Influence of Temperature and Oil Content on the Soil/Air Partition Coefficient for Hexachlorobenzene in Oil-Contaminated Rice Paddy Field Soil
2011
He, Xin | Chen, Shuo | Quan, Xie | Zhao, Huimin | Zhao, Yazhi
The soil/air partition coefficients (K SA ) for hexachlorobenzene (HCB) in oil-contaminated (crude oil and diesel) rice paddy field soils were measured in a solid fugacity meter at different oil concentrations over the temperature range of 5 to 30°C at 100% relative humidity. The results showed that values of K SA increased with a decrease of temperature. As for oil content, there is a critical separate phase concentration (CSPC) above which K SA increased with increasing of oil content. When oil content is above CSPC, oil plays a role as a separate phase that enhances the sorption capacity of the soil. At a given temperature (20°C) values of CSPC depended on the natural organic matter (NOM) contents of the soil, while for a given oil concentration they depended on the temperature. The normalized oil/air partition coefficients ) for HCB deduced from K SA for oils and experimentally determined with crude oil/quartz sand system were similar and 0.7–7 times higher than the normalized organic/air partition coefficient ), which implied that oil was a super sorbent. The enthalpies (ΔHSA) for crude oil and diesel were 64.9 and 55.7 kJ mol−1, respectively.
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