Impacts of pH and Electrolyte on Cadmium Desorption Characteristics in Contaminated Soil

In this paper, two kinds of different pollution degree soils denoted as L1 and L2 were used as test soils. Desorption experiment was carried out to study the impacts of pH and electrolyte on desorption characteristics of cadmium (Cd) in soils. The results showed that the variation trends of Cd desorption rates with increase in pH were similar. In other words, it decreased as pH increased. In acidic region, desorption rate of heavy metal Cd decreased rapidly as pH increased. When pH = 4, Cd desorption rate was largest; in neutral and alkaline regions (pH = 7-10), desorption rate of heavy metal Cd decreased slowly as pH increases. Cd desorption behavior was closely related to type and concentration of electrolyte. Under the same concentration, Cd desorption capabilities of three electrolytes in soils L1 and L2 could be expressed in following order: CaCl2> Ca (NO3)2> NaCl.