• Environmental Engineering Research
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• v.16 no.1
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• pp.1-9
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• 2011

During automotive painting, volatile organic compounds (VOCs) associated with the paint solvents are emitted to the atmosphere. Most VOC emissions come from spraying operations via the use of solvent-based paints, as the spraybooth air picks up gaseous solvent compounds and overspray paint materials. The VOCs consist of aromatic and aliphatic hydrocarbons, ketones, esters, alcohols, and glycolethers. Most VOCs (some hydrophilic VOCs are captured and retained in the water.) are captured by an adsorption system and thermally oxidized. In this paper, the processes involved in automotive painting and in VOC control are reviewed. The topics include: painting operations (briefly), the nature of VOCs, VOC-control processes (adsorption, absorption, biological removal, and thermal oxidation) and energy recovery from VOCs using a fuel reformer and a fuel cell, and the beneficial use of paint sludge.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.150-159
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• 1996

In this study, to obtain the basic data for the optimum moisture control system, moisture adsorption characteristics, adsorption isotherms models for water and surface physical characteristics of burley and flue-cured tobacco were investigated. By the hypothesis' the phenomenon of moisture adsorption of tobacco is the same as the first order reaction, the wetting constant (k) and equilibrium moisture content were obtained. And activation energy, frequency factors were also calculated by applying its data to Arrhenius equation. The Kamei's empirical formula of moisture adsorption isotherms showed the best agreement with the experimental data and its correlation coefficient (r) was 0.997. It can be seen that specific surface area of burley is 157 m2/g, that of flue-cured is 152 m2/g, -△H1 of adsorbed monolayer is 45,972 J/mol, 45,486 J/mol, respectively, and the condensation heat (40,595 J/mol) being caught in adsorbed multilayer is less than that of monolayer.

• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.250-260
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• 1996

Observed results of the adsorption between two competing anions for the shared sorption sites represent that the adsorption phenomena may depends on the characteristics of anion and available sorption sites in a given conditions. In binary systems, adsorption of one species can significantly influence the fate of the other anion, resulting in control of the extent of solute-adsorbate distributions throughout soil profile. And the proton-donation mechanisms by organic anions having a carboxyl as a functional group can also influence the adsorption of inorganic anions onto the hydroxylated sites of Fe and Al oxides. However, study of competitive adsorption of specifically adsorbed anions illustrates some of difficulties which arise in interpretation of reactions at oxide/aqueous solution interfaces. At least two factors prevented a simple analysis of reactions. First, at any pH value the maximum amount of adsorbate taken up at the surface depends on the identity of the anion. Second, it was necessary to postulate the sorption sites where the anion can be adsorbed. Hence, anions having non-specific adsorption characteristics are less capable for sorption sites, compared to those of specific adsorption characteristics, even though competition complies both ordinary and electrostatic interactions for sorption sites. Therefore, competition among chemical species in soil matrix can be of major significance in determining the effective mobility of any reactive anions with sorption sites.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.913-914
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• 2014

PE/PET 필름이 부착된 디스플레이 또는 유리기판 가공에 있어서 유리기판에 대한 고정은 필수 기술요소라 할 수 있다. 이러한 유리기판 위의 필름을 제거하기 위해서는 정밀한 절단기술이 필요하며, 평탄도가 일정하지 않는 유리기판에 대하여 균일한 압력을 가하여 일정한 평탄도를 유지하여 유리기판에 부착된 필름을 가공할 수 있다. 이러한 유리기판에 부탁된 필름을 가공할 수 있는 기술은 유리기판을 흡착시키는 공압기술과 정밀가공처리된 평탄도 $5[{\mu}m]$이상의 베이스(base)판 위에 유리기판을 고정할 수 있는 고정 압착시스템을 제안하고자 한다. 본 논문에서는 유리기판이나 표면의 부착된 필름커팅 시 유리기판위에 결함이 발생하지 않도록 유리기판을 흡착시키는 공압시스템 및 정밀가공시스템을 제안하고자 한다.

• Journal of the Mineralogical Society of Korea
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• v.11 no.1
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• pp.20-31
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• 1998

Adsorption of metal elements onto illite and halloysite was investigated at $25^{\circ}C$ using pollutant water collected from the gold-bearing metal mine. Incipient solution of pH 3.19 was reacted with clay minerals as a function of time: 10 minute, 30 minute, 1 hour, 12 hour, 24 hour, 1 day, 2 day, 1 week, and 2 week. Twenty-seven cations and six anions from solutions were analyzed by AAs (atomic absorption spectrometer), ICP(induced-coupled plasma), and IC (ion chromatography). Speciation and saturation index of solutions were calculated by WATEQ4F and MINTEQA2 codes, indicating that most of metal ions exist as free ions and that there is little difference in chemical species and relative abundances between initial solution and reacted solutions. The adsorption results showed that the adsorption extent of elements varies depending on mineral types and reaction time. As for illite, adsorption after 1 hour-reaction occurs in the order of As>Pb>Ge>Li>Co, Pb, Cr, Ba>Cs for trace elements and Fe>K>Na>Mn>Al>Ca>Si for major elements, respectively. As for halloysite, adsorption after 1 hour-reaction occurs in the order of Cu>Pb>Li>Ge>Cr>Zn>As>Ba>Ti>Cd>Co for trace elements and Fe>K>Mn>Ca>Al>Na>Si for major elements, respectively. After 2 week-reaction, the adsorption occurs in the order of Cu>As>Zn>Li>Ge>Co>Ti>Ba>Ni>Pb>Cr>Cd>Se for trace elements and Fe>K>Mn>Al, Mg>Ca>Na, Si for major elements, respectively. No significant adsorption as well as selectivity was found for anions. Although halloysite has a 1:1 layer structure, its capacity of adsorption is greater than that of illite with 2:1 structure, probably due to its peculiar mineralogical characteristics. According to FTIR (Fourier transform infrared spectroscopy) results, there was no shift in the OH-stretching bond for illite, but the ν1 bond at 3695 cm-1 for halloysite was found to be stronger. In the viewpoint of adsorption, illite is characterized by an inner-sphere complex, whereas halloysite by an outer-sphere complex, respectively. Initial ion activity and dissociation constant of metal elements are regarded as the main factors that control the adsorption behaviors in a natural system containing multicomponents at the acidic condition.

• Proceedings of the Korean Fiber Society Conference
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• 2001.04a
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• pp.333-337
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• 2001

• Journal of Wetlands Research
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• v.21 no.2
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• pp.152-156
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• 2019

The removal property of magnetic zeolite for the adsorption of aqueous ammonium ion was examined in this work. The surface modified magnetic zeolite was produced by hydrothermal synthesis. The complex of zeolite and $Fe_3O_4$ was established by the observation of SEM and XRD analysis and less than 12.6% of $Fe_3O_4$ content in magnetic zeolite was observed in the form of $Fe_3O_4$ particles. The optimum pH of adsorption was shown around 8 and the maximum adsorption linearly decreased with the increase of $Fe_3O_4$ content. The adsorption isotherm for aqueous ammonium ion was approximated by Langmuir equation. The developed surface modified magnetic zeolite adsorbent was recommended to control the nitrogen pollution for wetland environment system.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.455-469
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• 2008

VOCs (Volatile organic compounds) are known as one of the harmful chemicals, causing cancer and global warming. Therefore, the proper control, removal, and reduction of the emission of VOCs are important tasks for the environmental protection. Among the method of VOCs removal activated carbon bed is the most efficient and economical method. In this study, the adsorption performance of toluene gas was investigated using various activated carbons. To find out the adsorption efficiency, the H/D (Height/Diameter) of the activated carbon and GHSV (Gas Hourly Space Velocity) of the toluene gas were manipulated with various conditions. The effect of the temperature, humidity and toluene-MEK-IPA mixed gas on adsorption were also investigated. As a result, a high adsorption performance was found when GHSV is lower at room temperature and low humidity. It was also found that the adsorption efficiency of toluene-MEK-IPA mixed gas system was lower than that of toluene gas system.

• Korean Journal of Materials Research
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• v.29 no.5
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• pp.336-341
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• 2019

The gas adsorption isotherm requires accurate measurement for the analysis of porous materials and is used as an index of surface area, pore distribution, and adsorption amount of gas. Basically, adsorption isotherms of porous materials are measured conventionally at 77K and 87K using liquid nitrogen and liquid argon. The cold volume calibration in this conventional method is done simply by splitting a sample cell into two zones (cold and warm volumes) by controlling the level sensor in a Dewar filled with liquid nitrogen or argon. As a result, BET measurement for textural properties is mainly limited to liquefied gases (i.e. $N_2$ or Ar) at atmospheric pressure. In order to independently investigate other gases (e.g. hydrogen isotopes) at cryogenic temperature, a novel temperature control system in the sample cell is required, and consequently cold volume calibration at various temperatures becomes more important. In this study, a cryocooler system is installed in a commercially available BET device to control the sample cell temperature, and the automated cold volume calibration method of temperature variation is introduced. This developed calibration method presents a reliable and reproducible method of cryogenic measurement for hydrogen isotope separation in porous materials, and also provides large flexibility for evaluating various other gases at various temperature.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.798-802
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• 1998

Carbon granules were prepared by granulating a mixture of coconut shell powder and coal tar solution, and then by carbonizing at different temperatures. To control micropores of the carbonized granules, the deposition time of benzene vapor under nitrogen atmosphere was varied. For each prepared sample, SEM morphology and true density were investigated. The adsorption rates on the granules were measured with respect to oxygen and nitrogen by means of the Cahn D-200 system. Diffusivity, selectivity and amount of equilibrium adsorption for the gases were obtained from the measurement of adsorption rate. Based on the analysis of the adsorption characteristics, the optimum temperature and the deposition time for preparation of the molecular sieve carbon granules were found to be $800^{\circ}C$ and 10 minutes, respectively. At these optimal conditions, the selectivity coefficient, 26.4, 0f oxygen and nitrogen was obtained.