通过实验测定了二氧化硫(SO2)在HZSM-5型分子筛中的吸附性能,采用巨正则系综Monte Carlo方法建立相应的吸附模型,模拟计算相应的吸附行为。在实验与模拟结果相吻合的基础上,进一步模拟计算了SO2在HZSM-5型分子筛中的吸附等温线、吸附微观构型及吸附热等性质。结果表明:随着硅铝比(摩尔比)的增大,分子筛对SO2的吸附量降低,当硅铝比大于191时,硅铝比对SO2的吸附量影响很小。SO2分子主要吸附在氢离子和Al原子周围。在Al原子周围,SO2分子比较集中,同时发现氢离子的存在会阻碍SO2的扩散。在吸附量相同的条件下,SO2在HZSM-5型分子筛的吸附热随着硅铝比的升高而降低。
Adsorption of sulfur dioxide(SO2) on HZSM-5 zeolite was investigated by experiment and molecular simulation with the grand canonical assemblage Monte Carlo(GCMC) method.It is found that the simulated results are similar to the experimental data.Furthermore,some characteristic parameters of SO2 adsorbed on HZSM-5 zeolite(such as the adsorption isotherms,the adsorption micro-structure and the adsorption heat) were also simulated.The simulated results show that the adsorption capacity decreases as the n(Si)/n(Al) ratio increases,and when the n(Si)/n(Al) ratio is more than 191,it has little effect on the adsorption capacity.The absorbed SO2 molecules are mainly located around H+ and Al,and it tends to assemble around Al.In the channels,H+ hinders the spread of SO2 to some extent.Under the condition of the same adsorption capacity,the adsorption heat decreases as the n(Si)/n(Al) ratio increases.