High-throughput Molecular Simulation Of Metal-organic Frameworks For Radioactive Iodine And CH₃I Adsorption And Separation

Nuclear energy is an extremely promising energy source,but the radioactive substances(such as iodine)in nuclear exhausts have attracted significant nuclear-safety concerns.The metal-organic framework materials(MOFs)has been widely used in molecular simulation for gas adsorption and separation due to its many excellent properties.In this dissertation,large-scale MOF materials were selected to perform high-throughput molecular simulation studies on iodine vapor adsorption,iodine-water separation,and methyl iodide adsorption separation under industrial conditions(1.0 bar and 423 K),including examination of the regeneration performance of the materials and water stability.The results show:1.For the adsorption of iodine vapor,the material XAHQAA(Refcode in the Cambridge Cyrstal Structural Database,CSD)shows the highest adsorption capacity(13.57 g/g)up to date.The simulations also found that MOFs with pore size of 20～30 A,porosity of～0.93 and about 6200 m2/g accesible surface area is more favorable for the adsorption and storage of element iodine.Furthermore,the MOFs with interpenetrated structures is not conducive to the adsorption of iodine vapor.The iodine capacity of material QIYDIN after chemical modification can be increased by 20.26%.2.Through a large-scale simulation study of the separation of I2/H2O systems by MOF materials,it was found that the amount of iodine adsorbed by the material DAWMUL(Niodine=7.68 g/g)was much higher than other materials.The pressure swing adsorption(PSA)study was performed on 520 MOFs with better selectivity and adsorption capacity.The parameter of Adsorption Figure of Merit(AFM)was used to describe the material properties.After investigation,5 MOFs with the best overall performance were found to have good water stability.3.The adsorption behaviors of most MOFs for Methyl iodide are weakly affected by the impurity gas N02,indicating that MOFs is more benificial than other porous materials examined so far for this gas.More importantly,it was found that the activable NU-700 is the materials with the highest methyl iodine adsorption capacity(3.26 g/g)at present time,which also has very good properties for methyl iodine adsorption at high concentrations of N02,showing a promising application for this system.