Synthesis of ZSM-5 zeolites with different silica/alumina ratios and their performance in the removal of aniline and pyridine from model fuel through adsorption

A series of ZSM-5 zeolites with different silica/alumina ratios were synthesized and characterized by means of XRD, FT-IR, ICP, SEM, NH₃-TPD and N₂ sorption; their performance in the removal of aniline and pyridine from a model fuel through adsorption was then investigated. The results indicated that all the as-synthesized ZSM-5 zeolites have the MFI structure, although the actual silica/alumina ratio in the as-synthesized ZSM-5 zeolites is somewhat lower than that in the corresponding synthesis mixture. As expected, the acid amount of ZSM-5 zeolites decreases with the increase of the silica/alumina ratio. The adsorption denitrogenation performance of ZSM-5(1) and ZSM-5(2) with relatively lower silica/alumina ratios is superior to that of other two zeolite samples; meanwhile, the removal efficiency for pyridine over all ZSM-5 samples is higher than that for aniline. Moreover, adsorption isotherms of aniline and pyridine over ZSM-5(2) accord with the Langmuir-Freundlich adsorption model.