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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Triantafyllidis, K. S. | en |
| dc.contributor.author | Pinnavaia, T. J. | en |
| dc.contributor.author | Iosifidis, A. | en |
| dc.contributor.author | Pomonis, P. J. | en |
| dc.date.accessioned | 2015-11-24T16:47:43Z | - |
| dc.date.available | 2015-11-24T16:47:43Z | - |
| dc.identifier.issn | 0959-9428 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/9226 | - |
| dc.rights | Default Licence | - |
| dc.subject | ordered hexagonal structure | en |
| dc.subject | pore structure concept | en |
| dc.subject | mesoporous aluminosilicates | en |
| dc.subject | hydrothermal stability | en |
| dc.subject | bet equation | en |
| dc.subject | new-model | en |
| dc.subject | mesostructures | en |
| dc.subject | mfi | en |
| dc.subject | catalysts | en |
| dc.subject | tpaoh-teos-h2o | en |
| dc.title | Specific surface area and I-point evidence for microporosity in nanostructured MSU-S aluminosilicates assembled from zeolite seeds | en |
| heal.type | journalArticle | - |
| heal.type.en | Journal article | en |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.identifier.primary | Doi 10.1039/B705233b | - |
| heal.identifier.secondary | <Go to ISI>://000248917400020 | - |
| heal.identifier.secondary | http://pubs.rsc.org/en/content/articlepdf/2007/jm/b705233b | - |
| heal.language | en | - |
| heal.access | campus | - |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας | el |
| heal.publicationDate | 2007 | - |
| heal.abstract | In this work we provide evidence of microporosity in the nanostructured mesoporous aluminosilicates MSU-S/W-(BEA) synthesized from zeolite BEA seeds, based on the so called I-point plots (refs. 18-20) of the BET equation. Seventeen solids were characterized for their porous characteristics as follows: (i) one mesoporous aluminosilicate 2% Al-MSU-S/W-(BEA), ( ii) two typical mesoporous MCM- 41 materials, one pure silica and one aluminosilicate 2% Al-MCM41, (iii) three typical microporous zeolites, i. e., zeolites Y, ZSM- 5 and beta, (iv) two typical amorphous silica-alumina (ASA) samples, (v) five mechanical mixtures of mesoporous Al-MCM41 with zeolite beta at different addition percentages, and (vi) four amorphous or partially crystalline ZSM-5 based aluminosilicates. The P, V data from the nitrogen-adsorption isotherms of those porous solids were plotted according to the I-point modification of the BET equation in the form V[1 - ( P/ P-0)]/(P/ P-0) = CVm - (C - 1) V[ 1 - (P/ P-0)]. Plots of V[1 - (P/ P-0)]/(P/ P-0) vs. V[1 - (P/ P-0)] provided lines which have the shape of an inclined V, i. e. > and variable slopes corresponding to C - 1) from which the values of the C parameter were determined for the whole range of partial pressures 0 < P/P-0 < 1. The inversion point of the above plots, called the I- point, projected onto the V[1 - (P/P-0)] axis corresponds exactly to the volume of the monolayer V-m = VI[1 - (P-I/ P-0)], from which the value of the specific surface area SI (m(2) g(-1)) was determined. The shape of the I- plots depended strongly on the type of porous solids, i. e. microporous/ zeolitic and partially crystalline zeolitic materials with combined micro- and meso/ macroporosity; ordered mesoporous MCM-type materials; ASA materials with random mesoporosity; and mechanical mixtures of zeolite beta with MCM-41. The I-plot for the MSU-S/W(BEA) solid exhibited the combined characteristics of the plots of ordered mesoporous MCM-41 samples and of partially crystalline zeolitic materials, thus proving the presence of microporous domains within the homogeneous mesoporous structure of the MSU- S material. The I-plot result supports the proposed presence of protozeolitic subunits in the framework walls, of MSU-S, even though XRD and electron diffraction TEM studies have shown the material to be free of any zeolitic crystalline phase. The surface areas estimated by the I-method were similar to those provided by the BET model for the zeolitic and the ASA samples, while in the case of the ordered MCM-41 and MSU-S/W(BEA) mesostructures, two surface area values can be estimated based on different interpretations of the I- method, one similar to the value from the BET model and one supported by the modified CPSM model (refs. 31-34). | en |
| heal.publisher | The Royal Society of Chemistry | en |
| heal.journalName | Journal of Materials Chemistry | en |
| heal.journalType | peer reviewed | - |
| heal.fullTextAvailability | TRUE | - |
| Appears in Collections: | Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά). ΧΗΜ | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Pomonis-2007-Specific surface area.pdf | 369.94 kB | Adobe PDF | View/Open Request a copy |
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