First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

Download Full-text

Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽

10.3390/min11060611 ◽

2021 ◽

Vol 11 (6) ◽

pp. 611

Author(s):

Celia Marcos ◽

María de Uribe-Zorita ◽

Pedro Álvarez-Lloret ◽

Alaa Adawy ◽

Patricia Fernández ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Crystallite Size ◽

Archaeological Sites ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Infrared And Raman Spectroscopy ◽

First Time ◽

Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Download Full-text

The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽

10.3390/ma14102623 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2623

Author(s):

Monika Wójcik-Bania ◽

Jakub Matusik

Keyword(s):

Total Pore Volume ◽

Cross Linking ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

The Cross ◽

Chain Lengths ◽

First Time ◽

Substituent Influence ◽

Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

Download Full-text

Biodiesel Production on Monometallic Pt, Pd, Ru, and Ag Catalysts Supported on Natural Zeolite

Materials ◽

10.3390/ma14010048 ◽

2020 ◽

Vol 14 (1) ◽

pp. 48

Author(s):

Pawel Mierczynski ◽

Magdalena Mosińska ◽

Lukasz Szkudlarek ◽

Karolina Chalupka ◽

Misa Tatsuzawa ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Natural Zeolite ◽

Noble Metals ◽

Methyl Esters ◽

Physicochemical Characteristics ◽

Biodiesel Production ◽

X Ray Diffraction ◽

X Ray ◽

Yield Values ◽

Temperature Programmed

Biodiesel production from rapeseed oil and methanol via transesterification reaction facilitated by various monometallic catalyst supported on natural zeolite (NZ) was investigated. The physicochemical characteristics of the synthesized catalysts were studied by X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), temperature-programmed-reduction in hydrogen (H2-TPR), temperature-programmed-desorption of ammonia (NH3-TPD), Scanning Electron Microscope equipped with EDX detector (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) methods. The highest activity and methyl ester yields were obtained for the Pt/NZ catalyst. This catalyst showed the highest triglycerides conversion of 98.9% and fatty acids methyl esters yields of 94.6%. The activity results also confirmed the high activity of the carrier material (NZ) itself in the investigated reaction. Support material exhibited 90.5% of TG conversion and the Fatty Acid Methyl Esters yield (FAME) of 67.2%. Introduction of noble metals improves the TG conversion and FAME yield values. Increasing of the metal loading from 0.5 to 2 wt.% improves the reactivity properties of the investigated catalysts.

Download Full-text

A novel and potentially scalable CVD-based route towards SnO2:Mo thin films as transparent conducting oxides

Journal of Materials Science ◽

10.1007/s10853-021-06269-3 ◽

2021 ◽

Author(s):

Tianlei Ma ◽

Marek Nikiel ◽

Andrew G. Thomas ◽

Mohamed Missous ◽

David J. Lewis

Keyword(s):

Thin Films ◽

Photoelectron Spectroscopy ◽

Mixed Valence ◽

Chemical Vapour ◽

X Ray Diffraction ◽

X Ray ◽

Conducting Oxides ◽

Valence States ◽

3 Omega ◽

First Time

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

Download Full-text

Reactive Dual Magnetron Sputtering: A Fast Method for Preparing Stoichiometric Microcrystalline ZnWO4 Thin Films

Surfaces ◽

10.3390/surfaces4020013 ◽

2021 ◽

Vol 4 (2) ◽

pp. 106-114

Author(s):

Yannick Hermans ◽

Faraz Mehmood ◽

Kerstin Lakus-Wollny ◽

Jan P. Hofmann ◽

Thomas Mayer ◽

...

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Photoelectron Spectroscopy ◽

Fast Method ◽

X Ray Diffraction ◽

X Ray ◽

Glass Substrates ◽

Post Annealing ◽

Rf Signal ◽

First Time

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.

Download Full-text

Crystalline and Electrical Properties of Ferroelectric Silver Niobate-tantalate thin Films

MRS Proceedings ◽

10.1557/proc-655-cc11.5.1 ◽

2000 ◽

Vol 655 ◽

Cited By ~ 1

Author(s):

Jung-Hyuk Koh ◽

S.I. Khartsev ◽

Alex Grishin ◽

Vladimir Petrovsky

Keyword(s):

Temperature Stability ◽

Frequency Dispersion ◽

Processing Temperature ◽

High Temperature Stability ◽

X Ray Diffraction ◽

Ferroelectric State ◽

X Ray ◽

Ferroelectric Hysteresis ◽

First Time

AbstractFor the first time AgTa0.38Nb0.62O3 (ATN) films have been grown on the La0.7Sr0.3CoO3 (LSCO)/LaAlO3 single crystal as well as onto Pt80Ir20 (PtIr) polycrystalline substrate. Comprehensive X-ray diffraction analyses reveal epitaxial quality of ATN and LSCO films on the LaAlO3(001) substrate, while ATN/PtIr films have been found to be (001) preferentially oriented. Dielectric spectroscopy performed for ATN films and bulk ceramics in a wide temperature range 77 to 420 K shows the structural monoclinic M1-to-monoclinic M2 phase transition occurs in films at the temperature 60 °C lower than in ceramics. The tracing of the ferroelectric hysteresis P-E loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields remnant polarization of 0.4 μC/cm2 @ 77 K. Weak frequency dispersion, high temperature stability of dielectric properties as well as low processing temperature of 550 °C make ATN films to be attractive for various applications.

Download Full-text

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424618500633 ◽

2018 ◽

Vol 22 (09n10) ◽

pp. 814-820

Author(s):

Yingying Jia ◽

Ling Xu ◽

Bangshao Yin ◽

Mingbo Zhou ◽

Jianxin Song

Keyword(s):

Nickel Complex ◽

High Resolution Mass Spectrometry ◽

Dihedral Angles ◽

X Ray Diffraction ◽

Extinction Coefficients ◽

X Ray ◽

H Nmr ◽

First Time ◽

Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

Download Full-text

Synthesis of Galactomannan Sulfate-Citrate

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1049.218 ◽

2022 ◽

Vol 1049 ◽

pp. 218-223

Author(s):

Aleksandr S. Kazachenko ◽

Yuriy N. Malyar ◽

Anna S. Kazachenko

Keyword(s):

Biological Activity ◽

Ftir Spectroscopy ◽

X Ray Diffraction ◽

Absorption Bands ◽

X Ray ◽

Mixed Ester ◽

First Time ◽

Derivatives Of

Sulfated derivatives of polysaccharides have anticoagulant, hypolipedimic and other biological activity. In this work, a complex mixed ester of galactomannan, its sulfate-citrate, was obtained for the first time. The introduction of citrate and sulfate groups was proved by FTIR spectroscopy by the appearance of corresponding absorption bands. It was shown by X-ray diffraction that the introduction of the citrate group leads to the amorphization of the galactomannan structure.

Download Full-text

Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

Materials Express ◽

10.1166/mex.2021.1963 ◽

2021 ◽

Vol 11 (5) ◽

pp. 724-731

Author(s):

Hemin Liu ◽

Qian Huang ◽

Liang Zhao

Keyword(s):

Ambient Temperature ◽

Sulfate Solution ◽

Sulfate Attack ◽

Limestone Powder ◽

X Ray Diffraction ◽

X Ray ◽

Mineral Phases ◽

Adverse Influence ◽

Powder Content ◽

Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

Download Full-text

Exploiting superspace to clarify vacancy and Al/Si ordering in mullite

IUCrJ ◽

10.1107/s2052252518007467 ◽

2018 ◽

Vol 5 (4) ◽

pp. 497-509 ◽

Cited By ~ 2

Author(s):

Paul Benjamin Klar ◽

Iñigo Etxebarria ◽

Gotzon Madariaga

Keyword(s):

Density Functional ◽

X Ray Diffraction ◽

Intrinsic Structure ◽

Functional Theory ◽

New Approach ◽

X Ray ◽

Vacancy Ordering ◽

Harmonic Modulation ◽

First Time

Synchrotron single-crystal X-ray diffraction has revealed diffuse scattering alongside sharp satellite reflections for different samples of mullite (Al4+2xSi2−2xO10−x). Structural models have been developed in (3+1)-dimensional superspace that account for vacancy ordering and Al/Si ordering based on harmonic modulation functions. A constraint scheme is presented which explains the crystal-chemical relationships between the split sites of the average structure. The modulation amplitudes of the refinements differ significantly by a factor of ∼3, which is explained in terms of different degrees of ordering,i.e.vacancies follow the same ordering principle in all samples but to different extents. A new approach is applied for the first time to determine Al/Si ordering by combining density functional theory with the modulated volumes of the tetrahedra. The presence of Si–Si diclusters indicates that the mineral classification of mullite needs to be reviewed. A description of the crystal structure of mullite must consider both the chemical composition and the degree of ordering. This is of particular importance for applications such as advanced ceramics, because the physical properties depend on the intrinsic structure of mullite.

Download Full-text