长江中下游浅水湖沉积物对磷的吸附特征——吸附等温线和吸附/解吸平衡质量浓度

Characters of Phosphorus Sorption in Sediment of Shallow Lakes in the Middle and Lower Reaches of the Yangtze River:Sorption Isotherms and Adsorption-Desorption Equilibrium Mass Concentration

研究了长江中下游几个浅水湖泊表层沉积物磷吸附等温线和沉积物对磷的吸附 解吸平衡质量浓度。结果表明:沉积物对磷的吸附等温线同时符合Langmuir模型和Freundlich模型。据Langmuir模型计算,沉积物对磷的吸附容量为0 122～0 893mg g,且吸附容量与Al2O3,TFe2O3和有机磷(O-P)的含量均有较好的正相关关系。沉积物对磷的吸附存在吸附 解吸平衡点,不同沉积物在该点质量浓度为0 02～0 45mg L,有较大差异。该值与沉积物中总磷及无机磷有很好的正相关关系,与铁 铝磷及有机磷和有机质含量也有较好的正相关关系,而与钙磷及氧化钙只有较弱的正相关关系。结果还表明:富营养化严重的湖泊,沉积物有向上覆水释放磷的趋势。

Sorption isotherms of phosphorus and the phosphorus adsorption-desorption equilibrium mass concentration on surface sediments taken from the shallow lakes along the middle-lower reaches of the Yangtze River were determined in laboratory. The results indicated that adsorption isotherms curves were fitted to Langmuir equation as well as Freundlich equation. Based on Langmuir equation calculation, adsorption capacities varied from 0.122 to 0.893 mg/g, showing good affinities for Al_2O_3, TFe_2O_3 and O-P. Phosphorus adsorption-desorption equilibrium concentration was different on different sediments, and it varied from 0.02 to 0.45 mg/L. This concentration was significantly and positively correlated to total phosphorus and inorganic phosphorus, and preferably to Fe(Al)-P, O-P and organic matters, but inferiorly to Ca-P and CaO. The result also indicated that the sediment from heavy eutrophic lakes had the trend to release phosphorus into the overlying water.