滇池沉积物磷酸盐吸附和矿物学特征的研究

Adsorption of Phosphate and Mineral Characteristic in Sediment in Dianchi Lake

采用现场采样及室内分析测定方法,研究了滇池沉积物的矿物学组成以及沉积物对磷酸盐的吸附特性。结果表明,滇池沉积物粘土矿物的主要成分为高岭石,水云母次之,还含有少量的蛭石、绿泥石和蒙脱石。沉积物对湖水中磷酸盐(PO4-P)的吸附主要发生在0～6h内,在0～0.5h吸附速率大于5.0mg·g-1·h-1,之后基本达到了一种动态平衡。沉积物对PO4-P的吸附量随着初始浓度的升高而增加,等温吸附线表明滇池表层沉积物对湖水PO4-P的吸附容量约为5.0mg·g-1。酸性条件下,沉积物对PO4-P的吸附量较大,随着pH值的升高,吸附能力逐渐减小。

The clay mineral composition of sediments from Dianchi Lake mainly constituted kaolinite, followed, by illite, and small amounts of vermiculite, chlorite and montmorillonite. The adsorption on surface of the sediments mainly occurred within 0～ 6 hour, and then reached a dynamic equilibrium after 6 h, thus the adsorption rate within 0～ 30 minutes was bigger than 5.0 mg· g- 1· h- 1. P adsorption amount on the sediments enhanced with the increasing initial phosphate concentration. The adsorption isotherms of phosphate indicated that the adsorbed capacity was about 5.0 mg· g- 1 on surface of the sediments. In acidic condition, the adsorption ability was bigger than that in alkaline condition, and declined gradually with the increasing pH.