• Environmental Engineering Research
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• v.22 no.2
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• pp.141-148
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• 2017

Globalization, industrialization, mining, and uncontrolled population growth have fostered a shortage of potable water. Therefore, it has become imperative to understand an effective and reasonable water purification technique. A renewed interest in electrocoagulation (EC) has been spurred by the search for reliable, cost-effective, water-treatment processes. This paper has elucidated a technical approach for getting rid of heavy metals and total suspended solids (TSS) from synthetic water using an aluminum electrode. The effect of operational parameters, such as current density, inter-electrode distance, operating time, and pH, were studied and evaluated for maximum efficiency. This study corroborates the correlation between current density and removal efficiency. Neutral pH and a low electrode gap have been found to aid the efficacy of the EC setup. The outcome indicates that a maximum TSS removal efficiency of 76.6% occurred at a current density of $5.3mA/cm^2$ during a contact time of 30 min. In the case of heavy metals remediation, 40 min of process time exhibited extremely reduced rates of 99%, 59.2%, and 82.1%, for Cu, Cr, and Zn, respectively. Moreover, kinetic study has also demonstrated that pollutants removal follows first-and second-order model with current density and EC time being dependent.

• Membrane and Water Treatment
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• v.6 no.6
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• pp.439-449
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• 2015

Carbolic Acid which is called phenol is one of the important starting and/or intermediate materials in various industrial processes. However, its excessive release into environment poses a threat to living organisms, as it is a highly carcinogens and hazardous pollutant even at the very low concentration. Thus removal of phenol from polluted environments is very crucial for sustainable remediation process. We developed a low cost adsorption method for separating phenol from a model aqueous solution. The phenol adsorption was studied using two adsorbents i.e., Amber lite XAD-16 and Amber lite XAD-7 HP with a constant amount of resin 0.1 g at varying aqueous phenol concentrations ($50-200mgL^{-1}$) at room temperature. We compared the efficacy of two phenol adsorbents for removing higher phenol concentrations from the media. We investigated equilibrium and kinetics studies of phenol adsorption employing Freundlich, Temkin and Langmuir isotherms. Amberlite XAD-16 performed better than Amberlite XAD-7 HP in terms of phenol removal efficiency that amounted to 95.52%. Pseudo second order model was highly fitted for both of the adsorption systems. The coefficient of determination ($R^2$) with Langmuir isotherm was found to be 0.98 for Amberlite XAD-7 HP. However, Freundlich isotherm showed $R^2$ value of 0.95 for Amberlite XAD-16, indicating that both isotherms could be described for the isotherms on XAD-7 HP and Amberlite XAD-16, respectively.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.56-65
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• 2014

Contamination of explosive compounds in the soils of military shooting range may pose risks to human and ecosystems. As shooting ranges are located at remote places, active remediation processes with hardwares and equipments are less practical to implement than natural solutions such as bioremediaton. In this study, a series of experiments was conducted to select a suitable carbon source and to optimize dosing rate for the enhanced bioremediation of explosive compounds in surface soils and sediments of shooting ranges with indigenous microorganisms activated by external carbon source. Treatability study using slurry phase reactors showed that the presence of indigenous microbial community capable of explosive compounds degradation in the shooting range soils, and starch was a more effective carbon source than glucose and acetic acid in the removal of TNT. However, at higher starch/soil ratio, i.e., 2.0, the acute toxicity of the liquid phase increased possibly due to transformation products of TNT. RDX degradation by indigenous microorganisms was also stimulated by the addition of starch but the acute toxicity of the liquid phase decreased with the increase of starch/soil ratio. Taken together, the optimum range of starch/soil ratio for the degradation of explosive compounds without significant increase in acute toxicity was found to be 0.2 of starch/soil.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.379-379
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• 2018

MXenes are a new family of 2D transition metal carbide nanosheets analogous to graphene (Lv et al., 2017; Sun et al., 2018). Due to the easy availability, hydrophilic behavior, and tunable chemistry of MXenes, their use in applications for environmental pollution remediation such as heavy metal adsorption has recently been explored (Li et al., 2017). In this study, three-dimensional (3D) MXene ($Ti_3C_2T_x$) films with high adsorption capacity, good mechanical strength, and high selectivity for specific radionuclide from aquose solution were successfully fabricated by a polymeric precursor method using vacuum-assisted filtration. The highest removal efficiency on the films was 99.54%, 95.61%, and 82.79% for $Sr^{2+}$, $Co^{2+}$, and $Cs^+$, respectively, using a film dosage of 0.06 g/ L in the initial radionuclide solution (each radionuclide concentration = 1 mg/L and pH = 7.0). Especially, the adsorption process reached an equilibrium within 30 min. The expanded interlayer spacing of $Ti_3C_2T_x$ sheets in MXene films showed excellent radionuclide selectivity ($Cs^+$ and/or $Sr^{2+}/Co^{2+}$) (Simon, 2017). Besides, the MXene films was not only able to be easily retrieved from an aqueous solution by filtration after decontamination processes, but also to selectively separate desired target radionuclides in the solutions. Therefore, the newly developed MXene ($Ti_3C_2T_x$) films has a great potential for radionuclide removal from aqueous solution.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1519-1525
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• 2021

Hexavalent chromium (Cr(VI)) is recognized to be carcinogenic and toxic and registered as a contaminant in many drinking water regulations. It occurs naturally and is also produced by industrial processes. The reduction of Cr(VI) to Cr(III) has been a central topic for chromium remediation since Cr(III) is less toxic and less mobile. In this study, fermentative Fe(III)-reducing bacterial strains (Cellu-2a, Cellu-5a, and Cellu-5b) were isolated from a groundwater sample and were phylogenetically related to species of Cellulomonas by 16S rRNA gene analysis. One selected strain, Cellu-2a showed its capacity of reduction of both soluble iron (ferric citrate) and solid iron (hydrous ferric oxide, HFO), as well as aqueous Cr(VI). The strain Cellu-2a was able to reduce 15 μM Cr(VI) directly with glucose or sucrose as a sole carbon source under the anaerobic condition and indirectly with one of the substrates and HFO in the same incubations. The heterogeneous reduction of Cr(VI) by the surface-associated reduced iron from HFO by Cellu-2a likely assisted the Cr(VI) reduction. Fermentative features such as large-scale cell growth may impose advantages on the application of bacterial Cr(VI) reduction over anaerobic respiratory reduction.

• Advances in nano research
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• v.15 no.6
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• pp.541-550
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• 2023

The escalating growth of industrial sectors has led to a pervasive global problem—oil pollution, particularly in industrial areas. The release of substantial volumes of oil and its by-products into the environment has resulted in extensive contamination. Multiple factors contribute to the entry of these substances into water bodies and soils, thereby inflicting irreparable consequences on ecosystems, natural resources, and human health. Consequently, it becomes imperative to comprehend the characteristics and behavior of oil pollution, anticipate its impacts, and develop effective mitigation strategies. Understanding this intricate issue requires considering the physicochemical properties of the environment, the interactions between oil and sediments, and biological factors such as evaporation and dissolution. Although the oil industry has brought about remarkable advancements, its activities have raised significant concerns regarding pollution from extraction and production processes. Oil-rich nations face a particularly challenging predicament of soil pollution caused by petroleum compounds. The areas surrounding oil exploration mines and refineries often endure contamination due to oil leakages from storage tanks and transmission lines resulting from deterioration and damage. Investigating the dispersion of such pollutants and devising methods to remediate petroleum-contaminated soil represent crucial and intricate issues within the realm of environmental geotechnics.

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.9-16
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• 2012

Standardized remediation process for the soil contaminated with arsenic is insufficient due to characteristics of its anion-mobility and speciation changed by Eh-pH of soil. One of the well-known efficient remediation processes is the modified soil washing that particle separation process by only water. However, it is required that the treatment plan for the fine soil what was discharged after modified soil washing. Therefore, this research suggests the treatment plan that the recycling method using arsenic immobilization by FeS-$H_2O_2$. The batch experiments results for the arsenic immobilization showed that the water content was at least 50%, the injection of FeS and $H_2O_2$ (assay-35%) were 8% (w/watdrybase) and 0.2 mL/10 g of fine soil respectively. Arsenic concentration with KSLT was decreased about 95.4%. The results indicated that the mixing of FeS-$H_2O_2$ was highly efficient on the immobilization of As-contaminated soil. The mixing ratio as 13% of bentonite with 3% of cement (at based on 100% of immobilized fine soil) was satisfied with standard of liner for landfill construction.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.92-100
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• 2015

Unlike most other planning processes, brownfield planning generally requires a high level of technical and legal expertise due to potential site contamination. To successfully engage in inclusionary decision making, an adaptive collaboration strategy for brownfield planning is therefore critical. This study examines how a communicative planning approach can be used to overcome the challenge of enabling experts from different fields to work alongside lay people from the local community to achieve a properly balanced collaboration in brownfield planning. After identifying appropriate indicators for collaboration through a literature review of established communicative planning theory, these indicators are applied to the brownfield planning process, highlighting critical points of collaboration such as site prioritization, assessment, remediation, and redevelopment throughout. The results suggest the critical need for an adaptive model focusing on three aspects: 1. Facilitation of a balanced dialogue between the experts with social, cultural, and design-based knowledge and the ones with scientific and engineering-based knowledge, 2. Preparation of an appropriate tool for risk communication with the lay people, 3. Development of decision support system for the integration of expert-oriented technical data and public opinion-oriented subjective data.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.229-238
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• 2016

This study evaluated potential application of illite, which is produced at Yeongdong area in Korea, to remove radiocesium released to environmental system through severe nuclear accidents. The Yeongdong illite was formed by metamorphose of micaceous schist in hydrothermal condition, and composed of quartz, illite, and albite. Sorption distribution coefficient ($K_d$) of cesium by the Yeongdong illite was higher than the $K_d$ values for other clay minerals. It may be affected by preferential adsorption of cesium to Frayed Edge Sites (FES) on illite. Nonlinear isotherm models were suitable to describe the sorption processes for the Yeongdong illite. Its max. single layer capacity was $250,000{\mu}g\;kg^{-1}$ for cesium. Therefore, the Yeongdong illite could be an efficient and economic sorbent to prevent dispersion of radiocesium, and apply for remediation.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.127-136
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• 1999

In the past several years phytoremediation, defined as the use of plants for removing contaminants from media such as soils or water, has attracted a great deal of interest as a potentially useful remediation technology We attempted to assess the effectiveness of phytoremediation of diesel-contaminated soils in a green house. Screening test for selecting an appropriate plant was performed by observing the harmful effects of diesel dosage on the growth of 4 plants. Alfalfa was selected as a potentially useful plant among corn and barnyard grasses due to its high tolerance to the toxicity of diesel in growth. Bioremediation of the artificial diesel-contaminated soil packed in the PVC columns(0.3m in diameter $\times$ 1m in length) with air supplied, alfalfa planted, and alfalfa and air supplied was investigated for 100 days. The results of the column test showed plant effects on enhancing the biodegradation of diesel in the contaminated soils compared to the control column which had no plant. Injecting air to the columns during phytoremediation also showed additional effects on the removal rate of diesel. Comparison of microbial activity in each test column showed a beneficial effect of plants in the soil remediation processes. This results can be explained microbial activity in rhizosphere is a crucial factor for removing diesel.