Transition Metal Oxide Silicon Molecular Sieve Adsorption Mechanism Of Rare Gas

Since the rare gas was found and it has been widely applied to the field of optics, metallurgy and medicine, etc. Because the content of rare gase in Earth extremely rare,and it belongs to the rare resources, they need to be separated and purified to recycling, the current multi-use activated carbon and zeolite molecular sieve purification and recycling. Zeolite is an aluminosilicate having a hexagonal crystal lattice, and has important uses in the field of catalysis, adsorption, ion exchange separation. Therefore, the transition metal oxide silicon research applications in molecular sieve adsorption of rare gases have very important significance. In this paper, based on first-principles density functional theory (DFT) and the local density approximation (LDA) method, the following tasks are carried out(1)With the structure of kaolin as the basis, estabishing the silicon aluminium acidsilver AgSiA104molecular transition metal Ag sieve structure, studying the adsorption behavior of rare gases in the system, and o get the optimal adsorption site s near the Ag+siliconaluminiumacid silver surface. Although rare gas atom (He, Ne, Ar, Kr) occurs low energy in the vicinity of the silicon aluminium acid silver pores O bridge,SiO4tetrahedral repulsion energy barrier is not conducive to the absorption of rare gas atoms in kinetics.The adsorption of noble gas(He, Ne, Ar, Kr, Xe)isrespctively-10.4618kJ/mol,-23.8072kJ/mol,-38.4158kJ/mol,-40.5461kJ/mol and-105.778kJ/mol. Therefore the silicon aluminium acid silver AgSiA1O4system can be used to separate Xe atoms and other rare gases.(2)To replace the silicon aluminium acid silver molecular sieve Ag+ion with Na+, K+, respectively, establishing sodium aluminosilicate NaSiA1O4system and silicon aluminium acid potassium KSiA1O4system, and comparing with silicon aluminium acidsilver AgSiA1O4system to get the conclusion:in addition to the Xe atom is not conducive to the adsorption on acid potassium aluminium silicon KSiA1O4systemoutside, the rest of the rare gas can produce good adsorption effect in the three systems. The adsorption effect of potassium sodium aluminosilicate system and silicon aluminium system on Ar is the best, poorly on Xe adsorption effect; silicon aluminium acid silver system has strong adsorption of Xe. Research shows that,using the three kinds of molecular sieve can isolate and purifyXe and Ar atom rare gases.