Investigation of the various dealumination methods and their effect on the Y-zeolite structural crystallinity

This paper aims to study the modified zeolite Y using different dealumination methods and the effect of each of these methods on the structural framework of zeolite. The dealumination is performed by EDTA solution (acidic form), ammonium chloride (NH4Cl), and hydrochloric acid (HCl) solution. To investigate the effect of the dealumination process on the stability of the structures modified samples are studied using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersion X-ray (EDX). By comparing the three methods, it can be concluded that EDTA is the most suitable method because it is not only preserved the structure but also removed the extra-framework aluminum and increases the Si/Al ratio. In addition, in the hydrochloric acid treatment, the extra-framework aluminum is also removed, but in the calcination process (NH4Cl), the extra-framework aluminum is still present, and therefore, the Si/Al ratio is lower than the previous two methods.