Abstract
The natural montmorillonite is layered silicate minerals with considerable surface area and great adsorption capacity with the nuclear waste species. In this study, nuclear waste disposal environment constructed by experimental simulation in laboratory by using 13 kinds of organic matters with different functional groups in different pH environments. In the 13 kinds of propsed organic environmental conditions in comparison to the blank experiment decreased the adsorption of strontium on montmorillonite, except in Gallic acid and Humic acid environments. Gallic acid with a large number of negatively charged functional groups would occupy 1~2 Edge sites to reduce adsorption of strontium, but the negative functional groups contribute to more extra position to adsorb strontium on Montmorillonite. When the Humic acid is present, the amount of strontium on Montmorillonite increased slightly in the alkaline environment, however other organic environments are not conducive to adsorption of strontium. The mechanism of complex deformation of long carbon chain organic matter`s behavior are difficult to predict. In acid-base environment, the more alkaline environment conducive to nuclear waste species adsorption and acidic environment due to the high degree of proton-MMT on the surface cause strontium hard to access to the soil surface.In experiment of suspension solids, organic content of the environment will cause suspension solid increase, also due to protonated montmorillonite and the presence of organic amount. In the analysis of FTIR and XRD the impact of organic species can`t be very obvious to identify, but the XRD diffraction peaks shift with different pH environments. It is obvious that this is due to different amount of strontium adsorption. On the second part of this study the experimental data is simulated by MINEQL+. In the acidic environment, structure sites contribute to the adsorption of nuclear species. In the alkaline environment, the edge sites adsorption is the dominant mechanism. The simulating curve from MINEQL+ is very close to the experimental result, Therefore, the parameter fitting by MIENQL+ is good agreement with the actual situation predicted, and the physical model of our work is in line with the real situation. Further research direction might include the adding of larger amount organic species in solution. This will increase the change of simulating parameters and using a three-layer model fitting will make the mechanism more clearly.Keyword: Montmorillonite、strontium、adsorption、structure sites、edge sites、MINEQL+