离子化有机污染物在沉积物和水相间的平衡分配计算

本文从热力学平衡原理出发，推导出离子化有机污染物在沉积物／水相间分配系数的理论计算模型，并以苯酚，邻氯酚，２，４－二氯酚、五氯酚和苯胺的吸附实验数据为例，计算了它们在中性分子和带电荷的离子形态下的分配系数Ｋｄ和Ｋｄｉ。以及总体分配系数Ｋｄｏ研究结果表明，离子化有机污染物在沉积物和分配行为不仅与该化学物的ｐＫａ和存在形态有关。而且还取决于环境介质的ｐＨ。

STUDY ON EQUILIBRIUM PARTITION OF IONIZABLE ORGANIC CONTAMINANTS BETWEEN SEDIMENT AND WATER

Base on the chemical thermodynamic principle,the theoretical models for calculating equilibrium partition coefficients of ionizable organic pollutants between sediment and water phase in aquatic environment were derived. Taking experiment data of phenol, o-chlorophenol, 2 , 4-dichlorophenol, pentachlorophenol and aniline for example, the partition coefficients Kd and Kdi of these compounds to sediment under neutral molecule and charged ion, and total partition coefficient Kdo were calculated. The results show that the partitioning behavior not only relate with pKa and species of ionizable organic chemicals, but also depend on environmental medium pH.