Presence Of MnO Research Articles

An archaeometric assessment study of Seljuk period glazed tiles from Kılıçarslan Square (Konya, Turkey)

This study presents archaeometric analyses of glazed tiles produced with the cut-mosaic technique to reveal information about the Anatolian Seljuk period’s architecture and ceramic technology. The Persian Seljuk artists also used the same technique. For this purpose, physical, chemical, thermal, mineralogical, microstructural, and molecular analyses were carried out on the tiles from the Seljuk period unearthed in the Kılıçarslan Square excavation in Konya, the capital of the Anatolian Seljuk State from the twelfth-century to the beginning of the fourteenth-century. SEM, XRD, and Heat Microscopy analyses showed that the Seljuk period tiles were not fired at high temperatures like today’s tiles and were probably fired at temperatures below 1100 °C. WD-XRF analyses revealed that the glazes are classified into two categories, one being alkali varying the content of Na2O + K2O between 13 and 16 wt% (PbO between 0.5 and 2 wt%) and the other being lead-alkali type in which PbO content varies between 13 and 15 wt% and alkali content 10–14 wt%. The cobalt content in the blue color is around 0.2 wt%, and copper content in the turquoise-colored samples varies between 2.9 and 4.4 wt% depending on the lightness and darkness of the color (higher amount for tile 1 and tile 3, which are darker than the others). The brown color is obtained by the presence of MnO (3.3 wt%). Raman analysis showed that the difference in sintering temperature caused the color tone difference in Seljuk period tiles, and glazes were formed in the range of 800–1000 °C depending on the Ip values.

Investigating the effect of chemistry on the flash butt weldability of steels through a combination of experiments and modeling

Flash butt weld process parameters determine the weld quality. The presence of weld defects due to inappropriate process parameters leads to entrapment of oxides in the weld causes premature failure. It was also observed that the flash butt process parameter is dependent on the chemistry of the steel that is processed. The high weight percentage of Mn and Si leads to a higher weight fraction of the oxides during welding. Altering the flashing length and upset length leads to the elimination of weld defects achieving full joint strength. Thermodynamic calculations predict the oxides to be primarily FeO, Fe2O3 (hematite), and SiO2 (cristobalite) along with the presence of MnO, Mn2O3, and Cr2O3. The presence of Mn, Al, and Ti in the oxides at the fractured surface is correlated with the chemical potential of these elements in the liquid steel. It can be inferred from the modeling and experimental results that with an increase in temperature, a more liquid slag phase is formed as compared to solid oxides. Slag is less viscous and can be easily extruded during the upsetting stage as opposed to solid inclusion which can be trapped during the welding operation.

The Catalytic Impact of MnO Additive on the Selected Municipal Solid Waste Combustion Behavior Determined by Thermogravimetric Analysis

The thermogravimetric (TG) and kinetic analysis have been performed to evaluate the catalytic impact of MnO additive on selected municipal solid waste (SMSW) combustion behavior. Nineteen kinds of the SMSW have been collected, cleaned, dried, and grounded to the size of less than 1 mm and then mixed with the same mass ratio. The addition of an additive to the SMSW was completed by virtue of blending the10 mg SMSW with 0.5 mg the MnO powder and then was ground thoroughly in the mortar to obtain the homogeneous mixture of SMSW/5%MnO. Subsequently, the sample was brought into the crucible uniformly. The sample combustion in the chamber was carried out under non-isothermal conditions at the controlled heating program of 10 and 30 oC/min, a temperature range of 25-1000 oC, and an air atmosphere flowrate of 100 ml/min. The sample mass loss during temperature and time escalation was recorded by a computer automatically to be a TG curve. The 1st derivative of the TG curve to the temperature or time represented the rate of sample mass loss and denoted as the derivative thermogravimetric (DTG) curve. In accordance with both TG and DTG curves, then the characteristic temperature parameters were determined. The Coats-Redfern method has been adopted to evaluate kinetic parameters in this study. To understand the catalytic effect of the MnO, the blending SMSW/5%MnO results were compared with the pure SMSW ones. The results indicated that the MnO additive has promoted the initial temperature decomposition toward the lower value and provoked the increasing mass loss rate. Moreover, the presence of MnO also decreased the activation energy in the main combustion region. The overall results revealed that the MnO additive has significantly impacted the dynamic of thermal decomposition during the combustion processes.

Origin of the High Capacity Manganese-Based Oxyfluoride Electrodes for Rechargeable Batteries

In the quest for high energy density rechargeable batteries, conversion-type cathode materials stand out with their appealing multielectron transfer properties. However, they undergo a series of complex phase transitions upon initial cycling as opposed to conventional intercalation-type materials. Within this category, iron-based mixed-anion solid solutions (FeOxF2–x) have captured the most attention of the battery community, owing to their high theoretical capacity and moderate cyclability. In the meantime, it was recently demonstrated, via a series of electrochemical cycling experiments, the in situ preparation of manganese-based mixed-anion cathode materials based on decomposition of electrolyte salt LiPF6 in the presence of MnO. To take a step forward, we herein report a routine protocol to prepare 220 mAh g–1-class composite cathodes. In addition, we provide a comprehensive understanding of the in situ fluorination and locally reversible phase transitions using complementary analytical techniques. Th...

Electrochemical Performance of MnO2 for Energy Storage Supercapacitors in Solid-State Design

In this work, solid-state supercapacitors with ionic liquid gel polymer electrolyte and MnO 2 electrodes were fabricated and characterized. The MnO 2 electrode was prepared by ultra-short pulsed electrochemical deposition over flexible graphite substrates. The ionic liquid gel polymer electrolyte was prepared by immobilizing ionic liquid BMIBF 4 with PVdF-HFP. The electrochemical performance of the solid-state supercapacitor was evaluated by three electrochemical characterization techniques including cyclic voltammetry (CV), galvanostatic charge-discharge (CD), and electrochemical impedance spectroscopy (EIS). CV measurements were conducted at two different voltage ranges showing typical capacitive character evidenced from the nearly rectangular shape. Charge-discharge analysis showed specific energy and specific power values of 1.27 Wh kg -1 and 0.292 kW kg -1 , respectively. EIS analysis confirmed the capacitive character of the device and produced an areal capacitance density of 39.68 mF cm -2 (equivalent to a specific capacitance of 36.68 F g -1 ). The presence of MnO 2 in the electrodes was confirmed by Raman spectroscopy with two major peaks observed at 550 cm -1 and 630 cm -1 .

Effect of potassium permanganate dosing position on the performance of coagulation/ultrafiltration combined process

Abstract The effects of potassium permanganate (KMnO 4 ) dosing position on the natural organic matter (NOM) removal as well as membrane fouling were investigated in the coagulation/ultrafiltration combined process. KMnO 4 oxidation altered the NOM characteristics in terms of hydrophobicity and molecular weight, and destroyed humic substances originated from terraneous organisms in raw water. The optimal KMnO 4 dosage was 0.5 mg·L − 1 in the peroxidation enhanced coagulation process with respect to the dissolved organic carbon (DOC) removal. When KMnO 4 was dosed into both upstream and downstream of coagulation, namely in the proposed two-position dosing mode, coagulation and KMnO 4 oxidation worked individually on the apparent DOC removal. However, compared to the KMnO 4 addition prior to or after coagulation, the two-position dosing mode dramatically alleviated membrane fouling and reduced fouling irreversibility. This was attributed to the change of NOM characteristics as a result of KMnO 4 addition prior to coagulation and the presence of MnO 2 on membrane surface as a result of KMnO 4 addition prior to ultrafiltration. This work may provide useful information for the application of KMnO 4 oxidation in the coagulation/ultrafiltration combined system.

Remediation of fuel oil contaminated soils by activated persulfate in the presence of MnO<sub>2</sub>

Remediation of fuel oil contaminated soils by activated persulfate in the presence of MnO<sub>2</sub>

Structural, electrical and magnetic behavior in high-temperature sintered Zn1–x Mn x O

Nanocrystalline Mn-doped ZnO of compositions Zn1–x Mn x O (0 ≤ x ≤ 0.08) has been synthesised by chemical route for uniform substitution of Mn in Zn site and then sintered at 1300 °C. Systematic investigations show the effect of Mn doping level and the sintering temperature on the structural, electrical and magnetic properties of ZnO. The average size of the nanocrystalline particles is in the order of 30–50 nm, whereas the grain sizes of the sintered specimen are of the order of few microns. Substitution of Mn in ZnO has been confirmed from the X-ray diffraction peak shift. A few peaks related to secondary phases of MnO have been observed in the X-ray diffraction patterns of the doped samples. ZnO and Mn-doped ZnO show Ohmic behavior and increased resistivity value with the increasing concentration of Mn. Effect of Mn concentration in ZnO has also been reflected in the dielectric constant and dielectric loss values. All the sintered samples show paramagnetic behavior even though the presence of MnO with oxygen vacancies is evident in X-ray photoelectron spectroscopic study.

ChemInform Abstract: The Dual Role of Ionic Liquid BmimBF4, Precursor of N‐Heterocyclic Carbene and Solvent, in the Oxidative Esterification of Aldehydes.

Abstract Room temperature ionic liquid BmimBF 4 (1-butyl-3-methylimidazolium tetrafluoroborate) has been utilized in the N -heterocyclic carbene-catalyzed oxidation of aldehydes to yield esters. In the presence of MnO 2 as oxidant and of DBU and caesium carbonate as bases, aromatic, heteroaromatic and aliphatic esters have been isolated in good to excellent yields. The recyclability of the used ionic liquid along with the excess of inorganic reagents has been proved. The simple and cheap BmimBF 4 ionic liquid played the dual role of precatalyst and solvent. This is the first time that such a reaction has been carried out with an ionic liquid as solvent.

Improved Sintering Property of Y-Doped BaZrO3 by Mn Addition

The effect of Manganese oxide, MnO x , as a sintering aid, on the sintering behavior of BaZrO3-based systems has been systematically studied with two different groups of Mn-added systems (BaZr1.00Mn x O3 and BaZr0.95Y0.05Mn x O3-δ) and Mn-doped systems (BaZr1-x Mn x O3 and BaZr0.95-x Y0.05Mn x O3-δ). The sinterability of all systems is markedly improved with the use of Mn. The densification behavior has been analyzed by X-ray diffraction, Raman Spectroscopy, and Scanning Electron Microscopy after the sintering. The present results suggest that the sinterability is improved by the presence of MnO x and BaMnO3 as a liquid phase source. The addition of MnO x reduces the electrical conductivity of BaZr0.95Y0.05O3-δ significantly by the cation exchange reaction between Y3+ and Mn4+. The control of cation exchange reaction is of crucial importance in the improvement of both the sinterability, and the electrical conductivity of BaZrO3-based systems by the help of sintering aids.

Utilisation of post-consumer plastics in pre-reduction of higher manganese oxides in ferromanganese process

The pre-reduction of higher manganese oxides with post-consumer plastics as reductants has been investigated through experiments conducted in a laboratory scale horizontal tube furnace coupled with an off gas analysis through an online infrared (IR) gas analyser. Composite pellets of calcined manganese oxide (Mn3O4) with high density polyethylene (HDPE) (at C/O molar ratios of 1·5, 2·0 and 3·0) were heated rapidly to 1150°C under pure argon and the off gas was measured continuously by an IR analyser for CO, CO2 and CH4. The extent of reduction of Mn3O4 to MnO was calculated from a mass balance for removable oxygen. Solid reaction products were characterised by scanning electron microscopy and X-ray diffraction analysis was used to confirm the presence of MnO. The results indicate that Mn3O4 can be successfully pre-reduced to MnO using HDPE as a reductant. Gas analysis studies indicated that the polymer is first converted to CH4 which cracked partially or reformed to H2, C and/or CO. Reduction of Mn3O4 to MnO was subsequently effected by C, CO, H2 and the residual CH4.

Preparation and Characterization of Mn<sub>o.5</sub>Zn<sub>o.5</sub>Fe<sub>2</sub>O<sub>4 </sub>@Au Composite Nanoparticles and its Anti-Tumor Effect on Glioma Cells

To explore the preparation method and characters of a new gold nanoshells on maganese-zinc ferrite (Mno.5Zno.5Fe2O4@Au) composite nanoparticles. Mno.5Zno.5Fe2O4@Au nanoparticles with core/shell structure were synthesized by reduction of Au3+ with trisodium citrate in the presence of Mno.5Zno.5Fe2O4 magnetic nanoparticles (MZF-NPs) prepared by improved co-preciption with the character of superparamagnetism and detected by transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), energy dispersive spectrometry (EDS) and Marven laser particle size analyzer.Thermodynamic test was used to observe temperature change of various doses of Mno.5Zno.5Fe2O4@Au nanoparticles. The cytotoxicity of the Mno.5Zno.5Fe2O4@Au composite nanoparticles in vitro was tested by the MTT assay. The therapeutic effect of Mno.5Zno.5Fe2O4@Au composite nanoparticles combined with magnetic fluid hyperthermia (MFH) on human glioma cells were evaluated in vitro by an MTT assay.The results indicated that the Mno.5Zno.5Fe2O4@Au composite nanoparticles were prepared successfully. The core/shell particles were spherical with exact average diameter of them was 66.9nm.EDS showed each Mno.5Zno.5Fe2O4@Au nanoparticle contained Mn, Zn, Fe, O and Au elements, and this proved Au had successfully attached to Mn0.5Zn0.5Fe2O4.The result of thermodynamic test showed that Mno.5Zno.5Fe2O4@Au composite nanoparticles could serve as a heating source under alternating magnetic field (AMF) exposure leading to reach their steady temperature (40-45°C). Moreover, Mno.5Zno.5Fe2O4@Au composite nanoparticles didn’t show cytotoxicity in vitro. The therapeutic result reveals that Mno.5Zno.5Fe2O4@Au composite nanoparticles can significantly inhibit the growth of glioma cells.The conclusion was that the self-prepared Mno.5Zno.5Fe2O4@Au composite nanoparticles had strong magnetic responsiveness and good power absorption capabilities in the high frequency AMF,then they could suggested to be useful for glioma hyperthemia. Mno.5Zno.5Fe2O4 @Au composite nanoparticles can not only be directed to tumor region in a given magnetic field more exactly but also produce marked thermotherapy.

As(V) removal from aqueous media using α-MnO 2 nanorods-impregnated laterite composite adsorbents

We present a novel way of enhancing the utility of low cost readily available laterite by impregnating it with the α-MnO 2 nanorods, thus making a composite material suitable for the removal of As(V) from aqueous media. The composites were synthesized by two methods: (i) ball-milling of a physical blend of laterite with pre-synthesized MnO 2; and (ii) in situ formation of MnO 2 in the presence of laterite. The BET surface area of composites prepared by both methods was markedly higher compared to un-modified laterite, and the presence of MnO 2 in the composite was also confirmed by XRD analysis and TEM microscopy. The adsorption capacity for As(V) was found to be highly pH dependent and the adsorption kinetics followed a pseudo second-order kinetic model. The Langmuir adsorption isotherm was found to be the best model to describe the adsorption equilibrium of As(V) onto un-modified laterite as well both ball-milled and in situ formed composite. The adsorption capacities at room temperature and pH 7.0 were found to be 1.50 mg g −1, 8.93 mg g −1 and 9.70 mg g −1, for un-modified laterite, ball-milled and in situ formed composite, respectively.

Supercritical water oxidation of landfill leachate

In this paper, ammonia as an important ingredient in landfill leachate was mainly studied. Based on Peng–Robinson formulations and Gibbs free energy minimization method, the estimation of equilibrium composition and thermodynamic analysis for supercritical water oxidation of ammonia (SCWO) was made. As equilibrium is reached, ammonia could be totally oxidized in SCW. N 2 is the main product, and the formation of NO 2 and NO could be neglected. The investigation on SCWO of landfill leachate was conducted in a batch reactor at temperature of 380–500 °C, reaction time of 50–300 s and pressure of 25 MPa. The effect of reaction parameters such as oxidant equivalent ratio, reaction time and temperature were investigated. The results showed that COD and NH 3 conversion improved as temperature, reaction time and oxygen excess increased. Compared to organics, NH 3 is a refractory compound in supercritical water. The conversion of COD and NH 3 were higher in the presence of MnO 2 than that without catalyst. The interaction between reaction temperature and time was analyzed by using response surface method (RSM) and the results showed that its influence on the NH 3 conversion was relatively insignificant in the case without catalyst. A global power-law rate expression was regressed from experimental data to estimate the reaction rate of NH 3. The activation energy with and without catalyst for NH 3 oxidation were 107.07 ± 8.57 kJ/mol and 83.22 ± 15.62 kJ/mol, respectively.

Transformation kinetics and pathways of tetracycline antibiotics with manganese oxide

Tetracycline antibiotics including tetracycline (TTC), oxytetracycline (OTC) and chlorotetracycline (CTC) undergo rapid transformation to yield various products in the presence of MnO 2 at mild conditions (pH 4–9 and 22 °C). Reaction rates follow the trend of CTC > TTC > OTC, and are affected by pH and complexation of TCs with Mg 2+ or Ca 2+. Experimental results of TTC indicate that MnO 2 promotes isomerization at the C ring to form iso-TTC and oxidizes the phenolic-diketone and tricarbonylamide groups, leading to insertion of up to 2 O most likely at the C9 and C2 positions. In contrast, reactions of OTC with MnO 2 generate little iso-OTC, but occur mainly at the A ring’s dimethylamine group to yield N-demethylated products. CTC yields the most complicated products upon reactions with MnO 2, encompassing transformation patterns observed with both TTC and OTC. The identified product structures suggest lower antibacterial activity than that of the parent tetracyclines.

Synthesis of optically active spiro homo- and methanofullerenes

The selective synthesis of optically active spiro homofullerenes via reaction between [60]fullerene and cyclic diazoalkanes, generated in situ by oxidation of (−)-menthone hydrazone and d-(+)-camphor hydrazone in the presence of MnO 2, and the Pd(acac) 2–2PPh 3–4Et 3Al catalytic system was implemented for the first time. The optical rotations of the synthesized cycloadducts have been determined.

Infrared and Raman spectroscopic investigations of xMnO (100− x)[As 2O 3 TeO 2] glass system

xMnO·(100− x)[As 2O 3·TeO 2] glass system, with 0≤ x≤50 mol %, was prepared and investigated by FT-IR and Raman spectroscopies in order to determine its structure and the changes induced by the increasing of MnO content. The results offered by FT-IR and Raman spectroscopies suggest a structure formed by AsO 3, TeO 4 tbp and TeO 3 tp units. The presence of MnO 2 units was confirmed by FT-IR spectra only for high concentration of MnO.

Effects of MnO2 Addition on the Dielectric Behaviors of the PZT-PMN Ceramics

The PZT-PMN ceramics system proposed for piezoelectric transformation application was derived from Pb(Zr 0.52 Ti 0.48 )O 3 and Pb(Mg 0.66 Nb 0.33 )O 3 based compositions that obtained from the culombite method. The effect of MnO 2 addition on microstructure, physical properties and piezoelectric properties were investigated. The XRD results show that no phase transformation observed for all sintered PZT-PMN samples doped with MnO 2 . Presence of MnO 2 also improved their sinterability of the ceramics as evidenced by SEM micrographs. Though, MnO 2 addition tends to lower the dielectric constant in this ceramics but it improved Q m from 115 to a maximum value of 1669 in the ceramic with 8 mol% of MnO 2 . Also, increasing of d 33 from 28.53 to 114.19 pC/N was found for MnO 2 in range 0 to 4 mol%. However, the k p values are clearly increased with increasing of MnO 2 content.

Facile Synthesis of Heterocycles via 2-Picolinium Bromide and Antimicrobial Activities of the Products

The 2-picolinium N-ylide 4, generated in situ from the N-acylmethyl-2-picolinium bromide 3, underwent cycloaddition to N-phenylmaleimide or carbon disulfide to give the corresponding cycloadducts 6 and 8, respectively similar reactions of compound 3 with some electron-deficient alkenes in the presence of MnO2 yielded the products 11 and 12. In addition, reaction of 4 with arylidene cyanothioacetamide and malononitrile derivatives afforded the thiophene and aniline derivatives 15 and 17, respectively. Heating of picolinium bromide 3 with triethylamine in benzene furnished 2-(2-thienyl)indolizine (18). The structures of the isolated products were confirmed by elemental analysis as well as by 1H- and 13C-NMR, IR, and MS data. Both the stereochemistry and the regioselectivity of the studied reactions are discussed. The biological activity of the newly synthesized compounds was examined and showed promising results.

Photocatalytic activity of TiO2 and ZnO in the presence of manganese dioxides

Abstract The photocatalytic activity of TiO 2 and ZnO in the presence of MnO 2 , a particulate matter present in natural water and wastewater, has been studied. We found that a trace amount of MnO 2 particles deactivated TiO 2 photocatalysts, but its effect on the activity of ZnO was negligible. UV–visible diffuse reflectance spectra (DRS) and surface photovoltage spectroscopy (SPS) analysis implied that the interaction of MnO 2 with TiO 2 and ZnO could change the energetics of these two photocatalysts.