• 제목/요약/키워드: Isotherm model

검색결과 460건 처리시간 0.027초

흡착량의 비포화현상: 흡착등온식을 통한 고찰 (On the unsaturation adsorption phenomena : consideration through the adsorption isotherm)

    • 한국결정성장학회지
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    • 제8권2호
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    • pp.365-369
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    • 1998
  • 다분자흡착층에서의 흡착이론을 고려한다. 사용된 다분자흡착층 모형이 매우 간단한 것임에도 불구하고, 이로부터 유도된 흡착등온식은 실리카겔 기판상의 $Br_2$ 기체의 흡착과 같은 비포화흡착현상을 정성적으로 잘 설명하고 있다.

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실로퓨트에 의한 아세나프텐 흡착에 관한 등온흡착식, 동역학 및 열역학적 특성 (Isotherm, Kinetic and Thermodynamic Characteristics for Adsorption of Acenaphthene onto Sylopute)

  • 조다님;김진현
    • Korean Chemical Engineering Research
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    • 제58권1호
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    • pp.127-134
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    • 2020
  • 상용흡착제 실로퓨트에 의한 Taxus chinensis 유래 주요 타르 성분인 아세나프텐의 흡착 특성을 조사하였다. 초기 아세나프텐 농도, 흡착 온도 및 시간에 따른 흡착 데이터를 Langmuir, Freundlich, Temkin 및 Dubinin-Radushkevich 등온흡착식에 적용한 결과, Langmuir 등온흡착식이 가장 적합하였다. 동역학적 흡착 데이터는 유사 이차 속도식에 가장 잘 따름을 알 수 있었다. 열역학적 파라미터로부터 흡착 공정이 적합하며 비자발적 발열이었다. 등량흡착열은 흡착량에 의존하지 않아 실로퓨트의 표면에너지가 균일함을 알 수 있었다.

석탄비산재로 합성한 Na-A 제올라이트의 Ca2+와 Mg2+ 이온교환 성능평가 (Evaluation of Exchange Capacities of Ca2+ and Mg2+ ions by Na-A Zeolite Synthesized from Coal Fly Ash)

  • 이창한;이민규
    • 한국환경과학회지
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    • 제27권11호
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    • pp.975-982
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    • 2018
  • In this study, zeolite (Z-C1) was synthesized using a fusion/hydrothermal method from coal fly ash. The morphological structures of Z-C1 were confirmed to be highly crystalline with a cubic crystal structure. Exchange capacities of $Ca^{2+}$ and $Mg^{2+}$ ions in a single and a mixed solution reached equilibrium within 120 min. The exchange kinetics of these ions were well predicted by the pseudo-second-order rate equation. The exchange isotherms of the $Ca^{2+}$ and $Mg^{2+}$ ions matched the Langmuir isotherm better than the Freundlich isotherm. The maximum cation exchange capacities ($q_m$) obtained by the Langmuir isotherm model were 2.11 mmol/g (84.52 mg/L) and 1.13 mmol/g (27.39 mg/L) for the $Ca^{2+}$ and $Mg^{2+}$ ions, respectively.

The applicability of Freundlich's isotherm model for the leaching of solidified hazardous waste using cementitious binders

  • Youn Jong Ho;Lee Heon Mo;Jeong Byung Gon;Chung Yong Hyun
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • 제2권1호
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    • pp.9-19
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    • 1998
  • A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash(RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portalnd Rice Husk Ash Cement (PRHAC) which contained rice husk ash 50 percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

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광자극에 의한 수면상 단분자막의 특성변화 (Characteristics of monolayer in water by photoirradiation)

  • 구창권;송경호;박태곤;박근호;권영수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 C
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    • pp.1424-1427
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    • 1996
  • The pressure-area isotherm(${\pi}$-A isotherm) of 8A5H(4-octyl-4'-(5-Carboxyl-pentamethyleneoxy)-azobenzene) at the air/water interface were obtained. Using the Xe/Hg Xe 500w(93' model 68811), an activities of molecule at the air/water interface were certified. In addition, using a current-measuring technique, we investigated the abrupt changes of a current observed at the liquid-to-solid phase transition in a current-area (I-A) isotherm of a fatty acid monolayer at the air/water interface

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활성탄에 의한 Tharonil의 흡착특성에 관한 연구 (Study on Adsorption Characteristics of Tharonil from Aqueous Solution by Activated Carbon Adsorption)

  • 이종집;유용호
    • 한국안전학회지
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    • 제15권4호
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    • pp.88-94
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    • 2000
  • The adsorption characteristics of Tharonil on granular activated carbon were experimentally investigated in an adsorber and in a packed column. It was estabilished that the adsorption equilibrium of Tharonil on granular activated carbon was more successfully fitted by Freundlich isotherm equation than Langmuir isotherm equation in the concentration range from 1 to 1000 mg/1. Intraparticle diffusivities (pore and surface diffusivity) of Tharonil were estimated by the concentration-time curve and adsorption isotherm. The estimated values of pore diffusivity and surface diffusivity are $6.70{\times}10^{-6}$ and $2.0{\times}10^{-9}cm^2/s$, respectively. From comparison of intraparticle diffusivities, it was found that surface diffusion was the limiting step for adsorption rate. The break time and breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results.

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Adsorption of Cu(II) Ions onto Myristica Fragrans Shell-based Activated Carbon: Isotherm, Kinetic and Thermodynamic Studies

  • Syahiddin, D.S.;Muslim, A.
    • 대한화학회지
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    • 제62권2호
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    • pp.79-86
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    • 2018
  • This study reported the adsorption of Cu(II) ions onto activated carbon prepared from Myristica Fragrans shell (MFS AC) over independent variables of contact time, activating chemical (NaOH) concentration, initial adsorbate concentration, initial pH of adsorbate solution and adsorption temperature. The MFS AC structure, morphology and total surface area were characterized by FTIR, SEM and BET techniques, respectively. The Cu(II) ions adsorption on the MFS AC (activated using 0.5 M NaOH) fitted best to Freundlich adsorption isotherm (FAI), and the FAI constant obtained was 0.845 L/g at $30^{\circ}C$ and pH 4.5. It followed the pseudo first order of adsorption kinetic (PFOAK) model, and the PFOAK based adsorption capacity was 107.65 mg/g. Thermodynamic study confirmed the Cu(II) ions adsorption should be exothermic and non-spontaneous process, physical adsorption should be taken place. The total surface area and pore volume based on BET analysis was $99.85m^2/g$ and 0.086 cc/g, respectively.

석탄회로 합성한 제올라이트에 의한 Sr(II) 및 Cs(I) 이온의 제거 특성 (Removal Characteristics of Strontium and Cesium tons by Zeolite Synthesized from Fly Ash)

  • 감상규;이동환;문명준;이민규
    • 한국환경과학회지
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    • 제12권10호
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    • pp.1061-1069
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    • 2003
  • The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

활성탄에 대한 수소화 메탄의 흡착특성 (Adsorption Characteristic of Hydrogen and Methane on Activated Carbon)

  • 김은철;최대기;노경호
    • 한국수소및신에너지학회논문집
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    • 제16권4호
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    • pp.307-314
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    • 2005
  • In this work, a static volumetric method was experimentally implemented to measure the adsorption isotherm of hydrogen and methane by the activated carbon. The equilibrium data of stationary phase and mobile phase were correlated into the Langmuir, Freundlich, Langmuir-Freundlich, and Toth isotherms, respectively. In addition, the comparison between prediction and experimental data was made. By a nonlinear regression analysis, the experimental parameters in the equilibrium isotherms were estimated and compared. Then, the linear and quadratic equations for pressure and temperature to adsorption amounts were expressed. The adsorption amounts were increased with the pressure increase and the temperature decrease.

The applicability of Freundlichs isotherm model for the leaching of solidified hazardous waste using cementitious binders

  • Jong Ho Youn;Heo
    • 한국환경과학회지
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    • 제2권1호
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    • pp.9.2-19
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    • 1993
  • A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash (RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portaind Rice Husk Ash Cement (PRHAC) which contained rice husk ash U percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

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