Study On Zinc Exchange And Gas Adsorption Properties Of 4A And 13X Zeolites

Research on zeolite molecular sieves has always been a hot spot.Since synthetic zeolites are mostly powder,their role in various fields such as industry is greatly limited,which is necessary for the application of the granule zeolite.The purpose of this project is to study the zinc ion exchange performance of powder 4A zeolite,type 4A zeolite and type 13X zeolite and adsorption and separation performance of gas.Through the aqueous solution ion exchange method,the powder and the guanule 4A zeolite and the guanule 13X zeolite were exchanged by aqueous solution of zinc ion by aqueous solution,and the effects of different experimental conditions（including the original concentration of the solution,exchange time,solid-liquid ratio and temperature）on the degree of zinc exchange were investigated,and different exchange degrees degree of the powder and the guanule ZnNaA were prepared,which characterized by XRD,SEM and 273K-CO₂ adsorption isotherm.The adsorption and separation properties of the powder and the ZnNaA zeolite were compared.Finally,the following conclusions were drawn:1.The XRD pattern indicates that the intensity of the diffraction peak of the powder and the granule ZnNaA zeolite after exchange has decreased,but the skeleton structure of the original 4A zeolite remains.The crystal morphology of the zeolite after exchange has not changed from the SEM image;NLDFT model indicates that the pore size of the sample after exchange has changed,and the specific surface area and pore volume have increased.The gas adsorption separation performance of powdered ZnNaA zeolite and ZnNaA zeolite with different exchange degrees was studied.The results showed that the order of gas adsorption capacity of different exchange degree powders and ZnNaA zeolite was:CO₂>CO>CH₄>N₂;The adsorption capacity of the powder ZnNaA sample increases first and then decreases with the increase of ion exchange degree,and the separation ratio of gas increases with the increase of ion exchange degree.The adsorption capacity of the sample ZnNaA sample changes a little with the increase of ion exchange degree.Large,but the separation ratio of gas generally increases with the increase of ion exchange degree.2.The adsorption separation performance of powders and granules ZnNaA zeolites under the same exchange degree was compared.The results show that the separation ratio of the ZnNaA zeolite to gas is slightly higher than that of the powder ZnNaA zeolite under the same exchange degree.3.The exchanged granule ZnNaX zeolite was characterized.The results showed that the zeolite after exchange retained the original 13X structure.At the same time,the morphology of the zeolite did not change before and after the exchange,but the pore size,ratio of the surface area and pore volume of the zeolite are reduced.The adsorption performance of the ZnNaX zeolite on the gas under these conditions was studied.It was concluded that the adsorption capacity of the ZnNaX zeolite after exchange was CO₂>CO>CH₄>N₂,but the whole adsorption capacity of the ZnNaX zeolite to the gas was less than the 13X zeolite.In terms of separation ratio,the granule ZnNaX zeolite increased the CO₂/CO separation ratio by nearly 46%.