%, respectively, in the presence of K2S2O8 and H2O2. The persulfate-aided process was much less affected by •OH scavenger solvents such as t-butanol and DMSO. The novel persulfate-driven process was advantageously not affected from catalase (the H2O2 annihilator enzyme) which may exist in soil to eventually obstruct the H2O2 treatment of TNT wastes. This work establishes a comprehensive persulfate process for the first time and improves the existing process with H2O2 in the Fe(II)-EDTA degradation of TNT. Graphical abstract: (Figure presented.).