南四湖及主要入湖河流表层沉积物对磷酸盐的吸附特征

研究了南四湖及其主要河流人湖口18个表层沉积物对磷的吸附能力、吸附动力学及其吸附等温线,并对湖区沉积物对磷吸附特征及其理化特征之间的关系进行了探讨.结果表明,对于处于不同营养水平的沉积物,对磷酸盐的吸附具有一致的特征.在前10h沉积物对磷酸盐的吸附量基本达到或超过平衡吸附量的80%,并且在0～1.0 h内吸附反应迅速.在本研究条件下,表层沉积物的cEPC的变化范围为0.010～0.157mg·L-1, Qmax的变化范围是86.74～118.32 mg·kg-1, TQmax的变化范围是99.97～281.11 mg·kg-1·cEPC、NAP、m、Qmax和TQmax与Ads-P都具有显著的正相关关系,沉积物Ads-P含量可以作为指导南四湖水体污染程度的一项指标. m与TQmax之间具有显著的正相关性,吸附效率不仅体现的是对外来磷的吸附效率,还应当包含对本身释放磷的再吸附的效率.对于南四湖沉积物TQmax、NAP和Qmax起到同样的贡献.沉积物的NAP与cEPC之间呈显著正相关性,总的趋势就是,当上覆水中磷含量相等时,具有高的NAP的沉积物易于向上覆水体释磷,反之具有较低NAP的沉积物易从水中吸附磷.

Phosphate Adsorption Characteristics on Surface Sediments of Nansi Lake and Its Main Inflow Rivers

Adsorption capacity, isotherms and kinetics of phosphate onto the 18 surface sediments taken from Nansi Lake and its main inflow rivers were investigated in laboratory, and the relationships between physical and chemical properties of the sediments and their phosphate adsorption characteristics are discussed. The results indicate that the phosphate adsorption characteristics of sediments that are at different trophic levels are similar. The amount of phosphate adsorbed within 10 h almost reaches or exceeds 80% of the maximum adsorption of phosphate and the maximum adsorption rates occur within 0-1.0 h. C(EPC) ranges from 0.010 to 0.157 mg x L(-1), Q(max) from 86.74-118.32 mg x kg(-1), and TQ(max) from 99.97-281.11 mg x kg(-1) in the study. Between Ads-P and its c(EPC), NAP, m, Q(max) and TQ(max) have remarkable positive correlation. The content of Ads-P will serve as a index indicating the polluted level in Nansi Lake. Adsorption efficiency (m) has remarkable positive relationship with TQ(max). The m is the sum of adsorption efficiency of the sediments adsorbing the phosphorus coming from external and the phosphorus desorbed from the sediments. The NAP has positive correlation with c(EPC) and the trend is that the sediment with higher NAP easily desorbs phosphorus to the water, contrarily the sediment with lower NAP easily adsorbs phosphorus.