| 摘要: |
| 河流泥沙是水生态系统生源要素的重要附着载体，其微形貌及电荷特性直接关系着泥沙对溶解态的营养盐或污染物的吸附能力。本研究选取澜沧江中下游干流及主要支流为考察对象，采集28个河流水库断面的悬移质泥沙，采用原子力显微镜测定泥沙微表面电荷量，探究澜沧江泥沙的微表面电荷性质，研究纳米尺度下泥沙的微表面特性。研究结果表明：（1）微观界面，形貌对表面电荷分布影响明显，在纳米尺度下电势图与相位差图均展现出明显非均匀分布特征；（2）在流域分布上，不同区域表面电荷存在较大差异，流域沿程变化对泥沙表面电荷产生重要影响，总体变化呈现先减小后增大的趋势，表面电势值变化范围为-201.47~35.34 mV，表面电荷密度范围0.07?~3.65 m C/m2，不同区域电荷特性差别明显；（3）在梯级水电筑坝影响下，坝上坝下泥沙颗粒电势差与水库库容存在较好的线性相关关系，相关系数为0.8214，且坝下电势普遍高于坝上区域；（4）泥沙表面电势与磷吸附之间具有较强相关性，其相关系数为0.6657，同时表现出较好的线性拟合关系。研究结论对深入理解水电大坝建设对流域内污染物的迁移转化及解释泥沙的表面电性特征与污染物的吸附解吸机制具有重要科学意义，同时也可为流域水沙环境调控提供理论依据。 |
| 关键词: 澜沧江 河流泥沙 表面电势 表面电荷密度 原子力显微镜 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目（42061006，41571032） |
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| The relationship between microsurface charge characteristics and phosphorus adsorption of sediments in the middle and lower reaches of Lancang River |
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hanyidi, fukaidao, zhuqi, zhangnian
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Institute of International Rivers and Ecological Security, Yunnan University
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| Abstract: |
| The micromorphology and charge characteristics of river sediments play a crucial role in their ability to adsorb dissolved nutrients and pollutants, serving as essential carriers of biogenic elements in aquatic ecosystems. This study focused on the mainstream and major tributaries in the middle and lower reaches of the Lancang River. We collected suspended sediments from 28 river sections and utilized atomic force microscopy to measure their microsurface charges, aiming to illuminate the microsurface charge properties of Lancang River sediments and, by extension, the microsurface properties of bottom sediment. Our research revealed key findings: (1) Sediment morphology significantly influenced surface charge distribution at the microscopic level. Potential and phase difference maps showed distinct non-uniform patterns at the nanoscale. (2) Substantial variations in surface charge existed across different watershed regions, with changes along the watershed having a pronounced impact. These changes followed a decreasing-then-increasing trend, displaying surface potential values from -201.47 to 35.34 mV and surface charge density varying from 0.07 to 3.65 m C/m2. (3) The construction of terraced hydropower dams notably influenced sediment surface charge. The potential difference between sediment particles upstream and downstream of the dam exhibited a significant linear correlation with reservoir capacity, with a correlation coefficient of 0.8214; (4) The surface potential of sediment demonstrated a robust correlation with the variation pattern of phosphorus, as evidenced by a correlation coefficient of 0.6657. This relationship was further underscored by a well-fitted linear model. Generally, potentials were higher below the dam compared to above the dam. These research findings have significant scientific implications for understanding pollutant transport within watersheds, elucidating the surface electrical attributes of sediment, and comprehending the mechanisms of pollutant adsorption and desorption. |
| Key words: Lancang River river sediment surface potential surface charge density atomic force microscope |
