内蒙古部分河段沉积物磷的赋存形态及吸附行为

Phosphorus Forms and Behavior of Adsorption of the Sediments in Some Reaches of Inner Mongolia

为了研究内蒙古部分河段沉积物对磷的赋存形态及吸附性,对4个采样点的理化性质、磷形态、动力学及热力学吸附行为进行模拟,运用动力学、热力学模型对数据进行拟合.结果表明:各河段沉积物对磷的吸附动力学符合Lagergren准二级吸附速率方程; Langmuir等温吸附方程能更好地描述出沉积物对磷的静态吸附为单分子层吸附.得出最大吸附量在0.15～0.52 mg/g之间,最大值出现在老哈河.各采样点沉积物中总磷含量在183～239 mg/kg,总磷中以无机态磷为主,而主要的赋存形态为原生碎屑磷.研究发现,各采样点沉积物的磷含量均高于其相应上覆水的磷含量,说明沉积物对上覆水中磷的吸附量小于沉积物自身的磷含量,所以沉积物表现为"源",有向上覆水释放磷的潜力.

To study the phosphorus forms and adsorption behavior of the sediments of some reaches in Inner Mongolia,the physical and chemical characteristics of the four sampling sites,phosphorus forms,dynamics and isothermal of adsorption behavior were simulated and the adsorption kinetic and thermodynamic model were used to fit the data.The results showed that the adsorption kinetics of phosphorus in sediments of each reach conformed to the Lagergren quasi-second adsorption rate equation and the Langmuir isothermal adsorption equation was more suitable to describe the characteristics of static which was monolayer adsorption of phosphorus in sediments.It was found that the maximum adsorption capacity(Q max)of the four sampling sites was within 0.15~0.52 mg/g and the maximum value appeared in the Laoha River.The content of total phosphorus in the sediments of four sampling sites was 183~239 mg/kg,which formed mainly in inorganic and primary detritus.The investigation demonstrated that the phosphorus content of the sediment at each sampling site was higher than the corresponding overlying water,suggesting that amount of phosphorus adsorption of sediment from the overlying water was less than the phosphorus content of the sediment.So,the sediment is a“source”,which has the potential to release phosphorus to overlying water.