不同硅铝比Hβ沸石对二甲苯异构体吸附动力学的研究

Adsorption Kinetics of Xylene Isomers on Hβ Zeolites with Different Si/Al Ratios

通过静态吸附实验,测定了常温下对二甲苯和间二甲苯在不同硅铝比(SiO2与Al2O3的摩尔比)Hβ沸石上的吸附动力学数据。实验结果表明,Hβ沸石对对二甲苯和间二甲苯的平衡吸附量均随对二甲苯和间二甲苯初始浓度的增加而升高,相同条件下对二甲苯在Hβ沸石上的吸附量和吸附速率均大于间二甲苯;对二甲苯/间二甲苯在硅铝比为25和280及全硅Hβ沸石上的平衡分离系数分别为4.1,1.7,1.6,硅铝比为25的Hβ沸石吸附分离对二甲苯/间二甲苯的效果最好。对二甲苯在Hβ沸石上的吸附过程符合二级吸附动力学方程,间二甲苯在Hβ沸石上的吸附动力学数据与颗粒内扩散模型有较好的相关性。

Adsorption kinetics ofp-xylene and m-xylene on Hβ zeolites with different Si/AI ratios （ mole ratio of SiO2 to Al2O3 ） was studied through static experiments. Results showed that equilibrium adsorption capacities of p-xylene and m-xylene increased with their initial concentrations. Under the same conditions, adsorption capacity and adsorption rate of p-xylene were much higher than those of m-xylene. Equilibrium separation factors of p-xylene/m-xylene on HI3 zeolites with Si/Al ratios of 25, 280 and all-Si were 4.1, 1.7 and 1.6, respectively. Hβ zeolite with Si/Al ratio 25 was the best for p-xylene/m-xylene separation. Adsorption kinetic data of p-xylene on Hβ zeolite fitted well with the pseudo-second-order kinetics equation, and the intraparticle diffusion equation could related with m-xylene adsorption on Hβzeolite.