Preparation, characterization, and post-synthetic modification of layered MCM-22 zeolite precursor

Abstract

Hydrothermal synthesis of MCM-22(P) was carried out with two different silica sources, colloidal silica (28%) and silicic acid with different gel composition. The synthesis was carried out in stirring and static conditions with different crystallization time. MCM-22(P) modified with swelling-sonication method resulted in swollen MCM-22, while alkali treatment yielded desilicated MCM-22. The materials were characterized by X-ray diffraction, low-angle XRD, FE-SEM-EDX, FT-IR, TGA, $$\hbox {N}_{2}$$ adsorption and $$\hbox {NH}_{3}$$ -TPD analysis. The results revealed that MCM-22 has a layered sphere, doughnut like morphology and after modification, swollen and broken sphere was observed. Physicochemical analysis revealed that the materials’ mesoporosity increased and acidity also changed. Energy dispersive X-ray analysis revealed the high amount of desilication in alkali-treated MCM-22(P). SYNOPSIS Hydrothermal synthesis of layered MCM-22 using two different silica sources under stirring and static condition is reported. Layered zeolite MCM-22 synthesized from colloidal silica under stirring conditions was modified with swelling-sonication and alkali-treatment methods respectively. Crystal structure of MCM-22 remain unchanged while morphology was different when synthesized using different silica sources.