• Title, Summary, Keyword: Adsorption isotherm

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Adsorption characteristic of Cu(II) and phosphate using non-linear and linear isotherm equation for chitosan bead (비선형과 선형 등온흡착식을 이용한 키토산비드의 구리와 인산염의 흡착특성)

  • Kim, Taehoon;An, Byungryul
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.3
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    • pp.201-210
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    • 2020
  • 2 (Langmuir, Freundlich, Elovich, Temkin, and Dubinin-Radushkevich) and 3 (Sips and Redlich-Peterson)-parameter isotherm models were applied to evaluated for the applicability of adsorption of Cu(II) and/or phosphate isotherm using chitosan bead. Non-linear and linear isotherm adsorption were also compared on each parameter with coefficient of determination (R2). Among 2-parameter isotherms, non-linear Langmuir and Freundlich isotherm showed relatively higher R2 and appropriate maximum uptake (qm) than other isotherm equation although linear Dubinin-Radushkevich obtained highest R2. 3-parameter isotherm model demonstrated more reasonable and accuracy results than 2-parmeter isotherm in both non-linear and linear due to the addition of one parameter. The linearization for all of isotherm equation did not increase the applicability of adsorption models when error experiment data was included.

Altered Langmuir Adsorption Isotherm under the Consideration of the Displacement of Water Molecules with Adsorbate Ion at the Surface of Adsorbent (흡착제(吸着劑) 표면(表面)에서의 흡착질(吸着質)과 물분자(分子)의 치환(置換)을 고려(考慮)한 수정(修正) Langmuir 등온흡착식(等溫吸着式))

  • Kim, Dong-Su
    • Resources Recycling
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    • v.15 no.3
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    • pp.81-86
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    • 2006
  • Altered Langmuir adsorption isotherm has been suggested for adsorption reactions occurring in aqueous environment based upon the concept of the steric displacement between adsorbates and water molecules at the surface of adsorbent. For the adsorption of $Cd^{2+}$ on activated carbon, the suggested adsorption isotherm was shown to be more well applied to the experimental results compared with the classical Langmuir adsorption isotherm. Based on this, regarding the adsorption system which following the Langmuir model more precise design and controllable operation of the process were considered to be attainable when the adsorption process is analyzed employing the altered adsorption isotherm.

Adsorption isotherm and kinetics analysis of hexavalent chromium and mercury on mustard oil cake

  • Reddy, T. Vishnuvardhan;Chauhan, Sachin;Chakraborty, Saswati
    • Environmental Engineering Research
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    • v.22 no.1
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    • pp.95-107
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    • 2017
  • Adsorption equilibrium and kinetic behavior of two toxic heavy metals hexavalent chromium [Cr(VI)] and mercury [Hg(II)] on mustard oil cake (MOC) was studied. Isotherm of total chromium was of concave type (S1 type) suggesting cooperative adsorption. Total chromium adsorption followed BET isotherm model. Isotherm of Hg(II) was of L3 type with monolayer followed by multilayer formation due to blockage of pores of MOC at lower concentration of Hg(II). Combined BET-Langmuir and BET-Freundlich models were appropriate to predict Hg(II) adsorption data on MOC. Boyd's model confirmed that external mass transfer was rate limiting step for both total chromium and Hg(II) adsorptions with average diffusivity of $1.09{\times}10^{-16}$ and $0.97m^2/sec$, respectively. Desorption was more than 60% with Hg(II), but poor with chromium. The optimum pH for adsorptions of total chromium and Hg(II) were 2-3 and 5, respectively. At strong acidic pH, Cr(VI) was adsorbed by ion exchange mechanism and after adsorption reduced to Cr(III) and remained on MOC surface. Hg(II) removal was achieved by complexation of $HgCl_2$ with deprotonated amine ($-NH_2$) and carboxyl (COO-) groups of MOC.

A Study on the Adsorption Characteristics of Benzene using Activated Carbon from Sewage Sludge (하수슬러지 활성탄의 벤젠 흡착특성)

  • Kim, Jong-Moon;Chung, Chan-Kyo;Lee, Taek-Ryong;Min, Byong-Hun;Kim, Hyung-Jin;Kwon, Young-Shik
    • Clean Technology
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    • v.15 no.4
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    • pp.265-272
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    • 2009
  • In this study the experiments on the static adsorption of benzene were carried out using activated carbon made from sewage sludge. The experiment was performed at 303.15 K, 318.15 K and 333.15 K under the pressure up to 7.999kPa. Isothermal adsorption curves were obtained using Langmuir isotherm, Freundlich isotherm and Toth isotherm for comparison. Based on fitting the adsorption quantity of Benzene (q), the isothermal adsorption curves obtained from Langmuir isotherm and Toth isotherm showed the higher accuracy. Although there was little difference in accuracy between result from Langmuir isotherm and that from Toth isotherm, the adsorption quantity of Benzene (q) was expressed in terms of Langmuir isotherm because less parameters were required for Langmuir isotherm than for Toth isotherm. Moreover SEM images of the activated carbon from sewage sludge and the commercial activated carbon were taken to observe the pore size development. The results showed that the perforation development of the commercial activated carbon (DARCO A.C., SPG-100 A.C.) was better than that of activated carbon from sewage sludge. Adsorption quantity of benzene on commercial activated carbon was confirmed to be higher than that on activated carbon from sewage sludge. However the maximum adsorption quantity of benzene on activated carbon from sewage sludge was close to that on SGP-100 A.C. at 303.15K. Therefore, we may conclude that it is feasible to commercialize the process to manufacturing activated carbon from sewage sludge.

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Determination of the Frumkin and Temkin Adsorption Isotherms of Underpotentially Deposited Hydrogen at Pt Group Metal Interfaces Using the Standard Gibbs Energy of Adsorption and Correlation Constants

  • Chun, Jinyoung;Jeon, Sang K.;Chun, Jang H.
    • Journal of the Korean Electrochemical Society
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    • v.16 no.4
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    • pp.211-216
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    • 2013
  • At Pt(111), Pt(100), Pt, and Rh interfaces, the Frumkin adsorption isotherm of underpotentially deposited hydrogen (UPD H) and related electrode kinetic data are determined using the standard Gibbs energy of adsorption. The Temkin adsorption isotherm of UPD H correlating with the Frumkin adsorption isotherm of UPD H is readily determined using the correlation constants between the Temkin and Frumkin or Langmuir adsorption isotherms. At the Pt(111), Pt(100), Pt, and Rh interfaces, the lateral repulsive interaction between the UPD H species is interpreted using the interaction parameter for the Frumkin adsorption isotherm. The lateral repulsive interaction between the UPD H species at the Pt(111), Pt(100), Pt, and Rh interfaces is significantly different from the lateral attractive interaction between the overpotentially deposited hydrogen (OPD H) species at Pt, Ir, and Pt-Ir alloy interfaces.

A Study on VOCS Adsorption at Low Pressure (낮은 분압의 VOCs의 흡착에 관한 연구)

  • Song, Hun-Taek;Kan, Sung-Won;Min, Byong-Hun;Suh, Sung-Sup
    • Clean Technology
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    • v.9 no.4
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    • pp.153-161
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    • 2003
  • This study was carried out as a basic experiment for development of adsorption process in which benzene and toluene was adsorbed on activated carbon. In the static adsorption experiment, Adsorption character of benzene and toluene was studied by change of temperature and pressure. Activated carbon 12~20mesh and activated carbon 20~40mesh was used as adsorbents, Benzene, toluene and nitrogen as adsorbates. Experimental data were obtained to fitted to Langmuir isotherm and dependence was acquired. Parameters of adsorption heat and adsorption constant was obtained. Static adsorption experiment for binary mixtures confirmed that Langmuir isotherm parameters could be applicable to Extended Langmuir isotherm. Experimental technique used in this study only requires pressure measurement and this technique is different from the conventional method which measures gas mole compositions before adsorption and after adsorption. The dynamic adsorption experiment was carried out and the experimental results was compared with the computer simulation results. In this study, basic data was acquired to decide adsorption conditions in the process.

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Adsorption of manganese ion using polyaniline and it's nanocomposite: Kinetics and isotherm studies

  • Hallajiqomi, Milad;Eisazadeh, Hossein
    • Journal of Industrial and Engineering Chemistry
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    • v.55
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    • pp.191-197
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    • 2017
  • In this research, the preparation of polyaniline (PAn) nanocomposite as adsorbent and it's capability in manganese removal was investigated. The PAn nanocomposites were prepared using different kind of surfactants such as hydroxypropylcellulose (HPC), poly (vinyl pyrrolidone) (PVP), poly (vinyl alcohol) (PVA) and poly (ethylene glycol) (PEG) in the presence of $KIO_3$ as an oxidant. The products were characterized in terms of morphology and chemical structure with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Batch studies were performed to evaluate the influence of various experimental parameters including pH, adsorbent dosage, and contact time. Optimum conditions for manganese removal were found to be pH 10, adsorbent dosage of 10 g/L and equilibrium time 30 min. Also, the kinetic of adsorption system have been studied based on the assumption of pseudo-second order rate law. The experimental results have been analyzed using a pseudo-Langmuir adsorption isotherm and a pseudo-Freundlich adsorption isotherm models. The Freundlich adsorption isotherm model was found to represent the measured sorption data better than Langmuir adsorption isotherm. According to the evaluation using the pseudo-Freundlich model, the monolayer adsorption capacity ($q_{max}$) of PAn for manganese ions was obtained to be 50.251 mg/g.

The comparison of the adsorption characteristic of heavy metals onto soil mixed with food compost using retardation coefficient (지연계수를 이용한 음식물 퇴비 혼합 토양의 중금속 흡착특성 비교)

  • Joo, You-Yoen;Kang, Seon-Hong
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.2
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    • pp.245-250
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    • 2008
  • Adsorption experiment was carried out to find the adsorption capacity and characteristics of heavy metals(Cd, Pb) onto soil and mixed soil with food compost. Result showed that mixed soil having higher organic content adsorbed more heavy metal than soil, indicating that food compost can be used effectively to prevent soil pollution. Linear adsorption isotherm which adopted to find the adsorption characteristics was used to calculate Retardation Factor(R). The value of Retardation Factor(R)s of Pb and Cd in mixed soil, found as 34.54, 24.42 respectively, are higher than those in soil which were found as 4.64, 3.67, respectively. The value of Retardation Factor(R) using Freundlich adsorption isotherm could be presented by the functions of concentration and showed similar result as the linear one. But Freundlich adsorption isotherm showed higher relationship than linear one and the retardation factor(R) from freundlich adsorption isotherm was thought as more effective method to assess adsorption capacity because it could reflect gradient and intercept of the isotherm.

Determination of Adsorption Isotherm Parameters by Breakthrough Curves in Activated Carbon and Zeolite 13X Packed Bed (활성탄 및 제올라이트 13X를 충진한 흡착탑에서 파과곡선을 이용한 흡착등온식 상수의 결정)

  • Kang, Sung-Won;Min, Byung-Hoon;Suh, Sung-Sup
    • Applied Chemistry for Engineering
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    • v.16 no.1
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    • pp.131-138
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    • 2005
  • Freundlich isotherms and Toth isotherms were obtained for benzene adsorption on activated carbon and zeolite 13X in static experiments. Breakthrough curves of benzene were measured in adsorption bed packed with the same adsorbents. Relation between breakthrough times and partial pressure of benzene was analyzed and the Freundlich isotherm parameters were determined. Adsorption amount of benzene predicted by the analysis of breakthrough experimental results was relatively consistent with that predicted by the static experimental results. Dynamic experiments for activated carbon bed, where more symmetric breakthrough curves were obtained, produced smaller errors with zeolite bed.

Adsorption isotherm on the heterogeneous surface with spatially uneven periodic adsorption heat distribution (요철형 공간주기성을 갖는 Heterogeneous 표면 흡착열분포에 대한 흡착등온식)

  • 김철호;황보승
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.12 no.3
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    • pp.115-119
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    • 2002
  • An adsorption isotherm on the heterogeneous surface which has spatially periodic adsorption heat distribution was formalized. Usefulness of the formalized adsorption isotherm is discussed with the help of a model calculation. Statistical thermodynamics is used throughout.