Study on the law of cement ion erosion and its adsorption of Cs+
As an important part of radioactive waste repository,cement plays an important role in the construction of the repository and the solidification of waste.Cement will be exposed to complex underground environment for a long time,SO42-and Cl-in the soil might damage the cement structure and endanger the main constructure of disposal repository.In order to investigate the effect of SO42-and Cl-erosion on cement,the ionic erosion behavior of cement and its adsorption feature for Cs+were studied.The microstructure and physicochemical properties of cement before and after ion erosion were investigated by XRF、FT-IR、SEM、BET characterization methods.The results showed that SO42-and Cl-ions reacted with hydration products to form ettringite,Friedel salt and other expansion products,and the specific surface area and porosity of cement increased after ion erosion.With the increase of ion erosion strength and degree the deposition of erosion products in the pore of particle decreases the pore volume and specific surface area of cement particle.The results of adsorption experiments show that the adsorption capacity of cement for Cs+increases with the increase of erosion degree.Kinetic and isothermal model fitting results show that the adsorption of Cs+by cement before and after ion erosion is a single layer chemisorption,and ion erosion does not change the adsorption mechanism of cement for Cs+.
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