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        검색결과 474

        181.
        2015.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High crystallinity coke-based activated carbon (hc-AC) is prepared using a potassium hydroxide solution to adsorb carbon dioxide (CO2). The CO2 adsorption characteristics of the prepared hc-AC are investigated at different temperatures. The X-ray diffraction patterns indicate that pitch-based cokes prepared under high temperature and pressure have a high crystal structure. The textural properties of hc-AC indicate that it consists mainly of slit-like pores. Compared to other textural forms of AC that have higher pore volumes, this slit-poreshaped hc-AC exhibits higher CO2 adsorption due to the similar shape between its pores and CO2 molecules. Additionally, in these high-crystallinity cokes, the main factor affecting CO2 adsorption at lower temperature is the pore structure, whereas the presence of oxygen functional groups on the surface has a greater impact on CO2 adsorption at higher temperature.
        4,000원
        182.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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 N2/77 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.
        3,000원
        183.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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 CO2, 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 (4 m3, 5,000 ppm) showed CO2 removal efficiency of 95% and 88% within 1 hour, respectively.
        4,000원
        184.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recent studies have been reported the presence of Endocrine Disrupting Compounds, Pharmaceuticals and Personal Care Products (EDC/PPCPs) in surface and wastewater, which could potentially affect to the complicate behavior in coupled presence of nano-colloid particles and surfactants (adsorption, dispersion, and partitioning). In this study, the adsorption of EDC/PPCPs by Single Walled Carbon Nanotubes (SWNTs) as a representative of nano-particles in cationic surfactant solutions were investigated. Hydrophobic interactions (π-π Electron Donor-Acceptor) have been reported as a potential adsorption mechanisms for EDC/PPCPs onto SWNTs. Generally, the adsorptive capacity of the relatively hydrophobic EDC/PPCPs onto SWNTs decreased in the presence of cationic surfactant (Cetyltrimethyl Ammonium Bromide, CTAB). This study revealed that the competitive adsorption occurred between CTAB cations and EDC/PPCPs by occupying the available SWNT surface (CTAB adsorption onto SWNTs shows five-regime and maximum adsorption capacity of 370.4 mg/g by applying the BET isotherm). The adsorption capacity of 17α-ethinyl estradiol (EE2) on SWNT showed the decrease of 48% in the presence of CTAB. However, the adsorbed naproxen (NAP) surely increased by forming hemimicelles and resulted in a favorable media formation for NAP partition to increase SWNTs adsorption capacity. The adsorbed NAP increased from 24 to 82.9 mg/g after the interaction of CTAB with NAP. The competitive adsorption for EDC/PPCPs onto SWNTs is likely to be a key factor in the presence of cationic surfactant, however, NAP adsorption showed a slight competition through CH3-CH3 interaction by forming hemimicelles on SWNT surface.
        4,200원
        185.
        2014.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adsorption of volatile organic compounds (VOCs) was carried out using an activated carbon fiber (ACF) filter in an automobile. The adsorption capacities of formaldehyde, toluene, and benzene on an ACF filter were far better than those of a polypropylene (PP) mat filter and combined (PP+activated carbon) mat filter by batch adsorption in a gas bag. In a continuous flow of air containing toluene vapor through an ACF packed bed, the breakpoint time was very long, the length of the unused bed was short, and sharp "S" -type breakthrough curve was plotted soon after breakpoint, showing a narrow mass transfer zone of toluene on the ACF. The adsorption amount of toluene on the ACF filter was proportional to the specific surface area of the ACF; however, the development of mesopores 2-5 nm in size on the ACF was very effective with regard to the adsorption of toluene. The ACF air clarifier filter is strongly recommended to remove VOCs in newly produced automobiles.
        4,000원
        187.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The widespread occurrence of dissolved endocrine disrupting compounds(EDCs) and pharmaceutical active compounds(PhACs) in water sources is of concern due to their adverse effects. To remove these chemicals, adsorption of EDCs/PhACs on granular activated carbon(GAC) was investigated, and bisphenol A, carbamazepine, diclofenac, ibuprofen, and sulfamethoxazole were selected as commonly occurring EDCs/PhACs in the aquatic environment. Various adsorption isotherms were applied to evaluate compatability with each adsorption in the condition of single-solute. Removal difference between individual and competitive adsorption were investigated from the physicochemical properties of each adsorbate. Hydrophobicity interaction was the main adsorption mechanism in the single-solute adsorption with order of maximum adsorption capacity as bisphenol A ≻ carbamazepine ≻ sulfamethoxazole ≻ diclofenac ≻ ibuprofen, while both hydrophobicity and molecular size play significant roles in competitive adsorption. Adsorption kinetic was also controled by hydrophobicity of each adsorbate resulting in higher hydrophobicity allowed faster adsorption on available adsorption site on GAC. EDCs/PhACs adsorption on GAC was determined as an endothermic reaction resulting in better adsorption at higher temperature (40 ◦C) than lower temperature (10 ◦C#x25E6;C).
        4,600원
        188.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 새로운 실리콘 모노머를 사용하여 제조한 실리콘하이드로겔 콘택트렌즈와 2종류의 시판용 렌즈에 hyaluronan을 첨가한 다음 lysozyme, albumin, globulin 3종류 단백질에 대한 흡착량의 변화를 살펴보고자 한다. 방법: 실험실에서 제조한 렌즈는 HEMA(2-hydroxyethyl methacrylate, 96%, Junsei)와 TRIM (3-(trimethoxysilyl)propyl methacrylate, 98%, Aldrich) 등의 모노머를 사용하여 cast mould 방법으로 제조하였다. HA(Hyaluronic acid, LifeCore Biomedical) 첨가는 HA 에탄올 용액과 EDC (1-(3-(Dimethylamino)propyl)-3-ethylcarbodiimide methiodide, Aldrich) 용액을 사용하였다. HA의 첨가 전 후 렌즈의 함수율, 광 투과율 등의 물리적 특성 변화와 lysozyme, albumin, globulin이 포함된 인공눈물을 제조하여 48시간 동안 흡착량 변화를 살펴보았다. 각각의 단백질은 HPLC로 정량하였다. 결과: HA가 첨가된 렌즈의 함수율은 첨가 전의 값에 비해 약 10% 증가하였으며, 광 투과율은 큰 변화가 없었다. HA를 첨가한 렌즈에서 시간에 따른 HA의 용출량은 48시간 동안 지수함수 형태로 증가하였다. HA가 첨가되지 않은 렌즈에 비해 HA를 첨가한 모든 렌즈에서 단백질 흡착량이 감소하였으며, 흡착시간이 경과함에 따라 그 감소효과가 크게 줄었다. 단백질의 종류에 따른 흡착량은 lysozyme>globulin>albumin의 순으로 감소하였으며, SHL 렌즈에서 최대 80% 이상 감소하였다. 결 론: Hyaluronan이 첨가된 모든 실리콘하이드로겔 콘택트렌즈에서 단백질 흡착량이 감소하였다. 실리콘하이드로겔 렌즈에 3종류 단백질의 흡착 특성은 렌즈 표면의 친수성에 가장 크게 영향을 받음을 확인할 수 있었으며, 수소결합이 가능한 hyaluronan의 첨가로 인해 렌즈의 친수성을 증가시키고 이로 인해 단백질의 구조적 변성을 방지하여 단백질 흡착을 억제하는 것으로 생각된다.
        4,200원
        189.
        2014.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Three activated carbons (ACs) were prepared using NaOH (N) as an activating agent. Hy-drofluoricacid pre-leached rice husk was used as a precursor. After leaching, the precursor was washed with distilled water, dried, crushed, and then sieved; a size fraction of 0.3-0.5 mm was selected for carbonization in the absence of air at 600°C. The carbonization prod-uct (LC) was mixed with NaOH at ratios of 1:2, 1:3, and 1:4 (wt of LC: wt of NaOH) and the produced ACs after activation at 800°C were designated NLC21, NLC31, and NLC41, respectively. Surface and textural properties were determined using nitrogen adsorption at -196°C, scanning electron microscopy images, thermogravimetric analysis, and Fourier transform infrared spectra . These ACs were used as adsorbents for lead(II) from aqueous solutions. The effects of the textural properties and the chemistry of the carbon surfaces were investigated and the impact of the operation conditions on the capacity for lead(II) sorption was also considered. Modificationof NLC41 with H2O2 and HNO3 gave two other adsorbents, HNLC41 and NNLC41 respectively. These two new samples exhibited the highest removal capacities for lead(II), i.e.117.5 and 128.2 mg/g, respectively. The adsorption data fittedthe Langmuir isotherm and the kinetic adsorption followed pseudo-second order kinet-ics. The thermodynamic parameters have been determined and they indicated a spontaneous endothermic process.
        4,000원
        190.
        2013.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Recently, functional building materials which are made of sorption materials have been widely used as board products, inorganic paints and wall papers. These remove chemical substances(VOCs, HCHO) from indoor air by physical sorption or chemical reaction and control humidity by capillary condensation. Also these materials have been used as countermeasures to sick building syndrome (SBS). However, in case of using internal building materials, the hazardous substances affecting to indoor air quality are emitted from not only the material itself but also the subsidiary materials such as adhesives for construction. Particularly in case of wallpaper and flooring material, the amount of emission from adhesives for construction is larger than that from the material itself. Therefore, this research tried to develop a technology system that can improve the performance of adsorption, absorption and desorption of moisture including the construction process that can affect to indoor air quality. To attend this end, ‘porous securement manufacturing technology system’ and ‘porous keeping construction technology system’ are developed that can secure more micropores in the process of production and construction of inorganic paint and maintain them. Consequently the reduction performance of chemical substances(VOCs, HCHO) concentrations and the humidity control performance improved almost over 30% by the technology system of the Inorganic paint.
        4,000원
        191.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Expanded graphite (EG) was prepared using a drying process for application as an oil-adsorbent: the morphology, expansion volume, and oil absorption capacity of the EG were investigated. The expanded volume of the EG increased with an increasing reaction time and heat treatment temperature. The oil adsorption capacity of the EG was 45 g of n-dodecane per 1 g of EG. It is noted that the drying process of EG is a useful technique for a new oil-adsorbent.
        3,000원
        192.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, CO₂ adsorbent was produced for minimizing energy loss due to ventilation within the building. For improved selectivity about low concentration of CO₂ in multiple-use facilities, the ball type adsorbent was modified from a commercial zeolite, alumina, alkali metals and activated carbon with mixing LiOH, binder, and H₂O. We measured specific surface area, pore characteristic, and crystal structure of the modified adsorbent. Effects of alkalization on the absorptive properties of the adsorbents were investigated. Continuous column tests (2,000 ppm) and batch chamber tests (4m3, 5,000ppm) showed that the modified adsorbent indicated about the selectivity of CO₂ more than 9.7% (0.613 mmol/g) compared with ordinary adsorbents and CO₂ removal efficiency of 88.8% within l hour, respectively. It was estimated that the modified adsorbent was applicable to indoor environments.
        4,000원
        193.
        2013.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study and describe-from the point of view of the interactions of the adsorbed particles-three types of the adsorption isotherms, namely, Langmuir type adsorption isotherms, phase transition type adsorption isotherms, and adsorption limited type adsorption isotherms, which are observed by experiments. By introducing and using a one dimensional statistical occupancy model, we derived analytical adsorption isotherms for the no force, the attractive force, and the repulsive force exerted on the other adsorbed particles. Our derived adsorption isotherms qualitatively pretty well agree with the experimental results of the adsorption isotherms. To specify each adsorption type, Langmuir type adsorption is a phenomenon that occurs with no forces between the adsorbed particles, phase transition type adsorption is a phenomenon that occurs with the strong attractive forces between the adsorbed particles, and adsorption limited type adsorption is a phenomenon that occurs with the repulsive forces between the adsorbed particles. The theoretical analysis-only using fundamental thermodynamics and occupancy statistics though-qualitatively quite well explains the experimental results.
        4,000원
        194.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고도정수처리를 위한 관형 세라믹 정밀여과와 이산화티타늄(TiO2) 광촉매 첨가 PES (polyethersulfone) 구의 혼 성공정에서 주기적 물 역세척 시 유기물질의 영향 및 정밀여과(MF), PES 구 흡착, 광산화의 역할을 막오염에 의한 저항(Rf) 및 투과선속(J), 총여과부피(VT) 측면에서 기존의 질소 역세척 결과와 비교하였다. 휴믹산 농도가 증가함에 따라 급격한 막 오염으로 Rf는 증가하고 J는 감소하여, VT는 휴믹산 농도 2 mg/L에서 가장 높았다. 탁도 처리효율은 물과 질소 역세척 모 두 휴믹산 농도와 상관없이 비슷하였다. 유기물질 처리효율은 물 역세척 경우 최대 휴믹산 10 mg/L에서 최소 71.4%이었으나, 질소 역세척에서는 거의 일정하였다. 물과 질소 역세척 모두 MF 및 PES 구, 자외선의 혼성공정(MF + TiO2 + UV)에서 Rf가 최소이고, J와 VT는 최대였다. 탁도 및 유기물질의 처리효율도 물과 질소 역세척에 상관없이 MF + TiO2 +UV에서 최대였 고, 공정이 MF로 단순화될수록 처리효율도 점차 감소하였다. 하지만 물 역세척에서는 광산화 보다 흡착이, 질소 역세척에 서는 흡착 보다 광산화가 더 주요한 역할을 하였다.
        4,200원
        195.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 1차 아민(MEA, monoethanolamine)으로 개질한 입자상 활성탄(WSC-470)을 이용하여 실내 저농도 이산화탄소를 제거하고자 하였다. MEA 함침농도(6.1~42.7 wt.%)와 용매제(distillate water, ethanol, methanol) 종류에 따라 제조된 흡착제의 특성분석(BET, pore property, XPS)과 각 흡착제의 CO2가스에 대한 최대 흡착능, 3000 ppm의 저농도 CO2분위기에서의 흡착량을 측정하였다. MEA 농도가 증가할수록 물리적 특성인 비표면적, 공극률, 미세기공률 등은 감소한 반면, 표면 염기도 향상에 기여하는 질소 함량은 증가하였다. 이러한 물성변화로 인해 최대 흡착능은 초기 활성탄(RAC: 3.27 mmol/g) 대비 최대 71%(AC-MM(42.7, 40): 0.937 mmol/g)가 감소한 반면, 저농도 이산화탄소에 대한 선택적 흡착량은 45%(AC-MM(15.3, 40): 0.73 mmol/g)의 향상을 보였다.
        4,000원
        196.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고도정수처리를 위한 관형 세라믹 정밀여과와 이산화티타늄(TiO2) 광촉매 첨가 PES (polyethersulfone) 구의 혼성공정에서 유기물질의 영향 및 정밀여과(MF), PES 구 흡착, 광산화의 역할을 막오염에 의한 저항(Rf) 및 투과선속(J), 총여과부피(VT)를 통해서 비교 및 고찰하였다. 휴믹산의 농도가 증가함에 따라 급격한 막오염으로 인해 Rf 는 증가하고 J는 감소하였으며, VT는 휴믹산의 농도가 2 mg/L인 조건에서 가장 높았다. 광산화와 흡착의 영향을 알아보기 위해 휴믹산의 농도 4 mg/L와 6 mg/L에서의 결과를 비교하였다. 두 가지 조건에서 공통적으로 정밀여과(MF)만의 단독공정에서 막오염이 급격하게 진행되어 Rf값이 가장 높게 나타났고, 총여과부피(VT)는 광촉매와 자외선의 혼성공정(MF + TiO2 + UV)에서 가장 높은 값을 나타내었다. 탁도와 유기물질의 평균처리효율은 MF + TiO2 + UV 공정에서 가장 높은 값을 나타내었다.
        4,000원
        197.
        2013.02 구독 인증기관 무료, 개인회원 유료
        H2S adsorption characteristics of adsorbent made by fallen leaves were investigated. For analyses of the manufactured adsorbent, various methods such as scanning electron microscope(SEM) and measurements of BET surface area were adopted. As major adsorption characteristics, adsorption equilibrium capacity was measured by using a batch type experimental apparatus for operating variables such as adsorption temperature(25~45℃) and adsorbent types. The experimental result showed that the H2S adsorption equilibrium capacity of adsorbent made by fallen leaves decreased with increasing adsorption temperature due to physical adsorption phenomena. It was also found that the H2S adsorption capacity of the adsorbent increased remarkably by an acid treatment with HCl solution.
        4,000원
        198.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rhodiola sachalinensis fermentates by lactic acid bacteria were prepared using the adsorption process, and were investigated for changes of the main compounds and anti-oxidative activities during the adsorption and fermentation process. While the R. sachalinensis extract (RSE), which did not go through the adsorption process, showed little change in pH during fermentation and a significant reduction in the number of lactic acid bacteria, the pre-preparatory adsorption process was found to be helpful for promoting fermentation and for maintenance of bacterial numbers. The contents of total phenolic compounds mostly decreased during the adsorption process, but showed an increasing tendency to rebound during the fermentation process. The contents of salidroside and p-tyrosol in the RSE were 1153.3 ㎎% and 185.0 ㎎% respectively, and they did not significantly change after treatment with acid clay or bentonite as adsorbents, which were 1093.0 and 190.5 ㎎% by acid clay, and 882.2 and 157.3 ㎎% by bentonite. When the extract was fermented after treatment with acid clay or bentonite, the salidroside contents were decreased by 282.7 and 505.0 ㎎% respectively, but the p-tyrosol contents were increased by 714.0 and 522.4 ㎎% respectively. Compared to the DPPH radical scavenging activity of the RSE (66.8%) at the conc. of 0.1%, that of the fermented RSE, which went through adsorption process with acid clay or bentonite, was significantly increased to 79.4 and 72.7% respectively at the same concentration (p<0.05). Though fermentation by lactic acid bacteria was suppressed in the RSE, the results suggested that the adsorption process may promote fermentation without any change in the content of major active compounds. It is expected that fermentation by lactic acid bacteria could improve the antioxidant activity and various associated functionalities of R. sachalinensis.
        4,000원
        199.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        탄소 한외여과막 및 광촉매 혼성 수처리를 위해 관형 여과막 외부와 원통형 막 모듈 내부 사이 공간에 광촉매를 충전하였다. 광촉매는 PP (polypropylene) 구에 이산화티타늄 분말을 플라즈마 화학증착 공정으로 코팅한 것이다. 휴믹산과 카올린 모사용액을 대상으로 막오염을 최소화하기 위해 10분 주기로 10초 동안 물 역세척을 시행하였다. 기존 결과와 동일하게 휴믹산을 10 mg/L부터 2 mg/L로 변화시킴에 따라, 막오염에 의한 저항(Rf)이 감소하여 2 mg/L에서 최대 총여과부피 (VT)를 얻었다. 탁도와 휴믹산의 처리효율은 각각 98.9%와 88.7% 이상이었다. UF 및 UF + TiO2, UF + TiO2 + UV 공정의 처리 분율 결과, 광촉매 흡착과 광산화에 의해 탁도는 거의 처리되지 않았으나, 광촉매 흡착 및 광산화에 의한 휴믹산 처리 분율은 각각 2.5%, 12.3%이었다. 기존 결과와 비교하면, 분리막의 재질과 기공의 크기에 따라 광촉매 흡착과 광산화에 의한 휴믹산의 처리 분율이 다르게 나타났다. 공정이 단순화될수록 180분 운전 후 막오염 저항(Rf,180)은 증가하였고, 최종 투과선속(J180)은 소폭 감소하였다.
        4,000원
        200.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene is the thinnest known materials in the universe and the strongest ever measured. Graphene has emerged as an exotic material of the 21st century and received world-wide attention due to its exceptional charge transport, thermal, optical, mechanical, and adsorptive properties. Recently, graphene and its derivatives are considered promising candidates as adsorbent for H2 storage, CO2 capture, etc. and as the sensors for detecting individual gas molecule. The main purpose of this review is to comprehensive the synthesis method of graphene and to brief the adsorption behaviors of graphene and its derivatives.
        4,800원