长江中下游平原三个湖泊表层沉积物对磷的吸附特征

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

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.

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. 