重金属由水相到沉积物相的标准迁移自由能

Standard Free Energy of Transferring Heavy Metals from Aquatic Phase to Sedimentary Phase

采用电位法测定了淀山湖水体中,Cu、Zn、Pb、Cd等重金属的氯化物由水相到沉积物相的标准迁移自由能(△Gt0)。结果表明,重金属离子的△Gt0随沉积物-水悬浮液中的沉积物含量增加而减小;△Gt0的大小次序为:Cd2+>Pb2+>Cu2+>Zn2+,即Zn2+最易迁入沉积物中,而Cu2+、Pb2+、Cd2+依次减弱,这同重金属离子在沉积物/水两相间的分配系数大小相一致。

The standard molar free energy (△Gt0) of transferring heavy metal chlorides (CuCl2, ZnCl2, PbCl2, CdCl2) from aquatic phase to Dingshan lake's sedimentary phase has been determined by using potentiometry. △Gt0 of the heavy metal ions decreased with decrease of the contents of water in the sediments. The sequence of magnitude of △Gt0 was Cd2+ >Pb2+ >Cu2+ >Zn2+, Zinc transferring into sediments most easily, and copper, lead, cadmium reducing successively. This case is in agreement with magnitude of partition coefficients of heavy metals between the sedimentary and aquatic phases.