长江中下游平原三个湖泊表层沉积物对磷的吸附特征

以长江中下游太湖、巢湖和龙感湖等3个湖泊表层沉积物(0～1cm)为对象,研究了不同沉积物对湖水中磷的吸附特性,并探讨了沉积物表面特性和化学组分等因素对磷的吸附行为的影响.结果表明:表层沉积物对磷的吸附作用主要发生在快吸附过程的前1～2h之内;湖泊表层沉积物对磷的吸附基本符合修正后的Langmuir型等温方程,不同采样点的表层沉积物中本底磷吸附量(QNAP)以及磷饱和吸附量(Qmax)差别显著,与采样点所处环境条件有很大关系.同时,沉积物的饱和吸附量与比表面积、活性铁、铝含量和有机质含量有较好的正相关性,相关系数分别为0 92,0 98,0 78和0 96;活性铁、铝含量与有机质含量之间也有较好的正相关性;颗粒物Zeta电位在一定程度上影响沉积物对磷的吸附能力.

Characteristics of phosphorus sorption on surface sediments in three shallow lakes in the Yangtze River Basin

Phosphorus sorption (P sorption) on surface sediments in three shallow lakes in Yangtze River Basin was studied. The results indicated that P sorption mainly occurred within 2 h during the fast sorption process. P sorption on the sediments could be well fitted to the Langmuir isotherm equation modified with the native adsorbed phosphorus (NAP). The P sorption capacity and NAP varied from different sediment samples, depending on the site-specific environmental conditions. And the P sorption capacities were closely related to the specific surface area,the contents of iron/aluminum (oxy) hydroxides and organic matter. The correlation coefficients of on thes components were 0.92, 0.98, 0.78 and 0.92, respectively. The contents of iron/aluminum (oxy) hydroxides were also closely correlated with the contents of organic matter. P sorption was slightly affected by Zeta potential of sediments.