The adsorption characteristics of Cu(II) and Zn(II) on the sediments at the mouth of a typical urban polluted river in Dianchi Lake: taking Xinhe as an example

Abstract

This study is to determine the spatial distribution characteristics of Cu and Zn adsorption on the sediments of the estuary of Dianchi Lake, as well as the composite adsorption law of Cu and Zn on combinations of sediment organic matter, metal oxides, and organic–inorganic composites. The relationship between the adsorption contribution of each component of the substance. A static adsorption experiment was applied to the sediments in the estuary of Dianchi Lake. The relationship between adsorption capacity and sediment composition was analyzed through correlation analysis and redundant analysis. The results show that along the direction of the river flow and the vertical depth, the adsorption capacity presents a relatively obvious spatial distribution law; the change trend of sediment component content is not the same as the change trend of Cu and Zn adsorption capacity. The change trend of the sediment component content is not the same as the change trend of the adsorption amount of Cu and Zn, and the compound effect between the components affects the adsorption amount. The adsorption of Cu by the four groups of sediments after different treatments is more in line with the Freundlich isotherm adsorption model; When adsorbing Zn, the untreated and removed organic matter and iron-aluminum oxide group are in good agreement with the Freundlich model, while the organic matter-removed group and the iron-aluminum oxide removal group are more consistent with the Langmuir isotherm adsorption model; The adsorption contribution rate of organic–inorganic composites in sediments is not a simple addition of organic matter and iron-aluminum oxides, but a more complex quantitative relationship.

The Role of Surface Functional Groups of Iron Oxide, Organic Matter, and Clay Mineral Complexes in Sediments on the Adsorption of Copper Ions

“…The variation trend of the adsorption capacity of different components was inconsistent with SOM content, CEC, pH, iron oxide, and aluminum oxide, where the adsorption capacity did not exhibit a positive correlation with the factors. These results suggest that a high content of a certain component does not necessarily imply that it is the only factor driving the adsorption process [3]. minum oxides, and that of group C by pH.…”

“…Dianchi, the largest plateau and freshwater lake in the Yunnan Province, is located in the transition area between the river and lake and represents the most intense area of energy flow and material circulation. Additionally, the estuary is a place of abundant biodiversity within the lake [3]. Thus, the area is easily enriched through many factors, such as physical, chemical, or biological, leading to the diversification of metal-deposit forms at the estuary.…”

“…Sustainability 2023, 15, x FOR PEER REVIEW 3 of 17 biodiversity within the lake [3]. Thus, the area is easily enriched through many factors, such as physical, chemical, or biological, leading to the diversification of metal-deposit forms at the estuary.…”

“…Furthermore, factors such as estuary circulation and redistribution of river sediment (input, resuspension, exchange with the neighboring environment, etc. ), the salinity and pH of the waterbodies, redox, dissolved oxygen, and geological disturbances including earthquakes can affect the mobility and spatial distribution of metals through dissolution, deposition, and diffusion [3]. Pollutants can easily accumulate in river inlets, and the forms of metal deposition at estuaries show diversification [4].…”

“…Sediments are mainly composed of minerals (illite, kaolin, and montmorillonite). A combination of metal oxides (iron, aluminum, and manganese oxides) and organic matter (mainly humic and tannic acids) produce flocculent aggregates on the surface of mineral particles [3]. Metal-hydrated oxides and organic matter have surface hydroxyl groups that can adsorb metal ions, and clay minerals feature permanent structural charges.…”