scholarly journals Evaluation of the Antimicrobial Protection of Pharmaceutical Kaolin and Talc Modified with Copper and Zinc

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1173
Author(s):  
Fotini Martsouka ◽  
Konstantinos Papagiannopoulos ◽  
Sophia Hatziantoniou ◽  
Martin Barlog ◽  
Giorgos Lagiopoulos ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Photoelectron Spectroscopy ◽  
Antimicrobial Properties ◽  
Exchange Capacity ◽  
Elevated Concentration ◽  
Chemical Mapping ◽  
Exchange Method ◽  
X Ray ◽  
Copper And Zinc ◽  
Antimicrobial Protection

Six pharmaceutical pastes were prepared using chemically modified kaolin and talc powders. Tests were conducted to determine their structural and chemical characteristics as well as their antimicrobial protection, thus rendering them suitable for cosmetic and pharmaceutical uses. Kaolin and talc were treated chemically via the cation exchange method to load the clay particles with copper and zinc ions, two cations well known for their antimicrobial properties. Mineralogical analyses were conducted by using X-ray diffraction (XRD) before and after the modification, confirming the mineralogical purity of the samples. Scanning electron microscopy was also used in conjunction with energy dispersed spectroscopy (SEM-EDS) to obtain chemical mapping images, revealing the dispersion of the added metals upon the clay minerals surfaces. Moreover, chemical analysis has been performed (XRF) to validate the enrichment of the clays with each metal utilizing the cation exchange capacity. All modified samples showed the expected elevated concentration in copper or zinc in comparison to their unmodified versions. From the X-ray photoelectron spectroscopy (XPS), the chemical state of the samples’ surfaces was investigated, revealing the presence of salt compounds and indicating the oxidation state of adsorbed metals. Finally, the resistance of pastes in microbial growth when challenged with bacteria, molds, and yeasts was assessed. The evaluation is based on the European Pharmacopeia (EP) criteria.

Fe-loaded zeolites as catalysts in the formation of humic substance-like darkcoloured polymers in polycondensation reactions of humic precursors

Clay Minerals ◽  
2012 ◽  
Vol 47 (3) ◽  
pp. 355-364 ◽  
Author(s):  
S. Fukuchi ◽  
M. Fukushima ◽  
R. Nishimoto ◽  
G. Qi ◽  
T. Sato
Keyword(s):  
Cation Exchange ◽  
Photoelectron Spectroscopy ◽  
Ionic Species ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Catalytic Activities ◽  
Ion Exchange Reaction ◽  
Xrd Patterns

AbstractTo enhance the catalytic activities of zeolites for the polycondensation reactions of humic precursors, Fe was loaded into a zeolite via an ion-exchange reaction and the resulting product was subjected to calcination at 773 K. Two types iron-loaded zeolites were prepared using one equivalent (Fe-Z-1) and 10-equivalents (Fe-Z-10) of Fe2+ to the cation-exchange capacity of a natural zeolite from Niki town (Hokkaido, Japan). X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) spectra showed that the Fe(II) that was originally loaded into the cation-exchange sites in the zeolite became oxidized to a Fe(III) ionic species during the preparation. The catalytic activities of each zeolite were evaluated, based on the degree of darkening for reaction mixtures containing catechol, glycine and glucose as model humic precursors. The catalytic activities of Fe-Z-1 and Fe-Z-10 were higher than that for an untreated zeolite, and increased with the amount of Fe in the zeolite.

The Influence of Structure on Ba and K Uptake by a Synthetic Phyllomanganate

Clay Minerals ◽  
1994 ◽  
Vol 29 (2) ◽  
pp. 215-222 ◽  
Author(s):  
E. Paterson ◽  
R. Swaffield ◽  
L. Clark
Keyword(s):  
Chemical Analysis ◽  
Cation Exchange ◽  
Exchange Reaction ◽  
Charge Distribution ◽  
Photoelectron Spectroscopy ◽  
Basal Spacing ◽  
K Uptake ◽  
Selective Uptake ◽  
X Ray ◽  
Bulk Chemical

AbstractThe uptake of Ba2+ and K+ by a synthetic Na-phyllomanganate has been studied by chemical analysis, X-ray diffractometry and X-ray photoelectron spectroscopy. The changes in basal spacing arising from cation exchange have been used to monitor the progress of the exchange reaction and confirm the selectivity measured by bulk chemical analysis. However, the selective uptake of Ba2+ over Ca2+ is much greater than that of K+ over Na+ and it is suggested that charge distribution in the interlayer is important. The results are discussed in the light of recent advances in our understanding of the phyllomanganate structure.

Cation exchange in synthetic manganates: II. The structure of an alkylammonium-saturated phyllomanganate

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 957-964 ◽  
Author(s):  
E. Paterson ◽  
D.R. Clark ◽  
D. Russell ◽  
R. Swaffield
Keyword(s):  
Chain Length ◽  
Photoelectron Spectroscopy ◽  
Hydrocarbon Chain ◽  
Exchange Capacity ◽  
Basal Spacing ◽  
Water Molecules ◽  
Interlayer Water ◽  
X Ray ◽  
Alkyl Chains ◽  
Hydrocarbon Chain Length

AbstractA synthetic phyllomanganate saturated with a series of primary alkylammonium cations has been examined using XRD, chemical analysis and X-ray photoelectron spectroscopy. A linear relationship exists between the basal spacing of the saturated alkylammonium-manganate and the hydrocarbon chain length in the interlayer, and from the gradient it is concluded that the alkyl chains are perpendicular to the manganate sheet. This orientation is a function of both the charge density and the presence of a layer of water molecules immediately adjacent to the manganate basal surfaces. Evacuation results in the loss of this interlayer water and the structure of the organo-manganate is considerably disrupted. The extent to which the interlayer arrangement can be reinstated by rehydration is dependent on the chain length of the saturating organo-cation. For cations of chain length > C6 the C contents suggest that cation in excess of the exchange capacity is present in the interlayer, but the absence of any compensating anion and the release of amine on evacuation suggests that the excess C arises from the presence of free amine.

X-ray photoelectron spectroscopic analysis of halloysites with different composition and particle morphology

Clay Minerals ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 413-421 ◽  
Author(s):  
M. Soma ◽  
G. J. Churchman ◽  
B. K. G. Theng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cation Exchange Capacity ◽  
Spectroscopic Analysis ◽  
Surface Composition ◽  
Particle Morphology ◽  
Exchange Capacity ◽  
Surface Layers ◽  
X Ray ◽  
Fe Content ◽  
Before And After

AbstractThe surface composition of some halloysites with different particle morphology has been investigated by X-ray photoelectron spectroscopy (XPS) before and after removal of external Fe. The Fe(III) 2p3/2 binding energy of external Fe is appreciably smaller than that of structural Fe. Particle morphology is influenced by structural Fe content. The long-tubular halloysite has very little surface Fe, and its concentration tends to increase with the proportion of non-tubular particles in the samples. The spheroidal sample contains the most structural Fe which, however, does not appear to influence particle shape directly. Study by XPS indicates that Fe substitutes for Al in octahedral positions in approximately 1 : 2 proportion. As a result, an increase in octahedral vacancies and cation exchange capacity would be predicted. Further, halloysite layers within a crystal are generally inhomogeneous in composition. Built up like “onion skins”, the surface layers would either be enriched or depleted in Fe depending on the chemical environment in which crystal growth occurs.

scholarly journals Vis-Responsive Copper-Modified Titania for Decomposition of Organic Compounds and Microorganisms

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1194
Author(s):  
Maya Endo-Kimura ◽  
Bariş Karabiyik ◽  
Kunlei Wang ◽  
Zhishun Wei ◽  
Bunsho Ohtani ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Water Oxidation ◽  
Diffuse Reflectance Spectroscopy ◽  
Antimicrobial Properties ◽  
Localized Surface Plasmon ◽  
Intrinsic Activity ◽  
Ambient Conditions ◽  
Copper Species ◽  
X Ray

Seven commercial titania (titanium(IV) oxide; TiO2) powders with different structural properties and crystalline compositions (anatase/rutile) were modified with copper by two variants of a photodeposition method, i.e., methanol dehydrogenation and water oxidation. The samples were characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Although zero-valent copper was deposited on the surface of titania, oxidized forms of copper, post-formed in ambient conditions, were also detected in dried samples. All samples could absorb visible light (vis), due to localized surface plasmon resonance (LSPR) of zero-valent copper and by other copper species, including Cu2O, CuO and CuxO (x:1-2). The photocatalytic activities of samples were investigated under both ultraviolet (UV) and visible light irradiation (>450 nm) for oxidative decomposition of acetic acid. It was found that titania modification with copper significantly enhanced the photocatalytic activity, especially for anatase samples. The prolonged irradiation (from 1 to 5 h) during samples’ preparation resulted in aggregation of copper deposits, thus being detrimental for vis activity. It is proposed that oxidized forms of copper are more active under vis irradiation than plasmonic one. Antimicrobial properties against bacteria (Escherichia coli) and fungi (Aspergillus niger) under vis irradiation and in the dark confirmed that Cu/TiO2 exhibits a high antibacterial effect, mainly due to the intrinsic activity of copper species.

Alteration of smectites induced by hydrolytic exchange

Clay Minerals ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 15-24 ◽  
Author(s):  
S. Ramirez ◽  
D. Righi ◽  
S. Petit
Keyword(s):  
Infrared Spectroscopy ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Relative Increase ◽  
Exchange Capacity ◽  
Capacity Analysis ◽  
Soluble Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixed Layers

AbstractHydrolytic exchange was performed experimentally on four smectitic clays to evaluate the extent of clay alteration induced by this process and the associated ‘auto-transformation’ of H+ clays. Clay samples were Na-saturated and submitted to 10, 50 and 100 wetting-drying (WD) cycles and characterized after treatment using X-ray diffraction (XRD), infrared spectroscopy (FTIR) and cation exchange capacity analysis. Evidence for hydrolytic exchange was given by increasing amounts of exchangeable Mg2+ and precipitation of Na soluble salts for samples subjected to 100 WD cycles. Results indicated a decrease in the interlayer charge after 10 WD cycles but no further decrease was observed after 50 and 100 WD cycles. For one sample, XRD data indicated a decrease in the proportion of the smectite phase and a relative increase in the concentration of illite-smectite mixed layers also present in the sample. The results suggested that the reaction induces first a decrease in the layer charge and then a partial dissolution of some smectite layers.

Comprehensive multilayer film analysis with XPS, AES, and EDS

1992 ◽  
Vol 50 (2) ◽  
pp. 1784-1785
Author(s):  
N. C. Miller
Keyword(s):  
Photoelectron Spectroscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Composition ◽  
Ion Beam ◽  
Three Dimensional ◽  
Chemical Mapping ◽  
Vertical Diffusion ◽  
X Ray ◽  
Sample Rotation ◽  
Microscopic Features

Wavelength and energy dispersive x-ray spectroscopy (WDS and EDS) are routinely utilized to measure qualitatively and quantitatively the composition of microscopic features/phases of thickness 0.5 (μm or greater in solids. Surface spectroscopies, especially x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), are employed to determine surface chemistry and surface composition respectively of microscopic features 0.2-5 nm thick. The combined utilization of AES and EDS (or WDS) permits microanalysis of surface and subsurface features/phases. Two areas of improved analysis through combined utilization of AES and EDS are imaging/elemental mapping and measurement of vertical diffusion profiles. Strengths of XPS in complementing EDS/WDS will also be discussed.High resolution surface elemental or chemical mapping can be carried out with scanning Auger or secondary ion mass spectrometry (SIMS) microanalysis, respectively. In fact, both offer improved spacial resolution over WDS and EDS elemental x-ray dot mapping. Using sample rotation while removing material by ion beam sputter etching, three dimensional mapping can be carried out by either surface analysis technique, permitting microanalysis of buried features even in complex heterostructures.

Sorption of Eu(III) on Fe–montmorillonite relevant to geological disposal of HLW

2018 ◽  
Vol 106 (12) ◽  
pp. 971-983 ◽  
Author(s):  
Santosh Chikkamath ◽  
Madhuri A. Patel ◽  
Aishwarya S. Kar ◽  
Vaibhavi Raut ◽  
Bhupendra Singh Tomar ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Exchange Capacity ◽  
High Level Waste ◽  
Sudden Increase ◽  
Exchange Method ◽  
Sorption Data ◽  
Sorption Behaviour ◽  
Geological Disposal ◽  
Buffer Material

Abstract Montmorillonite (Mt) is the major clay mineral of bentonite, which is the candidate buffer material in the engineered barrier system for geological disposal of high level waste (HLW). The alteration of Mt due to its interaction with carbon steel (overpack) can produce Fe–Mt. In order to understand the basic properties of Fe–Mt, the sorption studies using Eu(III) are reported here. For this, Fe(III)–Mt was prepared by conventional cation exchange method using FeCl3 with Na–Mt. The obtained Fe(III)–Mt was then reduced to Fe(II)–Mt using ascorbic acid. Both the samples were characterized based on their X-ray diffraction, Fourier transform infrared spectra, cation exchange capacity and specific surface area. The batch sorption studies of Eu(III) were conducted for both Fe(III)–Mt and Fe(II)–Mt as a function of pH (3–10), ionic strength (0.001 M–1 M) and Eu(III) concentration (10−8–10−3 M). The distribution coefficient (Kd) was found to be higher for Fe(III)–Mt compared to Fe(II)–Mt and Na–Mt. The sudden increase in sorption in the pH range 4.5–6 and remaining constant beyond it indicates ion exchange mechanism at pH<4.5, with surface complexation mechanism dominating the sorption at pH>4.5. This is further corroborated by ionic strength dependent sorption data which shows decrease in sorption capacity of Fe–Mt with increasing ionic strength at low pH, but remaining more or less unchanged at higher pH. Eu(III) adsorption isotherm on Fe–Mt increased linearly with [Eu(III)] reaching saturation at 10−5 M and 10−4 M for Fe(III)–Mt and Fe(II)–Mt, respectively. The amount of iron released from Fe–Mt and Fe(II)/Fetotal during sorption were estimated to understand the effect on Eu(III) sorption behaviour by release of interlayer iron in Fe–Mt.

scholarly journals Soft-Templating of Sulfur and Iron Dual-Doped Mesoporous Carbons: Lead Adsorption in Mixtures

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 403
Author(s):  
Dipendu Saha ◽  
Connelly P. Richards ◽  
Robert G. Haines ◽  
Nicholas D. D’Alessandro ◽  
Madeleine J. Kienbaum ◽  
...  
Keyword(s):  
Drinking Water ◽  
Photoelectron Spectroscopy ◽  
Iron Content ◽  
Textural Properties ◽  
Water Source ◽  
Order Rate Constant ◽  
Elevated Concentration ◽  
Mesoporous Carbons ◽  
X Ray ◽  
Soft Templating

Lead pollution in drinking water is one of the most common problems worldwide. In this research, sulfur and iron dual-doped mesoporous carbons are synthesized by soft-templating with sulfur content 4.4–6.1 atom% and iron content 7.8–9 atom%. Sulfur functionalities of the carbons are expected to enhance the affinity of the carbon toward lead whereas iron content is expected to separate the carbon from water owing to its magnetic properties. All the carbons were characterized by pore textural properties, x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive x-ray (EDX). In order to study the Pb(II) removal efficiently of this carbon in competitive mode and to mimic the real-world use, one additional heavy-metal, including Cr(III), and four other commonly occurring metals—Na(I), K(I), Ca(II) and Fe (III)—are added with lead prior to adsorption experiments. It was observed that Pb(II) adsorption capacity of this carbon was not influenced by the presence of other metals. A highly elevated concentration of Na(I), K(I), Ca(II) and Fe(III) in the eluting solution compared to the initial dose suggested possible leaching of those metals from other salts as impurities, water source or even from the carbon itself, although the XPS analysis of the carbon confirmed negligible adsorption of those metals in carbon. From the equilibrium and kinetic data of adsorption, few parameters have been calculated, including distribution coefficient, diffusive time constant and pseudosecond order rate constant. The overall results suggest that these iron and sulfur dual-doped mesoporous carbons can serve as potential adsorbents for removal of lead from drinking water in the presence of other competing metals.

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