西北旱作农田黄土指纹图谱的光谱学鉴定

采用扫描电子显微镜(SEM)、 X射线荧光光谱(XRF)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR) 等手段对西北典型旱作农田黄土样品进行表征，Tessier连续提取法分析黄土Pb的赋存形态及含量。结果发现：黄土样品比表面积较大 (291 m2·g-1)，粉粒土壤占到80.87%的比例。黄土表面轮廓清晰，可见颗粒聚集形成叠片状结构，晶片厚约3～5 μm。黄土矿物相主要为石英和钾云母，同时含有少量钾长石和蛇纹石等。FTIR图谱表明高岭石和方解石也是构成黄土样品的重要组分，但有机质的特征峰不明显，说明土样中有机质含量较低。Tessier连续提取法表明：土样中Pb全量比陕西省和全国土壤Pb的平均含量要高，其中残渣态Pb占Pb全量的64.04%。黄土指纹图谱的鉴定可以为后续污染土壤修复研究提供参考。

Spectral Identification of Fingerprint Spectrum of Loess of Arid Farmland in Northwest China

The approaches of scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR) were mainly used to analyze the loess characteristics of arid farmland in northwest China, and the Tessier sequential extraction method was utilized to determine the Pb content of different chemical speciation. The results showed: that the specific surface area is 291 m2·g-1 and the silt particles account for 80.87% of total loess samples. The sample structure, composed of particles, appears on clear surface with chip thickness of 3～5 μm. The dominant mineral phase is quartz and potassium mica, with small amounts of K-feldspar and serpentine. In addition, the kaolinite and calcite are important components indicated from FTIR spectra with low content of organic matter. The content of Pb in loess sample is higher than that of Shaanxi province and nationwide, the residual speciation of Pb accounts for 64.04% of total Pb content. The achievements are significant for the remediation of polluted soil in future.