芘在不同粒径红树林沉积物团聚体上的吸附/解吸行为

Sorption /desorption behaviors of pyrene on mangrove sediment aggregates with different sizes

采用海藻酸钙凝胶包覆的方法,研究了芘在九龙江河口红树林区不同粒径沉积物团聚体上的吸附/解吸行为.结果表明,海藻酸钙凝胶包覆可有效减少沉积物团聚体粒径的改变,其等温吸附、吸附/解吸速率情况与未包覆沉积物团聚体存在明显差异.包覆后等温吸附曲线中吸附容量Kf值取决于总有机碳(TOC)的含量,非线性吸附常数n不仅与其硬碳和软碳的比值有关,还与团聚体复杂的孔隙结构存在着一定的关系.包覆后沉积物团聚体的快吸附速率常数值与沉积物团聚体的比表面积值正相关(krap=0.041S-0.0146,R2=0.9923).小粒径沉积物团聚体的"老化"现象较大粒径更为显著,使得其解吸量较小.

The sorption behaviors of pyrene （Pyr） to mangrove sediment aggregates treated with the enclosure of calcium alginate beads were investigated. Experimental results showed that the stabilization of mangrove sediment aggregates with different particle sizes was increased effectively with the presence of calcium alginate beads. Great difference existed in the sorption capacity for Pyr between the sediment aggregate with/without the enclosure of calcium alginate beads, which was also the cose for the sorption/desorption kinetic constant. The sorption capacity for Pyr was closely associated with the content of total organic carbon in mangrove sediment aggregates, and the nonlinear sorption constant was related to the ratio of carbonaceous to amorphous organic matter, and the complexity structure of mangrove sediment aggregate. Additionally, the rapid sorption kinetic rates were found to exhibit positive correlation with specific surface area of mangrove sediment aggregate （krap=0.041S-0.0146, R2=0.9923）, and the desorption capacity of Pyr in smaller aggregate was less than that in the larger ones, which can be explained by the higher aging degrees of smaller aggregate.