Interaction of the zeolitic tuff with Zn-containing simulated pollutant solutions

Trgo, Marina; Perić, Jelena

doi:10.1016/s0021-9797(03)00042-0

Cited by 82 publications

(44 citation statements)

References 35 publications

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“…These interactions might be attributed to different physicochemical reactions as dissolution, ion exchange, sorption, and possibly surface precipitation [35]. Changes in the major elementary composition of zeolites were analyzed and results are given in Table 1.…”

Section: Characterization Resultsmentioning

confidence: 99%

“…Changes in pH (step by step; acidic to alkaline) and ionic strength of the media might have caused exchange of H ? ions, binding of protons on the Lewis basic sites, removal of protons from the surface Bronsted acidic sites or removal of the protons that arrange the ion exchange (such as Na, K, Ca, Mg) [35] on zeolites surfaces. Although the exact mechanism was hard to define, this complex mechanism with zeolite treatments might have resulted proteins to possess anisotropic charge distribution on their surfaces and this might have caused increase in dipoles.…”

Section: Characterization Resultsmentioning

confidence: 99%

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Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

Kavak

Ülkü

2012

J Porous Mater

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The use of the clinoptilolite rich natural zeolites in biomedical applications such as in anticancer therapy, drug or drug support systems and as nutritive supplement is highly dependent on their behavior in digestive conditions. Aim of this study is to investigate structural stability of clinoptilolite rich natural zeolites in simulated digestion conditions and their interactions with digestive media and with Caco-2 (human colon adenocarcinoma) cells. X-ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyses of the clinoptilolite rich zeolite samples showed that zeolites preserved their structural stabilities during in vitro digestion. Slight interactions were detected in UV measurements of the digestive liquid media and FTIR spectra of the intestinal digested media powders. SEM results implied that zeolites might have a role in the aggregation of the digestive enzymes. Cytotoxicity test using colon cancer cells showed that clinoptilolite rich natural zeolites have cytotoxic effect against Caco-2 cells and cytotoxicity did not significantly change with respect to simulated digestion process.

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Section: Characterization Resultsmentioning

confidence: 99%

Section: Characterization Resultsmentioning

confidence: 99%

Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

Kavak

Ülkü

2012

J Porous Mater

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“…The immobilization of heavy metal ions from aqueous solutions on zeolite is a complex process consisting of ion exchange and adsorption, likely to be accompanied by precipitation of metal ion hydroxide complexes on active sites of the particle surface [23] [24]. Zeolite A4 was noted to have portrayed the highest adsorptive capacity for Pb in comparison with other zeolite samples.…”

Section: Adsorption Isothermsmentioning

confidence: 99%

pH Dependence of Lead Adsorption on Zeolites

Kabwadza-Corner¹,

Johan²,

Matsue³

2015

JEP

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The adsorption of Pb on zeolites A4, X, Y and mordenite was studied at various initial pH with the purpose of assessing the pH dependence of Pb adsorption. The adsorption was conducted using 0 -0.6 mM Pb(NO3)2 in the presence of 100 mM NH4NO3 and pH adjustment done using HNO3. The coexisting NH4NO3 served as a representative of other cations available in nature. The study was conducted at initial solution pH ranging from 3 -5. Adsorption results were analyzed using Langmuir isotherm analysis. Adsorption was noted to be dependent on pH with increasing adsorption as pH increased from 3 -5 for zeolites A4, X and Y. The adsorption of Pb on mordenite on the other hand did not show any dependence on pH since it was almost constant within the studied pH range. The adsorptive capacities were 2500, 2000, 588 and 179 mmol•kg −1 for A4, X, Y and mordenite, respectively. The results of this study can be used in designing or planning for the clean-up of polluted water using adsorption techniques. An important attribute of these findings was that the samples studied were shown to have the capacity of removing even very low concentration of Pb, a property which is hardly achievable by most adsorbents.

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“…A capacidade de adsorção das zeólitas é resultante da sua alta área superficial e de sua carga líquida negativa nos canais de sua estrutura que atraem cátions tais como metais pesados 5 . Por estas razões, diferentes zeólitas têm sido estudadas como adsorventes de contaminantes metálicos [6][7][8][9][10][11] , as zeólitas empregadas neste trabalho possuem as seguintes estruturas 12,13 :…”

Section: Introductionunclassified

Materiais magnéticos baseados em diferentes zeólitas para remoção de metais em água

Pergher¹,

Oliveira²,

Smaniotto³

et al. 2005

Quím. Nova

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Recebido em 6/4/04; aceito em 20/12/04; publicado na web em 25/5/05 MAGNETIC ZEOLITES FOR REMOVAL OF METALS IN WATER: In this work the adsorption features of zeolites (NaY, Beta, Mordenite and ZSM-5) have been combined with the magnetic properties of iron oxides in a composite to produce a magnetic adsorbent. These magnetic composites can be used as adsorbents for contaminants in water and subsequently removed from the medium by a simple magnetic process. The magnetic zeolites were characterized by XRD, magnetization measurements, chemical analyses, N 2 adsorption isotherms and Mössbauer spectroscopy. These magnetic adsorbents show remarkable adsorption capacity for metal ion contaminants in water.Keywords: zeolite/iron oxide composite; magnetic adsorbents; metallic contaminants. INTRODUÇÃOA aplicação de compósitos magnéticos para resolver problemas ambientais tem recebido considerável atenção nos últimos anos. Compósitos magnéticos podem ser usados para adsorver contaminantes de efluentes industriais e, após a adsorção, podem ser separados por um simples processo magnético. Alguns exemplos desta tecnologia são a utilização de partículas magnéticas para acelerar a coagulação em esgoto 1 , magnetita recoberta com polímeros para remoção de radionuclídeos do leite 2 e poli(oxi-2,6-dimetil-1,4-fenileno) para a remoção de corantes orgânicos 3 . Entretanto, estes materiais possuem baixa área superficial ou baixa capacidade de adsorção, o que limita sua aplicação. Além disso, a preparação destes materiais magnéticos demanda várias etapas, reagentes quí-micos especiais e procedimentos sofisticados. Nosso grupo vem desenvolvendo compósitos magnéticos, tais como argilas/óxido de ferro e carvão ativado/óxido de ferro com elevada área superficial e alta capacidade de adsorção 4 e, mais recentemente, adsorventes magnéticos de contaminantes metálicos baseados em diferentes zeólitas naturais impregnadas com óxido de ferro magnético.As zeólitas naturais são materiais acessíveis, de baixo custo e excelentes trocadores iônicos, razão pela qual são empregadas para a adsorção de contaminantes metálicos. A capacidade de adsorção das zeólitas é resultante da sua alta área superficial e de sua carga líquida negativa nos canais de sua estrutura que atraem cátions tais como metais pesados 5 . Por estas razões, diferentes zeólitas têm sido estudadas como adsorventes de contaminantes metálicos 6-11 , as zeólitas empregadas neste trabalho possuem as seguintes estruturas 12,13 : Zeólita YPossui a mesma estrutura da zeólita X, a diferença está na relação Si/Al. A zeólita X tem uma relação Si/Al compreendida entre 1 e 1,5; enquanto que a zeólita Y tem relação Si/Al maior que 1,5. A estrutura está esquematizada na Figura 1 e apresenta dois sistemas de canais interconectados entre si:• um sistema formado pela união de supercaixas α (diâmetro interno de 12,4 Å), às quais se ingressa por aberturas formadas por 12MR (anéis de 12 membros) de diâmetro igual a 7,8 Å e • um sistema de canais formado pela conexão alternada de caixas sodalitas (diâmetro...

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Interaction of the zeolitic tuff with Zn-containing simulated pollutant solutions

Cited by 82 publications

References 35 publications

Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

pH Dependence of Lead Adsorption on Zeolites

Materiais magnéticos baseados em diferentes zeólitas para remoção de metais em água

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