Interpreting Interactions between Ozone and Residual Petroleum Hydrocarbons in Soil

详细信息    查看全文

• 作者：Tengfei ChenAnca G. Delgado ; Burcu M. Yavuz ; Juan Maldonado ; Yi Zuo ; Roopa Kamath ; Paul Westerhoff ; Rosa Krajmalnik-Brown ; Bruce E. Rittmann
• 刊名：Environmental Science & Technology
• 出版年：2017
• 出版时间：January 3, 2017
• 年：2017
• 卷：51
• 期：1
• 页码：506-513
• 全文大小：439K
• ISSN：1520-5851

文摘

We evaluated how gas-phase O₃ interacts with residual petroleum hydrocarbons in soil. Total petroleum hydrocarbons (TPH) were 18 ± 0.6 g/kg soil, and TPH carbon constituted ∼40% of the dichloromethane-extractable carbon (DeOC) in the soil. At the benchmark dose of 3.4 kg O₃/kg initial TPH, TPH carbon was reduced by nearly 6 gC/kg soil (40%), which was accompanied by an increase of about 4 gC/kg soil in dissolved organic carbon (DOC) and a 4-fold increase in 5-day biochemical oxygen demand (BOD₅). Disrupting gas channeling in the soil improved mass transport of O₃ to TPH bound to soil and increased TPH removal. Ozonation resulted in two measurable alterations of the composition of the organic carbon. First, part of DeOC was converted to DOC (∼4.1 gC/kg soil), 75% of which was not extractable by dichloromethane. Second, the DeOC containing saturates, aromatics, resins, and asphaltenes (SARA), was partially oxidized, resulting in a decline in saturates and aromatics, but increases in resins and asphaltenes. Ozone attack on resins, asphaltenes, and soil organic matter led to the production of NO₃^–, SO₄^2–, and PO₄^3–. The results illuminate the mechanisms by which ozone gas interacted with the weathered petroleum residuals in soil to generate soluble and biodegradable products.