Influence of different processes of dealumination on acid properties of an H-ferrierite zeolite

Development of hierarchical EU-1 zeolite by sequential alkaline and acid treatments for selective dimethyl ether to propylene (DTP)

“…These results become reasonable because of the existence of amorphous phase of Si and Al species on the surface of the particles together with the defects of the crystal structure due to extra porosity after the demetalation. Unlike desilication, the dealumination treatment with HNO 3 was not much destructive for the zeolite crystals as reported for ferrierite (FER), mordenite (MOR), TON and BEA zeolites [16,[29][30][31]. One of the remarkable point was the increasing of XRD peaks for the desilicated samples after different acid treatments.…”

Aluminum-Phosphate Binder Formation in Zeolites as Probed with X-ray Absorption Microscopy

“…From Figure 8 it can be observed that H-ferrierite steamed at 500 °C, shows a strong contribution of the 27 Al MAS NMR resonance at 32 ppm, corresponding to {Al} EF species. 19,68,69 The resonance at 30 ppm is even more pronounced for H-ferrierite steamed at 600 °C. Furthermore, in Figure 9, the Al K- The inaccessible nature of these {Al} EF species follows from our results as well.…”

“…It is reported in the literature that leaching out {Al} EF from zeolite H-ferrierite after steam treatment is very difficult 68,69. It has been suggested that {Al} EF species in H-ferrierite are trapped in the structure as migration of aluminum to the surface has…”

A novel method for enhancing the stability of ZSM-5 zeolites used for catalytic cracking of LPG: Catalyst modification by dealumination and subsequent silicon loading

“…This may be owing to the formation of silanol groups, which are Lewis acid sites. 27 Al solid state MAS NMR spectroscopy can be used to determine the framework Al (FAl) and extra-framework Al (EFAl) [36,37]. In the present study, samples of ZSM-5 zeolite with 30% carbon nanotube having a mesopore and micropore structure were dealuminated with TCA selectively.…”

“…6 shows the 27 Al MAS NMR spectra of the HZSM-5 zeolite samples before (HZSM-5 CNT(30)) and after (HZSM-5 CNT(30):acid(TCA)) dealumination. A strong peak at ≈ 52 ppm is assigned to tetrahedrally coordinated FAl and a very weak peak at ≈ 0 ppm owing to octahedrally coordinated EFAl [36,37]. According to Fig.…”