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Special Issue "Zeolites and Related Porous Materials: Design, Synthesis, and Applications"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Physical Chemistry".

Deadline for manuscript submissions: closed (21 September 2019).

Special Issue Editors

Prof. Dr. Carlos Otero Arean
E-Mail Website
Guest Editor
Department of Chemistry, University of the Balearic Islands, E-07122 Palma, Spain
Interests: zeolites; nanostructured materials; gas adsorption; gas-solid interaction; heterogeneous catalysis; reactivity of solids
Dr. Montserrat Rodriguez Delgado
E-Mail Website1 Website2 Website3
Guest Editor
Department of Chemistry, University of the Balearic Islands, E-07122 Palma, Spain
Interests: zeolites; periodic porous solids; gas adsorption; gas-solid interaction; nano-drug delivery; water purification; absorption

Special Issue Information

Dear Colleagues,

As an introduction to this Special Issue of Molecules, let us briefly summarize the involved research field by defining zeolites as being three-dimensional aluminosilicates (tectosilicates) bearing an ordered array of channels and cavities (up to 50% of the total volume), which show a characteristic spatial arrangement and dimensions for each particular structure type. Zeolites can thus be regarded as being the archetype of periodic porous solids, as opposed to non-periodic porous materials, such as non-structured active carbons, xerogels and aerogels. The periodicity of the pore layout and regular pore size endows zeolites and related porous solids with the potential to act as molecular sieves and size-selective catalysts, and it also facilitates the engineering of a range of molecular superstructures in zeolite-based host–guest composites with applications in nano-photonic devices and chemical sensors (to name only a couple of examples). Aside from aluminosilicates, both natural and synthetic, several other porous materials merit consideration herein; among them, purely siliceous materials such as silicalite and nanoporous MCM-41 silica, as well as several aluminophosphates and silicoaluminophosphates.

The main applications of zeolites and related porous solids span such fields of use as: heterogeneous catalysts in the petrochemical industry; biomass upgrading and the production of fine chemicals; water softening and purification; environmental pollution control; gas separation, purification and storage; agriculture and aquaculture; medicine and biotechnology; as well as nano-photonic and nano-sensor devices. Research reports making a relevant contribution to any of these (or related) fields will be welcome in this Special Issue of Molecules. Also welcome are reports on novel methods of synthesis, which could be needed to optimize particle size, crystallinity or dimensionality for some specialized applications of zeolites.

Prof. Dr. Carlos Otero Arean
Dr. Montserrat Rodriguez Delgado
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Aluminophosphates
  • Biotechnology
  • Catalysis
  • Environmental pollution
  • Gas adsorption
  • Gas separation and purification
  • Gas storage
  • Host-guest nanosystems
  • Low dimensional zeolites
  • MCM-41
  • Medicine
  • Nanotechnology
  • Novel synthesis methods
  • Zeolites
  • Water purification

Published Papers (3 papers)

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Research

Open AccessArticle
The Exchange Mechanism of Alkaline and Alkaline-Earth Ions in Zeolite N
Molecules 2019, 24(20), 3652; https://doi.org/10.3390/molecules24203652 - 10 Oct 2019
Abstract
Zeolite N is a synthetic zeolite of the EDI framework family from the more than 200 known zeolite types. Previous experimental laboratory and field data show that zeolite N has a high capacity for exchange of ions. Computational modelling and simulation techniques are [...] Read more.
Zeolite N is a synthetic zeolite of the EDI framework family from the more than 200 known zeolite types. Previous experimental laboratory and field data show that zeolite N has a high capacity for exchange of ions. Computational modelling and simulation techniques are effective tools that help explain the atomic-scale behaviour of zeolites under different processing conditions and allow comparison with experiment. In this study, the ion exchange behaviour of synthetic zeolite N in an aqueous environment is investigated by molecular dynamics simulations. The exchange mechanism of K+ extra-framework cations with alkaline and alkaline-earth cations NH4+, Li+, Na+, Rb+, Cs+, Mg2+ and Ca2+ is explored in different crystallographic directions inside the zeolite N structure. Moreover, the effect of different framework partial charges on MD simulation results obtained from different DFT calculations are examined. The results show that the diffusion and exchange of cations in zeolite N are affected by shape and size of channels controlling the ion exchange flow as well as the nature of cation, ionic size and charge density. Full article
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Open AccessArticle
A Facile Strategy to Prepare Shaped ZSM-5 Catalysts with Enhanced Para-Xylene Selectivity and Stability for Toluene Methylation: The Effect of In Situ Modification by Attapulgite
Molecules 2019, 24(19), 3462; https://doi.org/10.3390/molecules24193462 - 24 Sep 2019
Abstract
A general strategy for preparing shaped toluene methylation catalysts with enhanced para-selectivity and stability is developed by extruding ZSM-5 zeolite with attapulgite as a binder. The novel attapulgite/ZSM-5 extrudate exhibited significantly higher para-selectivity and stability in comparison to the conventional alumina-bound ZSM-5 extrudate. [...] Read more.
A general strategy for preparing shaped toluene methylation catalysts with enhanced para-selectivity and stability is developed by extruding ZSM-5 zeolite with attapulgite as a binder. The novel attapulgite/ZSM-5 extrudate exhibited significantly higher para-selectivity and stability in comparison to the conventional alumina-bound ZSM-5 extrudate. The catalyst samples have been characterized by in situ X-ray diffraction, scanning electron microscope (SEM), NH3 temperature programmed desorption (TPD), thermogravimetric analysis (TGA) as well as n-hexane/cyclohexane physical adsorption. The enhanced catalytic performance of attapulgite/ZSM-5 extrudate is correlated with the in-situ modification of acid sites in the catalyst by mobile alkaline species, which is introduced via extrusion with attapulgite. Moreover, a higher para-selectivity was obtained over attapulgite-bound modified ZSM-5 extrudate. Such facile and universal strategy of extruding ZSM-5 catalysts with attapulgite as binder could pave a way for preparation of shaped zeolite-base catalyst with enhanced catalytic performance. Full article
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Open AccessArticle
Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy
Molecules 2019, 24(17), 3199; https://doi.org/10.3390/molecules24173199 - 03 Sep 2019
Abstract
We report a varying temperature infrared spectroscopic (VTIR) study with partial deuterium isotopic exchange as a method for characterizing proton mobility in acidic materials. This VTIR technique permits the estimation of activation energies for proton diffusion. Different acidic materials comprising classical proton-conducting materials, [...] Read more.
We report a varying temperature infrared spectroscopic (VTIR) study with partial deuterium isotopic exchange as a method for characterizing proton mobility in acidic materials. This VTIR technique permits the estimation of activation energies for proton diffusion. Different acidic materials comprising classical proton-conducting materials, such as transition metal phosphates and sulfonated solids, as well as different zeolites, are tested with this new method. The applicability of the method is thus extended to a vast library of materials. Its underlying principles and assumptions are clearly presented herein. Depending on the temperature ranges, different activation energies for proton transfer are observed irrespective of the different materials. In addition to the well-studied transition metal phosphates, Si-rich zeolites appear to be promising proton-transfer materials (with Eact < 40 kJ mol−1) for application in high-temperature (>150 °C) PEM fuel cells. They significantly outperform Nafion and sulfonated silica, which exhibit higher activation energies with Eact ~ 50 and 120 kJ mol−1, respectively. Full article
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