Manganese Carbonate Research Articles

Synthesis of Micro–Nano-assembled Manganese Carbonate via Aqueous Precipitation Assisted by Ethanol

ABSTRACT: The micro-nano assembled manganese carbonate (MnCO3) was synthesized via aqueous precipitation assisted by ethanol. The effects of the time and the flow rate to introduce ethanol on the morphology and size of products were carefully investigated. It reveals that ethanol may participate in the precipitation of MnCO3 nanoparticles, the retardant of aggregate fusion, and the reassembly of aggregates at different stage. By a delayed but prompt introduction of ethanol, we can regulate these effects to endow the micro-nano assembled MnCO3 with high surface area, uniform morphology, and calcination-resistant skeleton simultaneously. The synthesis of monodispersed micro-nano assembled MnCO3 at elevated concentrations of reactants is also available by introducing ethanol earlier.

Synthesis of MnFe2O4 hollow microspheres via a sacrificial templates approach

Manganese ferrite (MnFe2O4) hollow microspheres were synthesized through a sacrificial template approach using manganese carbonate (MnCO3) microspheres as sacrificial templates. Different from the literatures, the synthesis of MnFe2O4 hollow spheres was achieved through a one-pot hydrothermal process without subsequent calcination process. The temperature and reaction time of the hydrothermal process were set to be 180 °C and 8 h. The formation mechanism of the MnFe2O4 hollow microspheres was also investigated. Results indicate that the average diameter of the as-synthesized MnFe2O4 hollow microspheres is 1.2 μm. The shells of the hollow microspheres are composed of nanoparticles. During hydrothermal process, Mn2+ ions diffused outward and resulted in shell materials of MnFe2O4, thus MnCO3 templates were consumed and MnFe2O4 hollow microspheres were obtained.

In situ conversion of manganese carbonate to manganese oxide/hydroxide and its supercapacitive analysis in aqueous KOH solution

MnCO3 is considered to be a promising electrode material for supercapacitor (SC) and found to be a good material for supercapacitive performance than their counterpart manganese oxides. But the energy storage mechanism of MnCO3 in KOH aqueous solution is not known yet. Hence, in the present work, we have made an attempt to understand the involved energy storage mechanism for MnCO3. MnCO3 with submicron-sized particles are synthesized by simple, cost-effective co-precipitation method at ambient conditions and examined as electrode material for SC application by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in 2 M KOH electrolyte. To investigate the reason for charge storage mechanism, ex-situ X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) analysis were performed at the different stages of charges/discharge for MnCO3 in KOH electrolyte and a plausible energy storage mechanism is proposed. Hexagonal-MnCO3 transforms to respective oxide/hydroxide once it comes in contact with KOH solution. At the end of 2 h reaction time, Mn(OH)2 transforms to Mn3O4; however, complete transformation of Mn(OH)2 to Mn3O4 only occurred when external positive potential was applied. All these results were supported by studying pH and potential influence in the line of well known Pourbaix diagram. Considering all results presented in this manuscript, it is clearly observed that MnCO3 does not perform the electrochemical charge-discharge cycling, but it transforms completely to Mn3O4 in the first or second cycle, and thereafter, Mn3O4 does perform the reversible electrochemical charge-discharge cycling to enable high and stable capacitance.

Polydopamine-Coated Manganese Carbonate Nanoparticles for Amplified Magnetic Resonance Imaging-Guided Photothermal Therapy.

This study reports a multifunctional nanoparticle (NP) that can be used for amplified magnetic resonance image (MRI)-guided photothermal therapy (PTT) due to its surface coating with a polydopamine (PDA) shell. Importantly, by means of introducing the surface coating of PDA, large quantities of water can be trapped around the NPs allowing more efficient water exchange, leading to greatly improved MR contrast signals compared with those from NPs without the PDA coating. Further, a distinct photothermal effect can be obtained arising from the strong absorption of PDA in the near-infrared (NIR) region. By synthesizing multifunctional MnCO3@PDA NPs, for example, we found that the longitudinal relaxivity (r1) of MnCO3 NPs can improve from 5.7 to 8.3 mM-1 s-1. Subsequently, in vitro MRI and PTT results verified that MnCO3@PDA could serve as an excellent MRI/PTT theranostic agent. Furthermore, the MnCO3@PDA NPs were applied as an MRI/PTT theranostic agent for in vivo MRI-guided photothermal ablation of tumors by intratumoral injection in 4T1 tumor-bearing mice. The MR imaging result shows a significantly bright MR image in the tumor site. The MnCO3@PDA-mediated PTT result shows high therapeutic efficiency as a result of high photothermal conversion efficiency. The present strategy of amplified MRI-guided PTT based on PDA coating of NPs will be widely applicable to other multifunctional NPs.

Ferromanganese carbonate metasediments of the Sob area, Polar Urals: Bedding conditions, composition, and genesis

The paper presents the results of study of ferromanganese carbonate rocks in the Sob area (Polar Urals), which is located between the Rai-Iz massif and the Seida–Labytnangi Railway branch. These rocks represent low-metamorphosed sedimentary rocks confined to the Devonian carbonaceous siliceous and clayey–siliceous shales. In terms of ratio of the major minerals, ferromanganese rocks can be divided into three varieties composed of the following minerals: (1) siderite, rhodochrosite, chamosite, quartz, ± kutnahorite, ± calcite, ± magnetite, ± pyrite, ± clinochlore, ± stilpnomelane; (2) spessartite, rhodochrosite, and quartz, ± hematite, ± chamosite; (3) rhodochrosite, spessartite, pyroxmanite, quartz ± tephroite, ± fridelite, ± clinochlore, ± pyrophanite, ± pyrite. In all varieties, the major concentrators of Mn and Fe are carbonates (rhodochrosite, siderite, kutnahorite, Mn-calcite) and chlorite group minerals (clinochlore, chamosite). The chemical composition of rocks is dominated by Si, Fe, Mn, carbon dioxide, and water (L.O.I.): total SiO2 + Fe2O 3 tot + MnO + L.O.I. = 85.6−98.4 wt %. The content of Fe and Mn varies from 9.3 to 55.6 wt % (Fe2O 3 tot + MnO). The Mn/Fe ratio varies from 0.2 to 55.3. In terms of the aluminum module AlM = Al/(Al + Mn + Fe), the major portion of studied samples corresponds to metalliferous sediments. The δ13Ccarb range (–30.4 to–11.9‰ PDB) corresponds to authigenic carbonates formed with carbon dioxide released during the microbial oxidation of organic matter in sediments at the dia- and/or catagenetic stage. Ferromanganese sediments were likely deposited in relatively closed seafloor zones (basin-traps) characterized by periodic stagnation. Fe and Mn could be delivered from various sources: input by diverse hydrothermal solutions, silt waters in the course of diagenesis, river discharges, and others. The diagenetic delivery of metals seems to be most plausible. Mn was concentrated during the stagnation of bottom water in basin-traps. Interruption of stagnation promoted the precipitation of Mn. The presence of organic matter fostered a reductive pattern of postsedimentary transformations of metalliferous sediments. Fe and Mn were accumulated initially in the oxide form. During the diagenesis, manganese and iron oxides reacted with organic matter to make up carbonates. Relative to manganese carbonates, iron carbonates were formed under more reductive settings and higher concentrations of carbon dioxide in the interstitial solution. Crystallization of manganese and iron silicates began already at early stages of lithogenesis and ended during the regional metamorphism of metalliferous sediments.

Nanophotosensitive drugs for light-based cancer therapy: what does the future hold?

Nanophotosensitive drugs for light-based cancer therapy: what does the future hold?

Micronutrient supply through granular-coated single superphosphate under field conditions

ABSTRACTThe lack of efficient methods for soil-based micronutrient fertilization in field crops at sowing remains an important limiting factor for agricultural production in low fertility soils. Therefore, we evaluated the efficiency of single superphosphate (SSP) coated with either finely ground zinc (Zn) oxide or manganese (Mn) carbonate to supply Zn to corn (Zea mays L.), and Mn to soybean (Glycine max L.) and oat (Avena sativa L.) versus traditional sources (oxide and sulfate). One experiment for each micronutrient was performed under field conditions in two sequential growing cycles: rainy season (corn and soybean) and off-season (corn and oat). Treatments were combination of Zn or Mn fertilizers (oxide, sulfate, and SSP coated with Zn oxide or Mn carbonate) at rates of 1.25, 2.5, and 5.0 kg ha−1 of Zn or Mn, plus a control. Micronutrient fertilization showed, relative to the unfertilized control, significant increases in shoot biomass at flowering, crop yield (corn silage and soybean grain), and leaf concentration and shoot uptake of Zn and Mn during the rainy season. Residual effect of Zn on off-season corn crop represented a 43% increase in grain yield over the control. However, oat did not respond to residual Mn. The positive effects of Zn and Mn application on crop performance did not depend on fertilizer material, suggesting similar fertilizer-use efficiency. We concluded that banded application of SSP coated with either finely ground Zn oxide or Mn carbonate would be a viable option to supply these micronutrients at the time of sowing in micronutrient-deficient soils.

Manganese carbonate nanograined assembling macrocube via a facile hydrothermal process for high performance supercapacitors

Herein, a cubic architecture of a self-assembled nanograined manganese carbonate (cub-MnCO3) on a three-dimensional (3D) macro-porous nickel-foam (NF) via a low-temperature (160°C) hydrothermal process has been reported, which later is used as a binder-free supercapacitor electrode. The cub-MnCO3 architecture provides large open channels by the interconnection of numerous nanograined MnCO3 to enhance ion and electron diffusion pathways, facilitating the whole active electrode material by easier electrolyte penetration. The cub-MnCO3 electrode exhibits a specific capacitance of 476Fg−1 at 1Ag−1 in 1M KOH aqueous electrolyte solution, and excellent rate ability. The cycling performance of cub-MnCO3 has revealed capacitance retention of 83.8% after 5000 cycles at a high current density of 10Ag−1.

Hydrometallurgical Treatment for Mixed Waste Battery Material

Hydrometallurgical experiments are generally required to assess the appropriate treatment process before the establishment of the industrial recovery process for waste battery materials. The effects of acid systems and oxidants in metal leaching were studied. The comprehensive leaching effects of the citric acid were superior to the sulfuric acid. The potassium permanganate inhibits the dissolution of metals. Thermodynamic calculations showed that metals precipitate more easily in sulfuric acid system than in citric acid system. The Fe precipitation efficiency in sulfuric acid system was 90% at pH 3.5, but with considerable losses of Co (30%) and Ni (40%). The proper pH and organic/aqueous (O/A) ratio for Fe and Zn removal with Di-(2-ethylhexyl) phosphoric acid extraction were 2 and 0.5, respectively; while for the removal of Cu and Mn, the best pH and O/A ratio were 3 and 0.75, respectively. Crude manganese carbonate and a cobalt-nickel enriched liquid were obtained by selective precipitation in raffinate using an ammonium bicarbonate solution. In citric acid systems, the precipitation efficiency of Co, Ni, Mn, Fe, Cu and Zn were less than 20% at pH 7. The proper pH and O/A ratio for the separation of the metals in two groups (Ni/Co/Cu and Mn/Fe/Zn) were 1.5 and 2. The cobalt-nickel-copper enriched liquid was finally obtained.

Enhanced electrochemical properties of LiNiO2-based cathode materials by nanoscale manganese carbonate treatment

LiNiO2-based layered oxides are of great importance as cathode materials for rechargeable batteries. In this paper, illustrating LiNi0.8Co0.15Al0.05O2 as an example, the effect of nanoscale MnCO3 treatment on LiNiO2-based materials is investigated for the first time. The structures of materials and the properties about the object surface are characterized by XRD, SEM, TEM, EDAX and XPS. The results demonstrate that a part of MnCO3 is able to react with lithium impurities to form nonstoichiometric LixMnyO4 and the rest of MnCO3 is converted to MnO2 coating on the surface of the material in situ. After 100 repeated cycles at 1C, the modified material exhibits a capacity retention rate of 91.2%, while the bare material only remains 84.8%. And the modified material exhibits more significantly improved cycling stability when cycling at 60°C, maintaining 85.7% of its initial capacity at 1C after 100th cycles. The consumption of Li impurities can decelerate the decomposition of electrolyte during cycling, thus result in less resistive byproducts. Moreover, the obtained MnO2 coating layer acts as an isolating layer to suppress the drastic reaction between active material and electrolyte. This synergistic effect is responsible for the excellent properties of MnCO3-modified material.

Isotope (δ13C and δ18O) and genetic features of manganese carbonates of the Mazul deposit (Krasnoyarsk region)

New isotope and mineral data on manganese carbonates of the Mazul deposit (Krasnoyarsk region) in combination with morphology of ore bodies suggest that the ores were formed in several stages with the involvement of meteoric solutions through infiltration and, possibly, exfiltration mechanisms. Based on the geological–geochemical data, manganese carbonates of the Mazul deposit may be ascribed to a new genetic subtype of the catagenesis (epigenesis) zone.

Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO3, –MnO2, and –Mn2O3 Nanocomposites for Aerial Oxidation of Alcohols

Zinc oxide nanoparticles doped manganese carbonate catalysts [X% ZnOx–MnCO3] (where X = 0–7) were prepared via a facile and straightforward coprecipitation procedure, which upon different calcination treatments yields different manganese oxides, that is, [X% ZnOx–MnO2] and [X% ZnOx–Mn2O3]. A comparative catalytic study was conducted to evaluate the catalytic efficiency between carbonates and oxides for the selective oxidation of secondary alcohols to corresponding ketones using molecular oxygen as a green oxidizing agent without using any additives or bases. The prepared catalysts were characterized by different techniques such as SEM, EDX, XRD, TEM, TGA, BET, and FTIR spectroscopy. The 1% ZnOx–MnCO3 calcined at 300°C exhibited the best catalytic performance and possessed highest surface area, suggesting that the calcination temperature and surface area play a significant role in the alcohol oxidation. The 1% ZnOx–MnCO3 catalyst exhibited superior catalytic performance and selectivity in the aerial oxidation of 1-phenylethanol, where 100% alcohol conversion and more than 99% product selectivity were obtained in only 5 min with superior specific activity (48 mmol·g−1·h−1) and 390.6 turnover frequency (TOF). The specific activity obtained is the highest so far (to the best of our knowledge) compared to the catalysts already reported in the literatures used for the oxidation of 1-phenylethanol. It was found that ZnOx nanoparticles play an essential role in enhancing the catalytic efficiency for the selective oxidation of alcohols. The scope of the oxidation process is extended to different types of alcohols. A variety of primary, benzylic, aliphatic, allylic, and heteroaromatic alcohols were selectively oxidized into their corresponding carbonyls with 100% convertibility without overoxidation to the carboxylic acids under base-free conditions.

Solid state microwave synthesis of highly crystalline ordered mesoporous hausmannite Mn3O4films

Microwave calcination of ordered micelle templated manganese carbonate films leads to highly crystalline, ordered mesoporous manganese oxide, while similar temperatures in a furnace lead to disordered, amorphous manganese oxide.

Synthesis of peanut-like hierarchical manganese carbonate microcrystals via magnetically driven self-assembly for high performance asymmetric supercapacitors

Peanut-like hierarchical MnCO3 microcrystals assembled with floss-like nanowires are synthesized via a hydrothermal process and used as an active material for supercapacitors.

Tuning of synthesis conditions by thermal decomposition towards gadolinium-doped manganese carbonate nanoparticles with uniform size and high relaxivity

A low temperature thermal decomposition method has been developed to synthesize uniform-sized Gd-doped MnCO3 nanoparticles.

Discovery of the manganese carbonate rock yielding late Early Permian radiolarians in the Nishiki Group, Akiyoshi Belt, Southwest Japan

We identified a Permian manganese-bearing carbonate layer within the siliceous shales of the Nishiki Group in the Akiyoshi Belt, Southwest Japan. The Nishiki Group is an accretionary complex composed of massive sandstones, mudstones, and Permian radiolarian-bearing siliceous shales and bedded cherts. In this paper, we present the initial descriptions of the newly discovered Permian manganese carbonates. They contain well-preserved early Permian radiolarians, including Albaillella asymmetrica and Pseudoalbaillella cf. ishigai. Although Jurassic radiolarian-bearing manganese carbonate nodules have been documented in the accretionary complexes of Japan, those of Permian age have not been described until now. In addition, we present U-Pb ages of detrital zircons extracted from the Nishiki Group sandstones, which yield a weighted mean age of 268.7±2.1 Ma, slightly younger than the age of the radiolarians in the Nishiki Group.

Preparation of manganese oxide nanoparticles by thermal decomposition of nanostructured manganese carbonate

MnO and Mn2O3 nanoparticles were prepared in air and argon atmosphere by thermal decomposition of nanocrystalline manganese carbonate synthesized by reaction of manganese(II) nitrate with glycerol. Samples were characterized using transmission electron microscopy, simultaneous thermal analysis and X-ray diffraction analysis. Average sizes of prepared nanoparticles were calculated from XRD patterns using Scherrer equation. Also, the conditions for decomposition of manganese carbonate were optimized to obtain optimal nanoparticle sizes. Due to suitable sizes of prepared nanoparticles and the initial material, this method can be used in a wide range of industrial applications.

Oxygen carrying capability evaluation based on direct electrochemistry of highly loaded hemoglobin spheres

Hemoglobin-based oxygen carriers (HBOCs) are widely researched as blood substitute and mainly produced based on templates. As reported, their optimal size should be preferably less than 1µm and more than 100nm, but porous calcium carbonate (CaCO3) is the most common template to synthesis HBOCs and their average size is larger than 3µm. Therefore, in this study, we employed manganese carbonate (MnCO3) instead of CaCO3 for the production of much smaller multilayer hemoglobin (Hb) sphere with glutaraldehyde (GA) as the crosslinking agent. According to our previous work, the obtained {Hb/GA}n nanospheres were also immobilized on chitosan modified glassy carbon electrode (GCE) to evaluate their oxygen-carrying ability with electrochemical techniques. By comparison, {Hb/GA}5 demonstrates a higher sensitivity to oxygen, stronger carrying-oxygen ability and more stable properties than {Hb/GA}1. The present work suggests potential applications of HBOCs as blood substitute.

Enhanced removal of sulfamethoxazole with manganese-adapted aerobic biomass

The antibiotic sulfamethoxazole (SMX) has been widely detected in water bodies. Better insights about its biodegradation pathways are required for developing removal processes and also for understanding its environmental fate. This study applied manganese carbonate to develop a biomass enriched with manganese oxidizing bacteria, in an aerated bioreactor which was fed with a synthetic secondary effluent and operated with a sequence batch mode. After two-month adaptation, an effective biodegradation of SMX occurred. The removal efficiency, ranging from 40% to 98%, was dependent on the feeding concentrations and hydraulic retention time. The removal was mainly due to the biological oxidation of manganese since it was completely repressed when a bacteriostatic agent (sodium azide) was added.

Geology of Caphouse Colliery, Wakefield, Yorkshire, UK

The National Coal Mining Museum in West Yorkshire affords a rare opportunity for the public to visit a former colliery (Caphouse) and experience at first hand the geology of a mine. The geology at the museum can be seen via the public tour, limited surface outcrop and an inclined ventilation drift, which provides the best geological exposure and information. The strata encountered at the site are c . 100 m thick and are of latest Langsettian (Pennsylvanian) age. The ventilation drift intersects several coal seams (Flockton Thick, Flockton Thin, Old Hards, Green Lane and New Hards) and their associated roof rocks and seatearths. In addition to exposures of bedrock, recent mineral precipitates of calcium carbonates, manganese carbonates and oxides, and iron oxyhydroxides can be observed along the drift, and there is a surface exposure of Flockton Thick Coal and overlying roof strata. The coals and interbedded strata were deposited in the Pennine Basin in a fluvio-lacustrine setting in an embayment distant from the open ocean with limited marine influence. A lacustrine origin for mudstone roof rocks of several of the seams is supported by the incidence of non-marine bivalves and fossilized fish remains whilst the upper part of the Flockton Thick Coal consists of subaqueously deposited cannel coal. The mudstones overlying the Flockton Thick containing abundant non-marine bivalves are of great lateral extent, indicating a basin-wide rise of base level following coal deposition that may be compared with a non-marine flooding surface.