• Journal of Power System Engineering
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• v.3 no.2
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• pp.20-25
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• 1999

Experiments were carried out to investigate the characteristics of formaldehyde emission from the small gasoline engine and its reduction technologies. Catalytic converters used are Pt/Rh, Pd/Rh, Pd/Pt, $62cell/cm^2$ monolith type. The measurement of formaldehyde was conducted by using the method of DNPH-GC. From the experimental results, formaldehyde emission increased in a lean mixture due to incomplete combustion of the hydrocarbons. The order of catalytic activity of formaldehyde oxidation was Pt/Rh > Pd/Rh > Pd/Pt. As the distance from the exhaust manifold to the inlet of the catalyst became far, in spite of lower catalyst temperature, formaldehyde concentration decreased because of the adsorption of formaldehyde.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.56-57
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• 2019

Recently, the risk of fine dust is emerging in Korea. According to the OECD report, the incidence of hospitalization and mortality from lung disease is increased, and the incidence of lung cancer and mortality from ischemic heart disease with prolonged exposure are increased. In addition, indoor air quality has become an important factor affecting the human body as indoor life has increased due to the Industrial Revolution. Air pollutants that cause indoor air deterioration typically include particulate dusts as described above, formaldehyde and VOCs released in gaseous form from adhesive wood products used in building materials and furniture. May cause breathing problems. In this study, we analyzed the properties of adsorption matrix for improving indoor air quality using cork.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.25-26
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• 2021

Due to COVID-19, the spread of non-face-to-face culture is increasing the time spent indoors. Accordingly, it is necessary to reduce indoor air pollutants. Also, among building materials, there are paints. As the number of coatings increases, the coating film becomes thick, and there is a risk of cracking and falling off. Therefore, this study is to examine the adsorption properties of indoor air pollutants according to the number of coatings of a paint mixed with powdered activated carbon. In the experimental plan, the addition ratio of powdered activated carbon was selected as 30%, and the number of coatings was selected as primcoating, second coat, and finishing coat, and the concentration of formaldehyde and volatile organic compounds were measured. As a result, as the number of coatings increased, the concentration of formaldehyde and volatile organic compounds tended to decrease. This is considered to be due to the fact that not only the physical adsorption acted by the internal pores of the powdered activated carbon, but also because a lot of powdered activated carbon was present on the painted surface as the coating film was formed. However, since it is judged that there is an error in the concentration due to the inflow of external air as the chamber cover is opened to put the test object in the adsorption test process, it is considered that the experimental method needs to be supplemented.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.83-88
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• 2003

The woodceramics are porous amorphous carbon and glassy carbon composite materials. Woodceramics attracted a lot of attention in recent years because they are environmentally friendly and because of their unique functional characteristics such as catalysis, moisture absorption, deodorization, purification, carrier for microbial activity, specific stiffness, corrosion and friction resistance, and their electromagnetic shielding capacity. In this paper, we made new products of clay-woodceramics to investigate the industrial analysis and ethylene gas adsorption for basic data of building- and packging- materials keeping fruit fresh for a long time. Clay-woodceramics were carbonized for 3 h of heating in a special furnace under a gas flow of nitrogen(15 ml/min.) from 3 layers-clay-woodparticleboard made from pallet waste wood, phenol- formaldehyde resin(hereafter PF, Non volatile content:52%, resin content 30%), and clay(10%, 20% and 30%). Carbonization temperature was 400℃, 600℃ and 800℃. Experimental results shows that the higher the carbonization temperature, the higher the fixed carbon and the lower the volatile contents. The higher the clay content, the more the ash content. The higher the carbonization temperature, the more the ethylene gas adsorption. Carbonization temperature of 800℃ gave the best reslts as same as that of white charcoal and activated carbon.(800℃-clay-woodceramic: 5.36 ppm, white charcoal: 5.66 ppm, activated carbon: 5.79 ppm) The clay contents did not make difference of ethylene gas adsoption.

• Journal of the Korean Wood Science and Technology
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• v.14 no.4
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• pp.1-7
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• 1986

This investigation involves a study of the physical and chemical factors of Pinus densiflora SIEB. et ZUCC. and Quercus mongolica Fisher barks affecting on the adsorption of heavy mteal ions. The results obtained can be summarized as follows. 1. The capacity of the untreated bark to remove the Cu and Cd from solution was similar to or 5% higher than that of formaldehyde treated bark in both species. Considering that untreated bark lead to color-leaching problem, bark treated with formaldehyde are economical. 2. With decreasing particle size of bark(20-80), the adsorption ratio of the Cu and Cd from solution was increased. Quercus bark adsorbed more Cu and Cd at smaller particle size compared to Pinus bark. 3. The heavy metal eqilibrium adsorption of the bark from Cu and Cd solution was attained within 10 min. Pinus bark removed about 48% of the Cu and 41% of the Cd from solution in 10 min while Quercus bark removed about 50% during that period. 4. As the initial metal concentration increased. the absolute metal uptake was increased while percentage removal was decreased. At the lower metal concentration (10 ppm). Pinus and Quercus barks removed 77-94% of the Cu and 72-84% of the Cd. At high metal concentration (200 ppm), the adsorption ratio was 40% Cu and 25% Cd, respectivelty. 5. The maximum adsorption of the Cu and Cd from solution was obtained at pH 5-6 in filtrate. 6. With increased bark weight per given metal concentration, absolute removal of metal ion from solution was increased, but the percentage removal was decreased. The amount of adsorption was 4.2 mg Cu and 4.2 mg Cd per gr. Pinus, bark and 5.4 mg Cu and 4.3 mg Cd per gr. Quercus bark, respectively.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.1-6
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• 2006

In this study we proposed on effect of the photodecomcomposition of coated nanofiber by $Pd/TiO_2$ for the removal of formaldehyde gas as indoor air pollutant. The photocatalytic reactor was setup in the inside of rectangular box (volume 2 l), UV lamp and the coating nanofiber with $Pd/TiO_2$. This study investigated the reaction rate and the adsorption constant of Langmuir-Heinshelwood, conversion of formaldehyde gas on temperature ($40^{\circ}C{\sim}80^{\circ}C$), effect of conversion (%) under different concentration, and effect of conversion (%) with humidity level on added $SO_2$ gas. As results, the rate constant (k) and adsorption constant (ft) were 114.94ppmv/min, $0.0036ppmv^{-1}$, respectively. and the conversion (%) of formaldehyde gas on temperature ($40^{\circ}C{\sim}80^{\circ}C$) was decreased to about 24%, compare with the first conversion (%). In conversion effect of increasing humidity levels, the presence of sulfur dioxide further decreased than without sulfur dioxide. the decreasing reason of conversion with presence sulfur dioxide judged as a cause of interference factor on the decrease of contact chance with photocatalysts.

• Clean Technology
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• v.19 no.2
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• pp.134-139
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• 2013

VOCs such as formaldehyde and benzene in a control chamber were adsorbed onto gypsum incorporating oyster shell powder, which was solidified and dried. VOC was first exposed in air and then gypsum mortar was placed in the chamber for 180 min for adsorption. The mortar was prepared with 0, 10, 30, and 50% of oyster shell powder. Two initial concentrations of VOCs including formaldehyde were $27.7{\sim}28.5mg/m^3$ or $175{\sim}150{\mu}g/m^3$. We found out that the initial concentrations did not seem to make any difference in adsorption performance but higher oyster content strongly led to higher adsorption. We used a convection-diffusion-adsorption model to compare the experiment. The model which considers diffusion coefficients of adsorbates and affinity of the adsorbents well represented the experimental data with a fair agreement.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.27-35
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• 2010

To evaluate the basic characteristics and adsorption properties of commercial wood charcoal, we investigated the proximate analysis, porosimetry analysis, methylene blue adsorption, removal ratios of formaldehyde, and removal ratio of ethylene gas. Fixed carbon contents of traditional black and white charcoal, and mechanical charcoal were 51.8~76.6%, 72.9~84.6%, and 48.5~80.3%, respectively. Refining degrees of the most traditional black charcoal were 9, and those of white charcoal and mechanical charcoals were zero. Specific surface area of traditional black charcoal was 0.1~13.7 $m^2/g$, which was quite lower than that of white charcoal (53.2~372.6 $m^2/g$) and mechanical charcoals (224.3~464.6 $m^2/g$). Also, amounts of methylene blue adsorption were quite lower in black charcoal (0.53~1.97 mg/g) compared with white charcoal (2.68~7.68 mg/g) and mechanical charcoal (11.63~26.10 mg/g). Removal ratios of formaldehyde of the black charcoal were 11.4~26.7%, which is quite similar to white charcoal (17.9~34.9%) and mechanical charcoal (5.5~25.8%). Removal ratios of ethylene gas for traditional black charcoal, traditional white charcoal, and mechanical charcoal were 2.2~43.5%, 21.7~39.1%, 21.7~39.1%, respectively. There was no significant difference in the removal ratios of formaldehyde and ethylene gas among traditional black charcoal, traditional white charcoal, and mechanical charcoal.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.153-154
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• 2018

As the air pollution progresses, the pollution degree of the indoor air quality is increased, and when the pollution degree of the indoor air quality is increased, it causes respiratory diseases and skin diseases. In addition, volatile organic compounds are released from the materials used for architectural interior decoration, and volatile organic compounds are the main cause of polluting indoor air quality. In order to improve indoor air quality, we tried to secure indoor air quality pollution by using photocatalyst which has the function of decomposing harmful substances. photocatalyst is a material that promotes chemical reaction by absorbing light. The photocatalyst used in the experiment was TiO₂, In this study, an adsorption type hardener for reducing volatile organic compounds was prepared by photocatalytic reaction. the formaldehyde and CO₂ concentrations of the cured products were analyzed according to the TiO₂ content.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.936-941
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• 2010

This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.