不同温度下西安汉城湖沉积物吸附、释放特性和磷形态

以西安汉城湖为研究对象，2015年4月对湖体沉积物进行现场调查和采样分析，共设4个采样点，研究不同温度下沉积物磷的吸附释放特性及沉积物磷形态的分布。结果表明，沉积物磷等温吸附随着温度的升高而增大，吸附特征符合修正的Langmuir模型，最大吸附容量Qmax的范围为507.21~786.77 mg·kg-1。磷动力学吸附主要发生在实验进行前12 h之内，吸附量基本达到或超过72 h吸附平衡时吸附总量的85%。磷动力学释放量范围为2.02~11.058 mg·kg-1，且在6 h达到最大值。沉积物总磷的含量范围为655.37~1.809.38 mg·kg-1，以无机磷为主，沉积物不同形态磷含量为TP > IP > HCl-P > OP > NaOH-P。沉积物富营养化风险指数ERI的范围为5.92~11.86，在10℃和20℃时，4个采样点的ERI均在10以下，属于低风险，在30℃时，4个采样点的ERI均在10以上，属于中等富营养化风险。

Phosphorus sorption,release characteristic under different temperature and phosphorus fractions in sediments of Hancheng Lake in Xi'an

To evaluate the effect of temperature on phosphorus sorption and release,sediments characteristics from 4 sample points in the Hancheng Lake in xi'an,China, were analyzed along with the Phosphorus fractions present in the sediments. The maximum P adsorption capacity ranged from 507.21 to 816.77 mg·kg-1 with an increase observed at equilibrium upon a rise in temperature.In addition, the sorption data fit the modified Langmuir isotherm model. In the initial 12 h of the experiment,the behavior of the P sorption kinetics and the sorption amount reached or exceeded 85% of the equilibrium sorption amount in 72 h.The amount of released P ranged 2.02 to 11.058 mg·kg-1,reaching a maximum at 6 h. Furthermore, the total P(TP)content in the sediment ranged from 655.37 to 809.38 mg·kg-1, with inorganic P(OP)being dominant. The contents of the different P components can be summarized as follows:TP > IP > HCl-P > OP > NaOH-P. Moreover, the eutrophication risk index of sediments varied from 5.92 to 11.86,with the indexes of the four sampling points being below 10 at 10℃and 20℃ meaning low risk,although at 30℃ the indexes exceeded 10 indicating moderate risk.