• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.11-16
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• 1970

In application of manganese and silica to Akiochi soil, growth of rice plant with potassium was remarkably increased, but the growth without potassium was stunted and the number of the tiller was relatively reduced in comparison with that receiving potassium. The minus potassium plant developed tiny brown spots on the leaves and color of the leaves was dark green. They had smaller leaves and shorter stem while heading advanced. Roots with potassium were long and thick, and new ones developed, while roots without K were very poor, the branch and hair roots very thin, and severe root rot was observed. With minus potassium treatment, the root rot of Jin Heung(commercial variety) was more severe than Nonglim 6(Akiochi resistant). Growth of plant without potassium was very poor, and potassium content of the plant was very low, while nitrogen, phosphorus, silica, iron and manganese contents were higher than potassium supplied plant. Application of $Mn+SiO_2$ to Akiochi soil lowered iron content of plant, and iron content of the plant were also reduced by application of potassium. From the results obtained it can be concluded that root damage of minus potassium plant grown in Akiochi soil supplied $Mn+SiO_2$ was caused by potassium deficiency. Potassium, and $Mn+SiO_2$ applications lowered iron content in the plant grown on Akiochi soil.

• Membrane Journal
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• v.26 no.2
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• pp.116-125
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• 2016

This study described a synthesis of MF having a arsenic removal characteristics and the fundamental research was performed about the simultaneous removal system of both As(III) and As(V) ions with the composite nanofiber membrane (PMF) based on PVdF and MF materials for the water-treatment application. From the TEM analysis, the shape and structure of MF materials was investigated. The mechanical strength, pore-size, contact angle and water-flux analysis for the PMF was performed to investigate the possibility of utilizing as a water treatment membrane. From these results, the PMF11 showed the highest value of mechanical strength ($232.7kgf/cm^2$) and the pore-diameter of composite membrane was reduced by introducing the MF materials. In particular, their pore diameter decreased with an increase of iron oxide composition ratio. The water flux value of PMF was improved about 10 to 60% compared with that of neat PVdF nanofiber membranes. From the arsenic removal characterization of prepared MF materials and PMF, it was shown the simultaneous removal characteristics of both As(III) and (V) ions, and the MF01, in particular, showed the highest adsorption-removal rate of 93% As(III) and 68% As(V), respectively. From these results, prepared MF materials and PMF have shown a great potential to be utilized for the fundamental study to improve the functionality of water treatment membrane.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.547-553
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• 2018

An integrated iron and steel mill uses a large amount of water and produces wastewater which contains various contaminants such as iron, manganese, etc. Especially, in some regions of Southeast Asia, the concentration of silica in iron and steel mill wastewater is higher than in other countries. Silica is known to be one of the main causes for fouling in the membrane processes for water reuse. In cases of high concentrations of silica in iron and steel mill wastewater, the ferrous silicate tends to be formed. This could lead to higher fouling tendency depositing on the membrane surface. Therefore we conducted a pilot test to investigate the effect of silica and iron on the fouling tendency of reverse osmosis (RO) membrane for treating two types of wastewater from an integrated iron and steel mill. In this case of treated wastewater from iron and steel mill, RO pilot plant was operated with the fluxes 15.9LMH and 18.8LMH for 112 days to investigate the fouling characteristics. The results found that the fluctuation of flux was much wider than the average flux and the minimum permeability was low at 78%. In the case of treated runoff from an integrated iron and steel mill, the average concentration of iron was lower than in wastewater. RO pilot test was conducted with the flux 18.8LMH for 46 days. The results found that runoff had a lower fouling tendency and pre-treatment using microfiltration (MF) could minimize the fouling problem of RO.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1186-1191
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• 2006

Removal efficiency of As(III) through oxidation and adsorption in column reactors was investigated at different ratios of manganese-coated sand(MCS) and iron-coated sand(ICS) : MCS-alone, ICS-alone and both of ICS and MCS. The breakthrough of arsenic immediately occurred from a column reactor with MCS-alone. However, most of the arsenic present in the effluent was identified as As(V) due to the oxidation of As(III) by MCS. While five-times delayed breakthrough of arsenic was observed from a column reactor with ICS-alone. At a complete breakthrough of arsenic, the removed As(III) was 36.1 mg with 1 kg ICS. To find an optimum ratio of ICS and MCS in the column packed with both ICS and MCS, the removal efficiency of As(III) was investigated at three different ratios of ICS/MCS with a fixed amount of ICS. The breakthrough time of arsenic was quite similar in the different ratios ICS/MCS. However, much slower breakthrough of arsenic was observed as the ratio of ICS/MCS decreased. As the ratio of ICS/MCS decreased the concentration of As(III) in the effluent decreased and then showed below 50 ppb at an equal amount of ICS and MCS, suggesting more efficient oxidation of As(III) by greater amount of MCS. When a complete breakthrough of arsenic occurred, the removed total arsenic with an equal amount of ICS and MCS was 68.5 mg with 1 kg of filter material.

• Corrosion Science and Technology
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• v.21 no.1
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• pp.53-61
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• 2022

Alloys of Fe-(5.3-29.8)%Mn-(1.1-1.9)%Al-(0.4-0.5)%C were oxidized at 550 ℃ to 650 ℃ for 20 h to understand effects of alloying elements on oxidation. Their oxidation resistance increased with increasing Mn level to a small extent. Their oxidation kinetics changed from parabolic to linear when Mn content was decreased and temperature was increasing. Oxide scales primarily consisted of Fe₂O₃, Mn₂O₃, and MnFe₂O₄ without any protective Al-bearing oxides. During oxidation, Fe, Mn, and a lesser amount of Al diffused outward, while oxygen diffused inward to form internal oxides. Both oxide scales and internal oxides consisted of Fe, Mn, and a small amount of Al. The oxidation of Mn and carbon transformed γ-matrix to α-matrix in the subscale. The oxidation led to the formation of relatively thick oxide scales due to inherently inferior oxidation resistance of alloys and the formation of voids and cracks due to evaporation of manganese, decarburization, and outward diffusion of cations across oxides.

• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.83-89
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• 1996

In order to evaluate the air quality, dry and wet deposition samples were collected by deposit containers during four months in Inchon area. The samples were analyzed for its solid composition and trace elements(Ca, Cd, Cu, Fe, Mn, Ni, Pb, Zn). The main results are summarized below 1. The amounts of dry and wet deposition in Inchon area were 1.06~3.14 ton/$km^2$/month, and affected by the rainfall and suspended yellow sand. 2. Through the analysis of solid balance, we found that 50% of total solids(TS) was fixed suspend ed solids(FSS), 25% was fixed dissolved solids(FDS), and each of volatile suspended solids(VSS) and volatile dissolved solids(VDS) accounted for 12.5%. 3. The amounts collected by sampler for trace elements were 938 ~ 2,765 $\mu g$ calcium/10days sampler, 0.2 ~ 90.4 $\mu g$ cadmium/10days/sampler, 26 ~ 298 $\mu g$ copper/10days/sampler, 928 ~ 3,939 $\mu g$ iron/10days/sampler, 50 ~ 202 $\mu g$ manganese/10days/sampler, 4 ~ 37 $\mu g$ nickel/10days/sampler, 52 ~ 406 $\mu g$ lead/10days/sampler, and 97 ~ 1,317 $\mu g$ zinc/10days/sampler, respectively. 4. Using the manganese analysis, it was found that 76.1% of TS was from soil.

• Journal of Korea Foundry Society
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• v.29 no.3
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• pp.128-137
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• 2009

The effects of alloying elements on the mechanical properties of 3.6wt%C-2.6wt%C ductile cast iron poured into shell stack molds were investigated. The strength and hardness of the specimens obtained from the center layer in the 5-story stack mold were the lowest and those for other specimens were increased with increased distance from the center. The strength and hardness of the specimens obtained from the center layer were decreased with increased number of layers of the shell stack mold. The strength and hardness of the smaller specimens with the diameter of 9.5 mm were higher than those of 17.5 mm. On the other hand, the elongation of the former was lower than that of the latter. The strength and hardness were increased and the elongation was decreased roughly with the increased amounts of manganese and copper added, respectively. The strength and hardness were increased with the incrcased amount of molybdenum added to 0.40wt% and rather decreased with that to 0.80wt%. Those were greatly increased with the increased amount of tin added and the elongation was roughly decreased with it.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.773-795
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• 2008

The major import minerals of South Korea are copper ore, lead-zinc ore, iron ore, manganese ore and molybdenum ore. Oversea resources development of South Korea have 92 projects in 14 nations of Asia, 29 projects in 10 nations of America and Europe, and 14 projects in 9 nations of Middle Asia and Africa. But, most projects of them are found in Australia, China, Mongolia and Indonesia. The most projects of the Australia, China and Indonesia are interested in coal and a little projects of them have manganese, iron, lead-zinc, nickel, copper, gold, molybdenum, rare earth elements and uranium. The most projects of the Mongolia are interested in gold and rare earth elements. Representative ore deposits models of metal resources are Orogenic lode deposits, Volcanogenic massive sulphide deposits, Porphyry deposits, Sedimentary exhalative deposits, Mississippi valley type deposits, Iron oxide copper-gold deposits and Magmatic nickel-copper-platinum group element deposits based on global distribution, reverses and grades of their deposits models. If oversea mineral resources will be examined the mineral reserves, mineral mine production and ore deposits models of nations and then survey and investigate of mineral resources, we may be maintained ore body of high grade at survey area and decrease the investment risk.

• Journal of Environmental Health Sciences
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• v.36 no.6
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• pp.480-495
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• 2010

This study evaluated the distribution of the concentrations of nano-particles and heavy metals (08-Pb, Cr, Zn, As, Fe, 09-Pb, Cr, Zn, Cu, Ni, Mn) in Seoul, Chungnam A and Gwangyang from August to December, in 2008 5 times each in the Seoul area, 5 times in and Chungnam A area and from August to November, in 2009 14 times in the Chungnam A area, 8 times in the Gwangyang area. The examined results showed high concentration level from $PM_1$ through $PM_{0.1}$ in all three areas. These results were obtained the concentration of particles by diameter and statistically significant in Stage5 (1.0-0.56 ${\mu}m$) from the result of conducting Kruskal-Wallis H test (p < 0.05). In the case of the heavy metal concentration included in 0.10-0.056 ${\mu}m$, 0.056 ${\mu}m$, the lead concentration of Chungnam Asan area was 6.49 ng/$m^3$ and 9.93 ng/$m^3$, which was higher than 3.05 ng/$m^3$ and 4.22 ng/$m^3$ of Seoul, respectively. The concentration of iron in Seoul was 9.28 ng/$m^3$ and 13.24 ng/$m^3$, that appeared higher than 2.38 ng/$m^3$ and 3.23 ng/$m^3$ of Chungnam A area, respectively. The concentration level was similar to other metals except lead and iron in Chungnam A area and Seoul. From the concentration of heavy metal included in 0.10-0.056 ${\mu}m$, 0.056 ${\mu}m$, the lead concentration of Chungnam A area was 0.31 ng/$m^3$ and 0.12 ng/$m^3$ while Gwangyang was 0.28 ng/$m^3$, 0.06 ng/$m^3$. Thus Chungnam A area showed higher lead concentration than Gwangyang. The manganese concentration of Chungnam A area was 0.12 ng/$m^3$ and 0.03 ng/$m^3$ while Gwangyang was 0.21 ng/$m^3$ and 0.08 ng/$m^3$. Therefore, the concentration of Gwangyang appeared higher than that of Chunnam A area. These two metals showed statistically significant in 0.056 ${\mu}m$ (p < 0.05, p < 0.01). Among the concentration of heavy metal in all regions, the result demonstrated that the order of higher concentration is arsenic > iron > zinc > chrome > lead > nickel > copper > manganese.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.29-45
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• 2007

Biogeochemical characteristics involving redox processes in groundwater from a riverine alluvial aquifer was investigated using multi-level monitoring wells (up to 30m in depth). Anaerobic conditions were predominant and high Fe ($14{\sim}37mg/L$) and Mn ($1{\sim}4mg/L$) concentrations were observed at 10 to 20 m in depth. Below 20 m depth, dissolved sulfide was detected. Presumably, these high Fe and Mn concentrations were derived from the reduction of Fe- and Mn-oxides because dissolved oxygen and nitrate were nearly absent and Fe and Mn contents were considerable in the sediments. The depth range of high Mn concentration is wider than that of high Fe concentration. Dissolved organics may be derived from the upper layers. Sulfate reduction is more active than Fe and Mn reduction below 20 m in depth. Disparity of calculated redox potential from the various redox couples indicates that redox states are in disequilibrium condition in groundwater. Carbonate minerals such as siderite and rhodochrosite may control the dissolved concentrations of Fe(II) and Mn(II), and iron sulfide minerals control for Fe(II) where sulfide is detected because these minerals are near saturation from the calculation of solubility equilibria.