Systematic investigation was performed to understand the change of physiochemical properties in Y zeolite after the microwave (MW)-assisted dealumination (using mineral acid, HCl, and chelating agent, EDTA4−) and the subsequent alkaline treatment (of the dealuminated zeolites).
Microporous and Mesoporous Materials 333 (2022) 111736 Contents lists available at ScienceDirect Microporous and Mesoporous Materials journal homepage: www.elsevier.com/locate/micromeso On understanding the sequential post-synthetic microwave-assisted dealumination and alkaline treatment of Y zeolite Rongxin Zhang a, b, Run Zou b, Wei Li c, Yabin Chang c, Xiaolei Fan b, * a Research Institute of Petroleum Processing, SINOPEC, 18 Xueyuan Road, Beijing, 100083, China Department of Chemical Engineering and Analytical Science, School of Engineering, The University of Manchester, Manchester, M13 9PL, UK c Department of Materials, School of Natural Sciences, University of Manchester, M13 9PL, UK b A R T I C L E I N F O A B S T R A C T Keywords: Y zeolite Post-synthetic treatment Dealumination Microwave (MW) NMR Systematic investigation was performed to understand the change of physiochemical properties in Y zeolite after the microwave (MW)-assisted dealumination (using mineral acid, HCl, and chelating agent, EDTA4− ) and the subsequent alkaline treatment (of the dealuminated zeolites) The findings show that the combination of EDTA4− and hydrogen ions was effective to achieve dealumination of zeolite Y under MW irradiation, which formed complexed framework Al, instead of extra-framework Al (EFAl), to be extracted readily by the sequential alkaline treatment for mesopore formation Conversely, under the same MW condition, the use of HCl encouraged the formation of EFAl species in the defective Y framework, which did not benefit the mesopore formation The disclose of the distinct dealumination mechanisms of the MW-assisted method using different agents can benefit the further development of effective MW methods for dealumination of zeolites and/or making mesoporous zeolites Introduction Zeolites, as crystalline aluminosilicates with the intrinsic micropo rous frameworks, high specific surface areas and good thermal stability, are widely used in heterogeneous catalysis such as petrochemical refining processes [1] Specifically, zeolite Y (with the FAU topology), Beta (with the BEA topology) and ZSM-5 (with the MFI topology) have significant industrial values [2–4] During catalysis, the intrinsic microporosity of zeolites (pore sizes