Chromium adsorption in olive stone activated carbon

Pereira, Milton Rogério; Arroyo, Pedro Augusto; Barros, Maria Angélica Simões Dornellas de; Sanches, Viviane Monteiro; Silva, Edson Antônio da; Fonseca, Isabel; Lovera, Rafael García

doi:10.1007/s10450-006-0377-z

Cited by 15 publications

(13 citation statements)

References 14 publications

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“…where: C and q have the same meaning as described for the Freundlich isotherm; b is a constant that represents the adsorption bond energy (L/meq); q max is a constant that represent the maximum adsorption capacity (meq/g), corresponding to a monolayer covering the surface of the adsorbent (Maheria and Chudasama, 2006;Pereira et al, 2006).…”

Section: Isotherm Constructionmentioning

confidence: 99%

Determination of the maximum retention of cobalt by ion exchange in h-zeolites

Zola

Barros

Sousa-Aguiar

et al. 2012

Braz. J. Chem. Eng.

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-This work aimed to determine the maximum content of cobalt that can be incorporated by ion exchange in zeolites H-USY, H-Beta, H-Mordenite, and H-ZSM-5. To reach this goal, batch isotherms at 75ºC were constructed after addition of zeolite samples in flasks filled with cobalt nitrate solution. The equilibrium data were fitted to Langmuir, Freundlich, and Tóth adsorption isotherm models. Langmuir was the best model for zeolites H-Beta, H-Mordenite, and H-ZSM-5, whereas experimental data for H-USY were better fitted to the Freundlich isotherm model. From the isotherms, it was possible to determine the maximum cobalt exchange level (q max ) that can be incorporated in each zeolite through ion exchange. In this sense, H-USY presented the highest q max value (2.40 meq/g zeol ), while H-ZSM-5 showed the lowest one (0.64 meq/g zeol ).These results also show the influence of the zeolite framework related to the channel system, pore opening, presence of cavities and secondary porosity and SiO 2 /Al 2 O 3 ratio (SAR) on the maximum capacity and behavior of cobalt ion exchange in protonic zeolites.

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Section: Isotherm Constructionmentioning

confidence: 99%

Determination of the maximum retention of cobalt by ion exchange in h-zeolites

Zola

Barros

Sousa-Aguiar

et al. 2012

Braz. J. Chem. Eng.

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“…Pseudo-first-order and pseudo-second-order equations can be used assuming that the measured concentrations are equal to surface concentrations 13 . The pseudo-first-order rate lagergren model is 14 : dq = k 1 , ads(q e -q) dt Where, q (mg/g) is the amount of adsorbed heavy metals on the adsorbent at time t and k 1 , ads (min -1 ) is the rate constant of first-order adsorption 15 [17][18][19][20][21][22][23][24][25][26] q e the equilibrium sorption uptake, is extrapolated from the experimental data at time t = infinity. A straight line of log(q e -q) versus t suggests the applicability of this kinetic model.…”

Section: Kinetic Modeling In a Batch Systemmentioning

confidence: 99%

“…The Freundlich model which is an indicative of surface heterogeneity of the adsorbent is described by the following equation 21 .…”

Section: Freundlich Modelmentioning

confidence: 99%

“…Chem Sci Trans., 2018, 7(1), [17][18][19][20][21][22][23][24][25][26] Where, R is the universal gas constant (8.314 JK -1 mol -1 ), T is the absolute temperature (Kelvin) and K represents the equilibrium adsorption constants of the isotherm fits (K L , Langmuir equilibrium constant and K f , Freundlich equilibrium constant, which must be converted to SI units, by using the molecular mass of the RB dye) obtained from the isotherm plots. ∆H o and ∆S o values can be calculated from the slope and intercept of the linear plot of ln(K) versus 1/T.…”

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confidence: 99%

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Adsorption Studies on Rhodamine-B Removal from Aqueous Solution Using Acid Activated Strychnos Nux-Vomica Leaf Powder

2018

Chem Sci Trans

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Acid activated strychnos nux-vomica leaf powder (SLP) was employed for removal of the rhodamine-B (RB) dye from aqueous solution. Batch adsorption studies were carried out under varying conditions of dye concentration, adsorbent dose, contact time, pH and temperature. Removal efficiency was 92% in 50 min with 6.5 pH, 50 mg/L as dose, 50 mg/L RB concentration and 30 °C temperature. The equilibrium data the best fitted with Langmuir model. The adsorption followed Lagergren pseudosecond order kinetics. The values of free energy change (∆G°), enthalpy change (∆H°) and entropy change (∆S°) indicated the process to be spontaneous. The diffusion studies indicated that adsorption initially takes place by external mass transfer and later by intra-particle diffusion. The results indicate that SLP is a good adsorbent for the removal of RB from wastewater.

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“…This analysis provides the minimal conditions of diffusional resistances. As presented in Pereira et al (2006), the operational ratio is given by the Equation 5:…”

Section: Study Of Optimal Operational Flow Ratementioning

confidence: 99%

<b>Comparative study of the adsorption of cadmium and zinc on activated bone char

et al. 2017

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ABSTRACT. The goal of this work was to study the adsorption equilibrium of ions Zn 2+ and Cd 2+ using bovine bone char in fixed bed columns. Dynamic tests were performed with upstream flow fixed bed column, at 30 o C and average particle diameter of 0.08 mm. Initially, the optimal operating flow rate was determined, which was 4 mL min.-1 for both metals. The dynamic isotherms, obtained by mass balance in the breakthrough curves, were fitted to the Langmuir and Freundlich models. Simulations of the dynamics of ion adsorption provided satisfactory results, wherein the mass transfer coefficient was directly affected by the inflow concentration of ions, within the range of the study.Keywords: equilibrium data, heavy metals, mathematical model. Estudo comparativo da adsorção dos íons cádmio e zinco no carvão ativado de osso bovino RESUMO. O objetivo deste trabalho foi estudar o equilíbrio de adsorção de íons Zn 2+e Cd 2+ usando carvão de osso bovino em colunas de leito fixo. Testes dinâmicos foram realizados com o fluxo ascendente em coluna de leito fixo, a 30°C e diâmetro médio de partícula de 0,08 mm. Inicialmente, a vazão ótima de trabalho foi determinada, sendo de 4 mL min.-1 para ambos os metais. As isotermas dinâmicas foram obtidas pelo balanço de massa nas curvas de ruptura, e foram ajustadas aos modelos de Langmuir e Freundlich. A simulação da dinâmica de adsorção forneceu resultados satisfatórios para ambos os íons, em que o coeficiente de transferência de massa foi diretamente afetado pela concentração inicial dos íons metálicos.Palavras-chave: dados de equilíbrio, metais pesados, modelo matemático.

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Chromium adsorption in olive stone activated carbon

Cited by 15 publications

References 14 publications

Determination of the maximum retention of cobalt by ion exchange in h-zeolites

Determination of the maximum retention of cobalt by ion exchange in h-zeolites

Adsorption Studies on Rhodamine-B Removal from Aqueous Solution Using Acid Activated Strychnos Nux-Vomica Leaf Powder

<b>Comparative study of the adsorption of cadmium and zinc on activated bone char

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