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Influence of chemical dealumination on the properties of USY zeolite
Author(s) -
Bao ShuLin,
Wu Peng,
Xu QinHua
Publication year - 1993
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19930110202
Subject(s) - chemistry , zeolite , microporous material , mesoporous material , inorganic chemistry , adsorption , aluminosilicate , molecular sieve , pyridine , extraction (chemistry) , nuclear chemistry , catalysis , organic chemistry
Three series of dealuminated Y zeolites have been prepared by chemical extraction of hydrothermally dealuminated Y zeolite (USY) with H 2 Na 2 EDTA, HCl and H 4 EDTA. The unit cell constant, mesopore distribution, acidity and extraframework aluminum (EFAL) of the zeolites were studied with XRD, chemical analyses, adsorption, IR and NH 3 ‐TPD techniques. It was shown that H 2 Na 2 EDTA only removed EFAL species deposited in the pores of USY, by contrast, HCl and H 4 EDTA extract both extraframework and framework aluminum, and make the zeolite framework further dealuminated. Adsorption tests gave evidence that a secondary pore system exists in these dealuminated zeolites. H 2 Na 2 EDTA extraction increased both micropore and mesopore volumes, but after HCl and H 4 EDTA treatments, new mesopores formed and the micropore volume was decreased. The pyridine‐IR and NH 3 ‐TPD measurements demonstrated that EFAL had no evident contribution to the zeolite acidity.