Special Issue "Functional Design of Clay Minerals"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Crystallography and Physical Chemistry of Minerals".

Deadline for manuscript submissions: 15 July 2020.

Special Issue Editors

Prof. Dr. Huaming Yang
Website
Guest Editor
1. Centre for Mineral Materials, Central South University, Changsha 410083, China
2. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Interests: mineral materials; nanoclay; mineral surface; mineral-based catalyst; energy materials; computational simulation
Special Issues and Collections in MDPI journals
Dr. Yunfei Xi
Website
Guest Editor
School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, QLD 4001, Australia
Interests: clay minerals; organoclays; environmental remediation; mineral based nano composites; novel building materials

Special Issue Information

Dear Colleagues,

Functional design of clay minerals is a key strategy to realize its high value utilization. The special issue primarily focuses on the functional strategy and theoretical study of clay minerals, and their application in the environment, energy, and biomedicine fields. Functional design mainly includes the controllable loading of nanomaterials on the surface of clay minerals, interlayer structure adjust and interface binding behavior. Also the interaction of biological cells with clay minerals was emphasized. Furthermore, density functional theory (DFT) calculations can analyse the electronic structure and energy of functionalized clay minerals at the atomic molecular level.

Prof. Dr. Huaming Yang
Dr. Yunfei Xi
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. Minerals is an international peer-reviewed open access monthly 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 1600 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

  • clay minerals
  • nanotubular clay
  • functional design
  • energy and environmental applications
  • atomic molecular interface
  • DFT calculation.

Published Papers (5 papers)

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Research

Open AccessArticle
Structural Characterization of Octahedral Sheet in Dioctahedral Smectites by Thermal Analysis
Minerals 2020, 10(4), 347; https://doi.org/10.3390/min10040347 - 13 Apr 2020
Abstract
The structures of octahedral sheets of dioctahedral phyllosilicates show cis-vacant (cv) and trans-vacant (tv) configurations due to the different distributions of the octahedral cations over cis- and trans-sites. On the basis of the different dehydroxylation temperatures, [...] Read more.
The structures of octahedral sheets of dioctahedral phyllosilicates show cis-vacant (cv) and trans-vacant (tv) configurations due to the different distributions of the octahedral cations over cis- and trans-sites. On the basis of the different dehydroxylation temperatures, a thermal analysis is an effective method used to identify the cv and tv configurations of an octahedral sheet in dioctahedral smectites. The proportions of cv and tv configurations were determined by fitting the derivative thermogravimetry (DTG) curves. A wide range of cv and tv proportions were detected in the samples. The dehydroxylation temperatures of samples consisting of cv configuration are about 150 to 200 °C higher than those consisting of tv configurations. The samples were classified as tv varieties when octahedral Fe3+ > 0.46 mol/FU, and the pure tv dioctahedral smectites were found when Fe3+ > 1.8 mol/FU. A clear linear relationship was found between the content of octahedral Fe3+ and Al3+ and the proportion of cv and tv configurations. The substitution of Al3+ by Fe3+ in the octahedral sheets is the main factor for the formation of tv varieties. There was no relationship detected between the layer charge density, octahedral Mg2+ content, and the proportion of tv and cv. The present results indicate that the iron content has a significant effect on the structure of the octahedral sheet. Full article
(This article belongs to the Special Issue Functional Design of Clay Minerals)
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Open AccessArticle
Simple, Reproducible Synthesis of Pure Monohydrocalcite with Low Mg Content
Minerals 2020, 10(4), 346; https://doi.org/10.3390/min10040346 - 13 Apr 2020
Abstract
Monohydrocalcite (MHC) is a metastable hydrous calcium carbonate that requires Mg in the mother solution during formation in the laboratory. MHC prepared by previously reported methods always contains a large amount of Mg (Mg/Ca ratio up to 0.4) because of the simultaneous formation [...] Read more.
Monohydrocalcite (MHC) is a metastable hydrous calcium carbonate that requires Mg in the mother solution during formation in the laboratory. MHC prepared by previously reported methods always contains a large amount of Mg (Mg/Ca ratio up to 0.4) because of the simultaneous formation of amorphous Mg carbonate during synthesis, which has hindered detailed elucidation of the mineralogical characteristics of MHC. Here, we synthesized MHC at low temperature (5 °C) and found that it contained little Mg (Mg/Ca ratio < 0.01). X-ray absorption near-edge structure analysis of synthesized MHC revealed that the Mg present was structurally incorporated within the MHC, and that the chemical speciation of this Mg was similar to that of Mg in aragonite. Thus, low-temperature synthesis is an effective means of producing MHC without also producing amorphous Mg carbonate. Full article
(This article belongs to the Special Issue Functional Design of Clay Minerals)
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Open AccessCommunication
Geopolymer-TiO2 Nanocomposites for Photocsatalysis: Synthesis by One-Step Adding Treatment Versus Two-Step Acidification Calcination
Minerals 2019, 9(11), 658; https://doi.org/10.3390/min9110658 - 27 Oct 2019
Abstract
Geopolymer-TiO2 nanocomposites were prepared by two different techniques, namely the two-step acidification calcination treatment and one-step adding method. The potential photocatalytic activities of geopolymer-TiO2 nanocomposites prepared by the two different methods were tested and compared. Nanocomposites prepared via the one-step process [...] Read more.
Geopolymer-TiO2 nanocomposites were prepared by two different techniques, namely the two-step acidification calcination treatment and one-step adding method. The potential photocatalytic activities of geopolymer-TiO2 nanocomposites prepared by the two different methods were tested and compared. Nanocomposites prepared via the one-step process showed better photocatalytic activity. The amount of TiO2 particles loaded on the surface of the foaming materials was investigated by XRD and SEM-Mapping. By comparing with the sample obtained from two-step treatment, the TiO2 particles were distributed uniformly on the surface of the foaming materials for the sample obtained from the one-step method in this study. Results showed that the specific surface area of the geopolymer-TiO2 prepared by the one-step treatment process (28.67 m2/g) was significantly lower than the two-step acidification calcination process (215.04 m2/g), while the photocatalytic efficiency with methylene blue trihydrate (MB) was better. This is due to the more stable structure of geopolymer-TiO2 nanocomposites, the better dispersion and more loading of TiO2 particles on the foaming materials surfaces, leading to the enhanced photocatalytic activity. Full article
(This article belongs to the Special Issue Functional Design of Clay Minerals)
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Open AccessArticle
The Characterization and SCR Performance of Mn-Containing α-Fe2O3 Derived from the Decomposition of Siderite
Minerals 2019, 9(7), 393; https://doi.org/10.3390/min9070393 - 28 Jun 2019
Cited by 1
Abstract
In this work, a nano-structured iron-manganese oxide composite was prepared by calcining natural manganese-rich siderite at different temperatures (450, 500, 550, 600 °C, labeled as H450, H500, H550, H600, respectively), and their performances of selective catalytic reduction (SCR) of NO by NH3 [...] Read more.
In this work, a nano-structured iron-manganese oxide composite was prepared by calcining natural manganese-rich siderite at different temperatures (450, 500, 550, 600 °C, labeled as H450, H500, H550, H600, respectively), and their performances of selective catalytic reduction (SCR) of NO by NH3 were investigated. XRD, XRF, BET, XPS, SEM, and TEM were used to investigate the morphology, composition, and surface characteristics of the catalyst. The results showed that the decomposition of siderite occurred from 450 °C to around 550 °C during the calcination in air atmosphere; moreover, the siderite could be converted into nano-structured α-Fe2O3. The specific surface area of the material increased, and Mn2+ was transformed into Mn4+, which were beneficial to the SCR. Among these catalysts, H550 had the best SCR performance, with NO removal of 98% at a temperature window from 200 to 250 °C. The presence of water vapor and sulfur dioxide can inhibit the SCR performance of the catalysts, but this inhibition effect was not obvious for H550 at the optimum reaction temperature (250 °C). The findings presented in this study are significant toward the application of the Mn-rich siderite as a precursor in preparing the Fe-Mn oxides for catalytic de-NOx by SCR. Full article
(This article belongs to the Special Issue Functional Design of Clay Minerals)
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Open AccessArticle
Simple Synthesis and Characterization of Hexagonal and Ordered Al–MCM–41 from Natural Perlite
Minerals 2019, 9(5), 264; https://doi.org/10.3390/min9050264 - 30 Apr 2019
Cited by 1
Abstract
Silica reagents are expensive and toxic for use in the synthesis of mesoporous silica materials. It is imperative to take an interest in green silicon sources. In this paper, we report the synthesis of hexagonal and ordered aluminum-containing mesoporous silica materials (Al–MCM–41) from [...] Read more.
Silica reagents are expensive and toxic for use in the synthesis of mesoporous silica materials. It is imperative to take an interest in green silicon sources. In this paper, we report the synthesis of hexagonal and ordered aluminum-containing mesoporous silica materials (Al–MCM–41) from natural perlite mineral without addition of silica or aluminum reagents. A pretreatment process involving acid leaching, alkali leaching, and strongly acidic cation exchange resins treatment was critical to obtain silicon and aluminum sources from natural perlite mineral. The Al–MCM–41 material was synthesized via a hydrothermal reaction with hexadecyl trimethyl ammonium bromide (CTAB) as the template and subsequent calcination. The resulting mesophase had a hexagonal and ordered mesoporous structure, confirmed by small-angle X-ray diffraction (SAXRD) and transmission electron microscopy (TEM). Al–MCM–41 material had a high Brunauer–Emmet–Teller (BET) surface area of 1024 m2/g, pore volume of 0.72 cm3/g and an average pore diameter of 2.8 nm with a pore size distribution centered at 2.5 nm. The thermal behavior of the as-synthesized samples during calcination was investigated by thermogravimetry (TG) and differential thermogravimetry (DTG) analysis. The Al–MCM–41 material showed a negative surface charge in aqueous solution with the pH value ranging from 2 to 13. The variations of chemical structures from natural perlite to Al–MCM–41 were traced by wide-angle X-ray diffraction (WAXRD) and Fourier-transform infrared spectroscopy (FTIR). A proposed mechanism for the synthesis of hexagonal and ordered mesoporous silica materials from natural perlite is discussed. Full article
(This article belongs to the Special Issue Functional Design of Clay Minerals)
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