Characterization of arsenite (As(III)) and arsenate (As(V)) sorption on synthetic siderite spherules under anoxic conditions: Different sorption behaviors with crystal size and arsenic species

2022 ◽  
Author(s):  
Seon Yong Lee ◽  
Bongsu Chang ◽  
YoungJae Kim ◽  
Haeseong Jang ◽  
Young Jae Lee
Keyword(s):  
Crystal Size ◽  
Arsenic Species ◽  
Anoxic Conditions

Structure Characterization of Sintered CaO-Al2O3-SiO2 Glass-Ceramic Reinforced with Spodumene

2013 ◽  
Vol 834-836 ◽  
pp. 309-314
Author(s):  
Zi Fan Xiao ◽  
Jin Shu Cheng ◽  
Jun Xie
Keyword(s):  
Glass Ceramic ◽  
Energy Dispersive Spectrometry ◽  
Crystal Size ◽  
Bending Strength ◽  
Glass Ceramics ◽  
Structure Characterization ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray

A glass-ceramic belonging to the CaO-Al2O3-SiO2(CAS) system with different composition of spodumene and doping the Li2O with amount between 0~2.5 % (mass fraction) were prepared by onestage heat treatment, under sintering and crystallization temperature at 1120 °C for two hours. In this paper, differential thermal analysis, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and bending strength test were employed to investigate the microstructure and properties of all samples. β-wollastonite crystals were identified as the major crystalline phases, and increasing Li2O was found to be benefit for the crystallization and tiny crystalline phases remelting, resulting in the content of major crystalline phases increased first and then decreased with increasing the expense of spodumene. Meanwhile, the crystal size can be positively related with the content of Li2O. The preferable admixed dosage of spodumene can be obtained, besides the strength of glass-ceramics can be more than 90 MPa.

Physicochemical characterization of Pt and Ir particles deposited on Ce(1-x)Ru(x)O2 solid-solutions for CO oxidation

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3433-3440
Author(s):  
E. Gonzalez-A ◽  
R. Rangel ◽  
J. Lara ◽  
J. J. Alvarado ◽  
P. Bartolo
Keyword(s):  
Solid Solutions ◽  
Crystal Size ◽  
Sol Gel ◽  
Physicochemical Characterization ◽  
Metallic State ◽  
Wet Impregnation ◽  
Iridium Nanoparticles ◽  
Gel Technique ◽  
Near Future

AbstractPt/Ce1-xRuxO2 and Ir/Ce1-xRuxO2 catalysts were prepared through the sol-gel technique, under microwave heating. In a first step, the Ce1-xRuxO2 solid solutions were prepared. Subsequently, an incipient wet impregnation process was carried out to homogeneously achieve the dispersion, either of platinum or iridium nanoparticles. The Pt/Ce1-xRuxO2 and Ir/Ce1-xRuxO2 catalysts were characterized by means of SEM, XRD, XPS, TEM, and specific surface area measurements. Crystal size and shifting into the CeO2 structure were detected after ruthenium doping producing the Ce1-xRuxO2 solid-solutions. Trough XPS technique Pt and Ir nanoparticles were found evenly dispersed in a metallic state. Those features allow us to foresee that, in the near future, these materials could be used efficiently as catalysts for oxidation process.

Preparation and Characterization of Nano-SiCP Strengthened MCrAlY Graded Coating by Laser Multi-Layer Cladding

2012 ◽  
Vol 557-559 ◽  
pp. 1937-1940
Author(s):  
Dong Sheng Wang ◽  
Zong Jun Tian ◽  
Bin Yang ◽  
Li Da Shen
Keyword(s):  
Composite Coating ◽  
Crystal Size ◽  
Vickers Microhardness ◽  
Intermetallic Alloy ◽  
Mcraly Coating ◽  
Sic Particles ◽  
Graded Coating ◽  
Formation Heat ◽  
Equiaxed Grains

Nano-SiC/MCrAlY graded coating was prepared by laser multi-layer cladding on TiAl base intermetallic alloy using composite MCrAlY powders with 1%, 2%, and 3% nano-SiC particles (mass fraction) in turn. The microstructure and microhardness of the composite coating were analyzed by means of scanning electron microscope (SEM) and Vickers microhardness tester. The results show that the microstructure of the composite coating was refined and composed of fine equiaxed grains because of addition of nanometer SiC particles, and the crystal size becomes small with increasing the nano-SiC content in the coating. In addition, due to small size and formation heat of the nano-SiC particles, SiC particles decompose and form new carbides in the coating after laser cladding. The hardness of the composite MCrAlY coating is obviously improved due to enhancement of multi-carbide and refinement of structure.

scholarly journals In Situ IR Characterization of CO Interacting with Rh Nanoparticles Obtained by Calcination and Reduction of Hydrotalcite-Type Precursors

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
F. Basile ◽  
I. Bersani ◽  
P. Del Gallo ◽  
S. Fiorilli ◽  
G. Fornasari ◽  
...  
Keyword(s):  
Crystal Size ◽  
Liquid Nitrogen Temperature ◽  
Transmission Electron ◽  
In Situ Ir ◽  
Ft Ir ◽  
Co Disproportionation ◽  
Ft Ir Spectroscopy

Supported Rh nanoparticles obtained by reduction in hydrogen of severely calcined Rh/Mg/Al hydrotalcite-type (HT) phases have been characterized by FT-IR spectroscopy of adsorbed CO [both at room temperature (r.t.) and nominal liquid nitrogen temperature] and Transmission Electron Microscopy (TEM). The effect of reducing temperature has been investigated, showing that Rh crystal size increases from 1.4 nm to 1.8 nm when the reduction temperature increases from 750°C to 950°C. The crystal growth favours the formation of bridged CO species and linear monocarbonyl species with respect to gem-dicarbonyl species; when CO adsorbs at r.t., CO disproportionation occurs on Rh and it accompanies the formation of RhI(CO)2. The role of interlayer anions in the HT precursors to affect the properties of the final materials has been also investigated considering samples prepared from silicate-instead of carbonate-containing precursors. In this case, formation of RhI(CO)2 and CO disproportionation do not occur, and this evidence is discussed in terms of support effect.

Preparation and characterization of ITQ-29/polysulfone mixed-matrix membranes for gas separation: Effect of zeolite composition and crystal size

2012 ◽  
Vol 73 ◽  
pp. 116-122 ◽  
Author(s):  
Clara Casado-Coterillo ◽  
Jaime Soto ◽  
María T. Jimaré ◽  
Susana Valencia ◽  
Avelino Corma ◽  
...  
Keyword(s):  
Gas Separation ◽  
Crystal Size ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Separation Effect ◽  
Matrix Membranes

Structural Analysis of Prosthetic Coatings Elaborated by Electrochemical Deposition

2017 ◽  
Vol 758 ◽  
pp. 105-110
Author(s):  
Yousra Alaoui Selsouli ◽  
Mohammed Bey Damene ◽  
Abdelilah Benmarouane ◽  
Florica Simescu-Lazar ◽  
Joël Faure ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Alloy ◽  
Chemical Composition ◽  
Structural Analysis ◽  
Electrochemical Deposition ◽  
Crystal Size ◽  
Rietveld Method ◽  
X Rays ◽  
Titanium Alloy Ti6al4v

In this study, phosphocalcic coatings on titanium alloy Ti6Al4V substrate are elaborated using Electrodeposition (ELD) by adding optimized amount of hydrogen peroxide H2O2 into the electrolyte. Structural analysis is performed by X Rays Diffraction and the data are treated using the RIETVELD method. The characterization of the coatings elaborated by ELD showed that the H2O2 amount variation has an influence on the morphology, the crystal size and the chemical composition (monophasic or biphasic) of the coatings.

Synthesis and Characterization of Zinc Doped Hydroxyapatite for Bone Substitute Applications

2014 ◽  
Vol 660 ◽  
pp. 942-946
Author(s):  
Mohamad Firdaus Abdul Wahid ◽  
C.M. Mardziah ◽  
Koay Mei Hyie ◽  
N.R. Nik Roselina
Keyword(s):  
Crystal Size ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
Phase Changes ◽  
Precipitation Method ◽  
Zinc Ions ◽  
Crystal Shape ◽  
X Ray Diffraction ◽  
X Ray

Hydroxyapatite was prepared by using precipitation method. The substitution of zinc ions in hydroxyapatite structure was studied by several characterization techniques. Several concentration of zinc ions were substituted into hydroxyapatite. Characterization technique such as X-ray diffraction method was used to study the phase changes and the lattice parameters with the addition of zinc. Field emission scanning electron microscopy was used to examine the influence of zinc on the crystal size and the morphology of the as-synthesized powders. Based on X-ray diffraction result, the addition of zinc affects the lattice parameters and phase. The result showed that zinc ions were substituted in the structure. As zinc substitution increased, the lattice parameters a and c decreased. The crystal shape of hydroxyapatite without zinc ions was regular shapes while hydroxyapatite with zinc ions was irregular and also tends to agglomerates with single particle was calculated about 28 - 34 nm .

Microstructure Characterization Of Calcified Tissues By Xrd Using An Area Detector

2008 ◽  
Vol 1094 ◽  
Author(s):  
Alejandro Rodriguez-Navarro ◽  
Antonio G. Checa
Keyword(s):  
Crystal Size ◽  
Self Organization ◽  
Polycrystalline Materials ◽  
Area Detector ◽  
Mineral Components ◽  
Ordered Assembly ◽  
Diffraction Patterns ◽  
Calcified Tissues ◽  
Textured Materials

AbstractOrganisms can precipitate a wide array of minerals which they use to build calcified tissues (i.e., bone, mollusk shell, eggshell, coccolith) having highly sophisticated microstructures. The disposition of organic and mineral components building these materials is highly organized from the nano- to the millimeter scale. Their ordered assembly implies self-organization processes accorded in space and time, giving rise to highly sophisticated textured materials. The objective of our work is the study of fundamental processes in biomineralization such as self-organization processes and texture control in biomineral crystal aggregates. To study the order in the arrangement of shell making crystals we used area detectors available today in modern X-ray diffractometers. The 2D diffraction patterns, collected using such detectors, contain detailed information not only about the mineralogy but also about the microstructure characteristics of polycrystalline materials – crystal size, stress, crystallinity and crystallographic-texture. For instance, to understand microstructure development in mollusk shells, we use this type of detector to do microdiffraction analyses combined with high resolution SEM in order to follow the ordering mechanisms of crystals making these biomaterials.

Synthesis and characterization of anatase TiO2 nanotubes with controllable crystal size by a simple MWCNT template method

2012 ◽  
Vol 196 ◽  
pp. 435-440 ◽  
Author(s):  
Ju Hyung Kim ◽  
Xiao Hui Zhang ◽  
Jae Deuk Kim ◽  
Hoon Mo Park ◽  
Sang Bok Lee ◽  
...  
Keyword(s):  
Tio2 Nanotubes ◽  
Crystal Size ◽  
Anatase Tio2 ◽  
Synthesis And Characterization ◽  
Template Method

Characterization of Cellulosic Biomass Loaded with Iron and Arsenic Using High Energy X-Rays

2007 ◽  
Vol 20-21 ◽  
pp. 643-646 ◽  
Author(s):  
G. Cordeiro Silva ◽  
Regina Pinto de Carvalho ◽  
M. Sylvia S. Dantas ◽  
Virgínia S.T. Ciminelli
Keyword(s):  
Fine Structure ◽  
Arsenic Species ◽  
High Energy ◽  
Cellulosic Biomass ◽  
X Rays ◽  
Iron Ions ◽  
X Ray ◽  
X Ray Absorption ◽  
Exafs Spectra

The biosorption of arsenic species by dried lettuce leaves (L.sativa) was investigated. Arsenic sorption, that is not effective on in natura biomass, was enhanced when the biomass was previously loaded with Fe(III). Analysis of X-ray Absorption Near-Edge Spectroscopy (XANES) spectra showed that iron was incorporated as Fe(III) and arsenic as As(V), regardless the contact with the lowest or highest valence species of these elements. The features of Extended X-ray Absorption Fine-Structure Spectroscopy (EXAFS) spectra suggest that the nearest neighboring atoms of iron ions are the same in all the samples, even in the As-Fe loaded ones. These results indicate the arsenic oxyanions as the sorbed species on the iron-loaded biomass.

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