Study on Adsorption and Desorption Characteristics of Cd2+ and Cu2+ on the Surface Sediments of Sanhuhekou of Yellow River by Using ICP-MS.

In order to study the interaction mechanism between Cd2+, Cu2+ and surface sediments in the upper reaches of the Yellow River, the surface sediment of Sanhuhekou (YRSSM) was chosen as research object with inductively coupled plasma mass spectrometry (ICP-MS) as analysis method. The adsorption reaction condition such as liquid-solid ratio, reaction time and pH were optimized, and the adsorption and desorption characteristics of Cd2+ and Cu2+ onto the surface sediments under the optimized experimental conditions were studied. The results showed that the adsorption capacity of Cu2+ was greater than that of Cd2+, the equilibrium absorption capacity were 0.88 and 0.13 mg·g-1 under each optimum experimental condition, respectively. The adsorptions of Cu2+ and Cd2+ were in accord with the pseudo-second-order kinetic, while adsorption rate of Cu2+ was also greater than that of Cd2+. The adsorption thermodynamics data were in accordance with the Freundlich model and the fitting. Results showed that the adsorption process of Cu2+ and Cd2+ belonged to the preferential adsorption, and were endothermic and spontaneous processes. The desorption process showed that the Elovich equation were suitable for Cd2+ and Cu2+ and belonged to the heterogeneous diffusion. Multi-ions competitive adsorption and desorption experiments indicated that Cu2+ was influenced more by co-existing ion. The study revealed not only the mechanism of adsorption and desorption between Cd2+, Cu2+ and surface sediment in Sanhuhekou, but also the influence of coexisting ions on the adsorption and desorption characteristics. The results demonstrated that the distribution mechanism of heavy metals between solid-liquid phases, and provided a theoretical basis for the migration ability of heavy metals. It also had a guiding significance for establishing heavy metals preventive and control measures of the study area.