• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.307-311
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• 2012

This study was conducted to evaluate the dynamics of soil respiration (total soil and heterotrophic respiration) following fertilizer application in red pine forests. Fertilizer (N:P:K = 113:150:37 kg/ha), which reflects current practices in Korean forest, was applied in April 2011, and total soil and heterotrophic respiration rates were monitored from April 2011 to March 2012. Monthly variation of total soil and heterotrophic respiration rates were similar between the fertilizer and control treatments, as soil temperature was the dominant factor controlling the both rates. Total soil respiration rates during the study period were not significantly different between the fertilizer (0.504 g $CO_2\;m^{-2}\;h^{-1}$) and control (0.501 g $CO_2\;m^{-2}\;h^{-1}$) treatments. However, the proportion of heterotrophic respiration was higher in the fertilizer (78% of total soil respiration rates) than in the control (62% of total soil respiration rates) treatments. These results suggest that current fertilizer practices in Korea forest soil do not substantially affect total soil respiration rates.

• Journal of Environmental Impact Assessment
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• v.16 no.1
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• pp.27-33
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• 2007

Hexavalent chromium-contaminated soils are encounted at many unregulated discharge and improper handling of wastes from electroplating, leather tanning, steelmaking, corrosion control, and wood preservation industries. Contamination of hexavalent chromium in the soil is a major concern because of its toxicity and threat to human life and environment. Current technologies for hexavalent chromium-contaminated soil remediation are usually costly and/or cannot permanently prohibit the toxic element from entering into the biosphere. Thus, as an alternative technique, immobilization is seen as a cost-effective and promising remediation technology that may reduce the leachable potential of hexavalent chromium. The purpose of this paper is to develope an immobilization technique for the formation of the geochemically stabilized hexavalent chromium-contaminated soil from the reactions of labile soil hexavalent chromium forms with the added soluble phosphate and chromium reducing agent. From the liquid phase experiment, reaction order of chromium reducing agent, soluble phosphate, alkali solution shows the best removal efficiency of 95%. In addition, actual soil phase experiment demonstrates up to 97.9% removal efficiency with 1:1 molar ratio of chromium reducing agent and soluble phosphate. These results provide evidence for the potential use of soluble phosphate and chromium reducing agent for the hexavalent chromium-contaminated soil remediation.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.91-96
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• 2001

Restoration of contaminated soils to an environmentally acceptable condition is important. One of the newer techniques in soil remediation is a method based on electrokinetic phenomena in soils. The technology uses electricity to affect chemical concentrations and water flow through the pores of soils. An important advantage of electrokinetic soil remediation over other in-situ processes such as soil flushing is the capability of control over the movement of the contaminants. Because the migration of the contaminants is confined by the electric field, there is little dispersion outside the treatment zone. Furthermore, the process is effective for soils with low and variable permeability. In the present study, the distributions of cadmium in the electrokinetic processing of kaolinite under the condition of constant applied voltage are investigated. Cadmium accumulates near the cathode without reducing the diffusion of hydroxide ion into the soil. In keeping the catholyte pH at neutrality, cadmium migrates toward the cathode without any accumulation of cadmium near the cathode and is successfully removed at the cathode reservoir. It was also found that the progress of electrokinetic processing of cadmium could be gasped to a certain extent by monitoring the local voltage and the current density.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.502-522
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• 2022

Clay minerals are natural materials that show widespread applications in various branches of science, including environmental sciences, in particular the remediation of water contaminated with various water pollutants. Modified clays and minerals have attracted the attention of researchers in the recent past since the modified materials are seemingly more useful and efficient for removing emerging water contaminants. Therefore, modified engineered materials having multi-functionalities have received greater interest from researchers. The advanced clay-based materials are highly effective in the remediation of water contaminated with organic and inorganic contaminants, and these materials show enhanced selectivity towards the specific pollutants. The review inherently discusses various methods employed in the modification of clays and addresses the challenges in synthesizing the advanced engineered materials precursor to natural clay minerals. The changes in physical and chemical properties, as investigated by various characterization techniques before and after the modifications, are broadly explained. Further, the implications of these materials for the decontamination of waterbodies as contaminated with potential water pollutants are extensively discussed. Additionally, the insights involved in the removal of organic and inorganic pollutants are discussed in the review. Furthermore, the future perspectives and specific challenges in the scaling up of the treatment methods in technology development are included in this communication.

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.1-6
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• 2022

The Magnetic Force Control MFC technology is very useful because of its physical treatment process. Especially the Magnetic Separation MS technology is expected to contribute to SDGs 2030, Circular Economy and Carbon neutral 2050 realization. This paper describes the review of the IFMFC activity from 2010.The IFMFC is organized by three local committees of researchers in Japan, China and Korea. The IFMFC aims to exchange the information of the development results using the MFC technology and to educate the young researchers. The forum has been held in every year around three countries. In 2020 and 2021, the forum was organized by Zoom online due to the COVID-19. The 134 presentations were made up to 2020.The breakdown of these presentations are categorized to the environment remediation52%, material resource37% and fundamental research/technology11%. The Super Conducting Magnet SCM development promotes the MFC technologies. There are some impressive backgrounds as to the brilliant SM technology applications for many different magnetism ; SCM development, High Gradient Magnetic Separation HGMS, magnetic seeding method and magneto-Archimedes effect. This paper reviews the IFMFC activity according to those presented presentations.

• Journal of the Mineralogical Society of Korea
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• v.28 no.4
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• pp.309-323
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• 2015

This study was initiated to propose the method for human risk assessment suitable to metal mine area. Using a variety of exposure parameters extracted from the investigation of abandoned metal mines, the proposed method was applied to assess the risk of As and heavy metal contamination for inhabitants (male and female adults and child) within an abandoned mine area. Based on the results of risk assessment, in addition, target remediation concentrations of each media (soil, groundwater, and surface water) were estimated. The results indicate that total carcinogenic risk (TCR) and hazard index (HI) representing carcinogenic and non-carcinogenic risks, respectively, were calculated to exceed the tolerable levels (1.00E-6 and 1) with regard to two exposure pathways (groundwater and crop intakes) and As. Thus, the human risk of study area was evaluated to be significant. Based on the target risk (TR) for carcinogens, the remediation concentrations of soil were computed to be 6.83~6.85 mg/kg and 18.41~18.46 mg/kg for As and Pb, respectively. In terms of target hazard index (THI) for non-carcinogens, the remediation concentrations of soil were calculated to be 17.38 mg/kg for Cu and 9.13 mg/kg for As.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.403-409
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• 2005

Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by BTEX and MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc. In oil-contaminated environments, anaerobic biodegradation of BTEX and MTBE depended on the concentration and distribution of terminal electron acceptor. In this study, effect of electron acceptor on the anaerobic biodegradation for BTEX and MTBE-contaminated soil was investigated. This study showed the anaerobic biodegradation of BTEX and MTBE in two different soils by using nitrate reduction, ferric iron reduction and sulfate reduction. The soil samples from the two fields were enriched for 65 days by providing BTEX and MTBE as a sole carbon source and nitrate, sulfate or iron as a terminal electron acceptor. This study clearly shows that degradation rate of BTEX and MTBE with electron acceptors is higher than that without electron acceptors. Degradation rate of Ethylbenzene and Xylene is higher than that of Benxene, Toluene, and MTBE. In case of Benzene, Ethylbenzene, and MTBE, nitrate has more activation. In case of Toluene and Xylene, sulfate has more activation.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.23-33
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• 2001

Soil and groundwater contamination is an emerging national issue in recognition of the potential adverse impact to human health and ecosystem. In a recent registration, property owner's liability was addressed on the damages to neighbor's soil and groundwater caused by contaminant-plume migration. Soil and groundwater remediation is a technical and engineering project. But, the scientific and technical solutions for the project have been greatly influenced by social and political movement in the country. Governmental sectors, including local and central, should actively engage on this important issue through long-term planning and public investments. Government made regulations to prevent soil and groundwater contamination, not to punish private sector that has no technical and financial capability for solving such problems.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.9-13
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• 2015

Field experiment were carried out to investigate the formation of ground water flow and remediation of muddy tidal flat by installation of porous pile at the tidal flat of brackish river located in Hiroshima City, Japan. After the installation of porous pile, the concentrations of Dissolved Oxygen (DO) in the interstitial water in the porous pile increased with maximum concentration of 4 mg/L due to a formation of groundwater flow. It was observed that a increase in Oxidation Reduction Potential (ORP) and a decrease in Ignition Loss (IL) in the porous pile site and these must be caused by the increase of dissolved oxygen in the interstitial water. From these results obtained above, it is concluded that the porous pile is an effective technology for remediation of muddy tidal flats.