Utilizing sieving, sedimentation, centrifugation and cross-flow filtration (CFF), the particle size in yellow-brown soil was sequentially fractionated into five scales including fine sand (50～250μm), silt (5～50μm), coarse clay (1～5μm), fine clay (0.1～1μm), and nanocolloids(<0.1μm). Laser granulometry, transmission electron microscopy (TEM), and x-ray diffraction (XRD) were used to characterize these particles with different size. Results showed that the determined size of each particle was well consistent with the theoretical fractionation scale, indicating the availability and reasonableness of the fractionation method. TEM test displayed that nanocolloids were uniformly spherical with size range of 20~40 nm and good dispersion and distribution, but presented a few large granular aggregates.%以去离子水为分散剂,采用连续分级法,结合使用筛分、沉降、离心及错流超滤(CFF)等技术,将60目黄棕壤提取分级为细砂粒(50～250μm)、粉粒(5～50μm)、粗黏粒(1～5μm)、细黏粒(0.1～1 μm)、纳米微粒(＜0.1 μm)5个组分；采用激光粒度仪、透射电镜(TEM)、X射线衍射(XRD)等方法对分级结果进行了表征.激光衍射粒度分析所测得各组分实际粒径分布结果与划定的粒径分级范围均很好吻合,表明按上述方法对土壤颗粒进行分级是有效、可行的.TEM观察到的纳米粒级成分呈规则球形,绝大部分颗粒粒径在20～40nm之间,有少部分大颗粒团聚体存在.
展开▼
