Reduction and persulfate oxidation of nitro explosives in contaminated soils using Fe-bearing materials.
The oxidative and reductive transformation of nitro explosives in contaminated soils with Fe-bearing materials and persulfate (S2O8(2-)) was examined via batch experiments. Zero-valent cast iron [Fe(0)], steel dust from a steel manufacturing plant, and FeS rapidly reduced 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in soil under anaerobic conditions as long as a sufficient amount of water was present. The Fe-bearing materials also effectively activated persulfate to enhance the oxidative transformation of TNT and RDX in soil-water systems. Kinetically, reductive and oxidative transformations removed more than 90% of the explosives from a soil-water system within 5 h under the given conditions. Pseudo-first-order rates in the range of 0.7-23.4 h(-1) were observed. By increasing the concentration of persulfate or Fe-bearing materials, the oxidative transformation could be promoted. Treated soils via redox reactions using the Fe-bearing materials did not show significant toxicity, except for the case of TNT-contaminated soils oxidized by FeS-assisted persulfate. Considering the kinetics of explosive degradation and the toxicity of treated wastewaters and soils, Fe(0) or steel dust-assisted persulfate oxidation may be a safe option as an ex situ remediation process for the treatment of explosive-contaminated soils.
Department of Civil and Environmental Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, South Korea. quartzoh@ulsan.ac.kr.
Seok-Young
SY
Oh
Department of Civil and Environmental Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, South Korea. quartzoh@ulsan.ac.kr.
Hyun-Su
HS
Yoon
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
Tae-Yong
TY
Jeong
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
Sang Don
SD
Kim
Department of Environmental Engineering, Kongju National University, Cheonan 31080, South Korea.
Dong-Wook
DW
Kim
D004787:Environmental Pollution; D052918:Environmental Restoration and Remediation / Q000379:methods*; D053834:Explosive Agents / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D056910:Republic of Korea; D012989:Soil Pollutants / Q000737:chemistry*; D014227:Triazines / Q000032:analysis; D014303:Trinitrotoluene / Q000737:chemistry*
D053834:Explosive Agents; D012989:Soil Pollutants; D014227:Triazines; D014303:Trinitrotoluene; D007501:Iron