• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.493-500
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• 2023

The use of TiO₂ photocatalyst in the production of concrete blocks for the purpose of nitrogen oxide reduction is an issue of controversy due to the conflicting evidence on its effectiveness. Efforts have been made to reduce the level of nitrogen oxides in the environment by using of titanium dioxide (TiO₂). This study examined the effect of incorporating activated carbon into concrete blocks on the reduction of nitrogen oxides released into the atmosphere and the durability of the blocks. The efficiency of photocatalyst was enhanced through the addition of a surrounding conductive substance. The addition of activated carbon resulted in a significant increase in the electrical conductivity of photocatalytic blocks and improved durability. The cement mixture using 5 % TiO₂ and 15 % activated carbon exhibited the optimal mixing ratio for the purpose of nitrogen oxide removal. The effect of the addition of conductive carbon to the photocatalytic blocks was discussed with the results of conductivity, flexural and comprssive strength and nitrogen oxide removal test. The relationship between the addition of conductive carbon to the photocatalytic blocks and its resulting effects have been studied by several tests, including conductivity, flexural and compressive strength, and nitrogen oxide removal.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.113-116
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• 2003

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.885-889
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• 2012

In this study, amine and metal oxide additives were investigated to improve $CO_2$ adsorption capacity of activated carbons (ACs). The characteristics of surface modified ACs were studied by X-ray photoelectron spectroscopy (XPS), $N_2$ adsorption, X-ray diffraction (XRD), and BET. Amine surface treatment decreased specific surface area and pore volume of ACs, but increased alkalinity by the incorporated nitrogen functional groups. Adsorption capacities of amine functionalized ACs was larger than original ACs, because basic group which can react with $CO_2$ was grafted on the ACs surface. Presence of copper oxides on ACs also enhances the carbon dioxide adsorption. The copper oxides could increase the adsorption rate of carbon dioxides due to the acid-base interaction (or electron acceptor-donor interaction). It was found that copper oxide loading was a promising method to improve the $CO_2$ adsorption capacity of ACs.

• Journal of Climate Change Research
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• v.6 no.1
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• pp.41-47
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• 2015

This study was carried out simulating domestic utilization conditions of a wood pellet stove and a wood pellet boiler in order to determine emission factors (EFs) of macro-pollutants, i.e., carbon monoxide, nitrogen oxides, sulfur oxides, ammonia, particulate matters (total suspended particulate, $PM_{10}$, $PM_{2.5}$, black carbon) and trace pollutants (i.e., ten different volatile organic compounds). The composite pollutants EFs for the pellet stove were: for TSP 4.58 g/kg, for $PM_{10}$ 3.35 g/kg, for $PM_{2.5}$ 2.48 g/kg, CO 119.23 g/kg, NO 14.40 g/kg, $SO_2$ 0.17 g/kg, TVOC 37.73 g/kg, $NH_3$ 0.02 g/kg and emissions were similar to the pellet boiler appliance: for TSP 4.73 g/kg, for $PM_{10}$ 3.41 g/kg, for $PM_{2.5}$ 2.63 g/kg, CO 161.51 g/kg, NO 13.67 g/kg, $SO_2$ 0.19 g/kg, TVOC 45.22 g/kg, $NH_3$ 0.02 g/kg.

• Journal of Climate Change Research
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• v.6 no.1
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• pp.49-54
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• 2015

Manually fed firewood burning appliances, i.e., stove and boiler, were tested in order to determine emission factors (EFs) of macro-pollutants, i.e., carbon monoxide, nitrogen oxides, sulfur oxides, ammonia, particulate matters (total suspended particulate, $PM_{10}$, $PM_{2.5}$, black carbon) and trace pollutants (i.e., ten different volatile organic compounds). The composite pollutants EFs for the wood stove were: for TSP 15.45 g/kg, for $PM_{10}$ 6.53 g/kg, $PM_{2.5}$ 4.16 g/kg, CO 175.49 g/kg, NO 1.58 g/kg, $SO_2$ 0.15 g/kg, TVOC 48.02 g/kg, $NH_3$ 0.02 g/kg and emissions were similar to the wood boiler appliance: for TSP 12.23 g/kg, for $PM_{10}$ 5.84 g/kg, $PM_{2.5}$ 3.66 g/kg, CO 146.74 g/kg, NO 1.42 g/kg, $SO_2$ 0.15 g/kg, TVOC 47.78 g/kg, $NH_3$ 0.01 g/kg.

• Advances in materials Research
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• v.13 no.3
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• Environmental and Resource Economics Review
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• v.9 no.5
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• pp.853-876
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• 2000

The purpose of this paper is to come up with the measures for sustainable development of the agricultural sector in store for the strengthened U.N. Framework Convention on Climate Change. We analyze the spillover effects of Methane and Nitrous Oxides taxes (carbon tax) on the Korean agricultural sector. Unlike the other sectors, the agricultural sector has a unique characteristic generating greenhouse gas in the process of production itself even without consuming much fossil fuel. In order to estimate the impacts of those taxes, non-linear optimization method has been used with various assumed scenarios. The production effect, income and' price effect, and greenhouse gas emission reduction effect in the agricultural sector have been estimated through this method. The empirical results show that the paddy sector has a bigger tax effect than the livestock sector. In the paddy sector, the carbon tax has more impacts in the suburban areas than in the rural areas, while the swine farming section in the livestock sector has a conspicuous income effect in the midst of low greenhouse gas emission effect. These results allude us to apply graded tax rates to the crop, the livestock, and the region of different kind. Even if the agricultural sector has a less tax effect when compared with other industrial sectors, an environmental tax might be an effective measure to prevent global warming.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.404-408
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• 2001

This paper focuses on the pilot-scale investigation of direct recycling of electric arc furnace (EAF) stainless steelmaking dust. The direct recycling of EAF dust is to make pellets with the mixture of the dust and the reducing agent carbon, then introduce the pellets to the EAF. The valuable metals in the dust are reduced and get into the steel as the alloying elements. Experiments simulating direct recycling in an EAF were performed using an induction furnace. But it seems difficult to reduce all metal oxides in the dust so that some metal reducing agents added in the late stage of reduction process. The valuable metals in the dust were reduced partly by carbon and partly by metal reducing agent for the economical concern. The recovery of iron, chromium and nickel from the flue dust and the amount of metal oxides in the slag were measured. The results showed that the direct recycling of EAF stainless steelmaking dust is practicable. It wes also found that direct recycling of flue EAF stainless steelmaking dusts does not affect the chemistry and quality of stainless steel produced in the EAF. It is benefit not only for the environmental protection but also for the recovery of valuable metal resources in this way.

• Journal of Power System Engineering
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• v.22 no.1
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• pp.5-10
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• 2018

In order to employ factorial design on electronically-controlled diesel engine, effects of 5 factors on specific fuel consumption, nitrogen oxides and carbon monoxide were examined by fractional and full factorial design in this research. There were different results between fractional and full factorial design, then effect of variables as ambient condition and measurement of fuel consumption were confirmed. It was shown that ambient condition affected uniformly trend of nitrogen oxides and carbon monoxide. However, both ambient condition and measurement of fuel consumption had nothing to do with trend of specific fuel consumption and therefore it must be careful to employ factorial design on specific fuel consumption as response.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.443-448
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• 2011

The propellant has a short shelf-life because of nitrogen oxides that were released from nitrocellulose decomposition. As-received and surface-modified ACFs were applied to remove the nitrogen oxides with intend to extend the shelf-life of propellant. The specific surface area of modified ACFs was slightly decreased but nitrogen function groups such as pyridine, pyridone and pyrrol were created on the surface of ACFs. As a result, the NO removal capacity of the surface-modified ACF by propellant waste increased about twice than that of the as-received ACF. The shelf-life of propellant was extended about 1.25 times by accompanying surface-modified ACF.