• 공업화학
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• 제10권1호
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• pp.166-172
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• 1999

폐수중 중금속 이온을 제거하기 위한 방법으로 키토산 비드에 의한 금속 이온의 고정층 흡착 특성을 조사하였다. 게껍질로부터 키틴을 추출하고 이를 탈아세틸화 반응시켜 키토산을 제조하였다. 키토산은 비드로 만들어 중금속 흡착제로 사용하였다. 키토산 비드에 대한 $Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$ 이온의 단성분 평형 흡착 실험 결과로부터 Freundlich와 Langmuir 흡착등온식을 결정하였다. 흡착등온식에 의하면 키토산 비드에 대한 중금속 이온의 흡착 세기는 $Cu^{2+}$>$Co^{2+}$>$Ni^{2+}$의 순서로 나타났다. 키토산 비드에 대한 중금속 이온의 단성분 또는 다성분계 고정층 흡착 실험으로부터 흡착 파과곡선을 구하였다. 단성분 흡착등온식으로 다성분 흡착 평형을 예측할 수 있는 IAS (ideal adsorbed solution) 이론을 적용하여 LDFA (linear driving force approximation)에 의한 고정층 흡착 모델식을 수치해 기법으로 모사하여 실험결과와 비교하였다. LDFA에 의한 모델식을 적용한 결과 키토산 비드에 대한 중금속 이온의 단성분 및 다성분계 고정층 흡착거동을 잘 모사할 수 있었다.

• 한국환경과학회지
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• 제30권9호
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• pp.719-726
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• 2021

In this study, zeolitic materials were synthesized from Jeju Volcanic Rocks (JVR) using a fusion/hydrothermal method at NaOH/JVR ratios of 0.6 and 1.2. The crystallinities of the zeolitic materials at NaOH/JVR ratios of 0.6 and 1.2 were 25.5% and 59.0%, respectively. It was confirmed through the SEM image that the zeolitic materials covered the zeolite particle with a cube-shaped crystals. The Co ions adsorption by the zeolitic materials were to reach the adsorption equilibrium at 120 min. It could be better simulated in the pseudo-second order adsorption kinetic equation than in the pseudo-first order adsorption kinetic equation. The adsorption capacities (q_m) of Co ions could be to estimate Langmuir isotherm better than Freundlich isotherm. The maximum adsorption capacities (q_m) at NaOH/JVR ratios of 0.6 and 1.2 were 55.3 mg/g and 68.7 mg/g, respectively. It was found that there was a high correlation between the crystallinity of zeolitic materials and the adsorption capacity of Co ions adsorption.

• Korean Chemical Engineering Research
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• 제60권4호
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• pp.606-612
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• 2022

실내 거주 시간이 늘어나면서 발생하는 CO₂를 인체에 무해한 농도인 1,000 ppmCO₂ 이하로 유지하기 위해 연구들이 활발히 진행 중이다. 본 연구에서는 저농도 CO₂흡착제로서 KOH와 K₂CO₃와 같은 알칼리성 첨가제를 상용 활성탄에 함침하여 사용하였다. 흡착된 CO₂ 양은열중량분석기(TGA)와 chamber(CO₂ IR analyzer)로평가하였다. 비표면적이 928.5 m²/g인 상용 활성탄(AC)은 KOH가 함침 된 KOH/AC(13.6 m²/g)와 K₂CO₃가 함침 된 K₂CO₃/AC(288.8 m²/g)보다 비표면적이 높았다. 챔버실험결과, AC는 CO₂를 거의 흡착하지 않았지만, KOH/AC와 K₂CO₃/AC는 각각 93.5 mg_CO2/g_sample 및 94.5 mg_CO2/g_sample 흡착하였다. 이것은 비표면적 및 미세기공의 부피에 의한 물리적인 흡착 영향보다 알칼리성 활성점의 증가가 CO₂ 흡착에 더 유리하게 작용한 것으로 판단된다. KOH/AC와 K₂CO₃/AC의 재생성능은 chamber test 결과 대조군(K₂CO₃/Al+Si supports)과 비교했을 때 안정적으로 흡착 성능을 유지하는 것으로 나타났다(3회 반복 실험). 또한, KOH/AC와 K₂CO₃/AC는열중량분석기의절대습도 1%H₂O를고려한조건에서 145.7 mg_CO2/g_sample및 150 mg_CO2/g_sample로 나타났다. 따라서 KOH 및 K₂CO₃ 등과 같은 알칼리 성분의 함침은 상용 활성탄의 안정적인 흡착 및 재생 후 흡착성능을 나타내어, 실내 이산화탄소 저감을 위한 흡착제 개발에 적용될 수 있을 것으로 판단된다.

• Carbon letters
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• 제11권1호
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• pp.34-37
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• 2010

In this work, graphite nanofibers (GNFs) were prepared by ammonia and heat treatment at temperatures up to $1000^{\circ}C$ to improve its $CO_2$ adsorption capacity. The effects of the heat treatment on the textural properties and surface chemistry of the GNFs were investigated by $N_2$ adsorption isotherms, XRD, and elemental analysis. We found that the chemical properties of GNFs were significantly changed after the ammonia treatment. Mainly amine groups were formed on the GNF surfaces such as lactam groups, pyrrole and pyridines. The GNFs treated at $500^{\circ}C$ showed highest $CO_2$ adsorption capacity of 26.9 mg/g at 273 K in this system.

• 신재생에너지
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• 제5권4호
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• pp.46-51
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• 2009

The purpose of this study is to investigate selective adsorption of $CO_2$ from LFG (Landfill gas) by using commercialized NaX-type zeolite adsorbent under the ambient temperature and pressure. The experiment of $CO_2$ adsorption was carried out by using simulated LFG. The $CO_2$ adsorption capacity and separation efficiency of NaX-type adsorbent were investigated by analyzing gas flow rate and gas composition at inlet and outlet of the adsorption reactor. The adsorbed $CO_2$ were desorbed under decompression condition which 0.5 Torr or by air purge. Through the result to use simulated LFG, when the method of VSA was used, 73.2~75.3 mg of $CO_2$ was adsorbed per 1 g commercial adsorbent, when the method of air purge was used, 78.4~83.2 mg of $CO_2$ was adsorbed per 1 g of commercial adsorbent.

• Carbon letters
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• 제10권3호
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• pp.198-201
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• 2009

Among other filters such as light filter, wave filter, air filter, ultra filter and filter paper, a novel adsorption filter from thermostable polyester nonwoven fabrics immobilized with functional super activated carbon by means of quinoline soluble, activateable isotropic pitch binder were developed in this study. The activated carbon precursor is available in the market branded as coconut shell based activated carbon(CCS-AC) produced by Dongyang Carbon Co. Ltd. BET-surface area of this precursor was $1,355\;m^2/g$, after KOH-activation it increased over $2,970\;m^2/g$ and was named as super activated carbon. In the preliminary research, this precursor was impregnated with $PdCl_2$(0.188 wt%) $KMnO_4$(3 wt%) and redox-agent(CuCl2, 0.577 wt%) in order to promote TOF up to 100/h and Selectivity up 99% and patented as a functional AC for the ethylene adsorption. The enhancement of the isotropic pitch binder to the AC-immobilized adsorption filter was BET-surface area upgraded by $266\;m^2/g$ and promoted the Iodine- and MB-adsorption by 1.4 times, respectively and also micro pore wide ranges < $5{\AA}{\sim}30\;{\AA}$ >.

• 한국환경과학회지
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• 제22권7호
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• pp.847-853
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• 2013

Functionalized adsorbent has been synthesized by piperazine(Pz) on activated carbon. Quantitative estimations of $CO_2$ were undertaken using gas chromatography with GC/TCD and the prepared adsorbents were characterized by BET surface area and FT-IR. It was also studied effect of various parameters such as piperazine loadings and adsorption temperature. The specific surface area decreased from $1212.0m^2/g$ to $969.8m^2/g$ by impregnation and FT-IR revealed a N-H functional group at about $1400cm^{-1}$ to $1700cm^{-1}$. The $CO_2$ adsorption capacity at $20^{\circ}C$ and $50{\sim}100^{\circ}C$ was as follow: AC > Pz(10)-AC> Pz(30)-AC> Pz(50)-AC at $20^{\circ}C$ and Pz(10)-AC > AC > Pz(30)-AC> Pz(50)-AC at $50{\sim}100^{\circ}C$. Therefore, for high temperature flue gas condition, the Pz(10)-AC showed the highest adsorption capacity due to physical adsorption and chemical adsorption by amino-group content. The results suggest that activated carbon impregnated with Pz is an effective adsorbent for $CO_2$ capture from real flue gases above $50^{\circ}C$.

• Environmental Engineering Research
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• 제19권3호
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• pp.289-292
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• 2014

The effect of carbon dioxide ($CO_2$) on global warming is serious problem. The adsorption with solid sorbents is one of the most appropriate options. In this study, the most interesting adsorbent is granular activated carbon (GAC). It is suitable material for $CO_2$ adsorption because of its simple availability, many specific surface area, and low-cost material. Afterwards, GAC was impregnated with chitosan solution as impregnated granular activated carbon (CGAC) in order to improve the adsorption capacity of GAC. This research aims to compare the physical and chemical characteristics of GAC and CGAC. The experiment was carried out to evaluate the efficiency of $CO_2$ adsorption between GAC and CGAC. The results indicated that the iodine number of GAC and CGAC was 137.17 and 120.30 mg/g, respectively. The Brunauer-Emmett-Teller results (BET) of both GAC and CGAC show that specific surface area was 301.9 and $531.3m^2/g$, respectively; total pore volume was 0.16 and $0.29cm^3/g$, respectively; and mean diameter of pore was 2.18 and 2.15 nm, respectively. Finally, the $CO_2$ adsorption results of both GAC and CGAC in single column how the maximum adsorption capacity was 0.17 and 0.25 mol/kg, respectively; how degeneration time was 49.6 and 80.0 min, respectively; and how the highest efficiency of $CO_2$ adsorption was 91.92% and 91.19%, respectively.

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.628-635
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• 2016

Natural gas reformed hydrogen is used as a fuel of fuel cell vehicle, PSA process is used for the purification of reformed hydrogen. In this study, the performance of CO adsorbent in PSA process was evaluated. Zeolite adsorbents used in the commercial PSA process is used. The physical and chemical properties of adsorbents were characterized using BET apparatus, XRD, and FE-SEM. The breakthrough apparatus modified from GC was used for the CO breakthrough experiment, the quantitative analysis of CO adsorption capacity was performed using CO breakthrough curve. Zeolite 10X and 13X showed superior CO adsorption capacity than activated alumina. The CO adsorption capacity of zeolite 10X is more than twice of zeolite 13X even the BET surface area is low. It seems that the presence of $Ca^{2+}$ cation in zeolite 10X is beneficial to the adsorption of CO.

• 공업화학
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• 제30권1호
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• pp.29-33
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• 2019

탄소 nanotube, nanofiber 및 powder를 사용하여 아세틸렌 흡착실험을 수행한 결과 탄소 nanotube가 최적의 흡착성분을 보였다. 이를 지지체로 하여 Pd 농도 0~5%, 흡착온도 $30{\sim}80^{\circ}C$ 및 $C_2H_2/CO_2$의 비 3~10의 범위에서 3-요인, 3-수준의 Box-Behnken Design(BBD)으로 15개의 실험 조건을 설계했다. 이를 바탕으로 2차 다항식 회귀분석으로 운전조건에 따른 흡착량 예측식을 도출하였다. ANOVA 분석의 F-value 측정에 따라 흡착온도가 가장 큰 영향지수를 보였고 $C_2H_2/CO_2$의 비는 가장 작은 영향지수 보이는 것으로 나타났다. 하지만 주요인자 간의 교호작용은 거의 없는 것으로 분석되었다. 흡착량 최적화 분석에서 Pd 농도 3.0%, 흡착온도 $47^{\circ}C$ 및 $C_2H_2/CO_2=10$인 조건에서 22.0 mmol/g이 흡착되는 것으로 계산되었고 실제 실험치에 95.9%의 정확도를 보였다.