Composition Characteristics Of Organic Matter In Sediments Of Taihu Lake And Its Effect On Phosphorus Adsorption

Phosphorus is one of the main nutrient elements in lake eutrophication,the migration and transformation of phosphorus in sediment water interface is an important process that affects the concentration of phosphorus in water.In aquatic ecosystems,the process is influenced by the external factors of the water environment,but also affected by sediment characteristics.In order to study the relationship between phosphorus transport and transformation process and the characteristics of the sediment,the rich lake eutrophication in Taihu Lake as the research object,based on the field sampling method of combining analysis and indoor simulation experiment and analysis for different lake sediment organic matter,phosphorus content and composition characteristics,with different contents on the role of organic sediment phosphorus isothermal adsorption characteristics of organic matter in sediments of phosphorus adsorption and desorption of.The main conclusions of the study are as follows:1,The total organic matter content of Taihu sediments was 1.12-2.61%,with an average of1.60%.Zhushan Bay,Meiliang Bay and Xukou Bay sediment total concentration of organic matter to higher than other lakes.In sediment total organic matter,active organic matter accounted for the proportion of Taihu Lake sediment total organic matter 26-39% and active organic matter and total organic matter spatial trend of change is consistent.The proportion of dissolved organic matter in Taihu sediments is 9-24%,and its spatial difference is small.In the analysis of the ultraviolet spectrum,the molecular weight of the organic matter in Taihu is larger,and the degree of the higher degree of the humus is higher,The rich nutrition level of the highest Zhushan Bay,Fang of the organic matter in sediments of Meiliang Bay,constitutive high level and aromatic groups were higher.2,Based on physical and chemical methods of sediment organic matter fractions were analyzed.The results showed that the recombinant in the surface sediment of Taihu Lake is divided into the content of organic matter is much higher than that of light fraction organic matter,the content of up to 1.48 percent.Different in Taihu lake,Zhushan Bay,restructuring the highest content of organic matter.In the reorganization,High active humic acid and humic acid calcium in Meiliang Bay,Zhushan bay for recombination fraction is 58-65%,the proportion of higher than other lakes.3,The grain size of sediments in Taihu is mainly clay and silt,its content is about 93.81-96.09%.Taihu sediment total phosphorus content is 0.39-1.31mg/g,the highest content of Zhushan Bay 1.31mg/g.The contents of inorganic phosphorus is 0.23-0.91mg/g,ratio of total phosphorus was 58-76%,which was the highest content of 0.91mg/g in Zhushan bay.Sediment organic phosphorus content is 0.10-0.18mg/g,accounted for the proportion of total phosphorus for 14-31%.sediment iron and aluminum combined phosphorus content is 0.09-0.66mg/g,sediment naoh-p accounted for the proportion of total phosphorus24-50%.sediment of calcium and phosphorus content for the 0.19-0.29mg/g,the difference is small,accounted for the proportion of total phosphorus in the sediment 22-70%.4,The adsorption equilibrium of phosphorus in the sediments of Taihu lake is consistent with the Langmuir equation,The maximum adsorption amount of Xm was 5140(mg/kg).EPCo was 0.04-0.31mg/L,and the adsorption constant a showed a negative correlation.Comparison of EPCo and total phosphorus in the sediments of different lakes in Taihu.The center of the lake area,lake bay,west of Taihu and the mercury Bay Xukou EPCo is significantly greater than the total phosphorus concentration in the overlying water,Indicates that these areas have the risk of phosphorus release from sediments to the water body,while the South Taihu EPCo is less than the total phosphorus concentration of the overlying water,and the sediment to a certain extent,the adsorption of water phosphorus.5,Reorganization of sediment on phosphorus maximum adsorption amount 2780 mg/kg was the highest and the desorption rate of 8% is the lowest,indicating that the recombination of phosphorus adsorption capacity of the largest and the phosphorus has better accumulation,in lake sediments on the phosphorus mainly the "sink",it of lake eutrophication is mainly inhibitory effect.Removal of residual organic matter in sediments is less than that of the original sediments,The loss of organic matter leads to the decrease of the sorption capacity of sediment to phosphorus.The higher organic matter content in the sediment of Taihu,the higher the activity,the higher the phosphorus uptake,the stronger the ability of organic matter to phosphorus element.