Experimental study on nitrogen sorption and release in sediments of different functional areas in South Lake

South Lake, the landscape water in Changchun, is affected by human activities. The pollution has caused widespread concern. Although the water quality of South Lake has been improved after being taken a series of measures, the eutrophication problem still plagues researchers. In this paper, the laboratory simulation method was applied to study the sorption isotherms of sediments in South Lake, as well as the release characteristics of ammonia and TN under different temperatures and pH. The result shows that: When the ammonia of the overlying water was less than 10 mg/L, the adsorption presented linear trend. When the ammonia was over 10 mg/L, the adsorption presented a parabola. When the initial ammonia concentration was 17.9mg/L, the adsorption of nitrogen in the sediments of lotus pond reached the maximum 437.54mg/kg; When the initial ammonia concentration was 18.45mg/L, the adsorption of nitrogen in the sediments of the bridge reached the maximum 520.89mg/kg. The higher the temperature, the larger the release amount of TN and ammonia sediment was; The largest release of TN appeared at pH of 7, and for the ammonia, the peak emerged at pH of 10.