通过把硅铝分子筛的骨架脱铝过程简化为分子筛骨架中杂原子的扩散和空位的形成及迁移过程, 使用费克第二定律建立扩散方程, 得到任意时刻铝原子的浓度关于位置的函数, 并讨论了影响脱铝的几个重要因素. 用XPS、红外光谱和27Al--NMR测定在一定条件下处理后的氢型丝光沸石和ZSM--5的骨架硅铝比的变化, 并与由所建立的数学模型计算出的骨架硅铝比比较, 验证了公式的准确性.
The dealumination course of framework of Silicon-Aluminum molecular sieves (SAMS) was simplified as the diffusion of aluminium atoms in the framework as well as the formation and migration of vacancy sites. Based on this simplification in this paper, and the instantaneous concentration of aluminum atoms have been determined as a function of time and location according to Fick's Second Law. The critical parameters affecting the dealumination process was also discussed. The accuracy of the formulae is verified as the calculation results agree with the ratio of silicon to aluminum in Mordenite and ZSM-5 framework measured by XPS and infrared spectra and 27Al-NMR.
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