Simulation experiment on the geochemical behavior of cadmium, lead and mercury ions in the soil. Geological Bulletin of China

Adsorption, desorption and transportation experiments of Cd2＋, Pb2＋ and Hg2＋ in three different kinds of soil in Shanxi Province were studied in this paper respectively. Results show that the adsorption capacity of Cd2＋, Pb2＋ and Hg2＋ were all higher in clay-sized soil than that of sand-sized soil. Meanwhile, all these soils have strong adsorption capacity for Pb2＋, which was very difficult to desorb. The adsorption capacity of the three heavy metal ions in all three kinds of soil decreased in an order of Pb2+＞Cd2+＞Hg2+, whereas the desorption capacity is just opposite. This was mainly due to the close correlation of sorption capacity with different soil properties, hydration energy and hydration iron radius of metal ions. The isothernal adsorption of Cd2+ conformed to the Freundlich and Langmuir equation in different soils, the Henry equation was suitable for the Pb2+ adsorption, and the Langmuir equation for Hg2+. According to the soil column leaching test, penetration ratio of Hg2＋ through soils is highest, secondly Cd2＋and Pb2＋ is lowest which doesn′t pass the column after 20 days leaching. The transport capacity of three different kinds of soil texture for Cd2＋, Pb2＋and Hg2＋decreased in the order of Datong soil, Linfen soil and Taiyuan soil.