不同土壤物理性质下石油类污染物LIF发射特征研究

利用激光诱导荧光技术可对土壤中石油类污染物快速检测，不同土壤物理性质下，污染物荧光发射特征具有一定差异。为实现外场检测时快速制备合适的土壤样品，实验研究了土壤疏松度、颗粒度、湿度与土壤中石油类污染物荧光强度及光谱稳定性之间的关系。压片机压强大于2 MPa时土壤样品荧光光谱的稳定性较好，九种不同疏松度的土壤样品荧光强度的相对标准偏差为3.51%。不同粒径的机油土壤样品荧光强度差异较小，其中100目土壤样品的荧光光谱RSD值为2.25%。结果表明，土壤样品表面呈平整洁净时，所得样品荧光光谱的稳定性较好，土壤疏松度和颗粒度对荧光光谱的影响较小。湿度对土壤样品荧光发射的影响较大，当土壤湿度低于10%，荧光强度变化较小；湿度范围大于10%时，荧光强度变化较大。为利用LIF技术对外场土壤中石油类污染物检测时，快速有效制备土壤样品及准确测量提供参考。

Study on LIF Emission Characteristics of Petroleum Pollutants in Different Soil Physical Properties

The petroleum pollutants in soil can be rapidly detected with laser induced fluorescence technique. However, the fluorescence emission characteristic of each pollutant would be different under different soil physical properties. In order to prepare suitable soil samples rapidly in the field, the relationship between fluorescence intensity and spectral stability of soil organic pollutants, soil bulkiness, particle size and moisture was studied in this paper. The stability of the fluorescence spectra of the soil samples was better when the pressure was greater than 2 MPa, and the relative standard deviation of the fluorescence intensity of the nine soil samples with different porosity was 3.51%. The fluorescence intensity difference of the oil soil samples with different particle sizes was small, and the fluorescence spectrum RSD of 100-mesh soil samples was 2.25%. The results shows that the fluorescence spectrum is stable when the surface of the soil sample is flat and clean. The bulkiness and particle size of soil have little influence on fluorescence emission. When the soil moisture is less than 10%, the changes of fluorescence intensity is less significant , but when the humidity range is greater than 10%, the fluorescence intensity changes greatly. This paper provides references for the rapid and effective pretreatment and accurate measurement of petroleum contaminated soil samples in the field.