• Clean Technology
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• v.19 no.4
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• pp.370-378
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• 2013

This review has shown the capability of MOFs and ZIFs materials to adsorb $CO_2$ under typical PSA temperatures and pressures. The usual operating conditions are adsorption temperatures of $15{\sim}40^{\circ}C$ and adsorption pressures of 4~6 bar based on numerous PSA processes which are widely employed in gases industry for adsorptive separation of $CO_2$. The extent of $CO_2$ adsorption on the microporous materials depends on the metal species and organic linkers existing in the frameworks. The pore size and the surface area, and the process variables are the key parameters to be associated with the efficiency of the adsorbents, particularly adsorption pressures if other variables are comparable each other. The MOFs and ZIFs materials require high pressures greater than 15 bar to yield significant $CO_2$ uptakes. They possess a $CO_2$ adsorption capacity which is very similar to or less than that of conventional benchmark adsorbents such as zeolites and activated carbons. Consequently, those materials have been much less cost-effective for adsorptive $CO_2$ separation to date because of very high production price and the absence of commercially-proven PSA processes using such new adsorbents.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.31-37
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• 2013

To acquire enhanced adsorption capacity for especially targeted VOCs, activated carbon fiber of which surface area was $1,100m^2/g$ was selected and active metals were loaded. After screening study, Cr and Cu were selected as a base metal for improving adsorption capacity of activated carbon fiber. For acquiring better performance, metal loading, loading temperature, loading hours and kinds of loaded metals were changed as preparing variables. Properties measurement and adsorption capacity evaluation were performed. We found that the best conditions for metal loading were 5 hours loading at $100^{\circ}C$ and the adsorption capacity was enhanced almost double. Also we confirmed that more than 0.5 seconds contact time is needed for best adsorbate diffusion and adsorption over activated carbon fiber.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.277-285
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• 2007

The adsorption characteristics of multi-component solvent vapors including poorly-adsorbable chemicals such as toluene-xylene-MEK and toluene-MEK-IPA on the activated carbonaceous adsorbents were investigated in a stainless steel fixed bed of 10.2 cm ID and 50 cm in height in order to identify those carbons for eliminating and recovering solvent vapors from industrial emission sources. The used activated carbonaceous adsorbents were pelletized commercial activated carbons and activated carbon fiber. Breakthrough curves and adsorption capacity at atmospheric pressures were obtained. It has been found that non-polar and larger molecules have been adsorbed better than polar and smaller molecules. In special, alcohols and ketones were poorly adsorbed caused by competitive adsorbability in multi-component mixture system. However, it could be overcome by profitable employment of organization of cooperative system which was composed of different porosity activated carbonaceous adsorbents appropriately.

• Journal of the KSME
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• v.34 no.11
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• pp.877-886
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• 1994

흡착계의 선택은 냉동기의 본질적인 성능을 결정하기 때문에 사용하는 열교환기의 전열특성, 시스템의 구성 등과 함께 중요한 위치를 차지하고 있다. 따라서 사용목적에 맞는 흡착계의 선 택이 중요하다. 여기서는 흡착식 히트펌프의 성능특성과 실용화를 위한 연구 개발 요점 등을 정리하였다.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.60-68
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• 2006

소수 station의 수소분리정제를 위한 compact형 PSA 공정을 연구하였다. 기존 PSA 공정의 흡착탑이 차지하는 시스템의 공간을 줄이기 위하여 하나의 흡착탑 안에 다른 흡착탑을 넣어 흡착탑이 차지하는 공간을 최소화하였으며, 흡착탑 간의 열교환이 효과적으로 일어나도록 설계하였다. 수소 혼합물에 대한 활성탄으로 충진된 dual bed에서의 수소 혼합물에 대한 흡/탈착 동특성 실험을 실시하였으며, 시간에 따른 농도와 온도의 변화를 측정하였다. 수소 혼합물로는 $H_2/CO/CH_4/CO_2$ (69:2:3:26 vol.%) 를 사용하였으며, 흡착유량은 7LPM, 흡착압력은 9atm 조건에서 운전하였다. Inner bed와 outer bed의 성능은 각각의 열전달 특성의 차이로 인하여 다르게 나타났으나, 단일탑의 동특성보다는 우수한 성능을 보이고 있었다. 따라서 개발된 dual bed는 적은 부지를 차지하면서도, 보다 우수한 수소 분리 성능을 보일 수 있는 PSA 공정에 응용될 수 있음을 확인하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.162-165
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• 2006

유해성 유기물질로 오염된 토양의 복원을 위한 토양세척공정에서 계면활성제를 선택적으로 재이용하기 위해 활성탄을 이용한 흡착 칼럼의 성능을 평가하였다. 계면활성제로는 Triton X-100을 소수성 유해 유기물질로는 다환방향족 탄화수소의 하나인 phenanthrene를 사용하여 그 성능을 평가하였다. 계면활성제의 흡착은 phenartthrene에 비해 빠른 흡착 특성을 보였으며 phenanthrene은 계면활성제의 포화흡착상태에서도 지속적으로 흡착이 이루어졌다. 이는 계면활성제의 흡착이 종료된 이후에도 유해성 유기물질의 지속적인 흡착을 기대할 수 있어 계면활성제의 지속적인 재이용과 활성탄 사용시간의 증대를 가져올 수 있음을 의미한다. 이와 같은 활성탄 칼럼에서의 유해성 유기물질의 우수한 선택적 흡착 결과는 기본적으로 소수성 정도의 차이와 size exclusion에 의한 기작뿐만 아니라 활성탄에 흡착된 계면활성제에 의한 다환방향족 탄화수소의 추가적인 흡착이 일어나 전체적인 성능이 향상되는 것에 기인한다.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.765-771
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• 2018

In this study, the optimization of carbonization conditions in manufacturing processes was performed to improve the absorption performance of sewage sludge based sorbent used for treating $H_2S$ out of all odorous substances generated by various environmental facilities. Adsorbents applied were manufactured from the sewage treatment plant under different carbonization conditions, such as temperature and heating rate, and the correlation between the adsorption performance and physical properties of the adsorbents was verified. As a result, the adsorption performance of sludge at $900^{\circ}C$ with a heating rate of $10^{\circ}C/min$ was the best, and the SEM and BET analysis revealed that specific surface area and characteristics of pore (size, volume) were major parameters for the adsorption. In addition, the effect of K ions used for improving the adsorption performance of the optimum carbonization condition sorbent was insignificant for the sewage sludge based sorbent.

• Clean Technology
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• v.25 no.3
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• pp.189-197
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• 2019

In this study an optimization of the preparation conditions of activated carbon with a ternary metal ion material to treat $H_2S$, which is classified as a representative odor substance, was carried out. For a metal ion material for enhancing the adsorption performance of hydrogen sulfide, performance enhancement was confirmed by combining Li and Fe or a ternary combination (K, Li, Fe) based on KI, which is a substance promoting hydrogen sulfide adsorption performance. Also, it was determined by XRD analysis that the reaction of each active substance with $H_2S$ was because of binding. The adsorption performance increased more than 3 times with heat treatment of the adsorbent with nitrogen compared with heat treatment with air. The maximum adsorption constant ($q_m$) value of the optimum adsorbent was 97.07, which is 6 times higher than that of the existing K-based impregnated activated carbon. It was confirmed that the objective adsorption amount ($0.3g\;g^{-1}$) was secured by an equilibrium between the mass transfer rate and adsorption rate. From the results, it was confirmed that the performance improvement was noticeable even when activated carbon with a reagent grade activated carbon particle size was modified. It was confirmed that the adsorption performance exists at high relative humidity levels of 60 and 100%, and the optimized preparation can be applied to a wet process such as a scrubber downstream.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.472-478
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• 2013

Cu and Cr as a base metal and Pt, Pd as a supportive metal were selected for improving adsorption capacity of activated carbon fiber in eliminating especially targeted VOCs. Preparing variables such as metal loading, loading temperature, loading hours and kinds of loaded metals were changed. Properties measurement was carried out by SEM (scanning electron microscope), XRF (x-ray fluorescence analysis) and EDX (Energy Dispersive X-ray spectrometer) and adsorption capacity evaluation were also performed by gas analyzer. Under this study, the adsorption capacity of complex metal loaded activated carbon fiber was improved positively than that of single metal loaded activated carbon fiber. And we found that the best conditions for metal loading were 5 hours loading time at $100^{\circ}C$ and the adsorption capacity was enhanced almost double compared with other condition based activated carbon fiber. Cu-Cr-Pt-Pd loaded activated carbon fiber showed the best adsorption capacity. Also we confirmed that more than 0.5 second is necessary for adsorbate diffusion and adsorption over activated carbon fiber.

• Composites Research
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• v.35 no.2
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• pp.98-105
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• 2022

In this study, polyvinyl alcohol (PVA)/graphene oxide (GO)/iron oxide (Fe₃O₄) magnetic microgels were prepared using a microfluidic approach and the dye adsorption capacity of the microgels was confirmed. The adsorption capacity (q_e) of the gels was evaluated by varying the dye concentration, pH, and contact time with the microgels. The dyes used in this work were methylene blue (MB), crystal violet (CV), and malachite green (MG), and microgels showed the highest adsorption capacity (191.1 mg/g) in methylene blue. The microgels exhibited the highest adsorption capacity in the dye aqueous solution at pH 10 due to the presence of atomic nitrogen ions (N⁺) on the dye molecules. The adsorption isotherm studies revealed that the Langmuir isotherm is the best fit isotherm model for the dye adsorption on the microgels, indicative of monolayer adsorption. The kinetic analysis exhibited that the pseudo-second order model fits better than the pseudo-first order model, confirming that the adsorption process is chemisorption. In addition, the magnetic microgels showed good reusability and recovery efficiency. It was confirmed that the adsorption capacity of the gels maintains more than 70% of the initial capacity after 5 times of cycle experiments.