| Surface morphology and pore surface fractal characteristics of the sediment in the desilting basin of Queshan Reservoir were studied. Six sediment samples were collected and particle size, morphology, pore structure and fractal characteristics, surface elements distribution were analyzed as well. The objectives of this study were to investigate the reason for the differences among the pore surface fractal dimensions and fractal scales on the basis of different models, and discuss the effect of surface morphology of these sediment particles on their surface elements distribution. The results showed that these sediment particles with average diameter of 18-83 μm were mainly composed of clay, silt and fine sand. Their complex surface morphology and pore size distribution were reflected by wide range of the BET surface area (8.248-31.60 m2/g), average pore diameter (3.977-7.850 nm) and pore-size distribution (1.870-60.78 nm). Although the pore surface fractal dimensions (Ds), based on fractal FHH or thermodynamic models, were 2.67-2.89, and their fractal scales generally ranged from several nanometers to tens of nanometers, the differences were still observed in Ds values calculated from above two models because of inhomogeneity in surface pore size distribution. Therefore, the Ds based on pore-size distribution were 2.12-2.60, these values close to Ds calculated from fractal FHH models revealed that pore-size distribution could contribute significantly to Ds calculation. In addition, the heterogeneous surface adsorption sites of these sediment particles caused by much complex surface morphology had strong influence on the each element distribution on the particle surface. |
