昆明湖沉积物的组成和理化性质的粒度响应

Size-Response Characteristics of Components and Physico-Chemical Quantity of Sediments in Kunming Lake

文章采用扫描电镜、激光粒度仪、X-射线衍射光谱仪、全谱直读ICP发射光谱仪等现代大型仪器鉴定和常规化学分析技术,对不同筛分粒径下昆明湖沉积物颗粒的组成、形貌及物理化学性质进行了综合分析。结果表明,昆明湖沉积物颗粒主要以粉粒和黏粒为主,具有晶体结构,平均粒径为22.37～160.17μm;呈现不规则的块、片状形貌,表面粗糙,包含褶皱和孔隙(多为大孔和中孔)。在不同粒度下,沉积物颗粒中多数金属元素在粒度为22.37～55.67μm范围含量较高,TN、TP含量:粉砂粒级>中细砂粒级,N、P主要富集于粒径小于63μm的沉积物之中;CEC在17.30～21.30 cmol/kg之间,Zeta电位随粒度的增加变化不大,在-16.6～-16.3 mV之间波动。昆明湖沉积物属中性偏碱沉积物,在粒度为28.45～100.28μm范围内有机质含量较高。

This paper describes the application of an array of sophisticated instruments,including scanning electronic microscope,laser granularity meter,X-ray diffraction spectrum and straight-read-ICP,to the study of sediments of Kunming Lake,a well-known landscape waterbody in Beijing.The study involves comprehensive analysis of sediment particles with different screening sizes with respect to composition,morphology and physico-chemical properties.Results show the particles with crystal structure and mean diameters ranging from 22.37 to 160.17 μm are mainly composed of clay and powder particles,with the chemical property from neutral to slightly alkaline.The particles with the size between 28.45 to 100.28 μm have higher organic contents.Other results cover the findings about particles morphologic properties,Zeta potential and the chemical elements content such as metals and nitrogen and phosphorus.