Removal of Cr(III) in the fixed bed column and batch reactors using as adsorbent zeolite NaX

Barros, Maria Angélica Simões Dornellas de; Silva, Edson Antônio da; Arroyo, Pedro Augusto; Tavares, Célia Regina Granhen; Schneider, Ricardo; Suszek, Morgana; Sousa-Aguiar, Eduardo Falabella

doi:10.1016/j.ces.2004.07.040

Cited by 78 publications

(55 citation statements)

References 21 publications

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“…In fact, it was already reported the favorable aspect of such process (BARROS et al, 2002(BARROS et al, , 2004BASALDELLA et al, 2007;GAZOLA et al, 2006). Nevertheless, the chromium curves seemed to be less sharp in a competitive system than in a single solution probably due to higher diffusional resistances that implied a decrease in the mass transfer rates (McCABE et al, 1993;ZULFADHLY et al, 2001).…”

Section: Resultsmentioning

confidence: 97%

“…NaY had the unit cell composition . In order to obtain, as far as possible, the pure homoionic sodium form, the zeolites, as received, were contacted four times with 1 Mol L -1 solutions of NaCl at 60 o C. The samples were then washed each time with 2 L of hot deionised water and oven-dried at 100 o C. For the dynamic runs, the zeolites were pelletized and NaX or NaY pellets were subsequently screened and collected in an average diameter size of 0.180 mm as previously recommended as the optimal particle size for this fixed-bed system (BARROS et al, 2004).…”

Section: Zeolitesmentioning

confidence: 99%

“…-1 as this condition minimized the mass transfer resistances for single ion exchange of Cr 3+ ions (BARROS et al, 2004). Samples at the column outlet were taken regularly.…”

Section: Ion Exchange Unitmentioning

confidence: 99%

“…In single conditions, zeolites NaX and NaY exhibited remarkable selectivity for chromium cations (BARROS et al, 2004;BASALDELLA et al, 2007;GAZOLA et al, 2006). Nevertheless, in multicomponent ion exchange processes, it is supposed a lower efficiency due to competition to the sites.…”

Section: Introductionmentioning

confidence: 99%

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<b>Evaluation of NaX and NaY packed beds for chromium uptake from multicomponent solution<b>

et al. 2014

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ABSTRACT. In this paper the removal of chromium from Cr/Ca/Mg/K and Cr/Ca/Mg/K/Na solutions was investigated in NaX and NaY packed beds. The breakthrough curves presented some overshooting phenomena where chromium ions displaced the previous exchanged cations. Length of unused bed, overall mass transfer coefficient, operational ratio and dimensionless variance were obtained. According to such mass transfer parameters it was concluded that the chromium uptake is influenced by the competition and interaction of the entering ions. Such influences were verified through some differences in the dynamic selectivity obtained for each system. NaY seemed to have a higher affinity towards Cr 3+ and its sites were more efficiently used in the ion exchange process.Keywords: zeolite, breakthrough, multicomponent, ion exchange.Avaliação do processo de remoção do cromo em solução multicomponente em colunas de leito fixo utilizando as zeólitas NaX e NaY RESUMO. Neste artigo, a remoção do cromo foi investigada nas seguintes soluções multicomponentes: Cr/Ca/Mg/K e Cr/Ca/Mg/K/Na utilizando as zeólitas NaX e NaY em colunas de leito fixo. As curvas de ruptura mostraram que os íons de cromo deslocaram os cátions trocadores. Os parâmetros como zona de transferência de massa, o coeficiente global de transferência de massa, a relação operacional e variância adimensional foram obtidos. De acordo com estes parâmetros de transferência de massa, concluiu-se que a adsorção de cromo foi influenciada pela competição e interação dos íons de entrada. Essas influências foram verificadas pelas diferenças da seletividade obtidas para cada sistema dinâmico. A zeólita NaY teve maior afinidade para com o Cr 3+ e os seus sítios foram mais eficientemente ocupados no processo de troca iônica.Palavras-chave: zeólita, curvas de ruptura, multicomponente, troca iônica.

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Section: Resultsmentioning

confidence: 97%

Section: Zeolitesmentioning

confidence: 99%

“…-1 as this condition minimized the mass transfer resistances for single ion exchange of Cr 3+ ions (BARROS et al, 2004). Samples at the column outlet were taken regularly.…”

Section: Ion Exchange Unitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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<b>Evaluation of NaX and NaY packed beds for chromium uptake from multicomponent solution<b>

et al. 2014

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“…[12][13][14][15][16][17][18][19][20][21][22][23] Most reports focus only on breakthrough curves. However, Ernest et al 12) calculated elution curves containing not only the breakthroughs but also the tailings.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Elution Curves in Preparative Chromatography Using Anion-Exchange Resin for Cobalt Purification

2009

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There have been many studies on the modeling of elution and breakthrough curves of ion-exchange chromatography. A precise representation of elution curves using an appropriate mathematical model is significant for the application and expansion of ion-exchange chromatography. The significance of precise modeling particularly increases when the yield and purity of the product are important. However, no previous studies have proposed a model that can perfectly represent experimental elution curves. We investigated the purification of various metals by anion-exchange separation and determined an optimum condition for purification of an element through trial and error. An appropriate model replicating the elution curves accurately is greatly needed to reduce the testing phase. Consequently, this paper proposes a novel model called the plate theory in multi-path mode, in which three virtual paths are assumed. The results show that this model well represents the experimental elution curves. In addition, the model was validated by comparing the distribution coefficients obtained from the fitting results with those determined by previously reported batch experiments.

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Combination of Brønsted and Lewis Polymeric Catalysts for Efficient Conversion of Cellulose into 5‐Hydroxymethylfurfural (HMF) in Ionic Liquids

et al. 2015

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Stable oil‐in‐water high internal phase emulsions (HIPEs) with an internal phase volume fraction of 85 % were stabilized using Tween 85. The prepared poly(HIPEs) were first investigated as adsorbents to treat water polluted with CrIII, and then the catalysts with Lewis acidic sites was synthesized. The catalysts with Brønsted acidic sites were obtained by ion‐exchanging. The as‐prepared HIPEs–CrIII (PEs–CrIII) and HIPEs–SO3H (PEs–SO3H) possess open‐cell structure, interconnecting pores, and strong acidity, they are utilized as highly efficient catalysts for the conversion of biomass to 5‐hydroxymethylfurfural (HMF). These results showed maximum production yields for cellulose, glucose, and fructose of 37.0 %, 58.0 %, and 80.8 %, respectively. PEs–CrIII and PEs–SO3H can be very easily recycled at least four times without significant loss of activity. Herein, a new method is presented to transform cellulose by using two catalysts in a one‐pot process for meeting the varying demands involved at different reaction stages.

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Removal of Cr(III) in the fixed bed column and batch reactors using as adsorbent zeolite NaX

Cited by 78 publications

References 21 publications

<b>Evaluation of NaX and NaY packed beds for chromium uptake from multicomponent solution<b>

<b>Evaluation of NaX and NaY packed beds for chromium uptake from multicomponent solution<b>

Modeling of Elution Curves in Preparative Chromatography Using Anion-Exchange Resin for Cobalt Purification

Combination of Brønsted and Lewis Polymeric Catalysts for Efficient Conversion of Cellulose into 5‐Hydroxymethylfurfural (HMF) in Ionic Liquids

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