• Clean Technology
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• v.22 no.1
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• pp.16-28
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• 2016

Textile industry is considered as one of the most polluting sectors in terms of effluent composition and volume of discharge. It is well known that the effluents from textile dying industry contain not only chromatic substances but also large amounts of organic compounds and insolubles. The azo dyes generate huge amount of pollutions among many types of pigments. In general, the electrochemical treatments, separating colors and organic materials by oxidation and reduction on electrode surfaces, are regarded as simpler and faster processes for removal of pollutants compared to other wastewater treatments. In this paper the electrochemical degradation characteristics of dye wastewater containing CI Direct Blue 15 were analyzed. The experiments were performed with various anode materials, such as RuO₂/Ti, PtO₂/Ti, IrO₂/Ti and graphite, with stainless steel for cathode. The optimal anode material was located by changing operating conditions like electrolyte concentration, current density, reaction temperature and initial pH. The degradation efficiency of dye wastewater increased in proportion to the electrolyte concentration and the current density for all anode materials, while the temperature effect was dependent on the kind. The performance orders of anode materials were RuO₂/Ti > PtO₂/Ti > IrO₂/Ti > graphite in acid condition and RuO₂/Ti > IrO₂/Ti > PtO₂/Ti > graphite in neutral and basic conditions. As a result, RuO₂/Ti demonstrated the best performance as an anode material for the electrochemical treatment of dye wastewater.

• Journal of the Speleological Society of Korea
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• no.63
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• pp.1-8
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• 2004

The non-magnetic materials with non-conductive showing high structure dispersity were developed on the base of natural quartz and lava-scoria which was collected from Je-ju island in Korea, and treated by methane-chemical technology those were obtained novel properties of magnetization through the analyzing. Depending on the processing conditions and subsequent applications the materials produced by strong methane-chemical reaction (MCR) in alcohol solution showed concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, containing a dielectric material as a carrying nucleus, particularly the quartz on that surface one or more layers of different compounds were synthesized having thickness up to 10～50 nm and showing magnetic, electrical and other properties. It was confirmed in magnetizing process that powders of quartz and lava-scoria produced by MCR were better oil adsorbent as of oleophilic and floating matter on water surface although their specific gravities are comparably more than 1 in quartz or less than unity, as that of water, in lava-scoira. Therefore, it will be Possible and very useful to remove low density and light gravity oil spillage in difficult recovery from sea and inland water contamination spread on water surface, by marine accident and ship sinking accident occurring frequently in recent years, by way of magnetic adsorbent conveyer system in continuous, if it could be built up the mass Production system of water-floating magnetizable oleophilic adsorbent materials with use of iow cost and good Qualify lava-scoria spread on volcano district in Je-ju island. And, there will also be urgent advent of necessity with strong possibility to develop useful applications of various magnetic functional materials include oleophilic adsorbent for removal of sea oil-contaminants and maritime pollutants, and other kinds of various utilities in industrial applications and practical uses of novel functional materials in the fields of environments and health care applications with in deep expectation.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.1
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• pp.41-51
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• 2020

The purpose of this study was to investigate the possibility of eco-friendly/efficient recovery of valuable resources, such as Au from mine tailings, which are environmental pollutants in the Mongolian mine sector. For this purpose, this study selected 4 place of mine tailings of the Mongolian mines sector and carried out mineralogy evaluation of the valuable resources in the tailings. In this study, flotation was performed to separate and concentrate valuable resources in the tailings. Microwave nitric acid leaching was used to leach the valuable resources contained in the sample and to improve the Au grade. Chloride leaching attempted to leach Au from the leaching residues. XRD analysis of the tailings samples showed that most of the samples consisted of silicate minerals. As a result of confirming the content of the element through XRF analysis, the SiO₂ content was very high, the Fe₂O₃ content was 2.32-4.23%, and the content of PbO, CuO and ZnO components were all within 2%. As a result of flotation for the tailings samples, the recovery of Au was the highest in Bayanairag sample (95.38%). As a result of microwave nitric solution experiment on Au concentrate sample obtained by flotation, the content of Au in the microwave nitrate leaching residue increased by 12.15% from 192.72 g/ton to 216.14g/ton in Khamo sample, the highest increase was 57.58% in Bayanairag sample. TCLP tests on tailings generated after flotation showed dissolution characteristics within EPA. Chloride leaching test was performed to recover Au from solid residues. The leaching rate was 87.43-89.35% within 10 minutes. For Khamo sample, 100% Au was leached after 60 minutes of leaching time. Therefore, in order to process the tailings continuously generated in Mongolia, applying the same process as the present study is expected to effectively recover the valuable resources contained in the tailings.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.605-617
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• 2015

The ultimate goal of this research is to develop a botanical biofiltration system that combines a green interior, biofiltering, and automatic irrigation to purify indoor air pollutants according to indoor space and the size of biofilter. This study was performed to compare the stability of air flow characteristics and removal efficiency (RE) of fine dust within a wall-typed (vertical) botanical biofilter depending on humidifying cycle and to investigate RE of volatile organic compounds (VOCs) by the biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be suitable for indoor space utilization. As a result, relative humidity, air temperature, and soil moisture content (SMC) within the biofilter showed stable values regardless of three different humidifying cycles operated by the metering pump. In particular, SMCs were consistently maintained in the range of 27.1-29.7% during all humidifying cycles; moreover, a humidifying cycle of operating for 15 min and pausing for 45 min showed the best horizontal linear regression (y = 0.0008x + 29.09) on SMC ($29.0{\pm}0.2%$) during 120 hour. REs for number of fine dust (PM10) and ultra-fine dust (PM2.5) particles passed through the biofilter were in the range of 82.7-89.7% and 65.4-73.0%, respectively. RE for weight of PM10 passed through the biofilter was in the range of 58.1-78.9%, depending on humidifying cycle. REs of xylene, ethyl benzene, total VOCs (TVOCs), and toluene passed through the biofilter were in the range of 71.3-75.5%, while REs of benzene and formaldehyde (HCHO) passed through the biofilter were 39.7% and 44.9%, respectively. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was very effective for indoor air purification.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.283-293
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• 2008

The objectives of the study were firstly to provide fundamental data for establishment of total maximum daily load (TMDL) management in Ulsan City, and secondly to make practical application of stream health assessment with tolerance range by each species when physiochemical and fish investigations were carried out together. A total of 44 sites in Taehwa River, Hoiya River, Dong Stream, and Cheongryang Stream were selected to monitor water qualities seasonally and fish investigation was performed in August 2006. Among the parameters of water quality, biological oxygen demand (BOD) and dissolved oxygen (DO) related to respiration, total nitrogen (T-N) and total phosphorus (T-P) related to nutrient and eutrophication, and total suspended solids (TSS) and $NH_4$-N were compared with vertical box plot by 8 dominant species. According to the fish investigation, 12 families 33 species were found including endangered species (Pungitius kaibarae) and introduced species (Lepomis macrochirus, Micropterus salmoides), and appearance rate of Korean endemic species was greater in Taehwa River (29.2%) than others. As the results of tolerance range by species, Zacco koreanus, Rhynchocypris oxycephalus, Iksookimia longicorpa, and Squalidus gracilis majimae had limited low range by water quality parameters indicating preference of good water quality. Whereas, Carassius auratus and Pseudorasbora parva were found downstream and urban-streams which were exposed from frequent inflow of pollutants. It concludes that the results help distinguishing sensitive, intermediate, and tolerant species when we evaluate stream health assessment with fish, and further making practical application for conservation and restoration of aquatic ecosystem.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.134-141
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• 2000

For electrochemical treatment of industrial wastewater, the effects of voltage, distance between electrodes, initial pH and NaCl concentrations on removal of pollutants were investigated in a batch electrolysis system. Temperature and pH in electrochemical reactor increased with increase in supplied voltage, but no significant change in EC was found. Removal of COD, turbidity, T-N and T-P were also enhanced with increase in the voltage. On the conditions of short distances between electrodes and long electrochemical reaction times, it was found that COD and T-N were very effectively removed in the system. Regardless of the distances, more than 80% of turbidity and T-P were removed at the beginning of reaction. When initial pH of the wastewater was about 7, the highest efficiency of COD removal was found in the system. On the other hand, removal efficiency of turbidity was unlikely affected by initial pH of the wastewater. T-N removal was increased with increase in initial pH. T-P was successfully removed in the pH range of 5 to 9 with varying removal efficiency of 79 to 96% after 2 minutes of electrochemical reaction time. Addition of NaCl into the electrochemical reactor increased removal efficiency of electrochemical treatment. The highest removal efficiency of COD and T-P, turbidity and T-N was obtained at NaCl concentrations of 500mg/L, 1,000 mg/L and 500mg/L, respectively.

• Korean Journal of Environmental Agriculture
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• v.11 no.3
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• pp.185-193
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• 1992

To investigate differences in lead content in soils and paddy rices, affected by air pollutants from the Janghang Smelter, soil samples at the different directions, distances, and depths, surface(0-15cm depth) and subsurface(15-30cm depth) in 1982 and 1990, and rice plants at soil sampling sites in 1990 were separately collected at the Janghang Smelter area affected by combustible waste gas from the smelter chimney. Soil samples were extracted with $4M-HNO_3$ and plant samples were digested with mixture of $HNO_3$ and $HCIO_4$ for analyzing by atomic absorption spectrophotometry. The Pb contents in soils ranged from 10.3 to 644.8mg $kg^{-1}$. The average content in 1990 was higher than that in 1982. The Pb content in soils at sites nearer the center of the smelter was higher than that at sites farther from the center. The highest lead content was found at the east direction, and was low in order of east>north-north east>north east > north. The variation of Pb level in soils at east sites was more considerable than other directions. The Pb level in surface soils was higher than that in subsurface soils. The contaminated radius of Pb was until 3km all at east, north-north east and north east. A significant correlation was found between Pb content in surface soils of 1982 and that in surface soils of 1990, between Pb content in soils and contents of Cd and Zn in soils, and between Pb content in soils and soil properties as organic matter, available silicate, cation exchange capacity, exchangeable $Ca^{++}$, $Mg^{++}$ and $Na^+$. Pb content in brown rice was low in the panicle axis, and brown rice, and Pb content in stem was 3.26 times of that in brown rice. Pb content in brown rice ranged from 2.2 to 9.0 mg $kg^{-1}$.

• Journal of Environmental Impact Assessment
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• v.24 no.6
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• pp.561-577
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• 2015

The heavy metal accumulations of avian eggshells were studied in order to test a feral pigeon (Columba livia)'s eggshell as an indicator for the environmental monitoring of pollutants. The reviews on the eggs of the different 19 avian species showed that it is the eggshell rather than the egg content that can better reflect the heavy metals in the environment; in most cases the CVs (coefficients of variations) of the heavy metal concentrations in the eggshells were higher than those in the egg contents. This can indicate that the heavy metal accumulations are homeostatically controlled in the egg contents, but the accumulations in the eggshells are varied according to the environmental conditions. To test the reviews, the feral pigeon eggs from the two different sites, one representing urban and the other rural environment, were analyzed for lead (Pb) and cadmium (Cd). The result showed that the eggshells of the urban pigeons (Hangang) had the higher metal concentrations than those of the rural pigeons (Hampyeong). The same difference can also be found in the internal organs (liver, bone) and blood. However, the analyses of the egg contents between the two sites did not reveal the differences. In other words, the result suggests that the feral pigeons, like the other avian species, are able to control the heavy metals into the egg contents homeostatically. Therefore, it is more useful to use the feral pigeon eggshell rather than the egg content in case of monitoring heavy metals in different habitats.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.44-53
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• 2006

This study purposed to investigate air pollution in car shipping yards and, for this purpose, we selected an outdoor open-air yard and an indoor ramp into the ship and measured the concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10, PM2.5 and heavy metals in the air. The results of this study are as follows. No significant difference was observed in temperature and humidity between the outdoor and indoor workshop, and the average air flow was 0.52 m/s in the indoor workshop, which is higher than 0.19 m/s in the outdoor workshop(p<0.01). The average concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10 and PM2.5 according to workplace were 0.03 ppm(${\pm}0.01$), 0.03 ppm(${\pm}0.01$), 0.46 ppm(${\pm}0.22$), $39.44{\mu}g/m^3$(${\pm}2.45$) and $5.45{\mu}g/m^3$(${\pm}1.15$) respectively in the outdoor workshop, and 0.15 ppm(${\pm}0.05$), 0.22 ppm(${\pm}0.06$), 8.85 ppm(${\pm}3.35$), $236.39{\mu}g/m^3$(${\pm}58.21$) and $152.43{\mu}g/m^3$(${\pm}35.42$) respectively in the indoor workshop. Thus, the concentrations of gaseous substances in the indoor workshop were 4.9-19.2 times higher than those in the outdoor workshop, and the concentrations of fine dusts were 5.9-27.9 times higher(p<0.01). In addition, according to the result of investigating pollutant concentrations according to displacement and the number of car loaded when shipping gasoline cars into the ship, no significant relation between the number of cars loaded and pollutants was observed in shipping passenger cars, but the concentrations of nitrogen dioxide and carbon monoxide got somewhat higher with the increase of the number of cars loaded(p<0.05). In addition, the concentrations of nitrogen dioxide, carbon monoxide, PM10 and PM2.5 in the air were significantly higher when shipping recreational vehicles, the displacement of which is larger than passenger cars, than when shipping passenger cars(p<0.01). On the other hand, the average heavy metal concentrations of the air in indoor workshop were: lead $-0.05{\mu}g/m^3$(${\pm}0.10$); chromium $-0.90{\mu}g/m^3$(${\pm}0.18$); zinc $-0.38{\mu}g/m^3$(${\pm}0.24$); copper $-0.18{\mu}g/m^3$(${\pm}0.22$); and manganese and cadmium not detected. In addition, the complaining rates of 'asthma,' a major symptom of chronic respiratory diseases, were 18.5% and 22.5% respectively in indoor workers and outdoor workers. Thus the rate was somewhat higher in indoor workers but the difference was not statistically significant. The complaining rates of 'chronic cough' and 'chronic phlegm' were very low and little different between indoor and outdoor workers. The results of this study show that the reason for the higher air pollution in indoor than in outdoor workshop is incomplete combustion of fuel due to sudden start and over-speed when cars are driven inside the ship. In order to prevent high air pollution, efficient management measures should be taken including the observance of the optimal speed, the improvement of old ships and the installation of efficient ventilation system.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.31-44
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• 1986

For many years, $NO_2$ has been regarded as one of the elements among indoor air pollutants of urban homes, leading to increased public concerns on this gas. For the purpose of preparing the fundamental data for the evaluation and control of health effect relevant to $NO_2$ levels, authors measured the indoor (kitchen, living room, bed room) and outdoor $NO_2$ levels categorized by the type of house(apartment, detached dwelling) and cooking fuel(L.P.G., briquette) in the winter and summer, and surveyed the variables(kitchen ventilation, family size, parental smoking) may effect the indoor $NO_2$ levels. The level of $NO_2$ was measured by Palmes tube, and this survey was carried out at 110 homes in the Pusan area from October 1984 to September 1985. The obtained results were as follows: 1) The mean indoor and outdoor $NO_2$ level in winter and summer, respectively, was $0.029{\pm}0.012$ ppm and $0.022{\pm}0.012$ ppm in the kitchen, $0.022{\pm}0.009$ ppm and $0.018{\pm}0.010$ ppm in the living room, $0.017{\pm}0.008$ ppm and $0.016{\pm}0.010$ ppm in the bed room, and $0.021{\pm}0.007$ ppm and $0.016{\pm}0.007$ ppm outdoors. 2) In the category of the type of house and cooking fuel, the highest mean indoor and outdoor $NO_2$ level in the winter was in apartments using briquettes, and in the summer. the highest level was in apartments using L.P.G. 3) In the category of the type of house, the mean indoor and outdoor $NO_2$ level in the winter and summer was higher in the apartment group compared to detached dwelling. 4) In the category of the type of cooking fuel, the mean indoor and outdoor $NO_2$ level in the winter was higher in the briquette group, and in the summer, the L.P.G. group was higher. 5) In the category of the kitchen ventilation, family size, parental smoking and asthma attack history of children, there was an insignificant difference in the indoor $NO_2$ levels.