• Environmental Engineering Research
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• v.24 no.2
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• pp.339-346
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• 2019

In this research, applicability of electrochemical technology in removing nitrogenous compounds from solid waste landfill leachate was examined. Novel cathode material was developed at laboratory by introducing a Cu layer on Al substrate (Cu/Al). Al and mild steel (MS) anodes were investigated for the efficiency in removing nitrogenous compounds from actual leachate samples collected from two open dump sites. Al anode showed better performances due to the effect of better electrocoagulation at Al surface compared to that at MS anode surface. Efficiency studies were carried out at a current density of $20mA/cm^2$ and at reaction duration of 6 h. Efficiency of removing nitrate-N using Al anode and developed Cu/Al cathode was around 90%. However, for raw leachate, total nitrogen (TN) removal efficiency was only around 30%. This is due to low ammonium-N removal as a result of low oxidation ability of Al. In addition to the removal of nitrogenous compounds, reactor showed about 30% removal of total organic carbon. Subsequently, raw leachate was diluted four times, to simulate pre-treated leachate. The diluted leachate was treated and around 88% removal of TN was achieved. Therefore, it can be said that the reactor would be good as a secondary or tertiary treatment step in a leachate treatment plant.

• Current Photovoltaic Research
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• v.7 no.1
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• pp.21-27
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• 2019

Lifetime of Si photovoltaics modules are about 25 years and a large amount of waste modules are expected to be discharged in the near future. Therefore, the extraction and collection of valuable metals out of discharged Si modules will be one of the important technologies. In this study, we demonstrated that supercritical $CO_2$ extraction method can be effectively used to remove Cu, one of the abundant elements in the module, as well as its oxide form, $Cu_2O$. Especially, we proved that the addition of hexane as co-solvent is effective for the removal of both materials. The optimal ratio of $CO_2$ and hexane was 4:1 at a fixed temperature and pressure of $250^{\circ}C$ and 250 bar, respectively. In addition, it was proven that the removal of $Cu_2O$ was preceded via reduction of $Cu_2O$ to Cu.

• The Journal of Economics, Marketing and Management
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• v.10 no.6
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• pp.39-46
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• 2022

Purpose: The purpose of this study is to look at the current status and cases of ESG at home and abroad, and through this, seek ways to activate the ESG strategy of domestic SMEs and suggest a direction. Research design, data and methodology: This study examines the current status of ESG management at home and abroad and examples of companies through related literature on ESG management and performance. Through this, the strategic direction of ESG management of domestic SMEs was presented. Results: Compared to the government and major corporations, SMEs can be said to lack ESG management activities. ESG activities include environmental activities such as carbon neutrality, waste management, eco-friendly supply chain management, establishment of safety and health processes to improve workers' environment, expansion of governance to guarantee autonomy and profitability such as fair trade, protection of social and shareholder rights such as anti-corruption, etc. should be based on Therefore, there are difficulties in ESG activities of SMEs that lack funds and manpower. Conclusions: Compared to the government and major corporations, SMEs can be said to lack ESG management activities However, it will be possible to establish and implement ESG management strategies based on the strengths of SMEs and the characteristics of each company.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.85-92
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• 2022

In this article, we look at the application of BIM (Building Information Modeling) in sustainable infrastructures. In response to global warming, energy shortages, and environmental degradation, people are trying to build eco-friendly, low-carbon cities and promote eco-friendly homes. A "green" building is the entire life cycle of a building that includes maximizing the conservation of resources (energy, water, land, and materials), protecting the environment, reducing pollution, providing people with healthy, comfortable, and efficient use of space, and establishing harmony between nature and architecture. In the field of ecological and sustainable buildings, BIM modeling can be integrated into buildings with analog energy, air flow analysis, and solar building ecosystems. Using BIM technologies, you can reduce the amount of waste and improve the quality of construction. These technologies create "visualization" of digital building models through multidimensional digital design solutions that provide" modeling and analysis "of Scientific Collaboration Platforms for designers, architects, utility engineers, developers, and even end users. Moreover, BIM helps them use three-dimensional digital models in project design and construction and operational management.

• Journal of Soil and Groundwater Environment
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• v.27 no.1
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• pp.31-38
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• 2022

The common algae and industrial waste, chlorella and red mud, were co-pyrolyzed in carbon dioxide condition to fabricate iron-biochar composite. In order to investigate the direct effect of chlorella and red mud in the syngas generation and the property of biochar, experiments were performed using mixture samples of chlorella and red mud. The evolution of flammable gasses (H₂, CH₄, CO) was monitored during pyrolysis. The produced biochar composite was employed as a catalyst for persulfate activation for methylene blue removal. BET analysis indicated that the iron-biochar composite mainly possessed meso- and macropores. The XRD analysis revealed that hematite (Fe₂O₃) contained in red mud was transformed to Fe₃O₄ during co-pyrolysis. The composite effectively activated persulfate and removed methylene blue. Among the composite samples, the composite fabricated from the mixture composed of 1:2 chlorella:red mud showed the best performance in syngas generation and methylene blue removal.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1247-1260
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• 2022

The steel industry accounts for about 5% of the total annual global energy consumption and more than 6% of the total anthropogenic carbon dioxide emissions. Therefore, there is a need to increase energy efficiency and reduce greenhouse gas emissions in these industries. The utilization of coke oven gas, a byproduct of the coke plant, is one of the main ways to achieve this goal. Coke oven gas used as a fuel in many steelmaking process is a hydrogen-rich gas with high energy potential, but it is commonly used as a heat source and is even released directly into the air after combustion reactions. In order to solve such resource waste and energy inefficiency, several alternatives have recently been proposed, such as separating and refining hydrogen directly from coke oven gas or converting it to syngas. Therefore, in this study, recent research trends on the separation and purification of hydrogen from coke oven gas and the production of syngas were introduced.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.259-264
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• 2023

As the demand for lithium-ion batteries, a key power source in electric vehicles and energy storage systems, continues to increase for achieving global carbon neutrality, there is a growing concern about the environmental impact of disposing of spent batteries. Extensive research is underway to develop efficient recycling methods. While hydrometallurgy and pyrometallurgy methods are commonly used to recover valuable metals from spent cathode materials, they have drawbacks including hazardous waste and complex processes. Hence, alternative recycling methods that are environmentally friendly are being explored. However, recycling spent cathode materials still remains complex and energy-intensive. This study focuses on a novel approach called solid-state synthesis, which aims at regenerating the performance of spent cathode materials. The method offers a simpler process and reduces energy consumption. Optimal heat treatment conditions were identified based on experimental results, contributing to the development of sustainable recycling technologies for lithium-ion batteries.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4204-4212
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• 2023

Background: Storage reservoirs of radioactive waste could be the source of atmospheric pollution due to the efflux of aqueous aerosol from their water areas. The main mechanism of formation of aqueous aerosols is the collapse of gas bubbles at the water surface. In this paper, we discuss the potential influence of biological factors on gas ebullition in the water areas of the radioactively contaminated industrial reservoirs R-9 (Lake Karachay) and R-4 (Metlinsky pond) of the Mayak PA. The emission of the released non-dissolved gases captured with gas traps in reservoir R-9 was (88-290) ml/m² per day (2015) and in reservoir R-4 (270-460) ml/m² per day (2016). The analysis of gas composition in reservoir R-4 (60% methane, 35% nitrogen, 2.4% oxygen, 1.5% carbon dioxide) confirms their biological origin. It is associated with the processes of organic matter destruction in bottom sediments. The major source of organic matter in bottom sediments is the dying phytoplankton developing in these reservoirs. Conclusion: The obtained results form the basis to set a task to quantify the relationship between the phytoplankton development, gases ebullition and radioactive atmosphere contamination.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.404-411
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• 2015

In this study, the effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 9 halonitromethanes (HNMs) in biological activated carbon (BAC) process were investigated. Experiments were conducted at three water temperatures ($10^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of HNMs in BAC column. Dibromochloronitromethane (DBCNM) and tribromonitromethane (TBNM) showed the highest biodegradation efficiency, but chloronitromethane (CNM) and dichloronitromethane (DCNM) were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 7 HNMs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ($k_{bio}$) of 7 HNMs ranged from $0.0797{\sim}0.7657min^{-1}$ at $10^{\circ}C$ to $0.1245{\sim}1.8421min^{-1}$ at $25^{\circ}C$. By increasing the water temperature from $10^{\circ}C$ to $25^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 1.6~2.4 times.

• Composites Research
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• v.30 no.3
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• pp.175-180
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• 2017

Currently, since carbon fiber reinforced plastics (CFRPs) are lightweight and have excellent physical properties, their demand has increased dramatically. Many works have studied the CFRPs based on recycled thermoplastics. In this study, the applicability of recycled composite was evaluated using recycled polyethylene terephthalate (PET). PET was collected from waste materials used in beverage bottles and processed to produce PET films. Optimal thermoforming temperature and time were analyzed by comparing the mechanical properties with forming temperature and time difference for producing PET films. CF mat and PET film were used to determine the suitable parameters for the optimum thermoforming of CF/PET composites. The mechanical properties of each thermoforming condition were verified by bending test. The degree of impregnation of the PET film into the CF mat was evaluated by cross-sectional photographs, whereas the interfacial properties were evaluated by interlaminar shear strength (ILSS). Ultimately, it was confirmed that the thermoforming condition for forming the CF/recycled PET composites yielding the optimal mechanical and interfacial properties was at $270^{\circ}C$ for 5 minutes.