• 한국의류학회지
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• 제12권1호
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• pp.27-35
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• 1988

In order to investigate a practical application of the fibrous adsorbent to heavy metal ions, acrylic fibers were treated with the hydroxylamine solution that was producted by hydroxylamine hydrochloride and potasium hydroxide in a condition of strong alkaline and $70^{\circ}C$. The adsorption mechanism of copper(2) ion on the fibrous adsorbent, that is hydroxylaminated acrylic fibers, was studied. The adsorption of copper(2) ion was explained in terms of the activated adsorption that are formed the complex with the ligand, such as C=N, N-H, NHOH, on the surface of the adsorbent. The activation energy was evaluated to be 3.8 Kcal/mol. and the times of adsorption equilibrium was approximately 10 minutes. The uptake of copper(2) ion was found to be effected with the increase of temperatures and the pH dependence.

• 한국가스학회지
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• 제19권2호
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• pp.37-44
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• 2015

본 연구에서는 CBM의 1차 생산뿐 아니라 $CO_2$나 $N_2$ 주입을 통한 ECBM, 혹은 지중저장을 목적으로 석탄층에 $CO_2$를 주입할 때 발생할 수 있는 암체의 부피변화 영향을 고려하여 기존의 Langmuir 흡착 관계식을 개선하였다. 본 모델의 검증을 위해 $CO_2$나 $CH_4$, $N_2$의 단일성분 흡착실험 데이터에 기존 Langmuir 모델값과 본 모델의 결과값을 비교하였다. 그 결과, 기존 모델에서는 흡착용량이 큰 석탄일수록, 흡착친화도가 큰 가스일수록 실험값과 모델값 사이의 오차가 커지는 경향이 나타났지만 본 모델에서는 모든 조건에서 실험결과를 잘 묘사하였고 본 모델을 통해 예측한 부피변형률 역시 실험값과 유사함을 확인하였다. 이렇게 개선된 단일성분 흡착모델을 혼합가스의 흡착모델인 IAS 모델에 적용하여 부피변화가 고려된 IAS모델로 개선하였다. 그 결과 혼합가스에 대한 흡착거동 역시 기존 모델에 비해 정확도를 높였고 이는 Hall 등(1994)이 수행한 혼합가스의 흡착실험결과와의 매칭을 통해 확인하였다.

• 한국수처리학회지
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• 제26권6호
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• pp.143-152
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• 2018

The process parameters of ethyl violet from aqueous solution by activated carbon adsorption were carried out as a function of pH, temperature, contact time, initial concentration and temperature. The adsorption equilibrium data can be described well by the Langmuir and Freundlich isotherm models. Base on Langmuir constant ($R_L=0.0343{\sim}0.0523$) and Freundlich constant (1/n=0.1633~0.1974), This process could be employed as effective treatment for adsorption of ethyl violet. The kinetic experimental results showed that the adsorption process can be well described with the pseudo second order model. Based on the positive enthalpy (6.505 kJ/mol), the adsorption of ethyl violet onto granular activated carbon is endothermic. The negative Gibbs free energy (-1.169~-1.681 kJ/mol) obtained indicates that the adsorption process is spontaneous and physisorption.

• 상하수도학회지
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• 제8권1호
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• pp.34-43
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• 1994

It is well known that the adsorption character of activated carbon is dependent on the specific surface area and pore volume, but the relationship between the surface-chemical structure and the adsorption character has not been studied very often. The purpose of this study is to investigate the effect of the acidic surface functional groups of activated carbon and the adsorption characteristics of low concentration phenol. So three types of activated carbons and four different treatments were introduced to this isotherm experiment. These treatments were nontreatment, 1N $HNO_3$ treatment, 6N $HNO_3$ treatment, $H_2O_2$ treatment. The conclusions of this study are as followings. If the initial concentration of phenol is high as 5mg/l, the adsorption is dependent on the specific surface area. If the initial concentration of phenol is low as $100{\mu}g/l$, the adsorption is dependent on the average pore volume. The acidic surface functional groups prevent the adsorption of phenol molecules to activated carbon. And the adsorbed amount decreases more for $HNO_3$ treatment than for $H_2O_2$ treatment and more for concentrated $HNO_3$ treatment than for dilute $HNO_3$ treatment.

• 대한화학회지
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• 제35권3호
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• pp.204-210
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• 1991

Citrate 공침법으로 합성한 여러가지 perovskite형 복합산화물 흡착제에 대한 질소와 아르곤의 흡착등온곡선을 액체질소 온도에서 BET 중량 흡착장치를 사용하여 측정하였다. 여러 universal adsorption isotherm을 이용하여 흡착층의 통계적 두께 t를 구한 후, 측정한 흡착량을 각각의 통계적 두께 t에 대해서 도시하였다. 이 V-t plot으로부터 얻은 t-method 표면적과 BET 표면적을 비교하였다. 그리고 이 도시 결과에 입각해서 여러 universal adsorption isotherm의 적합성을 고찰하였다.

• Korean Chemical Engineering Research
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• 제56권6호
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• pp.909-913
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• 2018

A hydrocarbon trap (HT) plays an important role of controlling vehicle emissions in the so-called cold emission period by holding hydrocarbons until three way catalysts (TWCs) are thermally activated. In this study, we have investigated the adsorption characteristics of cation (H, La, K, and Ag)-exchanged ZSM-5 zeolites for hydrocarbons (propylene, n-butane, and toluene) by DFT (density functional theory)-based computational chemistry. Cation exchange is to improve the hydrothermal stability of zeolites and their adsorption capacity, thereby rendering cation-exchanged zeolites promising materials for HT. The idea of cluster approximation makes the calculation of adsorption energies superbly efficient in computation. The results showed that Ag-exchanged ZSM-5 would be the best for the adsorption of all three adsorbates, without often encountered Ag oxidation in experiments. Besides, the hydrothermal stability of La-exchanged ZSM-5 was confirmed from the change of geometrical parameters by cation exchange, and it showed good adsorption capacity for propylene and toluene. Hydrogen-exchanged ZSM-5 was also good for hydrogen adsorption, but had poor hydrothermal stability.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.527-534
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• 2012

FCC 연료가스로부터 에틸렌 회수를 위한 흡착공정을 개발을 위하여 활성탄(AC)과 탄소분자체(CMS)로 충진된 흡착탑의 흡착 동특성을 비교하였다. FCC 연료가스로는 6성분($CH_4/C_2H_4/C_2H_6/C_3H_6/N_2/H_2$,32:15:14:2:12:25 vol.%) 혼합가스를 이용하였으며, 흡착탑의 흡착 및 탈착파과 실험을 실시하였다. 활성탄 흡착탑의 경우 파과는 $H_2$ < $N_2$ < $CH_4$ < $C_2H_4$ < $C_2H_6$ 순서로 나왔으며, CMS 흡착탑의 경우는 $H_2$< $CH_4$ < $N_2$ < $C_2H_6$ < $C_2H_4$ 순서를 보였다. CMS 흡착탑은 활성탄 흡착탑보다 성능이 나쁘나, 속도분리의 특성으로 $CH_4$와 $N_2$뿐만 아니라 활성탄에서 제거하기 어려운 $C_2H_6$ 이상의 성분들을 흡착단계에서 제거할 수 있다. 흡착탑의 재생은 감압과정만으로는 두 흡착제 충진탑에서 충분히 재생되기 어려우며, 진공재생이 필요하다. 따라서 CMS를 이용하는 흡착공정은 전처리 공정으로 설계하고, 활성탄을 이용하는 흡착공정을 주요 분리기로 설계하는 압력진공순환식 흡착공정(PVSA)이 에틸렌 회수에 제안될 수 있다.

• Carbon letters
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• 제15권4호
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• pp.295-298
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• 2014

In this work, nanoporous carbons (NPCs) were prepared by the self-assembly of polymeric carbon precursors and block copolymer template in the presence of tetraethyl orthosilicate and colloidal silica. The NPCs' pore structures and total pore volumes were analyzed by reference to $N_2$/77 K adsorption isotherms. The porosity and elemental mercury adsorption of NPCs were increased by activation with carbon dioxide. It could be resulted that elemental mercury adsorption ability of NPCs depended on their specific surface area and micropore fraction.

• Carbon letters
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• 제11권3호
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• pp.206-210
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• 2010

Removal of dyes Reactive Blue 221, N Blue RGB and Acid Blue MTR using two different samples of activated carbon by static batch method was studied. Experimental data on optical density of solutions at different concentrations ranging from 10 to 100 mg/L and of solutions after adsorption on activated carbon samples were measured. Calibration curves were plotted and the amount of dye $q_e$ adsorbed was calculated. The data was fitted to Langmuir and Freundlich isotherms for two different carbon samples and different concentration and pH values. Constants were calculated from the slope and intercept values of the isotherms. Coefficient of correlation $R_2$ and Standard Deviation SD were also noted. The data fitted well to the isotherms. Carbon sample $C_1$ showed higher potential to adsorb all the three dyes. Adsorption was higher at lower concentrations. Carbon sample $C_2$ showed better adsorption in acidic pH as compared to in alkaline pH. From the analysis of the data capacity of $C_1$ and $C_2$ to remove the dyes from water have been compared.

• Journal of Electrochemical Science and Technology
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• 제11권2호
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• pp.117-131
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• 2020

The adsorption of N-[(E)-Pyridin-2-ylmethylidene] aniline, a Schiff base, on to mild steel surface in 1M HCl and 0.5 M H₂SO₄ solutions and the consequent corrosion protection were studied employing weight loss method, electrochemical impedance spectroscopy and potentiodynamic polarization measurements. DFT calculations were performed to investigate its interaction with the metal surface at the atomic level to understand its inhibition mechanism. The adsorption process is well described by the Langmuir isotherm. The thermodynamic parameters indicated that the adsorption is spontaneous and the interaction of the inhibitor at the mild steel surface is mainly through physisorption. The R_a values obtained in AFM studies for the uninhibited and inhibited sample in HCl media respectively are 0.756 and 0.559 ㎛, and that in H₂SO₄ media are 0.411 and 0.406 ㎛. The lesser roughness values of the inhibited sample shows the adsorption of the molecules onto the mild surface. The inhibition efficiencies were found to improve with concentration of the inhibitor and the maximum efficiency was observed at 400ppm in all the investigation methods adopted. The inhibitor was found to exhibit a higher efficiency in HCl media (95.7%) than in H₂SO₄ (92.8%). The theoretical and experimental results are found to be in good agreement.