Recommandations pour la détermination expérimentale de la capacité d'échange de cations des milieux argileux

Bardon, C.

doi:10.2516/ogst:1983037

Cited by 13 publications

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“…Microscopic image of halloysite hydrophobicity of halloysite. Firstly, the cation exchange capacity (CEC) of the mineral material was determined by using the cobalt(III) hexamine method [24][25][26][27][28]. The measured CEC was equal to 8.02 meq/100 g. Secondly the material was modified with hexadecyltrimethylammonium bromide (HDTMA-Br) in an amount equal to 1 CEC.…”

Section: Methodsmentioning

confidence: 99%

The influence of halloysite on the physicochemical, mechanical and biological properties of polyurethane-based nanocomposites

et al. 2020

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The impact of the addition of the nanofiller -halloysite -on the mechanical, physicochemical and biological properties of a nanocomposite, in which thermoplastic polyurethane fulfilled the role of the matrix was investigated. The nanocomposite was obtained by extrusion in three variants with 1, 2 and 3 wt % halloysite. The nanostructure of the obtained materials was confirmed using Atomic Force Microscopy (AFM). Based on the mechanical tests carried out, it was proven that the obtained nanocomposites were characterized by a tensile modulus greater than the polyurethane constituting the matrix. The density and hardness of the nanocomposites had changed within error limits compared to unmodified polyurethane. Biological tests showed no cytotoxicity of all the tested materials to normal human dermal fibroblasts (NHDF). Degradation tests were carried out in artificial plasma and showed that samples with 2 wt % halloysite addition had the best ratio of tensile strength and elongation at break to elasticity modulus.

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Section: Methodsmentioning

confidence: 99%

The influence of halloysite on the physicochemical, mechanical and biological properties of polyurethane-based nanocomposites

et al. 2020

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“…Elle est liée aussi au pH du sol, puisque plus le pH est élevé, plus la CEC s'accroît et plus la quantité de cations adsorbée augmente (Blanchard, 2000). La gamme de la CEC des argiles (entre 9 et 15 méq/100 g), nous indique que ces argiles sont probablement des kaolinites (Bardon, 1983). La capacité d'échange cationique d'une kaolinite se situe entre 5 et 15 méq/100 g (Samake, 2008).…”

Section: Appareillageunclassified

Extraction chimique des métaux lourds des argiles de la décharge finale d’Agoè-Nyivé au Togo

Bodjona¹,

Tchegueni²,

Bafai³

et al. 2018

Environnement, Ingénierie &Amp; Développement

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Déchets Sciences et Techniques -N°78 -Décembre 2018 RÉSUMÉ Une couche d'argile suffisamment épaisse, continue et homogène sous un dépôt de déchets constitue une barrière empêchant la pollution de la nappe phréatique si les lixiviats sont bien drainés à sa surface puis correctement traités. Depuis l'exploitation de la décharge d' Agoè-Nyivé (Lomé), très peu d'études, ont été réalisées sur l'état de pollution notamment en métaux lourds de la couche de base de la décharge composée d'argile. L'objectif de ce travail est d'évaluer la teneur de certains métaux (Pb, Cd, Ni, Cu et Zn) dans les échantillons de couches de base de la décharge finale d'Agoè-Nyivé afin d'évaluer leur potentielle migration vers la nappe. L'analyse qualitative des échantillons d'argile à travers la diffraction des rayons X, montre l'existence de quartz, de carbonates et de kaolinite avec des proportions variables d'un échantillon à l'autre. Une analyse complémentaire notamment la spectroscopie infrarouge montre la présence d'une kaolinite avec des bandes observées dans la région de vibration des hydroxyles situées à 3698, 3652 et 3622 cm -1 . Les teneurs en métaux lourds analysées après extractions sélectives montrent que le plomb et le nickel ont une forte propension à se lier respectivement à la fraction réductible et résiduelle. Par contre, le cadmium a une répartition quasi-égale dans les quatre fractions alors que le zinc est plus présent dans la fraction échangeable et acido-soluble avec des pourcentages variant de 18,75 à 76,67 %. La forte présence des métaux lourds constatée dans les fractions de sol où ils peuvent être facilement mobilisables montre le risque de leur migration vers les profondeurs. MOTS-CLÉS : argile, décharge, métaux lourds, contamination ABSTRACTA sufficiently thick layer of clay, continuous and homogeneous under a deposit of waste constitutes a barrier preventing pollution of the water table if the leachates are well drained on its surface and then properly treated. Since the exploitation of the landfill of Agoè-Nyivé (Lomé), very few studies have been carried out on the state of pollution, especially of heavy metals, of the base layer of the clay-filled landfill. The objective of this work, is to evaluate the content of heavy metals (Pb, Cd, Ni, Cu and Zn) in the base layer samples of the final discharge Agoè-Nyivé and evaluate their potential migration to the depths. The qualitative analysis of the clay samples through X-ray diffraction shows the existence of quartz, carbonate and kaolinite with varying proportions from one sample to another. Complementary analysis of the infrared spectroscopy shows spectra that reveal the presence of a kaolinite with bands observed in the vibrational region of the hydroxyls located at 3698, 3652 and 3622 cm -1 . The heavy metal contents in the clay samples show that lead and nickel have a strong propensity to bind respectively to the reducible and residual fraction. On the other hand, cadmium has an almost equal distribution in the four fractions while zinc is more present in t...

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Sources and pathways of artificial radionuclides to soils at a High Arctic site

Łokas

Bartmiński

Wachniew

et al. 2014

Environ Sci Pollut Res

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Activity concentrations, inventories and activity ratios of 137Cs, 238Pu, 239 + 240Pu and 241Am in soil profiles were surveyed in the dry tundra and the adjoining proglacial zones of glaciers at a High Arctic site on Svalbard. Vertical profiles of radionuclide activities were determined in up to 14-cm-thick soil sequences. Additionally, soil properties (pH, organic matter, texture, mineral composition and sorption capacity) were analyzed. Results obtained in this study revealed a large range of activity concentrations and inventories of the fallout radionuclides from the undetectable to the uncommonly high levels (inventories of 30,900 ± 940, 47 ± 6, 886 ± 80 and 296 ± 19 Bq/m2 for 137Cs, 238Pu, 239 + 240Pu and 241Am, respectively) found in two profiles from the proglacial zone. Concentration of these initially airborne radionuclides in the proglacial zone soils is related to their accumulation in cryoconites that have a large ability to concentrate trace metals. The cryoconites develop on the surface of glaciers, and the material they accumulate is deposited on land surface after the glaciers retreat. The radionuclide inventories in the tundra soils, which effectively retain radionuclides due to high organic matter contents, were comparable to the global fallout deposition for this region of the world. The 238Pu/239 + 240Pu activity ratios for tundra soils suggested global fallout as the dominant source of Pu. The 238Pu/239 + 240Pu and 239 + 240Pu/137Cs activity ratios in the proglacial soils pointed to possible contributions of these radionuclides from other, unidentified sources.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-014-3163-6) contains supplementary material, which is available to authorized users.

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Recommandations pour la détermination expérimentale de la capacité d'échange de cations des milieux argileux

Cited by 13 publications

References 0 publications

The influence of halloysite on the physicochemical, mechanical and biological properties of polyurethane-based nanocomposites

The influence of halloysite on the physicochemical, mechanical and biological properties of polyurethane-based nanocomposites

Extraction chimique des métaux lourds des argiles de la décharge finale d’Agoè-Nyivé au Togo

Sources and pathways of artificial radionuclides to soils at a High Arctic site

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