Microwave-assisted ionothermal synthesis of Fe-LEV molecular sieve with high iron content in low-dosage of eutectic mixture

Abstract

Abstract Iron-containing aluminophosphate molecular sieve with LEV topology (Fe-LEV molecular sieve) has been successfully synthesized by a microwave-assisted ionothermal method in low-dosage of eutectic mixture solvent, which is the first example of Fe incorporated aluminophosphates with the LEV-zeotype structure. The optimum synthetic conditions of this material were refined. The structure and morphology of a representative Fe-LEV sample, as well as the structure directing effect of eutectic mixture were thoroughly analyzed by various techniques including XRD, 27Al and 31P MAS NMR, ICP-AES, DR UV-Vis, ESR, XPS, N2 adsorption/desorption, NH3-TPD, SEM, TEM, EDX, CHN elemental analysis, TG-DTA and FT-IR spectra. It was found that the combined effect of the starting precursor and a suitable structure-directing agent yielded an appropriate crystallization system of Fe-LEV molecular sieve, for which choline cations and intact tetraethylammonium bromide molecules were identified to be the structure-directing agents. The calcined Fe-LEV molecular sieve exhibits higher specific surface area and iron content, as well as a medium acidity and special hierarchical structure with both micropores and mesopores, implying that these zeolitic materials have a great potential in some industrially relevant applications.