Competing Ion Exchange of Zn<sup>2+</sup> and Fe<sup>3+</sup> in NaY Zeolite

Ostroski, Indianara Conceição; Dantas, João Henrique; Silva, Edson Antônio da; Arroyo, Pedro Augusto; Barros, Maria Angélica Simões Dornellas de

doi:10.1260/0263-6174.30.4.275

Cited by 6 publications

(4 citation statements)

References 27 publications

(13 reference statements)

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“…Assim, a contribuição do processo de adsorção para a zeólita NaY é muito pequena, ou desprezível, perante a contribuição do processo de troca iônica para a quantidade total de cátions sorvida. Desta forma, a zeólita é um trocador iônico e não um adsorvente [5,8,27,28,29,30].…”

Section: Figura 4: Cromatografia De âNions Na Sorção Dos íOns A) Caunclassified

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

et al. 2017

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RESUMOO estudo do mecanismo de sorção e da influência do pH inicial da solução em materiais sólidos se faz necessário, pois o simples fato de alterar o valor de pH da solução pode alterar a capacidade de sorção de um adsorvato. Foi avaliada a sorção dos íons Ca 2+ e Mg 2+ em três valores de pH dependendo do ponto de carga zero (pHPCZ) em zeólita NaY ou sílica gel (pH < pHPCZ; pH = pHPCZ; pH > pHPCZ). Foi obtida a cinética de sorção e ajustados os modelos de pseudo-primeira ordem, pseudo-segunda ordem e difusão intrapartícula dos íons nos dois materiais de estudo. Na zeólita NaY o valor de pH que obteve maior capacidade de sorção foi o 4,3 (pH < pHPCZ) e o modelo de pseudo-segunda ordem obteve um melhor ajuste aos dados experimentais. Neste material a quantidade adsorvida é pequena quando comparada à troca iônica. Enquanto, na sílica gel a maior capacidade de sorção se deu no valor de pH de 6,7 (pH > pHPCZ) e o modelo que melhor se ajustou aos dados experimentais também foi o de pseudo-segunda ordem, concluindo-se que a adsorção é o principal mecanismo de sorção. Palavras-chave:Mecanismo de sorção; Sílica gel; Zeólita NaY; Ponto de carga zero. ABSTRACTThe study of the sorption mechanism and the initial pH of the solution influence in solid materials is necessary, because the simple fact of changing the pH of the solution can modify the sorption capacity of an adsorbate. It was evaluated the sorption of ions Ca 2+ and Mg 2+ at three pH values depending on the point of zero charge (pHPZC) on NaY zeolite or silica gel (pH < pHPZC; pH = pHPZC; pH > pHPZC). The sorption kinetics was obtained and adjusted by models of pseudo-first-order, pseudo-second-order and intraparticle diffusion of ions in the two studyied materials. In NaY zeolite adsorbent, the pH value had a higher sorption capacity was 4.3 (pH < pHPZC) and pseudo-second-order model showed a better fit to the experimental data. In this material the adsorbed amount is small when compared to ion exchange. While in the silica gel, the highest sorption capacity occurred at pH 6.7 (pH > pHPZC) and the model that best fit the data experimental was also the pseudo-second-order, concluding that the adsorption is main sorption mechanism.Keywords: Sorption mechanism; Silica gel; NaY zeolite; Point of zero chance. INTRODUÇÃOO aumento da população mundial e o desenvolvimento econômico introduziu uma enorme quantidade de contaminantes, como os íons metálicos [1]. A não remoção de metais de efluentes pode causar danos tanto à saúde humana quanto à indústria, pois metais como cálcio e magnésio são associados à dureza da água [2]. Para a remoção desses metais presentes nos efluentes, são utilizados diversos processos, como a precipitação química, coagulação, floculação, evaporação, decantação e processos com membrana [3]. Entretanto, em geral, estes processos apresentam alto custo operacional e/ou baixa eficiência no caso de baixas concentrações de metais dissolvidas nos efluentes [4,5,6,7]. Neste contexto, os processos de adsorção/troca iônica vêm se constituindo em alternat...

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Section: Figura 4: Cromatografia De âNions Na Sorção Dos íOns A) Caunclassified

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

et al. 2017

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“…Plots of the ratio outlet concentration of the incoming ion/concentration of the incoming ion in the feed solution versus time are well known as breakthrough curve. Mass balances in the column as well as the mass transfer parameters are reported elsewhere [8,9].…”

Section: General Theorymentioning

confidence: 99%

Ion Exchange Fundamentals and New Challenges

Barros¹,

LuizGimenes²,

Vieira³

et al. 2015

Mass Transfer - Advancement in Process Modelling

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Ion excνanμe is a stoicνiometric pνenomenon commonly used in water treatment as an end-of-pipe tecνnique. Sucν process is νiμνly influenced by mass transfer conditions and may be modeled by adsorption equations. "ltνouμν widely applied in industries its tνeo-ry νas not been completely understood and depends on tνe excνanμer cνaracteristics. Moreover, competitive systems may add complexity and decrease removal efficiency and excνanμer selectivity mainly in dynamic systems. In tνis cνapter some μeneral tνeory was presented and some detailed examples involvinμ alμinate biopolymer, bonecνar and zeolite in sinμle and competitive systems were discussed in batcν and continuous state.

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“…One of the most systematically studied and used zeolite is the faujasite type NaY. Its structure is stabilized for sodium ion; however, it can be subjected to an aqueous solution cation exchange with a high variety of ions. , The success of ion exchange depends on the ion involved, which in turn is associated with the cation–framework and cation–cation interaction energy, with the cation size, or with its localization in the zeolite cage. , There are some studies on NaY ion exchange efficiency; however, its effect on the zeolite/polymer composite physical properties, very relevant for sensor applications, have not been explored.…”

Section: Introductionmentioning

confidence: 99%

Ion Exchange Dependent Electroactive Phase Content and Electrical Properties of Poly(vinylidene fluoride)/Na(M)Y Composites

Lopes

Neves²,

Lanceros‐Méndez

2015

J. Phys. Chem. C

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Different metal ion exchanged NaY zeolite, Na(M)Y, were used to prepare poly(vinylidene fluoride) based composites by solvent casting and melting crystallization. The effect of different metal ion exchanged zeolites on polymer crystallization and electrical properties was reported. Cation−framework interactions and hydration energy of the cations determined that K + is the most efficient exchanged ion in NaY zeolite, followed by Cs + and Li + . The electroactive phase crystallization strongly depends on the ions present in the zeolite, leading to variations of the surface energy characteristics of the Na(M)Y zeolites and the polymer chain ability of penetration in the zeolite. Thus, Na(Li)Y and NaY induce the complete electroactive γ-phase crystallization of the crystalline phase of PVDF, while Na(K)Y only induces it partly and Na(Cs)Y is not able to promote the crystallization of the electroactive phase. Furthermore, different ion size/weight and different interaction with the zeolite framework result in significant variations in the electrical response of the composite. In this way, iinterfacial polarization effects in the zeolite cavities and zeolite−polymer interface lead to strong increases of the dielectric constant on the composites with lightest ions weakly bound to the zeolite framework. Polymer composites with Na(Li)Y show the highest dielectric response, followed by NaY and Na(K)Y. Zeolite Na(Cs)Y contributes to a decrease of the dielectric constant of the composite. The results show the relevance of the materials for sensor development.

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Competing Ion Exchange of Zn²⁺ and Fe³⁺ in NaY Zeolite

Cited by 6 publications

References 27 publications

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

Ion Exchange Fundamentals and New Challenges

Ion Exchange Dependent Electroactive Phase Content and Electrical Properties of Poly(vinylidene fluoride)/Na(M)Y Composites

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Competing Ion Exchange of Zn2+ and Fe3+ in NaY Zeolite

Cited by 6 publications

References 27 publications

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

Identificação dos mecanismos de sorção em zeólita NaY e sílica gel

Ion Exchange Fundamentals and New Challenges

Ion Exchange Dependent Electroactive Phase Content and Electrical Properties of Poly(vinylidene fluoride)/Na(M)Y Composites

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Product

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Competing Ion Exchange of Zn²⁺ and Fe³⁺ in NaY Zeolite