• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.558-562
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• 2006

Filtration experiments were conducted to determine the characteristics of manganese removal in filtration using 4 different filter media including sand and manganese sand(MS). Filtration velocity was 123 m/d and the flow rate was $3.9m^3/d$ per column. Duration of these experiments was about one year, and manganese dioxide accumulation, turbidity removal, manganese removal, and organic material removal were examined depending on filter media. When filter influent(residual chlorine 1.0 mg/L) with an average manganese concentration of 0.208 mg/L was fed through a filter column, the sand+MS and MS columns removed 98.9% and 99.2% of manganese respectively on an annual basis. When there is need to replace the sand filters with a MS filter to remove manganese, it was shown that the replacement of a partial sand filter with MS had adequate manganese removal.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2683-2688
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• 2011

Silica-manganese oxides with a core-shell structure were synthesized via precipitation of manganese oxides on the $SiO_2$ core while varying the concentration of a precipitation agent. Elemental analysis, crystalline property investigation, and morphology observations using low- and high-resolution electron microscopes were applied to the synthesized silica-manganese oxides with the core-shell structure. As the concentration of the precipitating agent increased, the manganese oxide shells around the $SiO_2$ core sequentially appeared as $Mn_3O_4$ particles, $Mn_2O_3+Mn_3O_4$ thin layers, and ${\alpha}-MnO_2$ urchin-like phases. The prepared samples were assembled as electrodes in a supercapacitor with 0.1 M $Na_2SO_4$ electrolyte, and their electrochemical properties were examined using cyclic voltammetry and charge-discharge cycling. The maximum specific capacitance obtained was 197 F $g^{-1}$ for the $SiO_2-MnO_2$ electrode due to the higher electronic conductivity of the $MnO_2$ shell compared to those of the $Mn_2O_3$ and $Mn_3O_4$ phases.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.564-570
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• 2013

Domestic treatment facilities for acid mine drainage (AMD) mostly used a passive treatment process. But some passive treatment facility discharged high manganese concentrations because it is required high pH (>9) for abiotic oxidation of Mn(II) to Mn(IV). This study was focused on the feasibility of biological manganese treatment using the manganese-oxidizing bacteria (Pseudomonas sp. MN5) from AMD and economical application method of it. To investigate the various conditions of water quality the most part of the experiments were based on batch test. And result of it showed that maximum manganese oxidation rate were $10.4mg/L{\cdot}h$ at the pH7. We also performed small column tests in which MOB were attached to the functional polyurethane (FPU) media containing alkaline chemicals. Manganese concentration decreased 42 mg/L to below 6 mg/L. But anaerobic condition formed by excessive bacterial respiration in column resulted in increasing effluent manganese concentration.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.4
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• pp.208-213
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• 2017

In this study, four inorganic pollutants (cadmium, chromium, manganese, lead), that could cause contamination events in drinking water distribution system, were selected and batch tests were carried out to determine the "minimum response concentration (MRC)", a part of Korean Contamination Warning system establishment. As the results, the minimum response concentration of cadmium was found to be 0.05 to 0.08 mg/L (0.005 mg/L : water quality standard) and that of chrome was 0.03 mg/L (0.05 mg/L). And the minimum reaction concentration was 0.005 mg/L for manganese (0.05 mg / L for water quality) and 0.02~0.08 mg/L for lead (0.01 mg/L).

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.357-366
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• 2004

Chronic exposure to high levels of manganese leads a pronounce and debilitating disorder known as manganism. Research on the toxic manifestation of manganese have focused primarily on its neurological effects because exposure to high levels of the metal produces a distinct and irreversible extrapyramidal dysfunction resembling the dystonic movements associated with Parkinson's physiological and biochemical systems in the body. The purpose of this study was to evaluate the effect of manganeses on primary rat calvarial cell growth and toxicity. The experimental groups were in concentration of 0, 10, 30, 60, 100, 300 ${\mu}M$. Cell activity was assessed at day 1 and day 3 using a fluorescent molecular probe. Cell proliferation was evaluated at day 1 and day 3 by MTT assay. The amount of total protein synthesis was measured at day 3 and day 7. The results were as follows: The proliferation of primary rat calvarial cells were inhibited by $MnCl_2$ in the concentration exceeding $100{\mu}M$. The primary rat calvarial cells treated with $MnCl_2$ showed similar protein synthesis to the control group except in 100 ${\mu}M$. These result suggest that manganese suppress the viability and protein synthesis of primary rat calvarial cells in concentration exceeding $100{\mu}M$.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.752-763
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• 1997

To evaluate the effect of manganese on the respiratory system, we investigated the respiratory symptoms of 63 male workers exposed to, fume containing manganese (Mn), iron (Fe) and silica (Si), and compared them with those of 66 male workers not exposed to the fume in a manganese alloy smelting factory. The prevalence ratios of the seven respiratory symptoms were not different between two groups. The presence of any respiratory symptom was not related with the age, duration of employment, smoking status of workers, and exposure to fume. In furnace workers, it was not related with the airborne Mn, Fe, and Si concentration in the total or respirable fume. Airborne Mn concentrations of all 4 furnaces in the respirable fume were below $1mg/m^3$. There were two suspicious cases of pneumoconiosis among furnace workers and one definite case(1/2) among casting workers who were not exposed to fume. The above results suggest that the exposure to the low airborne Mn concentration is not related with respiratory symptoms and pneumoconiosis. However, it is necessary to study the respiratory effects of Mn using the symptom questionnaire with consideration of the severity and persistence, of symptoms and the time interval from exposure.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.614-622
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• 2006

A Study on the characteristics of $Ta/Ta_2O_5/MnO_2$ capacitor applied $MnO_2$ by means of pyrolysis of manganese nitrate solution was carried out. Single phase of $MnO_2$ was obtained in the pyrolysis temperature range of 230 to $250^{\circ}C$ by TG/DSC analysis on manganese nitrate solution. Temperature of pyrolysis, concentration of manganese nitrate solution and the number of pyrolysis were selected for the basic parameters of embodying $MnO_2$ solid electrolyte and then the effects of these parameters on the characteristics of capacitor were estimated. The characteristics of capacitor pyrolyzed radiationally was superior to that of capacitor pyrolyzed convectionally on the basis of these optimized parameter conditions. It was verified that radiational pyrolysis formed smaller spherical $MnO_2$ particles than those of convectional one relatively and these facts resulted in forming uniform and dense solid electrolyte layer into the microporous sintered body of capacitor.

• Resources Recycling
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• v.17 no.1
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• pp.59-65
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• 2008

The adsorption features of nickel ion in wastewater on manganese dioxide from spent batteries were investigated for its usage as an adsorbent. The aquatic behavior of nickel ion was characterized by MINTEQ program and the considered influential variables on the adsorption of nickel ion were its initial concentration, reaction temperature, the amount of adsorbent, and pH. The adsorption ratio of nickel ion decreased with increasing its initial concentration and thermodynamic estimation has been carried out based on the adsorption characteristics of nickel ion depending on temperature. In addition, the adsorption of nickel ion was shown to be promoted according to the amount of manganese dioxide and a lot of nickel ions were adsorbed as the solution pH was raised.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.498-505
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• 2008

The selective catalytic oxidation of ammonia was carried out in the presence of natural manganese ore (NMO) and manganese as catalysts using a homemade 1/4" reactor at $10,000hr^{-1}$ of space velocity. The inlet ammonia concentration was maintained at 2,000 ppm, with an air balance. The manganese catalyst resulted in a substantial ammonia conversion, with adsorption activation energies of oxygen and ammonia of 10.5 and 22.7 kcal/mol, respectively. Both $T_{50}$ and $T_{90}$, defined as the temperatures where 50% and 90% of ammonia, respectively, are converted, decreased significantly when alumina-supported manganese catalyst was applied. Increasing the manganese weight percent by 15 wt% increased the lower temperature activity, but 20 wt% of manganese had an adverse effect on the reaction results. An important finding of the study was that the manganese catalyst benefits from a strong sulfur tolerance in the conversion of ammonia to nitrogen.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.160-163
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• 2001

In order to develop a nodule conveying system through a flexible pipe out of the deep-seabed manganese nodule miner, an experimental study of the solid-water slurry flow in vertical pipe is performed as the first stage of total experiments. Hydraulic characteristics of the pipe slurry flow such as slip velocity, transport concentration and pressure gradient are investigated for the size of particle, load ratio, and flow rate of water. The higher the load ratio is, the larger the transport concentration and pressure gradient become. The bigger the size of particles is, the larger the pressure gradient becomes. The effectiveness of the flow rate to hydraulic performance is also investigated. This results are to be used for designing crusher and pump, and operating the conveying device.