• 한국전기화학회:학술대회논문집
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• 2001.06a
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• pp.179-184
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• 2001

The diffusion layer within MEA(membrane electrode assembly) has been evaluated important factor for improvement of cell performance in DMFC. The diffusion layer in MEA structure leads to the reduction of catalyst loss in active catalysts layer as well as prevention of water-flooding in cathode. Cell performance is directly affected by interior properties of diffusion layer materials. Acetylene Black and $RuO_2$ with large pore size and low porosity compared to Vulcan XC-72R gave better performance caused by vigorous methanol diffusion and water removal. And $RuO_2$ as diffusion layer materials showed different behavior in anode and cathode compartment, that is, diffusion layers in anode and cathode side make methanol diffusion and water removal facilitate, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.449-455
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• 2016

Fog causes economic losses in transportation. It also results in health problems when it is combined with air pollutants. Considerable research efforts have focused on developing fog removal systems. However, most systems operate themselves after monitoring the fog. Additionally, continuous energy supply and maintenance are required to retain the fog-removal efficiency of the system. This study included the demonstration of a moss filter (a polyolefin mesh interlaced with moss) as a fog-removal method overcoming the limitations of the fog removal system. Three types of mosses with different surface structures were investigated to elucidate the relation between the moisture absorption rate and the structures. Among the different moss types, Hypopterygium japinicum showed the highest efficiency based on the smallest pore diameter and the largest total pore area. The visibilities with the moss filter and the polyolefin mesh were compared to perform the fog removal tests. The moss filter could provide a cost-effective and eco-friendly fog removal system with sustainability.

• Carbon letters
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• v.5 no.4
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• pp.191-196
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• 2004

The electrochemical removal (ECR) of water pollutants by activated carbon fiber (ACF) electrodes from wastewater was investigated over wide range of electrochemical reaction time. The ECR capacities of ACF electrodes were associated with their internal porosity and were related to physical properties and to reaction time. And, surface morphologies and elemental analysis for the ACFs after electrochemical reaction are investigated by SEM and EDX to explain the changes in adsorption properties. The FT-IR spectra of ACFs for the investigation of functional groups show that the electrochemical treatment is consequently associated with the homogeneous removal of pollutants with the increasing surface reactivity of the activated carbon fiber surfaces. The ACFs were electrochemically reacted to waste water to investigate the removal efficiency for the COD, T-N and T-P. From these removal results of pollutants using ACFs substrate, satisfactory removal performance was obtained. The outstanding removal effects of the ACFs substrate were determined by the properties of the material for adsorption and trapping of organics, and catalytic effects.

• Asian Journal of Turfgrass Science
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• v.9 no.4
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• pp.331-342
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• 1995

An investigation was performed to reveal the removal rates of organic constituents of the litters in a Phragmithea longivalvis grassland in a Delta of the Nakdong River, The removal rates of the inorganic and organic materials are determined by the mathematical models. The removal rates and time required to decay up to a percentage of each organic constituent were calculated using these new models. The removal rates of cold water soluble fractions, other carbohydrates, hot water soluble fractions, cellulose, crude fat, lignin and crude protein were 2.67, 1.39, 1.25, 1.02, 0.92, 0.49 and 0.47, respectively, The periods required to reach half time to the steady state of the removal and accumulation for cold water soluble fractions, other carbohydrates, hot water soluble fractions, cellulose, crude fat, lignin and crude protein of the litter were 0.26, 0.50, 0.55, 0.68, 0.75, 1.41 and 1.48 years, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.143-146
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• 2004

Natural zeolites have exhibited high sorption capacity for inorganic cations including heavy metals and ammonium. Moreover, they were proven to be effective for environmental applications such as permeable barriers for controlling the spread of cation-contaminated groundwater. However zeolites have little or no affinity for anionic species like chromium, as they possess a net negative structural charge. To achieve the simultaneous sorption for anionic contaminants, surfactant-modified zeolite (SMZ) has been employed as the possible sorbents. Current study focuses on simultaneous removal of heavy metals having different ionic form in aqueous solution, cadmium (C $d^{2+}$) and chromium (Cr $O_{4}$$^{2-}$), using newly developed materials, ZanF. ZanF, a potential alternative to SMZ, was derived from zeolite modified by Fe(II) chloride followed by reduction with sodium borohydride. Batch experiments were performed to estimate the removal efficiency of ZanF at different conditions. Under different pH ranging from 2 to 6, removal efficiency was investigated. And C $d^{2+}$ removal efficiency was estimated by varying background concentration of Cr $O_{4}$$^{2-}$, and vice versa. With the test results, ZanF was expected to be a possible reactive materials alternative to SMZ in permeable reactive barriers (PRBs) for treating the contaminated groundwater with cationic and anionic heavy metals.als.

• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.6-10
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• 2018

Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using ${\varphi}50mm$ filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with ${\varphi}400mm$ bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.43-51
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• 2024

The addition of oxygen scavengers to food products helps to reduce oxygen exposure, thereby mitigating deterioration, including changes in taste, odor, and color, as well as inhibiting microbial growth. Despite the advantages of the existing non-metallic oxygen removal materials in terms of safety for the human body and suitability for use in microwave ovens, their utilization has been limited due to their slow reaction initiation speed. Therefore, in the current study, sodium metabisulfite was impregnated into various porous media, including halloysite nanoclay, activated carbon, montmorillonite, and silica gel. The oxygen scavenger, produced by impregnating silica gel with sodium metabisulfite, demonstrated a 425% improvement in the initial oxygen removal rate compared to pure sodium metabisulfite. Additionally, sachets containing an oxygen-removing composition with an enhanced oxygen removal rate effectively decreased the oxygen concentration to less than 0.5% on the third day of storage in apple packaging, without elevating carbon dioxide levels. Moreover, it proved effective in preventing the browning of the apple surface. Therefore, the SM/SG oxygen-removal composition can be effectively applied to active food packaging by controlling the oxygen concentration within the packaging.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.561-568
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• 2019

Objectives: The most commonly detected heavy metals in rocks and soils, including Pb, Cd, Cu, Fe, Mn and As, are representative pollutants discharged from abandoned mines and have been listed as potential sources of contamination in drinking water. This study focused on increasing the removal efficiency of heavy metals from drinking water resources by surface modification of natural adsorbents to reduce potential health risks. Methods: Iron oxide coating and graft polymerization with zeolites and talc was conducted for bipolar surface modification to increase the combining capacity of heavy metals for their removal from water. The removal efficiency of heavy metals was measured before and after the surface modification. Results: The removal efficiency of Pb, Cu, and Cd by surface modified zeolite showed 100, 92, and 61.5%, respectively, increases compared to 64, 64, and 38% for non-modified zeolite. This implies that bipolar surface modified natural adsorbents have a good potential use in heavy metal removal. The more interesting finding is the removal increase for As, which has both cation and anion characteristics showing 27% removal efficiency where as non-modified zeolite showed only 2% removal. Conclusions: Zeolite is one of the most widely used adsorptive materials in water treatment processes and bipolar surface modification of zeolite increases its applicability in the removal of heavy metals, especially As.

• Advances in environmental research
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• v.12 no.2
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• pp.77-93
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• 2023

The water can be contaminated by natural sources or by industrial effluents. One such contaminant is fluoride. Fluoride contamination in the water environment due to natural and artificial activities has been recognized as one of the major problems worldwide. Among the commonly used treatment technologies applied for fluoride removal, the adsorption technique has been explored widely and offers a highly efficient simple and low-cost process for fluoride removal from water. This review paper the recent developments in fluoride removal from surface water by adsorption methods. Studies on fluoride removal from aqueous solutions using various carbon materials are reviewed. Various adsorbents with high fluoride removal capacity have been developed, however, there is still an urgent need to transfer the removal process to an industrial scale. Regeneration studies need to be performed to more extent to recover the adsorbent in field conditions, enhancing the economic feasibility of the process. Based on the review, technical strategies of the adsorption method including the Nano-surface effect, structural memory effect, anti-competitive adsorption and ionic sieve effect can be proposed. The design of adsorbents through these strategies can greatly improve the removal efficiency of fluoride in water and guide the development of new efficient methods for fluoride removal in the future. This paper describes brief discussions on various low-cost adsorbents used for the effective removal of fluoride from water.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.126-128
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• 1996