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        검색결과 460

        361.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        The several functions of manufactured the gypsum incorporating oyster shell powder coated by submicro-silver solutionand carrried out the tests for the adsorption of formaldehyde and antibiotic actions. Several environmentally- friendlyarchitectural materials, clay and flyash were tested for the comparison of the adsorption efficiency. The mortar by solidifiedand dried was exposed in the small chamber for the 180min with 4000µg/m3 of the initial concentration of formaldehydeand observed high removal efficiency which result was not any difference in adsorption performance of other tested materials.The microbial flora analysis of oyster mortar coated by submicro-silver solution and the similarity test were performed andobserved that the densities of Aeromonas sp. Enterococcus sp., and Micrococcus sp. were decreased and the densities ofStaphylococcus sp., Escherichia sp., Bacillus sp., were taphylococcus sp, Escherichia sp., and Bacillus sp. were increased.
        362.
        2014.01 KCI 등재 서비스 종료(열람 제한)
        Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time (t0.05), saturation time (t0.95), length of mass transfer zone (LMTZ), adsorptive capacity (W), and adsorption rate constant (Ka) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer LMTZ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.
        363.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        The adsorption of lithium ion onto zeolite was investigated depending on contact time, initial concentration, cation forms, pH, and adsorption isotherms by employing batch adsorption experiment. The zeolite was converted into different forms such K+, Na+, Mg2+, Ca2+, and Al3+. The zeolite had the higher adsorption capacity of lithium ion in K+ form followed by Na+, Ca2+, Mg2+, and Al3+ forms, which was in accordance with their elctronegativities. The lithium ion adsorption was explained using the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms and kinetic models. Adsorption rate of lithium ion by zeolite modified in K+ form was controlled by pseudo-second-order and particle diffusion kinetic models. The maximum adsorption capacity obtained from Langmuir isotherm was 17.0 mg/g for zeolite modified in K+ form. The solution pH influenced significantly the lithium ions adsorption capacity and best results were obtained at pH 5-10.
        364.
        2013.10 KCI 등재 서비스 종료(열람 제한)
        Na-A zeolite (Z-Cl) was synthesized from coal fly ash, which is a byproduct of coal combustion for the generation of electricity. The adsorption of Cu2+ and Zn2+ions onto Z-C1 was investigated via batch tests over a range of temperatures (303.15 to 323.15 K). The resultant experimental equilibrium data were compared to theoretical values calculated using model equations. With these results, the kinetics and equilibrium parameters of adsorption were calculated using Lagergren and Langmuir-Freundlich models. The adsorption kinetics revealed that the pseudo second-order kinetic mechanism is predominant. The maximum adsorption capacity (qmax) values were 139.0-197.9 mg Zn2+/g and 75.0-105.1 mg Cu2+/g. Calculation of the thermodynamic properties revealed that the absorption reactions for both Cu2+and Zn2+ were spontaneous and endothermic. Collectively, these results suggest that the synthesized zeolite, Z-C1, can potentially be used as an adsorbent for metal ion recovery during the treatment of industrial wastewater at high temperatures.
        365.
        2013.10 서비스 종료(열람 제한)
        Chloride adsorption is very ambiguous in the mechanisms of deterioration of concrete exposed to marine environment. Author suggested that chloride adsorption with cement hydrates depends on pH value of pore solution. However, adsorbed chloride ions can be dissolved in concrete under the combined deterioration environment of carbonation and chloride penetration. In the condition, the most crucial issue is the amount of dissolved chloride ions in cement paste due to carbonation. In this study, dynamics experiment was designed to quantify the effect of CaCO3 on chloride adsorption. Based on the experiment results, the final goal of this study is to develop integrated system for predicting chloride adsorption /desorption behaviors.
        366.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        The efficiency of coal-based activated carbon in removing methylene blue (MB) and phenol from aqueous solution was investigated in batch experiments. The batch adsorption kinetics were described by applying pseudo-first-order, pseudo-second-order, and first order reversible reaction. The results showed that the adsorption of MB and phenol occurs complexed process including external mass transfer and intraparticle diffusion. The maximum adsorption capacity obtained from Langmuir isotherm was 461.0 mg/g for MB and 194.6 mg/g for phenol, respectively. The values of activation parameters such as free energy (△G˚), enthalpy (△H˚), and entropy (△S˚) were also determined as -19.0∼-14.9 kJ/mol, 25.4 kJ/mol, and 135.2 J/mol K for MB and 51.8∼54.1 kJ/mol, -29.0 kJ/mol, and -76.4 kJ/mol K for phenol, respectively. The MB adsorption was found to be endothermic and spontaneous process. However, the CV adsorption was found to be exothermic and non-spontaneous process.
        367.
        2013.07 KCI 등재 서비스 종료(열람 제한)
        Functionalized adsorbent has been synthesized by piperazine(Pz) on activated carbon. Quantitative estimations of CO2 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 1212.0 m2/g to 969.8 m2/g by impregnation and FT-IR revealed a N-H functional group at about 1400 cm-1 to 1700 cm-1. The CO2 adsorption capacity at 20℃ and 50∼100℃ was as follow: AC > Pz(10)-AC> Pz(30)-AC> Pz(50)-AC at 20℃ and Pz(10)-AC > AC > Pz(30)-AC> Pz(50)-AC at 50∼100℃. 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 CO2 capture from real flue gases above 50℃.
        368.
        2013.07 KCI 등재 서비스 종료(열람 제한)
        This study was designed to synthesize mesoporous carbon, porous carbonic material and to characterize its surface in an attempt to adsorption methane gas(CH4). Synthesis of mesoporous carbon was carried out under two steps ; 1. forming a RF-silica complex with a mold using CTMABr, a surfactant, and TEOS, raw material of silica, and 2. eliminating silica through carbonization and HF treatment. The mesoporous carbon was synthesized under various conditions of synthesis time and calcination. Eight different types of mesoporous carbon, which were designated as MC1, MC2, MC3, MC4, MCT1, MCT2, MCT3, and MCT4, were prepared depending upon preparation conditions. The analysis of mesoporous carbon characteristics showed that the calcination of silica stabilized the mixed structure of silica and carbonic complex, and made the particle uniform. The results also showed that hydrothermal synthesis time did not have a strong influence on the size of pore. The bigger specific surface area was obtained as the hydrothermal synthesis time was extended. However, the specific surface area was getting smaller again after a certain period of time. In adsorption experiments, CH4 was used as adsorbate. For the case of CH4, MCT3 showed the highest adsorption efficiency.
        369.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        This is made of domestic and foreign coal activated carbon of five species, physicochemical adsorption efficient about sterilize products and micro harmful substances and is a result of the economic evaluation. The most well-developed micropores bed volume 123,409 of AC-1 activate carbon appeared to be the best next AC-2, AC-3, AC-4, AC-5 followed by activated carbon was investigated. PFOA and PFOS in the BV 96,000 when evaluating foreign types of adsorption activated carbon adsorption capacity was greater when more than PFOA, PFOS showed that the adsorption well. The economic evaluation of activated carbon usage in chloroform (CUR) was most excellent as a AC-1 4.3 g/day, the next AC-2, AC-3, AC-4, AC-5 there are two types of foreign economic order appears to have appeared, but the current domestic market when applying the price AC-1, AC-3, AC-2, AC-4, AC-5 order was investigated.
        370.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        철 (산수)산화물들 중 지표환경에서 가장 안정된 형태로 알려진 적철석의 비소에 대한 흡착제로서의 다양한 특성을 조사하고 비소와의 흡착특성을 규명하였다. 본 연구에서 합성된 적철석은 31.8g m2/g의 비표면적을 가졌으며, 전위차 적정법(potentiometric titration)에 의해 측정된 영전하점(point of zero salt effect, PZSE)은 8.5로 비소에 대한 높은 흡착능은 이러한 적철석의 특성들에 기인한 것으로 판단된다. 동일한 수용상 농도와 pH 2.0~12 범위에서 3가 비소와 5가 비소의 적철석에 대한 흡착량을 비교한 결과 3가 비소가 5가 비소보다 큰 흡착량을 보였다. 그리고 pH에 따른 흡착경향은 3가 비소의 경우에는 pH 9.2까지 지속적으로 흡착량이 증가하다가 그 이상의 pH에서는 흡착량이 급격하게 감소한 반면, 5가 비소는 pH 2.0에서 가장 높은 흡착량을 나타내다가 pH가 증가하면서 지속적으로 감소하는 것으로 조사되었다. 이러한 pH에 따른 흡착특성은 pH에 따라서 적철석의 표면전하 특성과 비소 화학종의 존재형태가 변화하기 때문인 것으로 판단된다. 흡착 반응속도에 대한 실험 결과에 의하면, 두 비소 종 모두 20시간 이내에 평형 흡착에 도달하는 것으로 나타났다. 그리고 비소의 화학종과 관계없이 적철석과의 흡착반응속도를 가장 잘 모사하는 반응속도 모델로는 유사이차(Pseudo-second-order) 모델로 평가되었으며, 5가 비소가 3가 비소보다 반응속도상수가 크게 나타났다.
        371.
        2012.11 서비스 종료(열람 제한)
        Chloride binding capacity in cementitious materials is a crucial factor for service life prediction of marine concrete. C-S-H phase have significant physical binding capacity for chloride ions. In this study, specific surface area of C-S-H with various Ca/Si ratio was measured. This study suggested effective way to compute maximum adsorption of bound chloride by C-S-H based on theory single molecular layer. In addition, surface potential is very important as a main mechanism for chloride binding adsorption. Thus, intrinsic equilibrium constant was obtained and surface potential of C-S-H was calculated in chemical equilibrium solution by means of PHREEQC. Based on the experiment results, to develop integrated system for prediction of chloride binding behaviors is final goals.
        372.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        The purpose of this work is to study the adsorption and desorption characteristics of acetone vapor and toluene vapor from adsorption tower in the VOCs recovery device. The six kinds of activated carbon with different pore structures were used and the adsorption and desorption characteristics were compared according to pore structure, desorption temperature, and adsorption method, respectively. Adsorption capacity of acetone vapor and toluene vapor by batch method was higher than that by dynamic method. Especially, activated carbon with medium-sized or large pores had more difference in adsorption capacity according to adsorption methods as a result of gradually condensation of vapors on relatively mesopore and large pores. Activated carbons with relatively large pores and relatively small saturated adsorption capacity had excellent desorption ability.
        373.
        2012.08 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 연안어장 준설퇴적물에 대한 영양염류(인공수 중 질산염과 인산염)의 흡착반응에서 흡착제, pH, 이온강도가 미치는 영향을 살펴보았다. 그리고 준설퇴적물을 이용해서 영양염류를 제거할 수 있는 가능성을 평가하고자했다. NO3--N(100μM, 10mM), PO43--P(100μM, 10mM)에 대한 흡착반응은 10분 이내에 완료되었고, 정상상태에서 100μM NO3--N과 100μM PO43--P가 각각 61%, 77% 제거 되었다. 900℃에서 준설퇴적물을 열처리했을 때 영양염류 제거율은 증가하지 않았다. CaO와 MgO 같은 첨가제를 사용하면 질산염의 제거율은 0%까지 감소했으나, 인산염 제거율은 98%까지 증가했다. 질산염과 인산염의 등온흡착은 Freundlich 식에 의해 잘 설명되었다(R2〉0.99). 흡착반응은 pH와 이온강도에 의해 거의 영향을 받지 않았다. 흡착반응시간이 짧고 영양염류 제거율이 상당히 높다는 연구결과는 연안어장 준설퇴적물이 영양염류 제거를 위해 실제로 사용될 수 있는 가능성을 보여준다.
        374.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        The removal property of Cu and Zn ions by chemical precipitation and adsorption using zeolite(Z-C1) prepared from coal fly ash(CFA) were evaluated in this study. Adsorption kinetic and equilibrium mechanisms described to analyze parameters and correlation factors with Lagergen 1st and 2nd order model and Langmuir and Freundlich model. Analysis of adsorption kinetics data revealed that the pseudo 2nd order kinetics mechanism was predominant. The equilibrium data in pH 3 - 5 were able to be fitted well to a Langmuir model, by which the maximum adsorption capacities(qmax) were determined at 124.9 - 140.1 mg Cu2+/g and 153.2 - 166.9 mg Zn2+/g, respectively. We found that Z-C1 has a potential application as absorbents in metal ion recovery with low pH.
        375.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        Adsorption experiment of carbon dioxide was performed on MCM41 silica with a 30 wt .% EDA(ethylenediamine) loading at different CO2 inlet concentration and various adsorption temperature. The surface characteristics of CO2 capturing agent were carried out using BET analysis, X-ray diffraction and FT-IR. The results of BET showed 781 m2/g for MCM41 and 464 m2/g for EDA/MCM41. X-ray diffraction results reveled typical hexagonal pore system. The higher sorption capacity of EDA/MCM41 was about 80 mgco2/gsorbent with 50% CO2 inlet concentration and 303 K adsorption temperature. The isosteric heat of adsorption in 303-353 K ranged from -25.47 to -28.24 KJ/mole for EDA/MCM41, which indicates CO2-EDA/MCM41 interaction with exothermic adsorption process. Finally, the performance of EDA/MCM41 in 10 consecutive sorption-desorption runs was a stable with only a minor drop in its sorption capacity.
        376.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        Zeolite 4A was synthesized by fusion method from coal fly ash discharged at the thermal power plants. The synthesized zeolite(FAZ) was characterized through particle size analyzer, XRD, XRF and SEM. N2 adsorption-desorption measurement was used to examine surface and pore structures. The adsorption experiments were carried out under dynamic conditions of trace SO2 in N2 to investigate SO2 adsorption capacity of FAZ. The experiments were conducted to characterize the breakthrough characteristics of SO2 in a fixed bed under different operating conditions including temperature(50-125℃), concentration of SO2(3000-10000 ppm) and FAZ with 4 kinds of commercial zeolite. The adsorption capacity of FAZ was 53.84 mgSO2/g adsorbent, larger than that of the same type commercial zeolite(WK4A).
        377.
        2012.05 KCI 등재 서비스 종료(열람 제한)
        The adsorption behavior of Eosin Y on activated carbon (AC) in batch system was investigated. The adsorption isotherm could be well fitted by the Langmuir adsorption equation. The kinetics of adsorption followed the pseudo-second-order model. The temperature variation was used to evaluate the values of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The positive value of enthalpy change ΔH° for the process confirms the endothermic nature of the process and more favourable at higher temperature, the positive entropy of adsorption ΔS° reflects the affinity of the AC material toward Eosin Y and the negative free energy values ΔG° indicate that the adsorption process is spontaneous. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size.
        378.
        2012.05 KCI 등재 서비스 종료(열람 제한)
        In this study, adsorption of polychlorinated biphenyls(PCBs) in transformer oil on powder activated carbon (PAC) and synthetic zeolite was evaluated. Adsorption characteristics of PCBs on the PAC and zeolite has been investigated in a batch system with respect to adsorbents amount and contact time. BET results showed 908 m2/g for PAC and 483 m2/g for zeolite. The adsorption capacity of PCBs increased with an increasing input amount of absorbent. The adsorption experimental results showed that PAC removed 90% of input PCBs in transformer oil while zeolite removed only 64%. Adsorption of PCBs to PAC and zeolite fit the Freundlich model well. The Freundlich parameter, Kf, for PAC and zeolite was 193.1 and 43.0 respectively, indicating that PAC is effect adsorbent for PCBs adsorption in transformer oil.
        379.
        2012.03 KCI 등재 서비스 종료(열람 제한)
        We investigated usefulness of chicken feather as bioadsorbent for removal of hexavalent chromium[Cr(Ⅵ)] and oil from aqueous solution. Chicken feather was chemically treated with DTPA, EDTA, NaOH and SDS, respectively. Among them, EDTA was the most effective in adsorbing Cr(Ⅵ). Cr(Ⅵ) uptake by chicken feather was increased with decreasing pH; the highest Cr(Ⅵ) uptake was observed at pH 2.0. By increasing Cr(Ⅵ) concentration, Cr(Ⅵ) uptake was increased, and maximum Cr(Ⅵ) uptake was 0.34 mmol/g. Cr(Ⅵ) adsorption by chicken feather was well described by Freundlich isotherm than Langmuir isotherm and Freundlich constant(1/n) was 0.476. As the concentration of chicken feather was increased, Cr (Ⅵ) removal efficiency was increased but Cr(Ⅵ) uptake was decreased. Most of Cr(Ⅵ) was adsorbed at early reaction stage(1 h) and adsorption equilibrium was established at 5 h. On the other hand, chicken feather adsorbed effectively oils including bunker-A and bunker-C. In conclusion, our results suggest that chicken feather waste could be used to remove heavy metal and oil; it is a potential candidate for biosorption material.
        380.
        2012.03 KCI 등재 서비스 종료(열람 제한)
        This work is to study the variations of adsorption characteristics of binary vapor according to packing system of double-layer bed by fixed bed experiment. Breakthrough curves of single and binary vapor composed of acetone and benzene on single-layer and double-layer adsorption bed composed of activated carbon (AC) and silica-aluminar (SA) were compared. Adsorptions of binary vapor on double-layer bed were influenced by the differences of surface area between adsorbents as well as the polarity difference between adsorbent and adsorbate. The roll-up phenomenon of acetone vapor was happened by replacement with competing adsorption between acetone vapor and benzene vapor on AC bed, but it was not happened on SA bed because acetone vapor and benzene vapor had less difference in affinity with SA bed. The breakthrough times of acetone vapor and benzene vapor on AC/SA double-layer bed were three times and 1.4 times larger respectively than on SA/AC double-layer bed, the differences of breakthrough times were relatively larger than the equilibrium adsorption capacities according to packing system of double-layer bed.