Oxidation of trichloroethylene in a porous medium with permanganate

摘要

Two sets of laboratory-scale column experiments were conducted to investigate permanganate oxidation of TCE in a sandy soil. In the first set of experiments, TCE either in dissolved phase (approx 0.005 g) or in free phase (approx 0.32 g) in soil was oxidized with KMnO_4 to evaluate the extent of reaction. In the second set of experiments, the impact of the reduction products [manganese dioxide (MnO_2) and protons] on the soil system was examined. Experiments indicated that KMnO_4 completely mineralized TCE when TCE was present in the sand in either a dissolved or a pure phase. Experiments of the impact of the reduction products on the soil showed that the pH value in the column effluent decreased from 6.7 to <2.0 in two columns with free phase TCE (7.6 and 16.3 g) present. Total dissolved iron (Fe_T), used as an indicator of metal leaching from the soil, increased as pH decreased, implying that low pH conditions, a result of TCE-KMnO_4 reactions, may facilitate metal leaching from the soil. MnO_2 was the dominant Mn species of the KMnO_4 reduction even under low pH (approx 2) conditions. At a pore velocity of 1 m/d, approximately 50