Adsorption of chromium (III), chromium (VI) and silver (I) on bentonite

ResumoEste trabalho tem como objetivo caracterizar a argila de Toritama, estado de Pernambuco, na sua forma "in natura" após ativação térmica a 500 °C visando sua utilização na remoção de Cd 2+ . A argila "in natura" foi caracterizada por meio de espectrometria de raios X por energia dispersiva (EDX), difração de raios X e análise textural usando adsorção física de nitrogênio (BET). As argilas ativadas termicamente (100, 200, 300, 400 e 500 °C) foram caracterizadas por difração de raios X. A argila ativada termicamente a 500 °C foi caracterizada por EDX e BET. A remoção do Cd 2+ pela argila ativada termicamente foi realizada em sistema de banho finito. O tratamento térmico modificou levemente a área, como mostrou a análise de área de superfície específica, mas não modificou a distribuição de diâmetro de poros. Os dados experimentais para o sistema de banho finito se ajustaram aos modelos estudados, Langmuir e Freundlich; no entanto, o modelo de Freundlich foi mais satisfatório. O processo de remoção de cádmio em sistema de banho finito pela argila de Toritama ativada termicamente a 500 °C só atinge o equilíbrio depois de 120 min e apresenta um percentual de cerca de 86,8% de remoção de cádmio.Palavras-chave: tratamento térmico, caracterização, argilas, metais pesados, adsorção. (100, 200, 300, 400 Abstract The purpose of this study is to characterize the clay of Toritama (Pernambuco, Brazil), in its form "in nature", and also after thermal activation at 500 °C, aiming its use in the removal of Cd 2+ . The clay "in nature" was characterized byg X-ray spectrometry by dispersive energy (EDX), X-ray diffraction (XRD), and surface area measurement by physical adsorption of nitrogen (BET). The thermally activated clay

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“…As argilas têm sido extensamente empregadas como adsorventes na remoção de metais pesados [8][9][10][11][12][13][14][15].…”

Section: Introductionunclassified

Remoção de cádmio a partir da argila de Toritama (estado de Pernambuco) ativada termicamente em sistema de banho finito

2009

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“…K sor est défini comme étant le rapport de la quantité de Cr(VI) fixée Q a (mg g -1 ) sur la quantité de Cr(VI) restante en solution (mg cm -3 ) (KHAN et al, 1995).…”

Section: Sorption Des Ions Chromateunclassified

“…La relation thermodynamique ΔG 0 = ΔH 0 -TΔS 0 ; associée à la relation de Vant'Hoff ΔG 0 = -RTlnK sor (KHAN et al, 1995), nous permet d'aboutir à l'équation :…”

Section: Sorption Des Ions Chromateunclassified

Étude des facteurs contrôlant la sorption de Cr(VI) sur une hydrotalcite de synthèse

Bakhti

Ouali

2007

rseau

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La sorption des ions chromate de solutions aqueuses sur une hydrotalcite de synthèse et sur son produit de calcination a été étudiée. L’interaction de ces matériaux avec les ions chromate montre que la cinétique de sorption est rapide et suit une expression de vitesse de sorption réversible du premier ordre. Les influences du pH, de la concentration en ions chromate de la solution et de la température ont été étudiées afin d’optimiser la sorption. Le traitement de solutions contenant de 10 à 200 mg L-1 de Cr(VI) a donné de bons résultats. Les capacités de sorption de ces matériaux sont 1,3 et 2,4 mmol g‑1 de Cr(VI), respectivement. L’étude de la réversibilité de la sorption des ions chromate indique qu’il est possible d’utiliser les hydrotalcites calcinées comme sorbants recyclables. Ceci suggère notamment que ces derniers pourraient constituer d’intéressants supports pour le piégeage d’ions chromate.The sorption of chromate ions from aqueous solutions onto a synthetic hydrotalcite and its calcination product was investigated. The interaction of these materials with chromate ions shows that the kinetics of sorption are fast and follow a first-order reversible model. The effects of pH, chromate ion concentration and temperature on the sorption were studied. Solutions containing from 10 to 200 mg L‑1 of Cr(VI) were successfully treated. The sorption capacities of these materials are approximately 1.3 and 2.4 mmol CrO42-, per g, for the hydrotalcite and its calcination product, respectively. The reversibility of the sorption of chromate ions suggests the possible use of the calcined hydrotalcites as recyclable sorbents, which may constitute useful supports for trapping chromate ions

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“…The surface of the adsorbent will be positively charged at lower pH, and it will not favor the adsorption of positively charged ions. Then it will favor the adsorption of Cr(VI) in the anionic form as HCrO 4 - [19,20].…”

Section: Effect Of Phmentioning

confidence: 99%

Removal of Chromium from Aqueous Solution Using Hybrid Membrane of Chitosan and Silicon Dioxide

Deng¹,

Kano²,

Inoue³

2016

JCCE

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Adsorption experiment from aqueous solutions containing known amount of chromium (Cr) using hybrid membrane of chitosan and silicon dioxide was explored to evaluate the efficiency of the membrane as sorbent for Cr(VI). Some variable parameters such as pH, contact time and the dosage of the membrane were optimized. Adsorption isotherms of Cr(VI) onto the hybrid membrane were measured with varying initial concentrations under optimized condition. Furthermore, the sorption mechanism of Cr by the membrane was investigated by applying Langmuir and Freundlich isotherm equations to the data obtained. The surface morphology of the membrane was determined by SEM (scanning electron microscope) for material characterization. The concentrations of Cr in solution are determined by ICP-MS (inductively coupled plasma mass spectrometry). Hybrid membrane of chitosan and silicon dioxide can be an efficient sorbent for Cr(VI).

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Adsorption of chromium (III), chromium (VI) and silver (I) on bentonite

Cited by 315 publications

References 21 publications

Remoção de cádmio a partir da argila de Toritama (estado de Pernambuco) ativada termicamente em sistema de banho finito

Remoção de cádmio a partir da argila de Toritama (estado de Pernambuco) ativada termicamente em sistema de banho finito

Étude des facteurs contrôlant la sorption de Cr(VI) sur une hydrotalcite de synthèse

Removal of Chromium from Aqueous Solution Using Hybrid Membrane of Chitosan and Silicon Dioxide

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