• Carbon letters
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• 제4권1호
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• pp.14-20
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• 2003

Based on the previous results of the equilibrium and batch adsorptions, the removal efficiency of the two-step surface-modified activated carbon ($2^{nd}AC$) for heavy metal ions such as Pb, Cd, and Cr in fixed column was evaluated by comparing with that of the as-received activated carbon (AC) and the first surface-modified activated carbon ($1^{st}AC$). The order of metal removal efficiency was found as $2^{nd}AC$ > $1^{st}AC$ $\gg$ AC, and the efficiency of the $2^{nd}AC$ maintained over 98% from the each metal solution. Increase of the removal efficiency by the second surface modification was contributed to maintain favorable pH condition of bulk solution during adsorption process. The removal of the heavy metals on the $2^{nd}AC$ was selective with Pb being removed in preference to Cr and Cd in multicomponent solutions and slightly influenced by phenol as the organic material.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.341-346
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• 2005

Nowadays, adsorption chillers have been receiving considerable attentions as they are energy-saving and environmental1y benign systems. A Fin & tube type heat exchanger in which adsorption/desorption take place is required more compact size. The adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to investigate the effect of fin pitch of fin & tube on the adsorption performance and to develop an optimal design fin & tube heat exchanger in the silica gel/water adsorption chiller. Previous study concluded that optimal particle size selected 0.5mm, type HO silica gel, and fundamental heat transfer & mass transfer experiments carried out. From the numerical results, the adsorption rate for the fin pitch 2.5mm is the highest than that for the fin pitch 5mm, 7.5mm and 10mm. Also cooling water & hot water temperature affect the adsorption rate.

• Korean Chemical Engineering Research
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• 제59권2호
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• pp.260-268
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• 2021

Adsorption is the most promising technology used to adsorb CO2 to reduce its concentration in the atmosphere due to its functional effectiveness. Various porous materials have been extensively synthesized to boost CO2 adsorption efficiency, for example, zeolite. Here, we report the synthesis process of zeolite adsorbent impregnated with amine, combining the benefit of these two substances. We compared conventional heating with microwave-assisted heating by varying concentrations of monoethanolamine in methanol (10% v/v and 40% v/v) as a liquid solution. The results showed that monoethanolamine impregnation helps significantly increase adsorption capacity, where adsorption occurs as a physisorption and not as chemisorption due to the adsorbent's steric hindrance effect. The highest adsorption capacity of 0.3649 mmol CO2 / gram adsorbent was reached by microwave exposure for 10 minutes. This work also reveals that a decrease in CO2 adsorption capacity was observed at a longer exposure period, and it reached a constant 40-minute adsorption rate. Impregnating activated zeolite with 40% monoethanolamine for 10 minutes in addition to microwave exposure (0.8973 mmol CO2 / gram adsorbent) is the maximum adsorption ability achieved.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2198-2206
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• 2018

We addressed the development of a novel, low-cost, and high-efficient material from hybrid materials, known as microcapsules. Microcapsules are a composite adsorbent made of a mixture of tannin, sericite and chitosan. The FT-IR analysis showed that the microcapsules contain hydroxyl, carboxyl, carbonyl, and amino groups, which play an important role in the adsorption of heavy metals. The microcapsules were able to remove 99% of Pb(II) in 30 min, and obtained a removal efficiency of more than (13-50)%, compared with the single adsorbents of tannin, chitosan, and sericite. In adsorption kinetic analysis, pseudo-second-order adsorption was more suitable than pseudo-first-order adsorption, and chemical adsorption did not limit the adsorption rate of Pb(II) ion. In isothermal adsorption, Langmuir adsorption was more suitable than Freundlich adsorption, and the maximum Langmuir adsorption capacity was 167.82 (mg/g). Furthermore, desorption and reusability studies, as well as the applicability of the material for wastewater treatment, demonstrated that microcapsules offer a promising hybrid material for the efficient removal of significant water pollutants, i.e., Pb(II) from aqueous solutions.

• Nuclear Engineering and Technology
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• 제16권3호
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• pp.161-168
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• 1984

습윤 조건하에서 triethylenediamine (TEDA) 합침황성탄소층의 시간에 따른 methyl iodide제거 효율을 예측하기 위한 흡착모델이 제안되었다. 습윤 조건하에서 평형 흡착용량과 유효 가공 확산 계수의 감소가 고려되었다. 예측된 값은 실험결과와 비교되었다.

• 한국대기환경학회지
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• 제17권1호
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• pp.67-74
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• 2001

In the manufacturing process of PCB , three kinds of VOCs such as aceton, methanol and 2-metoxyethanol are being used. In this study, adsorption characteristics of activated carbon fibers(ACFs) and active carbon were examined to temove these VOCs. The experimental results showed that ACF has better adsorption and regeneration efficiency than activated carbon. Phenolic-resin based ACF showed the highest adsorption capacity and the capacity was not decreased after repeated regeneration by steam. On the adsorption and desorption experiments for ternary components, preferential adsorption with roll-over phenomena was appeared. 2-Metoxyethanol was strong adsorbaste and it displaced adsorbed methanol and aceton.

• Carbon letters
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• 제2권2호
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• pp.109-112
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• 2001

For the adsorption of ammonia, activated carbon fibers (ACFs) were subjected to sulfuric acid treatment in order to modify the surface functional groups. The surface acid and base value of ACFs were measured using titration and FT-IR spectrometry. SEM was used to investigate the surface morphology. Acid treatments by $H_3PO_4$, $H_2SO_4$, and $HNO_3$ were performed to increase the adsorption capacity of $NH_3$. As a result, Cellulose-based ACF has high adsorption capacity for ammonia. The ammonia removal efficiency of ACF was the maximum which was treated by 15 wt% sulfuric acid at $100^{\circ}C$ for 60 min. The average pore diameter little increased from $19{\AA}$ to $20.8{\AA}$ and the specific surface area of ACF considerably decreased and acid values increased by 15 wt% sulfuric acid treatment. Ammonia reacted with sulfonyl radicals. After adsorption of ammonia, white material was grown on the surface of ACF through the adsorption of ammonia and it was determined to ammonium sulfate.

• 대한기계학회논문집B
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• 제31권2호
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• pp.116-124
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• 2007

An adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objective of this paper is to investigate the performance of silica gel-water adsorption chiller from the cycle simulation and to provide a guideline for design of the adsorption chiller. The effect of cycle time, inlet temperature and water flow rate on the cooling capacity and COP is quantified during the cycle operation. It is found that the performance of adsorption chiller is more sensitive to the change of inlet water temperature rather than the water flow rate. It is concluded that the COP is 0.57 in the standard conditions(hot water $80^{\circ}C$, cooling water $30^{\circ}C$, chilled water inlet temperatures $14^{\circ}C$ and cycle time 420sec).

• 대한환경공학회지
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• 제27권3호
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• pp.231-239
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• 2005

본 연구에서는 MTBE, 카드뮴의 점토광물 종류 및 물리화학적 특성에 따른 흡착 경향 및 계면동전위의 특성을 규명하고자 흡착시간, 혼합비(용매 대 흡착질 비), 오염물질의 농도, 휴믹산 및 pH 변화에 따른 회분식 흡착실험을 수행하였다. 혼합비가 증가할수록 초기농도에 상관없이 흡착량은 증가한 반면, 흡착 효율은 감소하였다. MTBE의 흡착량은 vermiculite> bentonite> CTAB-bentonite 순으로 높았으며, 카드뮴의 흡착량은 bentonite> vermiculite> CTAB-bentonite 순이었다. 이때 MTBE 흡착은 Freundlich 등온 흡착식에 가장 잘 부합되었으며, 카드뮴의 경우 Langmuir 등온 흡착식에 잘 적용되었다. 유기물 함량에 따른 MTBE의 흡착실험 결과 CTAB-bentonite는 유기물의 함량이 높을수록 흡착량이 증가하였으나 bentonite는 유기물 함량 1%, vermiculite는 5%에서 최대 흡착량을 보인 후 감소하였다. 반면 카드뮴은 유기물 함량이 증가할수록 모든 흡착제의 흡착량과 흡착율이 급격히 증가하였다. 카드뮴의 흡착량과 흡착율은 모든 흡착제에 대해 pH 8 이상부터 급격히 증가하였으며, pH 10 이상의 경우 흡착율이 90%까지 증가하였다. 또한 pH가 증가할수록 각 흡착제의 계면동전위는 감소하였고, 카드뮴의 농도가 증가할수록 계면동전위의 절대치가 감소하여 분산안정성이 낮아져 결과적으로 카드뮴의 흡착 효율이 증가하였다.

• 공업화학
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• 제34권6호
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• pp.576-583
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• 2023

본 연구는 돼지 뼈 기반의 바이오매스를 가지고 새로운 흡착재의 활용가능성을 조사하였다. 이를 위하여 돼지 뼈 기반 활성탄소(pig bone based activated carbon, PAC)의 물리화학적 특성을 확인하고 이산화탄소 흡착 성능을 고찰하였다. 활성화제로 KOH를 사용하였으며, 활성화 온도가 증가할수록 비표면적이 증가하며 이산화탄소의 흡착 효율도 증가하였다. 800 ℃에서 활성화된 샘플은 1208.7 m²/g로 가장 큰 비표면적을 나타내었으며, 273 K, 1 bar에서 3.33 mmol/g로 높은 이산화탄소 흡착 효율을 보였다. 그러나 활성화 온도가 900 ℃ 이상인 조건에서는 결정성의 변화 및 과활성화로 인하여 비표면적과 이산화탄소 흡착 효율이 감소하였다. 한편 이상흡착용액이론으로 그 선택도 계산을 수행하였을 때, 273 K, 0.8 bar 이하에서 PAC-900 샘플이 가장 좋은 선택도를 보였다. 이러한 결과는 273 K에서의 이산화탄소/질소 흡착은 900 ℃에서 돼지 뼈가 활성화될 때 탄산염이 분해됨으로써 형성된 하이드록시아파타이트의 이산화탄소 흡착성과 그 결정성으로 인해 높은 선택도가 얻어진 것으로 판단된다.