Preparation of ZSM-5 molecular sieve modified by kaolin and its CO2 adsorption performance investigation

Abstract

The ZSM-5 molecular sieve was prepared by the crystal species-assisted hydrothermal synthesis method using kaolin as raw material, and the molecular sieve were prepared by monometallic Na, Ni and bimetallic Ni–Na modification of the molecular sieve when using the isovolumetric impregnation method. It was found that the modified molecular sieve maintained the MFI structure of ZSM-5 molecular sieve, some mesopores appeared, and Na and Ni were uniformly dispersed on the inner and outer surfaces of the carrier by using XRD, ICP, FI-IR,UV–vis and BET. Moreover the presence of Na could increase the loading of metallic Ni. The effect of the modified molecular sieve on the CO2 adsorption performance was investigated using CO2 programmed temperature rise desorption (CO2-TPD). Na and Ni modification can increase the number of adsorption centers and improve the activity of adsorption centers on the surface of the adsorbent. Then Ni as an additive can enhance the interaction between metal and carrier, increase the density of active sites on the molecular sieve surface, and improve the adsorption performance on CO2. Among them, 1.5 Ni-0.6 Na/ZSM-5 adsorption has the better performance for CO2 adsorption with the bettert adsorption capacity of 1.97 mmol/g, which is 74% higher than ZSM-5, 84% higher than 2 Ni/ZSM-5, and 25% higher than 0.6 Na/ZSM-5.