Preparation, Characterization, and Applications as Heavy Metals Sorbents of Covalently Grafted Thiol Functionalities on the Interlamellar Surface of Montmorillonite

Mercier, Louis; Detellier, Christian

doi:10.1021/es00005a026

Cited by 236 publications

(180 citation statements)

References 47 publications

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“…Vermiculite, as montmorillonite, can adsorb heavy metals via two different mechanisms: (a) cation exchange at the planar sites, resulting from the interactions between metal ions and negative permanent charge (outer-sphere complexes) and (b) forma- Table V The percentages of metals extracted in the third fraction of Tessier applied directly on 1 g of sample tion of inner-sphere complexes through Si-O − and Al-O − groups at the clay particle edges (Kraepiel, Keller, & Morel, 1999;Mercier & Detellier, 1995;Schindler, 1976). Both mechanisms are pH dependent because in acid conditions most silanol and aluminol groups are protonated.…”

Section: Metal Uptake On Vermiculite and Release With Hclmentioning

confidence: 99%

The Efficiency of Vermiculite as Natural Sorbent for Heavy Metals. Application to a Contaminated Soil

Abollino

Giacomino

Malandrino

et al. 2006

Water Air Soil Pollut

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Vermiculite is a natural clay that has many applications as acoustic and thermal insulator, additive in concrete and plaster, fertilizer carrier and adsorbent. Moreover, clay minerals have been studied as adsorbent materials to remove heavy metals from industrial and/or municipal waste waters. In this work we have investigated the possibility to apply vermiculite for the clean-up of extracts resulting from the application of soil washing to a metal-contaminated soil collected from a polluted site in Italy. The soil was initially characterized for its total metal content; we also studied the availability of the pollutants by leaching at pH 5.0 and by Tessier's sequential extraction procedure. We tested a possible clean-up strategy, in which metals were extracted with hydroxylammonium chloride and vermiculite was used as natural sorbent for the decontamination of the extracting solutions. The possibility of recovering the metals by elution with acid and of reusing the clay was also demonstrated.

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Section: Metal Uptake On Vermiculite and Release With Hclmentioning

confidence: 99%

The Efficiency of Vermiculite as Natural Sorbent for Heavy Metals. Application to a Contaminated Soil

Abollino

Giacomino

Malandrino

et al. 2006

Water Air Soil Pollut

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“…Montmorillonite consists of layers of silicates with different combinations of silicon tetrahedra and aluminum or magnesium octahedra (Bhattacharyya and Sen 2006). Because of its high specific surface area and because of inner-sphere complexation (specific adsorption), it has high capacity for cation exchange with the interlayers and for formation of inner-sphere complexes that adsorb heavy metals such as arsenic (Kraepiel et al 1999;Mercier and Detellier 1995). As(III) adsorption resulted in the involvement of both solid-phase reaction and aqueous-phase reaction in As(III) photooxidation in the montmorillonite layer.…”

Section: Effects Of Initial As(iii) Concentrationmentioning

confidence: 99%

Solid surface photochemistry of montmorillonite: mechanisms for the arsenite oxidation under UV-A irradiation

Yuan

Wang

Ding

et al. 2015

Environ Sci Pollut Res

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Transformation of inorganic arsenic species has drawn great concern in recent decades because of worldwide and speciation-dependent pollution and the hazards that they pose to the environment and to human health. As(III) photooxidation in aquatic systems has received much attention, but little is known about photochemical transformation of arsenic species on top soil. As(III) photooxidation on natural montmorillonite under UV-A radiation was investigated by using a moisture- and temperature-controlled photochemical chamber with two black-light lamps. Initial As(III) concentration, pH, layer thickness, humic acid (HA) concentration, the presence of additional iron ions, and the contribution of reactive oxygen species (ROS) were examined. The results show that pH values of the clay layers greatly influenced As(III) photooxidation on montmorillonite. As(III) photooxidation followed the Langmuir-Hinshelwood model. HA and additional iron ions greatly promoted photooxidation, but excess Fe(II) competed with As(III) for oxidation by ROS. Scavenging experiments revealed that natural montmorillonite induced the conversion of As(III) to As(V) by generating ROS (mainly HO(•) and HO2(•)/O2(•-)) and that HO(•) radical was the predominant oxidant in this system. Our work demonstrates that photooxidation on the surface of natural clay minerals in top soil can be important to As(III) transformation. This allows understanding and predicting the speciation and behavior of arsenic on the soil surface.

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“…Os minerais argilosos formam um grupo de matrizes que têm a capacidade de inserir espécies, daí a denominação de hospedeiros, os quais favorecem a química de intercalação de várias moléculas orgânicas, como aminas alifáticas ou aromáticas [39][40][41][42][43] , organocátions [44][45][46][47][48][49] , metaloporfirinas 50 , complexos 51-57 ou polímeros [58][59][60][61][62][63][64][65][66][67] . A importância desses derivados está na sua utilização como materiais precursores para pilarização, adsorventes, catalisadores e eletrodos [68][69][70][71] . No caso específico da obtenção de materiais pilarizados busca-se geração de porosidade, que direciona a aplicação do material, melhorando suas especificidade e seletividade.…”

Section: Figura 6 Ilustração Da Reações De Modificação Da Superfícieunclassified

Híbridos inorgânico-orgânicos derivados da reação de filossicatos com organossilanos

Fonseca¹,

Airoldi²

2003

Quím. Nova

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Recebido em 24/6/02; aceito em 24/2/03 INORGANIC-ORGANIC HYBRIDS DERIVED FROM THE REACTION OF PHYLLOSILICATES WITH ORGANOSILANES.Silylation reactions involving hydroxylated surfaces are an important route for synthesis of new materials that could present selected properties, for application in different areas such as catalysis, chromatography, adsorption and electrochemistry. An overview of many synthetic routes, comprising organosilanes to yield phyllosilicates is now presented.Keywords: inorganic-organic hybrids; phylosilicates; silytation. INTRODUÇÃONestas últimas décadas, uma variedade de superfícies passou a despertar enorme interesse em aplicações, desde que se iniciou o processo de imobilização nesses suportes, graças ao uso de agentes sililantes. Esses agentes possibilitam a fixação de moléculas covalentemente em superfícies, sendo que diferentes grupos funcionais podem fazer parte das estruturas moleculares ancoradas 1 . Dentre essas superfícies inorgânicas sobressai à sílica gel, que continua sendo muito procurada para efetivação dos vários processos envolvidos na modificação química, com o intuito de se vislumbrar aplicações tanto do ponto de vista acadêmico como tecnológico 1,2 . De maneira idêntica à sílica, inúmeros materiais naturais ou sintéti-cos, como exemplo os minerais, também dispõem de grupos hidroxilados sobre a superfície, os quais desempenham papel fundamental na habilidade em reagir. No caso particular dos minerais argilosos, as suas propriedades lamelares permitem modificações quími-cas, que ocorrem por reações de intercalação de moléculas orgânicas ou troca dos cátions originalmente presentes nas lacunas interlamelares. Essa rota é eficaz para que se processe a imobilização de catalisadores complexos na estrutura de minerais, tornando possível a efetivação de reações no estado sólido, com grande semelhança àquelas que ocorrem em solução 3 . Este fato minimiza muitas barreiras técnicas e tecnológicas associadas ao uso desses complexos como catalisadores homogêneos.Apesar da facilidade experimental de algumas dessas reações, o interesse por compostos sintéticos aumentou desde que se puderam obter materiais com composição química definida e sem a presença de impurezas. Aspectos estruturais também podem ser controlados, de forma que, tanto estruturas cristalinas como defeituosas, podem ser sintetizadas, direcionando-as para aplicações mais específicas como, por exemplo, a catálise. Neste particular, destacam-se mais recentemente os filossilicatos modificados organicamente, os quais tiveram um grande impulso preparativo com o domínio do processo sol-gel [4][5][6][7][8][9][10][11][12] . Desse modo, a obtenção de novas estruturas, bem como o estudo mais detalhado das condições experimentais, aplicação desses novos compostos e até modelagem de sistemas, são importantes na tentativa de descoberta de novos materiais.No âmbito dessa abordagem uma revisão será apresentada, envolvendo algumas considerações sobre os métodos de modificação química de superfícies hidroxiladas com grupos orgânicos der...

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Preparation, Characterization, and Applications as Heavy Metals Sorbents of Covalently Grafted Thiol Functionalities on the Interlamellar Surface of Montmorillonite

Cited by 236 publications

References 47 publications

The Efficiency of Vermiculite as Natural Sorbent for Heavy Metals. Application to a Contaminated Soil

The Efficiency of Vermiculite as Natural Sorbent for Heavy Metals. Application to a Contaminated Soil

Solid surface photochemistry of montmorillonite: mechanisms for the arsenite oxidation under UV-A irradiation

Híbridos inorgânico-orgânicos derivados da reação de filossicatos com organossilanos

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