• Membrane Journal
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• v.32 no.5
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• pp.265-274
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• 2022

Separation of oily wastewater, which is a byproduct of various industries such as petroleum refineries, is essential to not exceed the tolerance limit of wastewater streams. Ceramic membranes show potential in oily wastewater separation, due to their excellent oil removal efficiency, good chemical, thermal, and mechanical stability, and simple operation. However, widespread application of ceramic membranes is limited due to high material cost of alumina, silica, and other ceramic based materials used to fabricate them. Recent efforts to reduce material cost have been made, using fly ash and clay. This review examines the fabrication and efficiency of ceramic membranes in oily wastewater separation according to material: silica, alumina, and waste ash.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.4
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• pp.571-576
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• 2023

The initial development plans for the six reactor designs, soon after the release of Generation IV International Forum (GIF) TRM in 2002, were characterized by high ambition [1]. Specifically, the sodium-cooled fast reactor (SFR) and very-high temperature reactor (VHTR) gained significant attention and were expected to reach the validation stage by the 2020s, with commercial viability projected for the 2030s. However, these projections have been unrealized because of various factors. The development of reactor designs by the GIF was supposed to be influenced by events such as the 2008 global financial crisis, 2011 Fukushima accident [2, 3], discovery of extensive shale oil reserves in the United States, and overly ambitious technological targets. Consequently, the momentum for VHTR development reduced significantly. In this context, the aims of this study were to compare and analyze the development progress of the six Gen IV reactor designs over the past 20 years, based on the GIF roadmaps published in 2002 and 2014. The primary focus was to examine the prospects for the reactor designs in relation to spent nuclear fuel burning in conjunction with small modular reactor (SMR), including molten salt reactor (MSR), which is expected to have spent nuclear fuel management potential.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.227-233
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• 2016

This study was designed to analyze the chemical compositions of 'Setoka' branch essential oils (SEBO) and to test their biological activities. 'Setoka' is a Citrus species widely cultivated in Jeju Island. At the present, 'Setoka' branches produced by thinning process were mostly discarded as a waste. Therefore, utilization of this branch waste has received much attention. 'Setoka' branch essential oils (SBEO) were prepared by treatment of its ethanol extracts with jojoba oil. SBEO were chemically analyzed using gas chromatograph-mass spectrometry (GC-MS), and following components were identified; ethyl linoleate (64.14%), ethyl palmitate (16.50%), neophytadiene (11.06%) and beta-citronellol (5.09%). The anti-inflammatory activity in the SBEO was examined using RAW 264.7 murine macrophage cells stimulated with LPS. As a result, the SBEO inhibited nitric oxide (NO) productions with a dose-dependent manner. In addition, SBEO showed good anti-microbial activities against drug-susceptible and -resistant skin pathogens such as Staphylococcus aureus and Propionibacterium acnes, which are acne-causing bacteria. Based on these results, we suggest that SBEO has the possibility for use as an anti-inflammatory and anti-microbial agent in cosmetic applications.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1678-1686
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• 2020

This study attempted to derive the possibility of using wood pellet using rice husk, which is an agricultural byproduct, and tried to improve the lower calorific value of rice hulls thorough expansion technology and combustion additives. In the physical and chemical analysis of rice husk, the result was obtained that the chlorine content was 0.09%, which did not meet the wood pellet quality standard of Korea. When making rice hulls into expanded rice husk through the expansion technology, the chlorine content decreased, resulting in a product of 0.02%, which is equivalent to the wood pellet standard of Korea, and the calorific value was also increased to 4,280 kcal/kg compared to the existing 3,780 kcal/kg. To obtain a product of 5,000 kcal/kg or more, borax, hydrogen peroxide, and sodium hydroxide was used as combustion improver. However the improvement in calorific value was insufficient. After conversion to coffee oil path using coffee grounds, which is a waste resource biomass, it is mixed into an expanded rice husk, and when the product is analyzed, the coffee oil 15 wt% mixed product shows an excess of 4,949 kcal/kg. When using rice husk, an agricultural byproduct, as wood pellets, it is considered desirable to use waste resources to improve the calorific value, and according to the results of this study, when mixing coffee oil, rice husk can be sufficiently used as wooden pellets.

• Clean Technology
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• v.29 no.3
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• pp.200-216
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• 2023

Ginkgo leaves are considered waste biomass and can cause problems due to the strong insecticidal actions of ginkgolide A, B, C, and J and bilobalide. However, Ginkgo leaf biomass has high organic matter content that can be converted into fuels and chemicals if suitable technologies can be developed. In this study, the effect of pyrolysis temperature, minimum fluidized velocity, and Ginkgo leaf size on product yields and product properties were systematically analyzed. Fast pyrolysis was conducted in a bubbling fluidized bed reactor at 400 to 550℃ using silica sand as a bed material. The yield of pyrolysis liquids ranged from 33.66 to 40.01 wt%. The CO₂ and CO contents were relatively high compared to light hydrocarbon gases because of decarboxylation and decarbonylation during pyrolysis. The CO content increased with the pyrolysis temperature while the CO₂ content decreased. When the experiment was conducted at 450℃ with a 3.0×U_mf fluidized velocity and a 0.43 to 0.71 mm particle size, the yield was 40.01 wt% and there was a heating value of 30.17 MJ/kg, respectively. The production of various phenol compounds and benzene derivatives in the bio-oil, which contains the high value products, was identified using GC-MS. This study demonstrated that fast pyrolysis is very robust and can be used for converting Ginkgo leaves into fuels and thus has the potential of becoming a method for waste recycling.

• Elastomers and Composites
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• v.42 no.4
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• pp.249-258
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• 2007

In this study, the EPDM powder which was surface activated by high temperature and shear pulverization process was prepared and the mechanical properties and odor material analysis were investigated. Analysis for particle size and size distribution of waste of the EPDM powder has been performed. The waste EPDMs used in this study were 4 types of solid, sponge, solid+sponge, and solid+metal. According to the results, the solid type showed the smallest particle size among the 4 types of EPDM powder. Effective surface devulcanization of EPDM powder could be obtained by the addition of the reclaiming agent. The dicumyl peroxide was considered as the best crosslink agent for dynamic vulcanization when the surface activated EPDM powder was blended with polyolefin in order to make TPE. Also, the optimum amounts of DCP was 6 phr in terms of surface crosslink reaction and mechanical properties of EPDM powder. The processes of water adsorption and rose oil addition were employed to remove the odor of EPDM powder caused by reclaiming agent. The GC/MS was used to analyze the odor compounds.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.207-218
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• 2017

In this study, pitch-based activated carbon fibers (ACFs) were modified with pyrolysis fuel oil (PFO). Carbonized ACF samples were activated at $850^{\circ}C$, $880^{\circ}C$ and $900^{\circ}C$. A scanning electron microscope (SEM) and a BET surface area apparatus were employed to evaluate the indoor radon removal of each sample. Among three samples, the BET surface area and micropore area of ACF880 recorded the highest value with $1,420m^2{\cdot}g^{-1}$ and $1,270m^2{\cdot}g^{-1}$. Moreover, ACF880 had the lowest external surface area and BJH adsorption cumulative surface area of pores with $151m^2{\cdot}g^{-1}$ and $35.5m^2{\cdot}g^{-1}$. This indicates that satisfactory surface area depends on the appropriate temperature. With the above scope, ACF880 also achieved the highest radon absorption rate and speed in comparison to other samples. Therefore, we suggest that the optimum activation temperature for PFO containing ACFs is $880^{\circ}C$ for effective indoor radon adsorption.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.583-591
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• 2002

Biodegradation of fat, oil, and grease (FOGs) plays an Important role in wastewater management and water pollution control. However, many industrial food-processing and food restaurants generate FOG-containing waste waters for which there Is no acceptable technology for their pretreatment. To solve these problems, this study evaluated the feasibility of effective FOG-degrading microorganisms on the biodegradation of olive oil and FOG-containing wastewater. Twenty-two strains capable of degrading FOGs were isolated from five FOG-contaminated sites for the evaluation of their FOG degradation capabilities. Among twenty-two strains tested, the lipase-producing Pseudomonas sp. strain D2D3 was selected for actual FOG wastewater treatment. Its biodegradability was performed at 3$0^{\circ}C$ and pH 8. The extent of FOG removal efficiency was varied for each FOG tested, being the highest for olive oil and animal fat (94.5% and 94.4%), and the lowest for safflower oil (62%). The addition of organic nitrogen sources such as yeast extract, soytone, and peptone enhanced the removal efficiency of FOGs, but the addition of the inorganic nitrogen nutrients such as $NH_4$Cl and $(NH_4)_2SO_4$ did not increase. The $KH_2PO_4$ sources in 0.25% to 0.5% concentrations showed more than 90% degradability. As a result, the main pathway for the oxidation of fatty acids results in the removal of two carbon atoms as acetyl-CoA with each reaction sequence: $\beta$-oxidation. Its lipase activity showed 38.5 U/g DCW using the optimal media after 9 h. Real wastewater and FOGs were used for determining the removal efficiency by using Pseudomonas sp. strain D2D3 bioadditive. The degradation by Pseudomonas sp. strain D2D3 was 41% higher than that of the naturally occurring bacteria. This result indicated that the use of isolated Pseudomonas sp. strain D2D3 in a bioaugmentating grease trap or other processes might possibly be sufficient to acclimate biological processes for degrading FOGs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.294-301
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• 2017

In this study, we found the optimal manufacturing conditions of livestock manure sludge RDF with the oil-drying method. We performed oil evaporation, oil drying and pelletizing of the sludge to evaluate the value of the product (sludge RDF), and measured the performance of the product using calorimeter and PXRF equipment. Also, we conducted the calorie comparison test between sludge RDF manufactured in this study and wood RDF generally used in the field. Experimental results showed that 30g of the sludge treated by vegetable oil at $130^{\circ}C$ for 25 minutes were the optimal conditions to make the sludge RDF (considering the aspects of eco-friendly and mass production). The caloric value of the sludge RDF manufactured in this study was 5211kcal/kg which is higher than that of wood RDF used widely in the market. Finally, PXRF results showed sludge RDF contains no heavy metals with the exception of sulfur. Therefore, we recommend more study about the sulfur control process for future development of the industrial manufacturing process.

• Journal of Life Science
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• v.34 no.10
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• pp.682-690
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• 2024

This study aimed to produce medium-chain-length polyhydroxyalkanoates (mcl-PHA) using oil extracted from spent coffee grounds (SCG) as a carbon source. The highest oil yields, 14.40%(w/w) and 14.49%(w/w), were achieved with an extraction time of 2 hr and an SCG/n-hexane ratio of 15:1. The fatty acid composition of the extracted SCG oil (EOC) primarily consisted of linoleic acid (45.08%), palmitic acid (35.56%), oleic acid (8.62%), and stearic acid (7.62%). Pseudomonas sp. HY61, isolated from soil, was used to biosynthesize mcl-PHA composed of 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and 3-hydroxydodecanoate using EOC. Under optimal flask conditions, the highest cell growth and mcl-PHA accumulation were observed with 5 g/l EOC, 72 hr, with NH₄Cl as the nitrogen source, at pH 7, 25℃, and a C/N ratio of 15:1. Batch fermentation resulted in a dry cell weight (DCW) of 0.92 g/l and mcl-PHA of 0.17 g/l after 72 hr. In contrast, fed-batch fermentation, with additional supplementation of EOC and NH₄Cl at 18, 30, and 42 hr, increased the DCW to 2.85 g/l and mcl-PHA accumulation to 0.67 g/l, approximately three times higher than batch fermentation. Gas chromatography confirmed that the mcl-PHA structure was consistent across both fermentation modes. The synthesized mcl-PHA had higher molecular weight and thermal decomposition temperatures compared to other mcl-PHA, suggesting its potential applications in packaging and biomedical fields. This study offers an economical approach for mcl-PHA production using waste EOC and Pseudomonas sp. HY61.