Mordenite‐Type Zeolite from Waste Coal Fly Ash: Synthesis, Characterization and Its Application as a Sorbent in Metal Ions Removal

Tuning the catalytic acidity in Al2O3 nanofibers with mordenite nanocrystals for dehydration reactions

The chemical and structural properties of Al2O3 are tuned for dehydration reactions. The synergy between the structured Al2O3 shaped as nanofiber and the acid site nature of the zeolite mordenite in the nanofiber improves the dehydration reaction.

Ultrasonic Pretreatment as a Tool for the Preparation of Low-Defect Zeolite Mordenite

The effects of the ultrasonic (US) pretreatment of synthesis gel for the preparation of mordenite zeolite were studied in comparison with the classical stirring method. Even though the US pretreatment was performed before the hydrothermal crystallization, it significantly affected the properties of the obtained mordenite crystals. The US-assisted procedure resulted in a material with improved textural characteristics, in particular, the micropore volume accessible for nitrogen molecules in the as-made form. On the other hand, mordenite prepared with the classical stirring method demonstrated comparable sorption properties only after a postsynthetic treatment. Moreover, in the case of US-pretreated mordenite, altered crystal shape and more homogeneous morphology were observed. ²⁹Si magic-angle spinning nuclear magnetic resonance (MAS NMR) demonstrated that the US pretreatment introduced structural changes on the atomic level, resulting in fewer defects (reflected in the number of silanol groups) and less pore blockage (affected by Na⁺ cations) for the as-made sample.

Recent advances in the synthesis and applications of mordenite zeolite - review

Among the many industrially important zeolites, mordenite is found to be interesting because of its unique and exceptional physical and chemical properties. Mordenite (high silica zeolite) is generally prepared by the hydrothermal method using TEA+ cations. TEA+ cations are the best templating agent, though they can create a number of issues, for instance, generating poison and high manufacturing cost, wastewater contamination, and environmental pollution. Hence, it is necessary to find a mordenite synthesis method without using an organic template or low-cost template. In this review, a number of unique sources were used in the preparation of mordenite zeolite, for instance, silica sources (rice husk ash, silica gel, silica fumes), alumina sources (metakaolin, faujasite zeolite) and sources containing both silica and alumina (waste coal fly ash). These synthesis approaches are also based on the absence of a template or low-cost mixed organic templates (for instance, glycerol (GL), ethylene glycol (EG), and polyethylene glycol 200 (PEG)) or pyrrolidine-based mesoporogen (N-cetyl-N-methylpyrrolidinium) modifying the mordenite framework which can create unique properties. The framework properties and optical properties (indium-exchanged mordenite zeolite) have been discussed. Mordenite is generally used in alkylation, dewaxing, reforming, hydrocracking, catalysis, separation, and purification reactions because of its large pore size, strong acidity, and high thermal and chemical stability, although the applications are not limited for mordenite zeolite. Recently, several applications such as electrochemical detection, isomerization, carbonylation, hydrodeoxygenation, adsorption, biomass conversion, biological applications (antibacterial activity), photocatalysis, fuel cells and polymerization reactions using mordenite zeolite were explored which have been described in detail in this review.