Journal articles: 'Manganese oxide'

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Liu, Haiyan, Olivier Pourret, Huaming Guo, Raul E. Martinez, and Lahcen Zouhri. "Impact of Hydrous Manganese and Ferric Oxides on the Behavior of Aqueous Rare Earth Elements (REE): Evidence from a Modeling Approach and Implication for the Sink of REE." International Journal of Environmental Research and Public Health 15, no. 12 (December 12, 2018): 2837. http://dx.doi.org/10.3390/ijerph15122837.

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In this study, models were used for the first time to investigate the fate and transport of rare earth elements (REE) in the presence of hydrous manganese and ferric oxides in groundwaters from the coastal Bohai Bay (China). Results showed that REE sorption is strongly dependent on pH, as well as hydrous manganese and ferric oxide content. Higher proportions of REE were sorbed by hydrous manganese oxide as compared to hydrous ferric oxides, for example in the presence of neodymium. In this case, a mean 28% of this element was sorbed by hydrous manganese oxide, whereas an average 7% sorption was observed with hydrous ferric oxides. A contrasting REE sorption behavior was observed with hydrous manganese and ferric oxide for all investigated groundwaters. Specifically, REE bound to hydrous manganese oxides showed decreasing sorption patterns with increasing atomic number. The opposite trend was observed in the presence of hydrous ferric oxides. In addition, these results suggested that light REE (from La to Sm) rather than heavy REE (from Eu to Lu) are preferentially scavenged by hydrous manganese oxide. However, the heavy REE showed a greater affinity for hydrous ferric oxides compared to light REE. Therefore, both hydrous manganese and ferric oxide are important scavengers of REE. This study shows the implication of hydrous manganese and ferric oxide sorption for the sink of REE in groundwater.

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Awaluddin, Amir, Riska Anggraini, Siti Saidah Siregar, Muhdarina, and Prasetya. "A one-pot synthesis of Fe-doped cryptomelane type octahedral molecular sieve manganese oxide for degradation of methylene blue dye." MATEC Web of Conferences 276 (2019): 06005. http://dx.doi.org/10.1051/matecconf/201927606005.

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The Fe-doped octahedral molecular sieve manganese oxides have been successfully synthesized by one-pot synthesis of the reaction between KMnO4 and glucose using sol-gel methods. The oxide products are then characterized by various techniques such as X-ray diffraction, scanning electron microscopy, atomic absorption spectroscopy and average oxidation state (AOS) of manganese in manganese oxides. The as-synthesized manganese oxide and Fe-doped manganese oxides are used as catalysts for the degradation of methylene blue dye using hydrogen peroxide as oxidants. The results indicated that the Fe-doped manganese oxide catalyst displayed much enhanced catalytic activities compared to undoped manganese oxide for methylene blue degradation. The differences in catalytic activities have been correlated with the difference in surface properties and crystallinity.

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Ye, Zhi Guo, Xian Liang Zhou, Hui Min Meng, Xiao Zhen Hua, Ying Hu Dong, and Ai Hua Zou. "The Electrochemical Characterization of Electrochemically Synthesized MnO₂-Based Mixed Oxides for Supercapacitor Applications." Advanced Materials Research 287-290 (July 2011): 1290–98. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1290.

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Nanostructured elements, including: manganese-molybdenum (Mn-Mo) oxide, manganese-molybdenum-tungsten (Mn-Mo-W) oxide, manganese-molybdenum-iron (Mn-Mo-Fe) oxide, manganese-molybdenum-cobalt (Mn-Mo-Co) oxide, manganese-vanadium-tungsten (Mn-V-W) oxide, manganese-vanadium-iron (Mn-V-Fe) oxide and manganese-iron (Mn-Fe) oxide, have been anodically deposited onto titanium substrates by employing an iridium dioxide interlayer (Ti/IrO2anode). The electrochemical characteristics of the resultant oxide deposits have been investigated by cyclic voltammetry (CV) in an aqueous 0.1 M Na2SO4solution. The voltammetric behaviors of the oxide deposits observed are significantly influenced by the doped elements. Molybdenum doping is found to be advantageous at improving the capacitance characteristics of anodically deposited manganese oxide. Comparatively, iron and vanadium doping are found to be unfavorable. The structure and crystallinity of these deposits have been identified by X-ray diffraction (XRD). The surface morphologies of these oxides were acquired from field emission scanning electron microscopes (FESEM). The high values of electrical parameters for the doped deposits are attributed to the net-like and sponge-like nanostructure, and low crystallinity of the doped manganese oxides. The deposit of Mn-Mo oxides exhibits an excellent capacitive-like behavior, possessing the maximum specific capacitance of 810 F g-1at a CV scan rate of 5 mV s-1in aqueous 0.1 M Na2SO4solution.

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Park, Yaewon, Shuang Liu, Terrence Gardner, Drake Johnson, Aaron Keeler, Nathalia Ortiz, Ghada Rabah, and Ericka Ford. "Biohybrid nanofibers containing manganese oxide–forming fungi for heavy metal removal from water." Journal of Engineered Fibers and Fabrics 15 (January 2020): 155892501989895. http://dx.doi.org/10.1177/1558925019898954.

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Manganese-oxidizing fungi support bioremediation through the conversion of manganese ions into manganese oxide deposits that in turn adsorb manganese and other heavy metal ions from the environment. Manganese-oxidizing fungi were immobilized onto nanofiber surfaces to assist remediation of heavy metal–contaminated water. Two fungal isolates, Coniothyrium sp. and Coprinellus sp., from a Superfund site (Lot 86, Farm Unit #1) water treatment system were incubated in the presence of nanofibers. Fungal hyphae had strong association with nanofiber surfaces. Upon fungal attachment to manganese chloride–seeded nanofibers, Coniothyrium sp. catalyzed the conformal deposition of manganese oxide along hyphae and nanofibers, but Coprinellus sp. catalyzed manganese oxide only along its hyphae. Fungi–nanofiber hybrids removed various heavy metals from the water. Heavy metal ions were adsorbed into manganese oxide crystalline structure, possibly by ion exchange with manganese within the manganese oxide. Hybrid materials of fungal hyphae and manganese oxides confined to nanofiber-adsorbed heavy metal ions from water.

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Liang, Mengyu, Huaming Guo, and Wei Xiu. "Mechanisms of arsenite oxidation and arsenate adsorption by a poorly crystalline manganese oxide in the presence of low molecular weight organic acids." E3S Web of Conferences 98 (2019): 04009. http://dx.doi.org/10.1051/e3sconf/20199804009.

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Manganese oxides are considered as one of the effective oxides capable of oxidizing arsenite and reduce the toxicity of arsenic. Since low molecular weight organic acids (LMWOAs) commonly found in nature can act as reducing and chelating agents for manganese oxides, it is particularly important to investigate how these organic acids with different numbers of carboxyl groups like citrate and EDTA affect oxidation and adsorption of arsenic by manganese oxides. In this study, low As(V) adsorption on manganese oxide is slightly enhanced by citrate and EDTA, which results from the increase in active sites via reduction of manganese oxide by LMWOAs. However, citrate and EDTA have different effects on the oxidation of As(III). MnIII/II citrate autocatalytic cycle as a manganese-based redox system decreases As(III) oxidation rate, but EDTA does not yield autocatalysis, which slightly increases the oxidation rate of As(III). Reduction of manganese oxide by EDTA and chelation between Mn(II) and EDTA lead to exposure of more active sites. Our research highlights the different effects of low molecular weight organic acids on the reactions between arsenic and manganese oxide.

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Nadtochii, A. A., D. O. Stepanenko, N. E. Khodotova, and V. S. Kyrychok. "THERMODYNAMIC MODELING OF BEHAVIOR OF COMPONENTS IN SLAG SYSTEMS CHARACTERISTIC IN THE MANUFACTURE OF MANGANESE FERROAL ALLOYS." Fundamental and applied problems of ferrous metallurgy, no. 35 (2021): 263–74. http://dx.doi.org/10.52150/2522-9117-2021-35-263-274.

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The aim of the study is to find highly efficient schemes for the use of secondary raw materials and waste-free technologies that will return valuable chemical elements to the metallurgical redistribution, primarily manganese. This problem cannot be solved without a theoretical substantiation of physicochemical conditions, the creation of which will allow to achieve a fuller use of the potential of the useful properties of the studied materials. Analysis of the main physicochemical properties of manganese-containing materials, in particular ferroalloy slags, will allow to obtain the initial data and intervals of values of parameters necessary for further research on the development of an effective technology for processing manganese slags. Thermodynamic equilibrium calculations in the system Mn-Si-Ca-Al-Mg-O show that the increase in the amount of free manganese oxide is associated with a certain value of basicity, the achievement of which provides the predominant binding of silica to calcium silicates. The increased content of MgO oxide increases the amount of free oxides of silicon and manganese. The ratio of oxides in the system affects the viscosity and crystallization characteristics of this system. The degree of reduction of oxides is determined by the activities of the components of the slag phase, which depends on its chemical composition and temperature. Calculation of activities in the system based on manganese oxide showed that increasing the basicity, and magnesium oxide content in the system increases the activity of manganese oxide and the addition of aluminіum oxide - decreases, which coincides with the data obtained by calculating the equilibrium phase distribution. The analysis of the data obtained in the calculation of the activities of components in a complex slag system based on manganese oxide justifies the feasibility of reprocessing metallurgical manganese slag, which will return manganese to the metallurgical redistribution.

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Zhang, Lichun, Liping Kang, Hao Lv, Zhikui Su, Kenta Ooi, and Zong-Huai Liu. "Controllable synthesis, characterization, and electrochemical properties of manganese oxide nanoarchitectures." Journal of Materials Research 23, no. 3 (March 2008): 780–89. http://dx.doi.org/10.1557/jmr.2008.0091.

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Flowerlike manganese oxide microspheres and cryptomelane-type manganese oxide nanobelts were selectively synthesized by a simple decomposition of KMnO4 under mild hydrothermal conditions without using template or cross-linking reagents. The effect of varying the hydrothermal times and temperatures on the nanostructure, morphology, compositional, and electrochemical properties of the obtained manganese oxides was investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies showed that the flowerlike manganese oxide microspheres could be obtained at relatively low hydrothermal temperatures, while high hydrothermal temperatures were favorable for the formation of cryptomelane-type manganese oxide nanobelts. A morphology and crystalline evolution of the nanostructures was observed as the hydrothermal temperature was increased from 180 to 240 °C. On the basis of changing the temperatures and hydrothermal reaction times, the formation mechanism of cryptomelane-type manganese oxide nanobelts is discussed. Cyclic voltammetry (CV) was used to evaluate the electrochemical properties of the obtained manganese oxide nanostructures, and the results show that the electrochemical properties depend on their shape and crystalline structure. This easily controllable, template-free, and environmentally friendly method has the potential for being used in syntheses of manganese oxide nanomaterials with uniform morphologies and crystal structures.

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Wright, Mitchell H., Saad M. Farooqui, Alan R. White, and Anthony C. Greene. "Production of Manganese Oxide Nanoparticles by Shewanella Species." Applied and Environmental Microbiology 82, no. 17 (June 24, 2016): 5402–9. http://dx.doi.org/10.1128/aem.00663-16.

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ABSTRACTSeveral species of the bacterial genusShewanellaare well-known dissimilatory reducers of manganese under anaerobic conditions. In fact,Shewanella oneidensisis one of the most well studied of all metal-reducing bacteria. In the current study, a number ofShewanellastrains were tested for manganese-oxidizing capacity under aerobic conditions. All were able to oxidize Mn(II) and to produce solid dark brown manganese oxides.Shewanellaloihicastrain PV-4 was the strongest oxidizer, producing oxides at a rate of 20.3 mg/liter/day and oxidizing Mn(II) concentrations of up to 9 mM. In contrast,S. oneidensisMR-1 was the weakest oxidizer tested, producing oxides at 4.4 mg/liter/day and oxidizing up to 4 mM Mn(II). Analysis of products from the strongest oxidizers, i.e.,S.loihicaPV-4 andShewanella putrefaciensCN-32, revealed finely grained, nanosize, poorly crystalline oxide particles with identical Mn oxidation states of 3.86. The biogenic manganese oxide products could be subsequently reduced within 2 days by all of theShewanellastrains when culture conditions were made anoxic and an appropriate nutrient (lactate) was added. WhileShewanellaspecies were detected previously as part of manganese-oxidizing consortia in natural environments, the current study has clearly shown manganese-reducingShewanellaspecies bacteria that are able to oxidize manganese in aerobic cultures.IMPORTANCEMembers of the genusShewanellaare well known as dissimilatory manganese-reducing bacteria. This study shows that a number of species fromShewanellaare also capable of manganese oxidation under aerobic conditions. Characterization of the products of the two most efficient oxidizers,S. loihicaandS. putrefaciens, revealed finely grained, nanosize oxide particles. With a change in culture conditions, the manganese oxide products could be subsequently reduced by the same bacteria. The ability ofShewanellaspecies both to oxidize and to reduce manganese indicates that the genus plays a significant role in the geochemical cycling of manganese. Due to the high affinity of manganese oxides for binding other metals, these bacteria may also contribute to the immobilization and release of other metals in the environment.

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Niu, Sida, Liqun Zhao, Xiaoju Lin, Tong Chen, Yingchao Wang, Lingchao Mo, Xianglong Niu, et al. "Mineralogical Characterization of Manganese Oxide Minerals of the Devonian Xialei Manganese Deposit." Minerals 11, no. 11 (November 9, 2021): 1243. http://dx.doi.org/10.3390/min11111243.

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The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined.

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Fatma F Ali, Ahmed S Buhedma, Zohar Ashoor, Tarq A Nouh, and Rasha R Atiya. "Response of seedling barley (Hurdeom vulgar, L.) to foliar fertilization of nano-oxides (Fe, Cu, Mg)." Journal of Advanced Zoology 44, S6 (November 26, 2023): 391–95. http://dx.doi.org/10.17762/jaz.v44is6.2161.

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Background. An experiment was conducted at the Grain Technology Laboratory, Crop Department, Faculty of Agriculture, Omar Al-Mukhtar University, during the 2023 season. The experiment utilized a completely randomized design to study the response of barley to foliar application of fine nanoscale iron, manganese, and copper fertilizers. The application was carried out as foliar spray at two different doses, two weeks and one month after sowing, using 3 kg capacity pots with 20 seeds per pot. The experiment included three observations for each treatment, with the nanoscale iron, manganese, and copper oxides applied at a concentration of 1 cmol/L. The data revealed the following: Significant positive response of barley shoots to foliar application of nanoscale iron, manganese, and copper fertilizers in various growth indicators, including shoot weight, shoot length, leaf area, crop growth rate, and specific leaf weight. High significant differences were observed in the effect of nanoscale iron, manganese, and copper oxides on the average shoot weight, crop growth rate, and leaf area. Copper oxide and manganese oxide showed the highest means, followed by iron oxide, compared to the control. Iron oxide exhibited the highest specific leaf weight for barley shoots, followed by copper oxide and then manganese oxide, compared to the control treatment.

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Ibrahim, Suriani, Tawatchai Charinpanitkul, Eiry Kobatake, and Mana Sriyudthsak. "Nanowires Nickel Oxide and Nanospherical Manganese Oxide Synthesized via Low Temperature Hydrothermal Technique for Hydrogen Peroxide Sensor." Journal of Chemistry 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/9138961.

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Binary catalyst nickel oxides (NiO) and manganese oxides (MnO) were prepared individually via hydrothermal route. The catalysts were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) analysis, cyclic voltammetry (CV), and amperometry. Morphology studies revealed physical structure of nanowires nickel oxide and spherical manganese oxide with estimated length of 0.3–2.3 μm and diameter of 0.2–0.8 μm, respectively. Surface areas obtained for nickel oxide and manganese oxide were 68.9 m2 g−1and 45.2 m2 g−1, respectively. Cyclic voltammetry exhibits electrochemical responses corresponding to the electrode surfaces. The linear responses of the binary catalyst modified gold electrodes with NiO-MnO were observed in the concentration range from 31.8 μM to 0.5 mM with the detection limit of 62.5 μM.

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Karakurkchi, Ann V., Nykolay D. Sakhnenko, Maryna V. Ved’, Ihor S. Luhovskyi, Hryhoriy A. Drobakha, and Maryna V. Mayba. "Features of Plasma Electrolytic Formation of Manganese- and Cobalt-Containing Composites on Aluminum Alloys." Advances in Materials Science and Engineering 2019 (August 7, 2019): 1–13. http://dx.doi.org/10.1155/2019/6381291.

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This paper presents the results of studies on the electrochemical treatment characteristics of aluminum and alloys in alkaline electrolytes. It is shown that the heterogeneity of the alloys composition complicates the formation of the surface oxide layer. To homogenize the treated surface and obtain oxide coatings doped with manganese and cobalt, electrolytes based on KOH and K4P2O7 with the addition of KMnO4 and CoSO4 were used. Plasma electrolytic oxidizing (PEO) in these electrolytes in the range of current densities 5–20 A/dm2 allows to obtain mixed oxide coatings which contained both aluminum oxide matrix and doping metal oxides Al2O3·MnOx and Al2O3·CoOy. It is shown that an increase in the PEO current density and the concentration of manganate- and cobalt(II) ions in the solution leads to an increase the content of dopant metals in the coatings outer layer. The incorporation of manganese and cobalt oxides in the composition of the surface layers was confirmed by the results of X-ray structural analysis. The rational modes of aluminum alloys PEO treatment were substantiated to obtain coatings with manganese and cobalt contents up to 25–40 аt.%. Formed oxide systems have a developed surface and high adhesion to the base metal and show an increased corrosion resistance and catalytic activity. This allows us to view them as promising materials for air- and water-cleaning technologies and internal combustion engine waste gas purification systems.

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Liu, Winnie, Jihua Hao, Evert J. Elzinga, Piotr Piotrowiak, Vikas Nanda, Nathan Yee, and Paul G. Falkowski. "Anoxic photogeochemical oxidation of manganese carbonate yields manganese oxide." Proceedings of the National Academy of Sciences 117, no. 37 (August 31, 2020): 22698–704. http://dx.doi.org/10.1073/pnas.2002175117.

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The oxidation states of manganese minerals in the geological record have been interpreted as proxies for the evolution of molecular oxygen in the Archean eon. Here we report that an Archean manganese mineral, rhodochrosite (MnCO3), can be photochemically oxidized by light under anoxic, abiotic conditions. Rhodochrosite has a calculated bandgap of about 5.4 eV, corresponding to light energy centering around 230 nm. Light at that wavelength would have been present on Earth’s surface in the Archean, prior to the formation of stratospheric ozone. We show experimentally that the photooxidation of rhodochrosite in suspension with light centered at 230 nm produced H2 gas and manganite (γ-MnOOH) with an apparent quantum yield of 1.37 × 10−3 moles hydrogen per moles incident photons. Our results suggest that manganese oxides could have formed abiotically on the surface in shallow waters and on continents during the Archean eon in the absence of molecular oxygen.

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Li, Su Jun. "Synthesis and Application of Manganese Oxide Based Nanomaterials." Advanced Materials Research 830 (October 2013): 33–36. http://dx.doi.org/10.4028/www.scientific.net/amr.830.33.

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Manganese oxide is one of the most attractive inorganic materials because of its structural flexibility and wide applications in catalysis, ion exchange, electrochemical supercapacitors, molecular adsorption, biosensors, and so on. In recently, manganese oxides nanomaterials, including MnO, MnO2and Mn3O4, have attracted great interest as anode materials in lithium-ion batteries and water treatment due to their high theoretical capacity, environmental benignity, low cost, and special properties. Hence, manganese oxides nanostructures with excellent properties and various morphologies have been successfully synthesized. Herein, we provide a recent development of the synthesis of manganese oxides nanomaterials and their application.

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Liu, C. S., L. J. Zhang, C. H. Feng, C. A. Wu, F. B. Li, and X. Z. Li. "Relationship between oxidative degradation of 2-mercaptobenzothiazole and physicochemical properties of manganese (hydro)oxides." Environmental Chemistry 6, no. 1 (2009): 83. http://dx.doi.org/10.1071/en08053.

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Environmental context. Manganese (hydro)oxide is one kind of the most important natural minerals that are capable of oxidising organic contaminants with a wide range of functionality. However, the oxidative reactivity of manganese (hydro)oxides for organic pollutant degradation may depend on their individual physicochemical properties. It is important to determine a relationship between their oxidative reactivity and physicochemical properties. Abstract. The oxidative reactivity of manganese (hydro)oxides is important for geochemical transformation of organic pollutants. Here, 2-mercaptobenzothiazole (MBT) degradation by six manganese (hydro)oxides, including γ-MnOOH, β-MnO2, α-MnO2, γ-Mn2O3, δ-MnO2, and MO-700, were investigated with different initial MBT concentrations, manganese (hydro)oxide dosages and pH values. The results show the oxidative reactivity of manganese (hydro)oxides towards MBT degradation strongly depends on their physicochemical properties. Specific surface area and reduction potential of manganese (hydro)oxides were positively correlated with MBT degradation rates, whereas pH at the point of zero charge (pHPZC) of manganese (hydro)oxides and apparent activation energy (Ea) were negatively correlated. A high average oxidation state with the same chemical valence always corresponds to high oxidative reactivity. Such findings provide some insights into understanding the transport and fate of organic pollutants in the presence of different manganese (hydro)oxides in the natural environment.

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Lee, Sun Hee, Dae Hoon Park, Seong-Ju Hwang, and Jin-Ho Choy. "Effect of Copper Doping on the Crystal Structure and Morphology of 1D Nanostructured Manganese Oxides." Journal of Nanoscience and Nanotechnology 7, no. 11 (November 1, 2007): 4029–32. http://dx.doi.org/10.1166/jnn.2007.080.

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We have tried to control the aspect ratio and physicochemical properties of 1D nanostructured manganese oxides through copper doping. Copper-doped manganese oxide nanostructures have been synthesized by one-pot hydrothermal treatment for the mixed solution of permanganate anions and copper cations. According to powder X-ray diffraction and electron microscopic analyses, all the present materials commonly crystallize with α-MnO2-type structure but their aspect ratio decreases significantly with increasing the content of copper. Such a variation of crystallite dimension is attributable to the limitation of crystal growth by the incorporation of copper ions. X-ray absorption spectroscopic studies at Mn K- and Cu K-edges clearly demonstrate that the average oxidation state of manganese ions is increased by the substitution of divalent copper ions. Electrochemical measurements reveal the improvement of the electrode performance of nanostructured manganate upon copper doping, which can be interpreted as a result of the decrease of aspect ratio and the increase of Mn valence state. From the present experimental findings, it becomes certain that the present Cu doping method can provide an effective way of controlling the crystal dimension and electrochemical property of 1D nanostructured manganese oxide.

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Lynch, Sheridan, Genevieve Lynch, Will E. Lynch, and Clifford W. Padgett. "Crystal structures of four dimeric manganese(II) bromide coordination complexes with various derivatives of pyridine N-oxide." Acta Crystallographica Section E Crystallographic Communications 75, no. 8 (July 30, 2019): 1284–90. http://dx.doi.org/10.1107/s2056989019010557.

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Four manganese(II) bromide coordination complexes have been prepared with four pyridine N-oxides, viz. pyridine N-oxide (PNO), 2-methylpyridine N-oxide (2MePNO), 3-methylpyridine N-oxide (3MePNO), and 4-methylpyridine N-oxide (4MePNO). The compounds are bis(μ-pyridine N-oxide)bis[aquadibromido(pyridine N-oxide)manganese(II)], [Mn2Br4(C5H5NO)4(H2O)2] (I), bis(μ-2-methylpyridine N-oxide)bis[diaquadibromidomanganese(II)]–2-methylpyridine N-oxide (1/2), [Mn2Br4(C6H7NO)2(H2O)4]·2C6H7NO (II), bis(μ-3-methylpyridine N-oxide)bis[aquadibromido(3-methylpyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(H2O)2] (III), and bis(μ-4-methylpyridine N-oxide)bis[dibromidomethanol(4-methylpyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(CH3OH)2] (IV). All the compounds have one unique MnII atom and form a dimeric complex that contains two MnII atoms related by a crystallographic inversion center. Pseudo-octahedral six-coordinate manganese(II) centers are found in all four compounds. All four compounds form dimers of Mn atoms bridged by the oxygen atom of the PNO ligand. Compounds I, II and III exhibit a bound water of solvation, whereas compound IV contains a bound methanol molecule of solvation. Compounds I, III and IV exhibit the same arrangement of molecules around each manganese atom, ligated by two bromide ions, oxygen atoms of two PNO ligands and one solvent molecule, whereas in compound II each manganese atom is ligated by two bromide ions, one O atom of a PNO ligand and two water molecules with a second PNO molecule interacting with the complex via hydrogen bonding through the bound water molecules. All of the compounds form extended hydrogen-bonding networks, and compounds I, II, and IV exhibit offset π-stacking between PNO ligands of neighboring dimers.

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Sobańska, Zuzanna, Joanna Roszak, Kornelia Kowalczyk, and Maciej Stępnik. "Applications and Biological Activity of Nanoparticles of Manganese and Manganese Oxides in In Vitro and In Vivo Models." Nanomaterials 11, no. 5 (April 22, 2021): 1084. http://dx.doi.org/10.3390/nano11051084.

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The expanding applications of nanotechnology seem to be a response to many technological, environmental, and medical challenges. The unique properties of nanoparticles allow for developing new technologies and therapies. Among many investigated compounds is manganese and its oxides, which in the form of nanoparticles, could be a promising alternative for gadolinium-based contrast agents used in diagnostic imaging. Manganese, which is essential for living organisms as an enzyme cofactor, under excessive exposure—for example, due to water contamination or as an occupational hazard for welders—can lead to neurological disorders, including manganism—a condition similar to Parkinson’s disease. This review attempts to summarise the available literature data on the potential applications of manganese and manganese oxide nanoparticles and their biological activity. Some of the published studies, both in vitro and in vivo, show negative effects of exposure to manganese, mainly on the nervous system, whereas other data suggest that it is possible to develop functionalised nanoparticles with negligible toxicity and novel promising properties.

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Farkas, Bence, Marek Bujdoš, Filip Polák, Michaela Matulová, Martin Cesnek, Eva Duborská, Ondřej Zvěřina, et al. "Bioleaching of Manganese Oxides at Different Oxidation States by Filamentous Fungus Aspergillus niger." Journal of Fungi 7, no. 10 (September 28, 2021): 808. http://dx.doi.org/10.3390/jof7100808.

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This work aimed to examine the bioleaching of manganese oxides at various oxidation states (MnO, MnO·Mn2O3, Mn2O3 and MnO2) by a strain of the filamentous fungus Aspergillus niger, a frequent soil representative. Our results showed that the fungus effectively disintegrated the crystal structure of selected mineral manganese phases. Thereby, during a 31-day static incubation of oxides in the presence of fungus, manganese was bioextracted into the culture medium and, in some cases, transformed into a new biogenic mineral. The latter resulted from the precipitation of extracted manganese with biogenic oxalate. The Mn(II,III)-oxide was the most susceptible to fungal biodeterioration, and up to 26% of the manganese content in oxide was extracted by the fungus into the medium. The detected variabilities in biogenic oxalate and gluconate accumulation in the medium are also discussed regarding the fungal sensitivity to manganese. These suggest an alternative pathway of manganese oxides’ biodeterioration via a reductive dissolution. There, the oxalate metabolites are consumed as the reductive agents. Our results highlight the significance of fungal activity in manganese mobilization and transformation. The soil fungi should be considered an important geoactive agent that affects the stability of natural geochemical barriers.

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Yang, Huan, Mengxuan Han, and Pingping Jiang. "Research Progress on the treatment of arsenic pollution by manganese oxide." E3S Web of Conferences 261 (2021): 04032. http://dx.doi.org/10.1051/e3sconf/202126104032.

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Arsenic is a kind of protoplasmic poison, which exists widely in the natural environment. Consuming too much arsenic can cause a number of health problems. Manganese oxide plays an important role in arsenic pollution removal technology. In this paper, arsenic hazard and its treatment methods and the application of manganese oxides in arsenic pollution treatment are summarized, and the prospect of research on arsenic pollution treatment by manganese oxides is put forward.

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You, Z., G. Li, Z. Peng, L. Qin, Y. Zhang, and T. Jiang. "Reductive roasting of iron-rich manganese oxide ore with elemental sulfur for selective manganese extraction." Journal of Mining and Metallurgy, Section B: Metallurgy 53, no. 2 (2017): 115–22. http://dx.doi.org/10.2298/jmmb150223008y.

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It is very important to selectively reduce manganese oxide over iron oxide for extraction of Mn from iron-rich manganese ore. In this study, reductive roasting of an iron-rich manganese oxide ore with elemental sulfur as reductant was investigated. The experimental results demonstrated that manganese dioxide can be selectively reduced with elemental sulfur and extracted via acid leaching, which was largely depended on the sulfur addition. Lower sulfur addition (S/Mn molar ratio<1.0) results in higher selectivity, which is independent of roasting temperature. More than 95% manganese and less than 10% iron were extracted through acid leaching under the roasting conditions of 400-600?C with S/Mn molar ratio of 0.6. The contents of manganese sulfide and sulfate in the roasted product increased with increasing sulfur addition, while they decreased distinctly at temperatures above 550?C. The thermodynamic analysis also proved that manganese dioxide is more easily reduced than iron oxide by sulfur at 300-900 K. The phase transformations during reductive roasting revealed that sulfides (MnS and FeS2) were favored at temperatures lower than 550?C whereas the oxides (MnFe2O4 and Fe3O4) were predominant at higher temperatures. The reduction of iron oxide mainly occurred at large sulfur additions (S/Mn>2.0) and the roasting temperature exerted a significant impact on the phase composition of roasted product.

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Azimova, G. R. "STUDY OF LOW-TEMPERATURE OXIDATION OF CARBON MONOOXIDE ON Cu–Mn–Fe CATALYTIC OXIDE SYSTEMS OBTAINED BY THE SOL-GEL COMBUSTION METHOD." Azerbaijan Chemical Journal, no. 2 (June 2, 2022): 93–99. http://dx.doi.org/10.32737/0005-2531-2022-2-93-99.

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The oxidation of carbon monoxide was studied on oxide Cu–Mn–Fe catalytic systems with metal ratio Cu:Mn:Fe=1:1:1; 2:1:1; 1:2:1 and 1:1:2 obtained by the sol-gel method with combustion. The results of X-ray phase analysis showed that the catalytic systems have a complex phase composition. Along with double oxides of manganese and iron, ferrites of copper-, manganese, copper manganite, manganese-substituted copper ferrites were formed (CuFe2O4; Mn0.43Fe2.57O4, Mn0.98Fe2.02O4; CuMn2O4; Cu1.2Mn1.8O4; Cu0.5Mn0.5Fe2O4). It has been found that depending on the ratio of metals in the catalyst, the reaction start temperature is in the temperature range of 120–1700C. And after 3–5 minutes after the start of the reaction, the conversion begins to increase sharply, reaching 100% within the next 5 minutes

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Yang, Xin Sheng, Li Qin Yang, Li Lv, and Yong Zhao. "Preparation and Properties of Novel Bonded Perovskite Manganite Oxides." Advanced Materials Research 79-82 (August 2009): 1723–26. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1723.

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The two-phase perovskite manganese composites have potential application in the field of spintronics, as the observed enhanced low-field magnetoresistance in this kind of composite. To prepare the real manganite-based two-phase composition, the concept of bonded perovskite manganese was put forward recently. In this article we review main research results in these bonded perovskite manganite oxide composites and give some expectation.

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Huang, Qi, Wei Ma, and Mei Han. "The Preparation and Properties of Seawater Purification and Resource Recycling Function Materials." Advanced Materials Research 233-235 (May 2011): 677–79. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.677.

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A kind of manganese oxide which could purify seawater arisesed at the historic moment. Lithium manganese oxide was synthesized by coprecipitation method and the manganese oxide was prepared by extracting lithium from lithium manganese oxide. The characteristics of the manganese oxide were studied by X-ray diffraction and transmission electron microscopy. The characteristics showed that the manganese oxide was pure spinel structure and about 100 nm in length. There were experiments to study the effects of oil and phenol removal in the seawater. At the same time recycling lithium from seawater was tested. The results showed that the manganese oxide could not only remove oil and phenol but also recycle lithium.

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Young, Jay A. "Manganese(IV) Oxide." Journal of Chemical Education 78, no. 10 (October 2001): 1327. http://dx.doi.org/10.1021/ed078p1327.

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Saroyan, Hayarpi, Dimitra Ntagiou, Kyriazis Rekos, and Eleni Deliyanni. "Reactive Black 5 Degradation on Manganese Oxides Supported on Sodium Hydroxide Modified Graphene Oxide." Applied Sciences 9, no. 10 (May 27, 2019): 2167. http://dx.doi.org/10.3390/app9102167.

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Sodium hydroxide-modified graphene oxide was used as manganese oxides support for the preparation of nanocomposites via a one-pot preparation route for the degradation of Reactive Black 5. The nanocomposites were characterized for their structure by X-ray diffraction, for their textural properties by Nitrogen adsorption, and for their surface chemistry by Fourier transform infrared spectroscopy, potentiometric titration, and thermal analysis measurements. The nanocomposites prepared showed to possess high activity for the degradation/oxidation of Reactive Black 5 at ambient conditions, without light irradiation, which was higher than that of the precursors manganese oxides and can be attributed to the synergistic effect of the manganese oxides and the modified graphene oxide.

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Koju, Rashmi, Agni Dhakal, Sushila Gwachha, Dev Raj Joshi, Tista Prasai Joshi, and Sujen Man Shrestha. "Adsorption of Inorganic As(III) from Aqueous Solutions by Iron-Manganese Oxide." Scientific World 13, no. 13 (August 7, 2020): 46–50. http://dx.doi.org/10.3126/sw.v13i13.30538.

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Arsenic contamination in water is well noted public health issue in Nepal and elsewhere. Adsorbents are important chemical means to purify the arsenic contaminated water. In this study the adsorption of As(III) on iron manganese oxide has been investigated as a function of different parameters. Herein, two iron based adsorbents, iron-manganese oxide-1 (Fe-Mn oxide-1) and iron-manganese oxide-2 (Fe-Mn oxide-2) were prepared by oxidation and co-precipitation methods. Adsorbents were characterized by powder X-ray diffraction (XRD) and scanning electron microscope (SEM). Within 4 hours of reaction time, 90% of the arsenic was removed by both Fe-Mn oxides and removal efficiency of the Fe-Mn oxide-1 was obtained higher than that of Fe-Mn oxide-2. Pseudo-second order model was well fitted to describe adsorption kinetic (R2 =0.99) for both adsorbents. Removal efficiency of the absorbents decreased with increase in the pH value and increased with increase in the concentration of adsorbent in the suspension. Based on the result, the synthesized Fe-Mn oxides have significant potential applications in the inorganic arsenic treatment in the water.

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Marincaş, Alexandru-Horaţiu, and Petru Ilea. "Enhancing Lithium Manganese Oxide Electrochemical Behavior by Doping and Surface Modifications." Coatings 11, no. 4 (April 15, 2021): 456. http://dx.doi.org/10.3390/coatings11040456.

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Lithium manganese oxide is regarded as a capable cathode material for lithium-ion batteries, but it suffers from relative low conductivity, manganese dissolution in electrolyte and structural distortion from cubic to tetragonal during elevated temperature tests. This review covers a comprehensive study about the main directions taken into consideration to supress the drawbacks of lithium manganese oxide: structure doping and surface modification by coating. Regarding the doping of LiMn2O4, several perspectives are studied, which include doping with single or multiple cations, only anions and combined doping with cations and anions. Surface modification approach consists in coating with different materials like carbonaceous compounds, oxides, phosphates and solid electrolyte solutions. The modified lithium manganese oxide performs better than pristine samples, showing improved cyclability, better behaviour at high discharge c-rates and elevated temperate and improves lithium ions diffusion coefficient.

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Craddock, Paul T. "The Many and Various Roles of Manganese in Iron and Steel Production." Materials Science Forum 983 (March 2020): 57–63. http://dx.doi.org/10.4028/www.scientific.net/msf.983.57.

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Manganese oxide and metallic manganese have made a long and varied contribution to the production of iron and steel through the centuries, long before Sir Robert Hadfield’s alloy manganese steel first produced in 1882. Although quite well known empirically, this contribution has sometimes been misunderstood or misrepresented.The success of some of the early so-called ‘natural steels’ was the presence of manganese oxides in the iron ores used.Manganese oxide was already used as a flux from the early days of the production of crucible steel in Asia and it now appears that it was used as a flux from the inception of the otherwise very different later European crucible steel technologies. After the introduction of crucible steel making in Britain in the 18th century, foreign competitors believed that the reason for the success of the processes used at Sheffield was a secret flux and studies on recently discovered 18th century crucibles in Sheffield have shown that process was indeed fluxed with manganese oxide.The function of manganese in the later European crucible steel industry has been rather overshadowed and confused historically by the very different ‘Carburet of manganese’, a strange concoction, patented by Josiah Heath in 1839 added to iron or steel to purify the metal. At the time the chemistry of the process was misunderstood and many acrimonious and inaccurate claims were made, crucially confusing the very different functions of manganese oxide and manganese metal, overshadowing the part already played by manganese oxide for almost a century previously..Finally manganese and its salts played a crucial role in the Bessemer process of steel making.

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Tarutis, W. J., and R. F. Unz. "Iron and manganese release in coal mine drainage wetland microcosms." Water Science and Technology 32, no. 3 (August 1, 1995): 187–92. http://dx.doi.org/10.2166/wst.1995.0140.

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The primary mechanisms responsible for the removal and retention of iron, manganese, and sulfate in constructed wetlands receiving acidic mine drainage (AMD) include the formation of metal oxides and sulfides within the sediments. This study was initiated to determine the kinetics of metal ion liberation, under reducing conditions, from synthetic and naturally occurring iron and manganese oxides typically found in AMD precipitates. Rates of metal ion liberation were determined during time series incubations of an organic substrate (spent mushroom compost) to which five metal oxides of varying crystallinity (amorphous and crystalline oxides of iron and manganese; natural AMD oxide) were added. All experiments were carried out in silicone-sealed polycarbonate centrifuge tubes incubated at 22°C for a period of 3, 7, 10, 14, 21 or 28 days. Tubes were sacrificed after each incubation period and were analyzed for redox potential, pH, sulfide, and metals. All tubes exhibited reducing potentials within 3 days coupled with rapidly increasing concentrations of iron and manganese. Liberation of iron and manganese decreased with increasing mineral crystallinity (amorphous > natural AMD ≫ crystalline). The results suggest that metal ion liberation from oxide minerals may be an important source of iron and manganese within constructed wetlands receiving AMD.

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Malinenko, V. P., L. A. Aleshina, A. L. Pergament, and G. V. Germak. "Switching Effects and Metal−Insulator Transition in Manganese Oxide." Journal on Selected Topics in Nano Electronics and Computing 1, no. 1 (December 2013): 44–50. http://dx.doi.org/10.15393/j8.art.2013.3005.

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Latta, Drew E., Christopher A. Gorski, and Michelle M. Scherer. "Influence of Fe2+-catalysed iron oxide recrystallization on metal cycling." Biochemical Society Transactions 40, no. 6 (November 21, 2012): 1191–97. http://dx.doi.org/10.1042/bst20120161.

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Recent work has indicated that iron (oxyhydr-)oxides are capable of structurally incorporating and releasing metals and nutrients as a result of Fe2+-induced iron oxide recrystallization. In the present paper, we briefly review the current literature examining the mechanisms by which iron oxides recrystallize and summarize how recrystallization affects metal incorporation and release. We also provide new experimental evidence for the Fe2+-induced release of structural manganese from manganese-doped goethite. Currently, the exact mechanism(s) for Fe2+-induced recrystallization remain elusive, although they are likely to be both oxide-and metal-dependent. We conclude by discussing some future research directions for Fe2+-catalysed iron oxide recrystallization.

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Li, Wei, Wen Huai Tian, and Lu Qi. "The Influence of Particle Characteristic of Manganese Dioxide on Performance of Spinel Lithium Manganese Oxide." Materials Science Forum 852 (April 2016): 816–21. http://dx.doi.org/10.4028/www.scientific.net/msf.852.816.

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Several kinds of chemical manganese dioxide with different particle characteristic were prepared by redox reaction in liquid phase. Then, spinel lithium manganese oxide was synthesized by liquid impregnation. The result implied that the influence of particle characteristic on test result is important. The spinel lithium manganese oxide prepared by spherical MnO2 has better cycle performance than the spinel lithium manganese oxide prepared by MnO2 with irregular shape .The spinel lithium manganese oxide with little particle size has high initial specific capacity. The spinel lithium manganese oxide prepared by MnO2 with anemone shape has high specific capacity and stable cycle performance.

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Sun, Shuo, Haoran Yu, Lanlan Li, Xiaofei Yu, Xinghua Zhang, Zunming Lu, and Xiaojing Yang. "Sodium Borohydride Treatment to Prepare Manganese Oxides with Oxygen Vacancy Defects for Efficient Oxygen Reduction." Metals 12, no. 7 (June 21, 2022): 1059. http://dx.doi.org/10.3390/met12071059.

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Manganese oxides are often used as catalysts for oxygen reduction reactions due to their low price and high stability, and they have been extensively studied. However, the poor electrical conductivity and low intrinsic activity of manganese oxides restrict its application in oxygen reduction. In this paper, the manganese oxide octahedral molecular sieve is used as the research object, and the oxygen reduction performance of the material is adjusted by the surface reduction etching treatment of sodium borohydride. After being treated with 8 mmol/L sodium borohydride, the oxygen vacancy content of the manganese oxide octahedral molecular sieve was 26%. The manganese oxide octahedral molecular sieve showed the best performance, and its half-wave potential was 0.821 V. Tests show that the material has excellent electrical conductivity and high oxygen reduction kinetics. The generation of appropriate oxygen vacancies on the surface directly improves the chemical properties of the material surface, regulates the ratio of Mn3+/Mn4+ on the surface of the nanorod, and increases the oxygen reduction adsorption sites on the surface of the material. On the other hand, the electrical conductivity of the material is adjusted to increase the electron transfer rate during the oxygen reduction process, thereby enhancing the oxygen reduction activity.

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Suresh Raj, A. M. Edwin, C. Mallika, O. M. Sreedharan, and K. S. Nagaraja. "Manganese oxide–manganese tungstate composite humidity sensors." Materials Letters 53, no. 4-5 (April 2002): 316–20. http://dx.doi.org/10.1016/s0167-577x(01)00499-2.

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Manavalan, Rajesh Kumar, Karolinekersin Enoch, Alexey Sergeevich Volegov, Gurunathan Angusamy, and Sitakumaravel Nallasivam. "Review on Medical Applications of Manganese Oxide (Mn2+, Mn3+, and Mn4+) Magnetic Nanoparticles." Journal of Nanomaterials 2024 (February 20, 2024): 1–29. http://dx.doi.org/10.1155/2024/1073915.

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Apart from our imagination, the nanotechnology industry is rapidly growing and promises that the substantial changes that will have significant economic and scientific impacts be applicable to a wide range of areas, such as aerospace engineering, nanoelectronics, environmental remediation, and medical healthcare. In the medical field, magnetic materials play vital roles such as magnetic resonance imaging (MRI), hyperthermia, and magnetic drug delivery. Among them, manganese oxide garnered great interest in biomedical applications due to its different oxidation states (Mn2+, Mn3+, and Mn4+). Manganese oxide nanostructures are widely explored for medical applications due to their availability, diverse morphologies, and tunable magnetic properties. In this review, cogent contributions of manganese oxides in medical applications are summarized. The crystalline structure and oxidation states of Mn oxides are highlighted. The synthesis approaches of Mn-based nanoparticles are outlined. The important medical applications of manganese-based nanoparticles like magnetic hyperthermia, MRI, and drug delivery are summarized. This review is conducted to cover the future impact of MnOx in diagnostic and therapeutic applications.

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Volchyn, I. A., S. V. Mezin, and A. O. Yasinetsky. "PECULIARITIES OF ABSORPTION OF SULFUR DIOXIDE AND NITROGEN OXIDE IN SUSPENSIONS AND SOLUTIONS OF MANGANESE COMPOUNDS." Energy Technologies & Resource Saving, no. 4 (December 20, 2020): 49–56. http://dx.doi.org/10.33070/etars.4.2020.05.

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It is proposed to use manganese compounds to reduce emissions of sulfur and nitrogen oxides, large deposits of which are in Ukraine. The results of experimental studies of the binding of sulfur dioxide and potassium permanganate of nitric oxide in water by manganese oxide are presented. In the experiments, the model gas in the form of small bubbles was passed through the reactor with liquid. Heat and mass transfer processes between the gas and liquid phases occurred on the bubble surface. The gas-liquid contact time is the bubble rise time. The absorption reactions take place in the liquid phase. Complete absorption of sulfur dioxide takes place in an acidic environment, provided that the molar ratio MnO2 / SO2 is not less than 2. The reaction product is manganese sulfate, which is a useful product. The maximum absorption of nitrogen oxide is achieved at a molar ratio of KMnO4 / NO not less than 5. The reaction forms a precipitate of manganese oxide, which can later be used in the desulfurization process. Bibl. 12, fig. 6, tab. 3.

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Jasinski, Jacek B., Dominika Ziolkowska, Monika Michalska, Ludwika Lipinska, Krzysztof P. Korona, and Maria Kaminska. "Novel graphene oxide/manganese oxide nanocomposites." RSC Advances 3, no. 45 (2013): 22857. http://dx.doi.org/10.1039/c3ra42254b.

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Ahmed, Mohamed F., Mostafa A. Ibrahim, Ahmed S. Mansour, Ahmed N. Emam, Ashraf B. Abd El-Razik, and Eman Tawfik. "Metal-based-oxide nanoparticles assisted the in vitro culture growth of Populus alba as micronutrients: essential metabolic processes and genetic stability." RSC Advances 13, no. 17 (2023): 11577–90. http://dx.doi.org/10.1039/d2ra05941j.

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40

Afonasenko, Tatyana N., Daria V. Yurpalova, Zakhar S. Vinokurov, Andrey A. Saraev, Egor E. Aidakov, Valeriya P. Konovalova, Vladimir A. Rogov, and Olga A. Bulavchenko. "The Formation of Mn-Ce-Zr Oxide Catalysts for CO and Propane Oxidation: The Role of Element Content Ratio." Catalysts 13, no. 1 (January 16, 2023): 211. http://dx.doi.org/10.3390/catal13010211.

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The MnOх-ZrO2-CeO2 oxide catalysts were synthesized by co-precipitation method with varying (1) Zr/Zr + Ce molar ratio at constant manganese content of 0.3; (2) manganese content at constant Zr/Ce molar ratio of 1; (3) Mn/Mn + Zr molar ratio at constant Ce content of 0.5. Catalysts are characterized by XRD, N2 adsorption, TPR, and XPS. The catalytic activity of all the series was tested in the CO and propane oxidation reactions. In contrast to the variation of the manganese content, the Zr/Zr + Ce molar ratio does not significantly affect the catalytic properties. The dependence of the catalytic activity in CO oxidation on the manganese content has a «volcano» shape, and the best catalytic performance is exhibited by the catalyst with Mn/(Zr + Ce) = 1. In the case of propane oxidation reaction, there is «sigma» like dependence, activity increases with increase of Mn/(Mn + Zr + Ce) molar ratio up to 0.3, stabilizing with a further increase in the manganese content. XRD and XPS have shown that with an increase of the Mn concentration in the MnOx-ZrO2-CeO2 catalysts, the amount of crystalline manganese oxides such as Mn2O3 and Mn3O4, as well as the surface concentration of Mn cations, increases. While the content of MnxZryCe1-x-yO2 solid solution decreases, the concentration of manganese cations (x) in volume of MnxZryCe1-x-yO2 mixed oxide grows. The maximum activity in CO oxidation corresponds to the balance between the amount of the solid solution and the concentration of manganese cations in the volume of mixed oxide. The propane oxidation reaction is less sensitive to the state of manganese ion rather than to its amount. In this case, a decrease in the content of the MnxZryCe1-x-yO2 solid solution with increase in manganese amount in catalyst is compensated by an increase in content of crystalline manganese oxides and the surface concentration of manganese.

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Zhao, Liqun, Sida Niu, Xianglong Niu, Tong Chen, Yingchao Wang, Lei Li, Fei Huang, Huaying Wu, Lingchao Mo, and Min Zhang. "Manganese Oxide Minerals from the Xiangtan Manganese Deposit in South China and Their Application in Formaldehyde Removal." Minerals 12, no. 5 (April 28, 2022): 552. http://dx.doi.org/10.3390/min12050552.

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Because of the nano-scale tunnel constructed by the active Mn-O octahedron in cryptomelane, cryptomelane-type manganese oxides have high activity in the oxidation of several volatile organic compounds (VOCs). Natural cryptomelane, in the form of supergene oxide manganese ore, carpets much of South China. In the lower part of the Datangpo Formation of Nanhua System on the southeastern Yangtze Platform, cryptomelane is one of the major manganese oxides in black shale of the Xiangtan manganese deposit in this deposit. Formaldehyde is a dominant indoor pollutant among volatile organic compounds (VOCs), and applications of synthetic cryptomelane have been reported to eliminate it. To study the removal capacity of naturally outcropping cryptomelane, representative samples of manganese oxide (the primary mineral component of cryptomelane) from the Xiangtan Mn deposit were analyzed in this study. The chemical composition, crystal structure and micromorphology of the manganese oxide minerals were explored using ICP-AES, XRD, EPMA, SEM and HR-TEM techniques. Fine-grained and poorly crystalline, these minerals consist primarily of cryptomelane, along with minor amounts of pyrolusite, hollandite, lithiophorite, limonite and quartz. Natural cryptomelane is a monoclinic crystal, and its cell parameters are refined. The results of catalytic tests revealed that natural cryptomelane has obvious catalytic activity in the oxidation of formaldehyde in a static environment under room temperature. This study may provide a natural mineral material as an inexpensive and efficient catalyst for the purification of formaldehyde in industrial or indoor air treatment.

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KIM, BONG-SEO, SU-DONG PARK, HEE-WOONG LEE, DONG-YOON LEE, and WON-SUB CHUNG. "ELECTRONIC STATE CALCULATION OF MANGANESE DIOXIDE ELECTRODE WITH ADDITIVE TRANSITION METALS." International Journal of Modern Physics B 20, no. 25n27 (October 30, 2006): 4255–60. http://dx.doi.org/10.1142/s0217979206041185.

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The electronic states of manganese dioxide substituted with transition metals were theoretically calculated by DV-Xα method, cluster model was Mn 15 O 56 and Mn 14 XO 56 (X = transition metal). The energy band gap of manganese-X oxides is lower than that of manganese dioxide from theoretical calculation. Also it is identified that the electrical conductivity of manganese-tungsten oxide is better than that of manganese dioxide from experiment of anodic deposition method. It is confirmed that the theoretical calculation coincides with experimental results.

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Elmacı, Gökhan, Carolin E. Frey, Philipp Kurz, and Birgül Zümreoğlu-Karan. "Water oxidation catalysis by using nano-manganese ferrite supported 1D-(tunnelled), 2D-(layered) and 3D-(spinel) manganese oxides." Journal of Materials Chemistry A 4, no. 22 (2016): 8812–21. http://dx.doi.org/10.1039/c6ta00593d.

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Новохацкая, А. А., and Г. Я. Акимов. "Роль избыточного марганца в формировании структуры и транспортных свойств манганита (Nd-=SUB=-0.67-=/SUB=-Sr-=SUB=-0.33-=/SUB=-)-=SUB=-1-x-=/SUB=-Mn-=SUB=-1+x-=/SUB=-О-=SUB=-3-=/SUB=- (x=0; 0.2), спеченного при 1273-1473 K." Физика твердого тела 60, no. 7 (2018): 1378. http://dx.doi.org/10.21883/ftt.2018.07.46127.009.

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AbstractThe Nd_0.67Sr_0.33MnO_3 manganite is a material promising for application as a cathode for medium-temperature solid oxide fuel elements. A high electrical conductivity of such a cathode is the parameter determining the efficiency of the operation of a fuel element. In this report, the effect of influence of excess manganese on the structure and the conductivity of manganite ceramics with compositions (Nd_0.67Sr_0.33)_1– x Mn_1 + x O_3± Δ ( x = 0, 0.2) sintered at temperatures 1273–1673 K is presented for the first time. The existence of 20% excess manganese in the initial manganite powder after sintering is shown to lead to that the conductivity of the obtained ceramics in the temperature range 823–1073 K is several times higher than the conductivity of the ceramics without excess manganese.

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Sullivan, LA, and AJ Koppi. "Manganese oxide accumulations associated with some soil structural pores .II. Composite coatings and translocation." Soil Research 31, no. 3 (1993): 227. http://dx.doi.org/10.1071/sr9930227.

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The morphology and composition of some composite coatings-containing manganese oxide coatings and impregnations-that were associated with the structural pores in a black earth (Typic Pellustert) subsoil layer were examined using light microscopy, electron microscopy, and electron micro-analytical techniques. Detailed examination of composite coatings indicates, firstly, that subsurface coatings and impregnations of manganese oxides had been formed by the burial of surface accumulations of manganese oxides with coatings of other soil components, and secondly, that fine-textured soil material had been translocated and deposited in a form which was virtually indistinguishable from that of the soil matrix.

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Nohma, T., T. Saito, N. Furukawa, and H. Ikeda. "Manganese oxides for a lithium secondary battery — composite dimensional manganese oxide (CDMO)." Journal of Power Sources 26, no. 3-4 (May 1989): 389–96. http://dx.doi.org/10.1016/0378-7753(89)80151-x.

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47

A Begimkulova, S. h., S. h. E Mirzayev, R. H a s a n o v, M. R a j a b o v a, A. I v a n e s, and A. M Nasimov. "STUDY OF ADSORPTION PROPERTIES OF Mg2+ MODIFIED Li - Mn SPINEL." 2022-yil, 3-son (133/1) ANIQ FANLAR SERIYASI 1, no. 1 (February 20, 2023): 1–8. http://dx.doi.org/10.59251/2181-1296.v1.1.1860.

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In this work, the oxide phase of the spinel structure Li1.33Mn1.67O4 4 partially replaced manganese with Mg2+ ions, and the effect of lithium manganese oxides on adsorption properties was studied. Li1.33MgxMn(1.67-x)O4 oxide with a spindle structure doped with Mg2+ ion was synthesized by sol-gel method and calcined at 600 °C for 5 hours. Experiments were conducted to study the effect of pH, gelation time, adsorbent dose, contact time and Li+ concentration. The synthesized oxides of Li1.33MgxMn(1.67x)O4 were described using X-ray radiation. The characteristics of Li1.33MgxMn(1.67x)O4 were studied by X-ray diffraction (XRD).

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A Begimkulova, S. h., S. h. E Mirzayev, R. H a s a n o v, M. R a j a b o v a, A. I v a n e s, and A. M Nasimov. "STUDY OF ADSORPTION PROPERTIES OF Mg2+ MODIFIED Li - Mn SPINEL." 2022-yil, 3-son (133/1) ANIQ FANLAR SERIYASI 1, no. 1 (February 20, 2023): 1–8. http://dx.doi.org/10.59251/2181-1296.2023.v1.1.1860.

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In this work, the oxide phase of the spinel structure Li1.33Mn1.67O4 4 partially replaced manganese with Mg2+ ions, and the effect of lithium manganese oxides on adsorption properties was studied. Li1.33MgxMn(1.67-x)O4 oxide with a spindle structure doped with Mg2+ ion was synthesized by sol-gel method and calcined at 600 °C for 5 hours. Experiments were conducted to study the effect of pH, gelation time, adsorbent dose, contact time and Li+ concentration. The synthesized oxides of Li1.33MgxMn(1.67x)O4 were described using X-ray radiation. The characteristics of Li1.33MgxMn(1.67x)O4 were studied by X-ray diffraction (XRD).

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Amiruddin, Erwin, Amir Awaluddin, Salomo Sinuraya, Heri Hadianto, Muhammad Deri Noferdi, and Ainun Syarifatul Fitri. "Study of Iron Oxide Nanoparticles Doped with Manganese for Catalytic Degradation of Methylene Blue." Journal of Physics: Conference Series 2049, no. 1 (October 1, 2021): 012021. http://dx.doi.org/10.1088/1742-6596/2049/1/012021.

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Abstract:

Abstract Modification of iron oxide nanoparticles by doping with transition metals has been intensively reported and many applications have been proven. Magnetic and structural properties, and the catalytic activity of undoped and manganese doped iron oxide nanoparticles for degradation of methylene blue have been studied. Preparation of undoped and manganese doped iron oxide nanoparticles was done by ball milling method using Logas natural sand as raw materials. The magnetic properties of the samples were determined using vibration sample magnetometer (VSM). A detailed analysis of the loop hysteresis reveals a reduction of saturation magnetization of the samples towards higher manganese-doping concentration (wt.%). The reduction in magnetization from 13.25 to 11.67 emu/g and enhanced the coercivity on manganese-doped samples from 224.35 to 352.18 Oe are observed to produce an improvement in the catalytic activity for manganese doped iron oxide nanoparticles compared to undoped samples. Catalytic activity of undoped and manganese doped iron oxide nanoparticles in the degradation of methylene blue was studied through ultraviolet visible spectroscopy (UV-Vis). Manganese doped iron oxide nanoparticles exhibit better catalytic activity for degrading methylene blue (88.880%) compared to that for undoped iron oxide nanopartices (81.805%) for 300 minutes reaction time.

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Wong, She-Tin, and Soofin Cheng. "Pillared layered manganese oxide." Journal of Thermal Analysis 40, no. 3 (September 1993): 1181–92. http://dx.doi.org/10.1007/bf02546881.

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Journal articles on the topic 'Manganese oxide'

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