Synthesis of ZSM-22 in Static and Dynamic System Using Seeds

Abstract

ZSM-22 was synthesized using various sources of silica, organic template 1,6-diaminohexane, under hydrothermal conditions, with and without agitation during crystallization. Subsequently, the crystallized material was used as seeds to accelerate the crystallization process. Characterization of the ZSM-22 samples was performed by XRD, ATG/DTG and FT-IR. It was found that it is possible to synthesize ZSM-22 employing colloidal silica and pyrolytic silica as silicon sources only if the system is stirred during crystallization. The crystallization time for these systems was 13 hours, longer times of crystallization do not significantly increase the crystallinity of the sample. The addition of seeds significantly accelerates the crystallization of ZSM-22, reducing the crystallization time to only 7 hours, with stirring and with systems employing colloidal silica.

Development of ZSM-22/Polyethersulfone Membrane for Effective Salt Rejection

“…This is probably due to the plausible isomorphous substitution of Si 4+ and al 3+ during calcination in the zeolite framework. Small bands at around 1710 cm −1 can be traced to the insignificant vibration of Al-O-Al, amounting to lower aluminium species in the zeolite structure [65,66]. Meanwhile, Figure 3b displayed identical FTIR spectra of ZSM/PES membranes.…”

Simultaneous Removal of Soot and NOx from Diesel Engines over Three-Dimensionally Ordered Macroporous ZSM-5-Supported MMnOδ Catalysts

“…To resolve these drawbacks, the seed-assisted method has been applied to decrease the crystallization time and optimize the synthetic conditions. 29,30 The seed-assisted process is relatively simple and requires few raw materials. Many previous reports have demonstrated that Mn-based composite oxides exhibit great advantages in soot combustion and low-temperature SCR because of their low cost and good oxidation/reduction ability resulting from the variable valence state of Mn (Mn 4+ , Mn 3+ , and Mn 2+ ).…”

“…Although unmodified poly­(methyl methacrylate) (PMMA) as a macroporous template does not need a complex synthesis process, this may decrease the crystallization temperature of zeolite and extend the crystallization time. To resolve these drawbacks, the seed-assisted method has been applied to decrease the crystallization time and optimize the synthetic conditions. , The seed-assisted process is relatively simple and requires few raw materials. Many previous reports have demonstrated that Mn-based composite oxides exhibit great advantages in soot combustion and low-temperature SCR because of their low cost and good oxidation/reduction ability resulting from the variable valence state of Mn (Mn 4+ , Mn 3+ , and Mn 2+ ). − Therefore, the combination of 3DOM ZSM-5 and Mn-based oxides is a promising approach for the removal of NO x and soot simultaneously.…”