• Carbon letters
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• v.9 no.1
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• pp.23-27
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• 2008

The adsorption and reduction of Cr (VI) to Cr (III) by surface modified activated carbon (AC) in an aqueous solution was studied. The effects of surface modifications on the properties of the carbons were investigated by the analysis of specific surface area, carbon surface pH, acid/base surface values and functional groups. In order to understand the Cr(VI) adsorption and reduction ratio from Cr(VI) to Cr(III), the Cr adsorption capacity of AC was also measured and discussed by using inductively coupled plasma and UV spectrophotometer. The modifications bring about substantial variation in the chemical properties whereas the physical properties such as specific surface area, pore volume and pore size distribution nearly were not changed. Total Cr adsorption efficiency of as-received activated carbon (R-AC) and nitric acid treated activated carbon (N1-AC and N2-AC) were recorded on 98.2, 99.7 and 100%. Cr(III) reduction efficiency of R-AC increased largely from 0.4% to 28.3% compared to N1-AC and N2-AC.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1165-1171
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• 2022

In this paper, the results of an experimental study were presented by measuring and comparing the flexural strength and deformation on the carbon fiber sheet strength reinforced concrete beam considering end anchorage effect. For this purpose, total six specimens of 100×100×600mm size were prepared and tested according to the KDS 14 20 20. The specimens were categorized in three cases as reference beams without strengthening, beams carbon fiber strengthened but not anchored and beams carbon fiber strengthened also anchored. Experimental results showed that the end anchorage contributed to increase the flexural strength about 42% greater than that of carbon fiber sheets alone, and the number and width of cracks were relatively increased. The results support a considerable effects of end anchorage for carbon fiber strengthened reinforced concrete beams in enhancing the flexural performance. Further studies are needed in durability and long term behavior of carbon fiber sheet strengthened reinforced concrete beams.

• Journal of Internet Computing and Services
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• v.25 no.3
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• pp.55-70
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• 2024

This study aims to compare the differences in the carbon neutral agendas of the two countries based on the differing interest positions of the media in the two countries, as well as to analyze the carbon neutral media coverage in South Korea and China. It also seeks to identify the major topics emphasized in the carbon neutral news agenda setting process in the two countries. A total of 49,227 news articles from South Korea and 105,680 news articles from China, covering the period from the declaration of carbon neutrality in both countries in 2020 to May 9, 2022, were collected. CONCOR and topic modeling analyses were performed on these texts. The results found that South Korean media showed a preference for covering carbon neutrality from the perspective of its inhabitants, whereas Chinese media demonstrated a preference for covering carbon neutrality from the viewpoint of the nation. The discourses on coverages largely focus on areas such as energy strategy, business strategy, industrial growth, and international cooperation, with an obvious lack of discourse on the environment. The findings of this study expect to serve as a primary reference in establishing a news coverage strategy which is environmentally sustainable for the media.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.87-92
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• 2017

Objective of this experiment was to evaluate the effect on pepper growth to application of biochar pellet in case of development of soil carbon sequestration technology. The treatments consisted of control as a general agricultural practice method, pellet (100% pig compost), biochar pellets with mixture ratio of pig compost (9:1, 8:2, 6:4, 4:6, 2:8) for comparison of total carbon contents, $NH_4-N$ concentrations, and total biomass in the pots applied with biochar pellets after pepper harvesting. The application rates of biochar pellet was 8.8 g/pot regardless of their mixed rates based on recommended amount of application (440 kg/10a) for pepper cultivation. For the experimental results, Total carbon contents in the treatments were low from 1.8 to 2.6 fold as compared to the control. $NH_4-N$ concentrations were not significantly different among the treatment plots as compared to the control, but $NO_3-N$ was not detected in the all treatment plots. However, total biomass was not only significantly different between the control and 2:8 (biochar : pig compost) biochar pellet application plot even if the other treatments were low. Therefore, this biochar pellet application might be further modified for soil carbon sequestration in agricultural farming practices.

• The Korean Journal of Ecology
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• v.8 no.1
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• pp.7-14
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• 1985

Biomass, carbon, nitrogen and phosphorus standing crops of bethic community were estimated at the trophic levels in the intertidal zone of Kum river estuary. Annual mean biomass of zoobenthos was 130.5g/$m^2$, body fraction 26.7g/$m^2$ and shell fraction 103.8 g/$m^3$. Biomass estimated as ash-free dry weight was total 28.9g/$m^2$, body fraction 20.2g/$m^2$ and shell fraction 8.7g/$m^2$ Carbon standing crops of zoobenthos were 15.9gC/$m^2$, in which organic carbon content was 7.0gC/$m^2$ and carbonate carbon was 8.9gC/$m^2$. Production efficiency by carbon standing crops from sediment to herbivores and carnivores and 10.6% and 16.0% in phosphorus, respectively. Annual primary production of benthic algae was crudely estimated to 329g.dw/$m^2$/yr by using the biomass and turn-over rate of benthic algae.

• Carbon letters
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• v.4 no.3
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• pp.140-145
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• 2003

Antibacterial behaviors of PAN-based activated carbon fibers (ACFs) containing silver metal were investigated. The effects of surface and pore structures of the ACFs were studied by $N_2$/77 K adsorption and D-R plot as a function of silver loading content. The antibacterial activities were investigated by a dilution test against Staphylococcus aureus (S. aureus; gram positive) and Klebsiella pnemoniae (K. pnumoniae; gram negative). As experimental results, the ACFs showed some decreases in specific surface areas, micropore volumes, and total pore volume with an increase of silver content. However, the antibacterial activities of the ACFs were strongly increased against S. aureus as well as K. pnumoniae, which could be attributed to the presence of antibacterial metal in the ACFs system.

• Carbon letters
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• v.13 no.2
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• pp.61-72
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• 2012

Dye removal from waste water via adsorption by activated carbons (ACs) developed from agricultural wastes represents an ideal alternative to other expensive treatment options. Physical and chemical ACs were prepared from rice husks. The textural properties of the ACs were characterized by Brunauer-Emmett-Teller-$N_2$ adsorption and scanning electron microscopy. The chemistry of the carbon surface was investigated by Fourier transform infrared spectroscopy, base and acid neutralization capacities, pH of the active carbon slurry, and $pH_{pzc}$. The adsorption capacities of the ACs for the basic dye (methylene blue) and acid dye (acid green 25) were determined using parameters such as contact time, pH, and temperature. NaOH-ACs showed the highest surface area and total pore volume, whereas steam-ACs showed the lowest ones.

• Carbon letters
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• v.11 no.2
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• pp.90-95
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• 2010

Carbon materials such as graphite and graphene exhibit high electrical conductivity. We examined the electrical conductivity of synthetic and natural graphene powders after the chemical reduction of synthetic and natural graphite oxide from synthetic and natural graphite. The trend of electrical conductivity of both graphene (synthetic and natural) was compared with different graphite materials (synthetic, natural, and expanded) and carbon nanotubes (CNTs) under compression from 0.3 to 60 MPa. We found that synthetic graphene showed a marked increment in electrical conductivity compared to natural graphene. Interestingly, the total increment in electrical conductivity was greater for denser graphite; however, an opposite behavior was observed in nanocarbon materials such as graphene and CNTs, probably due to the differing layer arrangement of nanocarbon materials.

• BMB Reports
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• v.29 no.4
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• pp.343-352
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• 1996

The biosynthesis of phospholipid and the composition of fatty acid were analyzed in mitochondria isolated from Chlorella ellipsoidea treated with carbon sources (glucose, sucrose, raffinose) during the culture. The growth of Chlorella and total lipid contents in mitochondria treated with various carbon sources was increased to compare with the control. When Chlorella mitochondria was treated with various carbon sources, four kinds of phospholipid were increased predominantly. The major fatty acids utilized for the biosynthesis of the phospholipid were analyzed linoleic acid (average 25.18%) and stearic acid (average 10.52%) in the control. But, it was shown that the major fatty acids in Chlorella mitochondria treated with glucose were stearic acid (average 30.93%), palmitic acid (average 17.47%) and stearic acid (average 20.31%), linoleic acid (average 16.68%) in sucrose treatment and oleic acid (average 17.17%), palmitic acid (average 15.64%) in raffinose treatment.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.57-72
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• 1990

The oxidation of carbon monoxide on a catalyst, $LaSrNiCoO_3$ was investigatigated with a plug flow system. Kinetic quantities such as reaction-rate, reaction order and Arhenius-parameters at various reactor temperature from 200$^\circ$C to 300$^\circ$C were determined. Also, the optimum condition for the oxidation of carbon monoxide with this catalyst was determined and are as follows. Partial pressure of oxigen ; 428mmHg Partial pressure of carbon monoxide ; 332mmHg Mixed moral ratio of oxigen and Carbon monoxide ; 1.3 : 1 Total gas flow ; 224ml/min Reaction temperature ; 340$^\circ$C The reaction kinetic equation at the optimum condition, temperature range from 200$^\circ$C to 340$^\circ$C, are as follow. $$ $v = Ae^{6.5Kcal/RT} [CO]^{0.93 \sim 0.98} [O_2]^{0.42 \sim 0.50}$ $$ In addition to this, numerical calculation were performed to evaluate the mass and heat transfer effect on this system.