Morphological and Chemical Analyses of Manganese Dioxide Accretions on Mexican Ceramics

2004 ◽  
Vol 852 ◽  
Author(s):  
Caitlin R. O'Grady
Keyword(s):  
Manganese Dioxide ◽  
Microscopic Analysis ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Metropolitan Museum Of Art ◽  
The Arts ◽  
Spot Tests ◽  
Scanning Electron

ABSTRACTMicroscopic analysis of West Mexican ceramics (dating between in the collection of the Department of the Arts of Africa, Oceania and the Americas at the Metropolitan Museum of Art has established five different morphological types of manganese dioxide (MnO2) accretions. The accretions result mostly from a combination of bacterial and weathering activity in post-depositional contexts. Optical microscopy, scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDS) and x-ray fluorescence (XRF) were successful; whereas microchemical spot tests, x-ray diffraction (XRD) and Raman spectroscopy proved inconclusive in the identification and differentiation of the five morphologies. Accretion morphology and substrate characteristics, together, suggest scenarios for the mechanism of formation and offer a qualitative tool for authentication. Accretions were documented using photomicrography, categorized based on empirical observations; sampled and analyzed using SEM-EDS and ND-XRF.

scholarly journals Borax-Cross-Linked Guar Gum-Manganese Dioxide Composites for Oxidative Decolorization of Methylene Blue

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Rohan S. Dassanayake ◽  
Erandathi Rajakaruna ◽  
Noureddine Abidi
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Manganese Dioxide ◽  
Guar Gum ◽  
Spectrophotometric Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Decolorization Efficiency ◽  
Desorption Mechanism ◽  
Scanning Electron

Borax-cross-linked guar gum-manganese dioxide (GGB-MnO2) composite was synthesized using an environmentally friendly synthesis route and investigated for its efficiency of decolorizing methylene blue (MB) dye solution by an ultraviolet-visible (UV-Vis) spectrophotometric study. The GGB-MnO2 composite was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The composite (1.2 g/L) exhibited excellent oxidative decolorization of MB (30 mg/L, 50 mL) solution to over 99% in 6, 13, and 40 min at pH 4, 7, and 10, respectively. The complete decolorization of MB occurred via a catalytic adsorption-oxidation-desorption mechanism. The GGB-MnO2 composite showed very good reusability and was stable after ten successive cycles with negligible losses of the decolorization efficiency.

Solid State Synthesis and Characterization of Spintronics Material Cd0.55 Hg0.45 Te

2010 ◽  
Vol 44-47 ◽  
pp. 2299-2306
Author(s):  
H.M.Noor Ul Huda Khan Asghar ◽  
M. Asghar ◽  
M.S. Awan
Keyword(s):  
Solid State ◽  
Synthesis And Characterization ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Cubic Crystal ◽  
X Ray ◽  
Edx Analyses ◽  
Scanning Electron

Polycrystalline spintronic material (Cd0.55Hg0.45Te) was synthesized by conventional solid state reaction. The samples ( = 5 mm and T = 1.5 mm) were prepared by uni-axial pressing. Samples were melted at 800°C for 3-2 hours. For chemical analyses, surface morphology and structural analyses, scanning electron microscopy (SEM) equipped with EDX system and X-ray diffraction studies were performed. XRD confirmed the cubic crystal structure. The Lattice constant of (Cd0.55Hg0.45Te) as determined by XRD was 0.6464 nm. The Miller indices (hkl) have been found by using crystallography method. The observed planes were (200), (210) and (331). The EDX analyses showed the typically compositions: Te 24.8% Cd 14.8% Al 5% and O2 46.4 % & C 9% (3 hours treatment) and Te 28.1% Cd 16% Al 4.1% and O2 39.3 %, Si 0.360% & C 12.1% (2 hours treatment) however we could not find any representative peak for Hg in all of the EDX analyses.

scholarly journals Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4631 ◽  
Author(s):  
Juan Aliaga ◽  
Pablo Vera ◽  
Juan Araya ◽  
Luis Ballesteros ◽  
Julio Urzúa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Charge Transfer Resistance ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

Wool supported manganese dioxide nano-scale dispersion: a biopolymer based catalyst for the aerobic oxidation of organic compounds

RSC Advances ◽  
2015 ◽  
Vol 5 (76) ◽  
pp. 61759-61767 ◽  
Author(s):  
Ahmad Shaabani ◽  
Zeinab Hezarkhani ◽  
Elham Badali
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Manganese Dioxide ◽  
Aerobic Oxidation ◽  
X Ray Diffraction ◽  
Potassium Permanganate Solution ◽  
X Ray ◽  
Nano Scale ◽  
Oxidation Of Organic Compounds ◽  
Scanning Electron

A wool supported manganese dioxide nano-scale dispersion was synthesized by soaking wool in a potassium permanganate solution and characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM).

scholarly journals The Effect of Nb Supplement on Material Characteristics of Iron with Lamellar Graphite

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Ahmet Oktay Devecili ◽  
Rifat Yakut
Keyword(s):  
Electron Microscopy ◽  
Cast Iron ◽  
Iron Alloy ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Abrasion Test ◽  
X Ray ◽  
Grey Cast ◽  
Lamellar Graphite ◽  
Scanning Electron

In this experiment a cast iron alloy consisting of 0.019, 0.151, 0.431, and 0.646% niobium by weight was set and the microstructure solidification of iron with lamellar graphite was provided. These alloys were subjected to an abrasion test and chemical analyses of the microstructure were done by using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). In addition to this, phase compositions were characterised by X-ray diffraction (XRD). Tests of mechanical strength, hardness, and tension were also applied to the alloys. The results of this experiment demonstrated that the addition of niobium to iron with lamellar graphite caused an increase in the abrasion resistance by 15%. This experiment shows that adding niobium improves the mechanical properties of grey cast iron.

Effect of Growth Temperature on the Morphology of ZnO Films Grown in Aqueous Solutions

2012 ◽  
Vol 531-532 ◽  
pp. 388-391
Author(s):  
Qiu Fang Wu ◽  
Si Si Wang ◽  
Feng Lan Yao ◽  
Chun Mei Zhang ◽  
Mi Dan Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aqueous Solutions ◽  
Growth Temperature ◽  
Hexagonal Lattice ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Scanning Electron

The well-aligned nanoflower and nanorod films were synthesized using zinc acetate- sodium hydroxide aqueous solutions at different growth temperature. These microstructures were characterized with field emission scanning electron microscopy and the X-ray diffraction. The predominant c-axis growth of hexagonal lattice was observed in the ZnO films, and the growth temperature was found to play an important role in controlling the morphology of ZnO films. Mechanism of formation of varying morphologies was discussed.

Mineralogy of Weathered Flue Gas Desulfurization Sludges

1988 ◽  
Vol 136 ◽  
Author(s):  
S. V. Mattigod ◽  
Dhanpat Rai ◽  
J. M. Zachara ◽  
J. E. Amonette
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diffraction Analysis ◽  
Flue Gas ◽  
Flue Gas Desulfurization ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Equilibrium Solubility ◽  
X Ray ◽  
Scanning Electron

ABSTRACTSamples of flue gas desulfurization sludge were characterized chemically and mineralogically. X-ray diffraction analysis indicated that the major crystalline components in the sludge samples were calcite, hannebachite, gypsum, and quartz. Identification of major compounds was confirmed through morphological and chemical analyses using scanning electron microscopy with energy dispersive X-ray analysis. In a related study, equilibrium solubility measurements of these samples corresponded with known solubilities of calcite, hannebachite, and gypsum.

scholarly journals Kaolinization processes in the phyolitic rocks of Kefalos, Kos island, Aegean Sea, Greece

2001 ◽  
Vol 34 (3) ◽  
pp. 867 ◽  
Author(s):  
D. PAPOULIS ◽  
P. TSOLIS - KATAGAS
Keyword(s):  
Electron Microscopy ◽  
Aegean Sea ◽  
Chemical Analyses ◽  
Bulk Rock ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Assemblages ◽  
Analytical Scanning Electron Microscopy ◽  
Scanning Electron

Kaolin occurrences in the South Kefalos peninsula, Kos island, Aegean sea, Greece, are products of hydrothermal alteration of rocks of rhyolitic composition. The chemical, mineralogical and textural characteristics of kaolin occurrences were investigated by X-Ray diffraction (XRD), Analytical scanning electron microscopy (SEM) and bulk rock chemical analyses. Attempts have been made to correlate the primary with secondary mineral assemblages and to establish the factors controlling the stepwise character of the transition from the fresh rhyolitic to kaolinized rocks. The kaolinization processes follows two main alteration pathways: I) Kfeldspar —» Mixed-layer kaolinite-smectite —» kaolinite —> dickite. II) Na-plagioclase —> kaolinite —> dickite

scholarly journals Natural vs. Synthetic Phosphate as Efficient Heterogeneous Compounds for Synthesis of Quinoxalines

2021 ◽  
Vol 22 (24) ◽  
pp. 13665
Author(s):  
Abbas Amini ◽  
Azadeh Fallah ◽  
Ahmad Sedaghat ◽  
Ahmad Gholami ◽  
Chun Cheng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Reaction Times ◽  
Atomic Ratio ◽  
Energy Dispersive ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recyclable Catalysts ◽  
Scanning Electron

Natural phosphate (NP) and synthetic fluorapatite phosphate (SFAP) were proposed as stable, inexpensive, readily available and recyclable catalysts for the condensation of 1,2-diamines with 1,2-dicarbonyls in methanol to afford quinoxaline at room temperature. NP provided as high as 92–99% yield for quinoxalines in short reaction times (i.e., 1–45 min), while SFAP created quinoxalines with 87–97% yield in 60–120 min. From the chemical analyses, X-ray fluoresecency, X-ray diffraction, energy dispersive X-ray and Fourier-transform infrared spectroscopy methods, two main phases (CaO, P2O5) appeared in NP together with other low content phases (SiO2, Fe2O3). Compared to other phases, apatite (CaO and P2O5 as Ca10(PO4)6) played a major role in the catalytic activity of NP. SFAP with similar Ca/P atomic ratio showed a relatively lower catalytic activity than NP for the condensation of 1,2-diamine with 1,2-dicarbonyl in methanol at ambient temperature. To investigate the recyclability of catalysts, the surface properties of NP and 6-recycled NP were investigated using scanning electron microscopy, energy dispersive X-ray and Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods. Some differences were observed in NP and 6-recycled NP’s particle size, surface area, the volume and size of pores, and the content of elements; nevertheless, the use–reuse process did not noticeably change the catalytic property of NP.

scholarly journals Kaolin deposits of Leucogia, Rhodope, Greece: Processes of Kaolinization

2001 ◽  
Vol 34 (3) ◽  
pp. 875
Author(s):  
D. PAPOULIS ◽  
P. TSOLIS - KATAGAS
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Metamorphic Rocks ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Textural Characteristics ◽  
X Ray ◽  
Scanning Electron

Kaolin deposits of residual origin associated with metamorphic rocks (leucocratic gneisses and schistgneisses) occur in Leucogia area, NE Greece. The chemical, mineralogical and textural characteristics of kaolin deposits were investigated by X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and chemical analyses. Attempts have been made to correlate the primary and secondary assemblages and to establish the factors controlling the step-wise character of the transition from the fresh gneisses to kaolinized rocks. The kaolinization process seems to follow two alteration pathways: (i) Sodic plagioclases ? Halloysite ? Kaolinite. (ii) K-Feldspars ? Kaolinite.

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