• Carbon letters
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• 제3권4호
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• pp.219-225
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• 2002

The two-step surface modifications of activated carbon was carried out to improve the adsorption capacity of toxic heavy metal ions in liquid phase. Physical and chemical properties of the as-received activated carbon (AC) and two kinds of surface-modified activated carbons ($1^{st}AC$ and $2^{nd}AC$) were evaluated through the BET analysis, surface acidity, and oxides measurements. Specific surface area and pore volume did not significantly change, but surface oxide-group remarkably increased by the surface modification. Equilibrium and batch adsorptions of the various metals, such as Pb, Cd, and Cr, using AC, $1^{st}AC$, and $2^{nd}AC$ were performed at initial pH 5. The adsorption capacity and rate of $2^{nd}AC$ were higher than those of AC and $1^{st}AC$. The carboxylic/sodium carboxylate complex groups were developed from the two-step surface modification of activated carbon, which strongly affected the adsorption of metal ions.

• Journal of Pharmaceutical Investigation
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• 제25권4호
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• pp.331-338
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• 1995

In order to screen appropriate preservatives for the suspension containing sucralfate, neusilin and hydrotalcite, the patterns and mechanism of the adsorption and desorption of several preservatives on these antacids were studied. The employed preservatives were parabens(methyl, propyl, butyl), chlorhexidine diacetate and sorbic acid. While none of parabens were adsorbed on three antacids, chlorhexidine diacetate was strongly adsorbed on all the antacids employed, especially on hydrotalcite. Sorbic acid was not adsorbed on neusilin and hydrotalcite, however, 65% of sorbic acid was adsorbed on sucralfate. The adsorption of chlorhexidine diacetate on neusilin and hydrotalcite was partly physical and partly chemical, while its adsorption on sucralfate was almost chemical. Sorbic acid was completely deserted from sucralfate. In all cases, the adsorption isotherms were fitted well to both Freundlich equation and Langmuir equation. Based on these results, parabens and sorbic acid were the preservatives of choice for the suspension containing sucralfate, neusilin and hydrotalcite.

• 한국안전학회지
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• 제34권6호
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• pp.22-28
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• 2019

In South Korea, the enact of Korean Coast Guard Act-1 manages physical and chemical oil-dispersants. Oil snare, which is made of polypropylene, is newly added to the aforementioned act, and it has advantage on the ease of recovery compare to other adsorbents. This study synthesized bunker B-oil with diesel-oil and bunker C-oil to perform an adsorption test based on three samples which were manufactured in South Korea. As a result, adsorption test revealed 5.2 g/g more adsorption than the previous results from the act. Additional toluene test revealed that all the samples satisfied 90.0%, however coloured samples could release its pigment on the marine environment. Thus, colorless samples are recommended on the risk management of marine accidents. The study on the basic direction of the calculation of the test items and the standard value for the quality control of the oil snare was also carried out.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.394-401
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• 2014

In order to minimize a building energy consumption with ventilation, a development of smart ventilation system is very important. In this study, a dry adsorbent that is main element of smart ventilation system was developed for removing indoor $CO_2$, and evaluate the adsorption performance. Specific surface area, pore characteristic and crystal structure of the modified sorbent was measured to analyze physical properties. From this analysis, it was found that the developed absorbent has a low specific surface area, due to mesopores of substrate was filled with metal contained raw material. Additionally, through analysis of the adsorption properties, the developed adsorbent was shown a adsorption form of mesopore (type IV), which means adsorption amount was rapidly increased at the part of high-pressure. Order to applying for the field, chamber test was performed. Continuous column tests (2,500 ppm) and batch chamber tests ($4m^3$, 5,000 ppm) showed $CO_2$ removal efficiency of 95% and 88% within 1 hour, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.164-165
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• 2022

In order to solve problems such as acceleration of resource use and environmental pollution, experiments were conducted with the aim of producing indoor finishing materials that can adsorb fine dust and carbon dioxide using gelite and polymer, which are porous materials. Based on the previous experiment, gelite was substituted at each level in a matrix having a polymer S738P substitution rate of 12.5%, and the results are as follows. As the substitution rate of gelite increased, the amount of fine dust and carbon dioxide adsorption increased, which is believed to be due to physical adsorption due to the high porosity of gelite. However, further experiments are needed as the overall adsorption amount is not high due to the filling inside the matrix due to the polymer.

• Advances in environmental research
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• 제6권2호
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• pp.113-125
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• 2017

Santa Barbara Amorphous-15(SBA-15) nanoparticles were utilized as the inexpensive and effective adsorbents to remove methylene blue dye from the aqueous solution.SBA-15 was created by Zhao et al method. Infrared spectroscopy, X-ray diffraction and scanning electron microscopy (SEM) were used for the evaluated physical properties of SBA-15. The results of diffraction X-ray indicated that was the crystalline structure for it. Also IR spectroscopy indicated was a silica the whole structure of the groups and SEM image verify the structure of relatively identical particles size of SBA-15. Factors affecting adsorption including the amounts of adsorbent, pH and contact time were investigated by a SBA-15 nanomaterial design. The extent of dye removal enhanced with increasing initial dye concentration and pH from 4 to 10. The higher percentage adsorption were obtained under optimum conditions of variables (sorbent dose of 200 mg/liter, initial MB concentration 10 mg/liter, initial pH of 10 and temperature of $25^{\circ}C$). Maximum adsorption happened after the 2 hour and the kinetic processes of the dyes adsorption were described by applying the pseudo-first-order and the pseudo-second-order and the relatively High correlation with the kinetic Ellovich models. It was found that the pseudo-second-order models kinetic equation described the data of dye adsorption with a good correlation (R2>0.999) which indicated chemisorption mechanism. Freundlich and Langmuir adsorption models were investigated in conditions of variables (adsorbent dose 0.01 gr/liter, MB concentration 10, 20, 30 mg/liter, pH of 4, 7, 10, contact time 90 min and temperature of $27^{\circ}C$). The adsorption data were represented by Langmuir isotherm model. These values are higher than the adsorption capacities of some other adsorbents that have recently been published in the literature.

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.83-87
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• 2012

활성탄소섬유를 사용하여 염소소독 후 수돗물 내에 부산물로 존재하는 4종 트리할로메탄을 제거하였다. THMs의 종류별 농도 및 용액의 온도를 달리하면서 흡착실험을 수행하고 활성탄소섬유의 표면특성에 따른 흡착능력과 흡착메카니즘을 살펴본 결과, 4종의 THMs은 모두 Langmuir 타입의 흡착등온곡선을 보이면서 매우 신속하게 활성탄소섬유에 흡착되었다. THMs의 흡착은 활성탄소섬유의 표면에 균일하게 발달된 미세공의 입구에 물리적 및 화학적 수소결합으로 이루어졌다고 판단된다. Langmuir 타입은 특히 저농도 오염원 일때 제거효율이 높기 때문에 수돗물 내에 약 $30{\mu}g/L$ 수준으로 존재하는 THMs의 제거에는 활성탄소섬유가 매우 효과적임을 알 수 있다. 4종 THMs 종류별 흡착량은 큰 차이는 없으나 chloroform, bromodichloromethane, dibromochloromethane, 및 bromoform 의 순서로 증가하였다. 이는 brom 원자수의 증가와 일치하며 극성의 감소로 용해도가 낮아짐에 따라 흡착량이 증가한 것이다.

• 공업화학
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• 제25권6호
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• pp.632-638
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• 2014

입상활성탄을 사용하여 new fuchsin 염료를 흡착하는데 필요한 흡착등온선과 흡착동역학 및 열역학 파라미터들에 대하여 조사하였다. 흡착평형은 Langmuir 흡착등온식이 가장 잘 맞았으며, 등온흡착평형관계로부터 Langmuir 식과 Freundlich 식의 분리계수를 평가한 결과, 분리계수값이 각각 $R_L$ = 0.023, 1/n=0.198로 입상활성탄에 의한 new fuchsin 염료의 흡착조작이 유효한 처리방법이 될 수 있음을 알았다. Dubinin-Radushkevich 식으로 구한 흡착에너지값(E = 0.002 kJ/mol)과 Temkin 식으로부터 구한 흡착열상수값(B = 1.920 J/mol)으로부터 흡착공정이 물리흡착공정임을 알았다. 흡착공정에 대한 동력학적 해석을 통해 흡착반응은 유사이차반응속도식이 유사일차반응속도식과 비교하여 일치도가 높은 것으로 나타났으며, 입자 내 확산이 흡착공정의 지배단계이었다. 열역학적 해석을 통해 평가된 엔탈피 변화값(92.49 kJ/mol)과 활성화에너지값(11.79 kJ/mol)으로부터 흡착공정이 흡열반응으로 진행되었다. 또한, 엔트로피 변화값이 313.7 J/mol K로 흡착공정의 무질서도가 증가하였다. 온도가 올라갈수록 자유에너지값이 감소하는 것은 활성탄에 대한 new fuchsin 염료의 흡착반응은 온도가 올라갈수록 자발성이 높아지는 것으로 판단되었다.

• Journal of Electrochemical Science and Technology
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• 제4권2호
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• pp.61-70
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• 2013

Corrosion inhibition of carbon steel in 2M HCl by some benzohydrazide derivatives (I-III) was studied using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques at $30^{\circ}C$. Polarization studies showed that all the investigated compounds are of mixed type inhibitors. Temperature studies revealed a decrease in efficiency with rise in temperature and corrosion activation energies increased in the presence of the hydrazide derivatives, probably implying that physical adsorption of cationic species may be responsible for the observed inhibition behavior. Electrochemical impedance studies showed that the presence of benzohydrazide derivatives decreases the double layer capacitance and increases the charge transfer resistance. The adsorption of these compounds on carbon steel surface was found to obey Temkin's adsorption isotherm. Synergistic effects increased the inhibition efficiency in the presence of halide additives namely KI and KBr. An inhibition mechanism was proposed in terms of strongly adsorption of inhibitor molecules on carbon steel surface.

• 환경위생공학
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• 제13권2호
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• pp.76-81
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• 1998

The technology of removing phosphorous, considered as one of the most important control nutrients causing eutrophication in various water bodies, have been investigated by many researchers. In this study, casts which can be obtained from the vermicomposting of mixing sewage sludge and cow manure, were used as an adsorbent, and their effects of several physical/chemical factors on the efficiencies of phosphorous adsorption were examined by batch tests. Generally, it could be showed that the efficiencies of phosphorous adsorption were very influenced by cast dosage, temperature and agitation speed. If we reflected the adsorption capacity(k) and adsorption intensity(1/n) of Freundlich isotherm, we couldn't consider casts as a good adsorbent for removing phosphorous. But, because casts were relatively excellent in cation exchange, in point of waste recycling, we could know that they were capable of removing phosphorous. The SEM observation revealed that the evident variations were hardly seen, but particle sizes of cast were relatively bigger and showed forms of smaller plate than before.