改性Cu-ZSM-11和Cu-ZSM-5分子筛催化分解一氧化氮性能

ACTIVITY OF MODIFIED Cu-ZSM-11 AND Cu-ZSM-5 ZEOLITE MOLECULAR SIEVES FOR DECOMPOSITION OF NITROGEN OXIDES

采用水热法合成法合成ZSM-11和ZSM-5分子筛,采用一步离子交换法制备了改性ZSM-11和ZSM-5系列催化剂。通过X射线衍射、电感耦合等离子体发射光谱和红外光谱对催化剂进行表征。结果表明:ZSM-5型催化剂负载的离子量高于ZSM-11型催化剂。催化剂中的共存离子Cu2+,Ce3+和Ni2+对两种类型分子筛振动所产生的影响不同,共存离子对ZSM-11的影响较大,表明2种类型分子筛骨架的结构存在差异。催化试验结果表明:Cu-ZSM-11催化剂催化稳定性高于Cu-ZSM-5催化剂。Ce3+和Ni2+改性的Cu-ZSM-11和Cu-ZSM-5催化剂的催化活性都有所提高,但Ce3+和Ni2+改性的Cu-ZSM-11催化剂的催化活性高于Cu-ZSM-11和对应的改性Cu-ZSM-5催化剂。随空速的增大,2种催化剂的催化活性先增大后减小,在空速约为0.6(g·s)/mL左右时达到最高活性。

ZSM-11 and ZSM-5 zeolite molecular sieves were synthesized by the hydrothermal method,and modified ZSM-11 and ZSM-5 type catalysts were prepared by one-step ion exchange.The prepared catalysts were characterized by X-ray powder diffraction,atomic emission spectroscopy with inductively coupled plasma atomization and Fourier transform infrared spectroscopy.The results show that the deposition amount of coions Cu^2＋,Ce^3＋ and Ni^2＋ in ZSM-5 type catalyst is higher than that of ZSM-11.The coions in ZSM-11 have a greater impact on the vibration of the ZSM-11 zeolite framework.This shows that the framework property is different in the two kinds of zeolite.The results of the catalyzing test indicate that the catalytic stability of Cu-ZSM-11 is better than that of Cu-ZSM-5 and the activity of modified Cu-ZSM-11 with Ce^3＋ and Ni^2＋ is higher than that of Cu-ZSM-11 and the corresponding modified Cu-ZSM-5.The activities of Cu-ZSM-5 and Cu-ZSM-11 first increase and then decrease with the increase of space velocity.When the space velocity reaches about 0.6（g·s）/mL,the activity reaches the maximum.