The titration of clay minerals

Tournassat, Christophe; Grenèche, Jean‐Marc; Tisserand, Delphine; Charlet, Laurent

doi:10.1016/j.jcis.2003.11.021

Cited by 113 publications

(57 citation statements)

References 24 publications

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“…2 shows the deconvolution of the 950-750 cm −1 wavenumber region. As expected, three main bending bands are present (δ AlAlOH , δ AlFeOH , and δ AlMgOH ) based on the structural formula of MX80 smectite clay [10]: 2 Na 0.28 . Once the background was removed, the spectrum was fitted with three bending bands in the region 950-820 cm −1 corresponding to δ AlAlOH (∼919 cm −1 ), δ AlFeOH (∼882 cm −1 ), and δ AlMgOH (∼848 cm −1 ).…”

Section: Resultssupporting

confidence: 79%

“…In part I [10], we presented Na-and Ca-MX80 montmorillonite surface charge data obtained by combining potentiometric backtitration technique [7,11,12] with cation exchange capacity (CEC) measurements [13]. This is a powerful combination, as it can be used to identify each phenomenon that contributes to surface charge as a whole: dissolution processes, variations of the net proton edge surface charge, cation and proton exchange mechanisms, adsorption of ionic pairs, and precipitation of new phases.…”

Section: Introductionmentioning

confidence: 99%

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The titration of clay minerals

Tournassat

Ferrage

Poinsignon

et al. 2004

Journal of Colloid and Interface Science

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149

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Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

The titration of clay minerals

Tournassat

Ferrage

Poinsignon

et al. 2004

Journal of Colloid and Interface Science

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149

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“…Taking into account an edge surface area of 26 m 2 /g for the Na-illite (Table 1), the 0.4 x 1.5 mole of H/kg clay ( For synthetic Na-montmorillonite, considering an edge surface area of 11 m 2 /g (Table 1), the 0.6 mole of H/kg clay (Table 2) of exchangeable protons, corrected by a coefficient of 1.4 as explained above for illite, corresponds to 46 H/nm 2 . This value is above the value expected from crystallographic considerations (Tournassat et al, 2004;Bourg et al, 2007) pointing to the presence of either additional sites not located on the edge (e.g. due to defects in the structure of this poorly crystallized synthetic material) or to remaining hydration water molecules in the interlayers not exchanged in the time scale of the experiment.…”

Section: Nmr Results On Dry Samplesmentioning

confidence: 54%

“…They should therefore correspond to protons of structural OH groups. Based on FTIR (Fourier Transform Infrared) measurements, Tournassat et al (2004) have shown that these structural OH groups are not likely to exchange with D2O at 25°C in a timescale comparable to the one used in the present study i.e.…”

Section: Nmr Results On Dry Samplesmentioning

confidence: 72%

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Montavon

Guo

Tournassat

et al. 2009

Geochimica et Cosmochimica Acta

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. Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study. Geochimica et Cosmochimica Acta, Elsevier, 2009, 73 (24) AbstractThe aim of the present work was to quantify accessible porosities for iodide and for a water tracer (HTO) on water-saturated compacted clay samples (illite, montmorillonite and MX-80 bentonite) and to relate these macroscopic values to the forms of water in these porosities (surface/bulk water, external/internal water). Low field proton NMR was used to characterize and quantify the forms of water. This enabled the three different populations (structural OH, external surface and internal surface water) to be differentiated on hydrated clays by considering the difference in proton mobility. An accurate description of the water forms within the different populations did not appear possible when water molecules of these populations were in contact because of the occurrence of rapid exchange reactions. For this 2 reason, it was not possible to use the low resolution NMR method to quantify external surface and bulk water in fully water-saturated compacted clay media at room temperature. This latter information could however be estimated when analyzing the samples at -25°C. At this temperature, a distinction based on the difference in mobility could be made since surface water remained in a semi-liquid state whereas bulk water froze. In parallel, accessible porosities for anions and HTO were determined by an isotopic dilution method using capillaries to confine the materials. HTO was shown to probe the whole pore volume (i.e. the space made of surface and bulk water). When the surface water volume was mainly composed of interlayer water (case of montmorillonite and bentonite), iodide was shown to be located in the pore space made of bulk water. When the interlayer water was not present (case of illite), the results showed that iodide could access a small fraction of the surface water volume localized at the external surface of the clay particles.

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“…Cation exchange capacity (CEC) is a measure of the cations, which balance the negative charge sites of the clay [34]. CEC is usually expressed as the retained excess cation quantity divided by the sample mass.…”

Section: Determination Of Cation Exchange Capacity (Cec)mentioning

confidence: 99%

Study on adsorption behavior and separation efficiency of naturally occurring clay for some elements by batch experiments

et al. 2012

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KEYWORDSThis paper describes the versatile nature of clay that was obtained from Suez Gulf, Suez city, Egypt, as a new low cost natural resource which is non toxic to ecosystem and highly effective adsorbent material. The properties of the natural clay and its significance in removing Th(IV) and Ce(IV) as a representative of tetravalent actinides and lanthanides, respectively, La(III) as a representative of trivalent lanthanides as well as homologues of americium and Sr(II) as one of the fission products, in aqueous solutions have been studied, in order to consider its application for nuclear waste treatment. Batch experiments have been carried out to determine the effect of various factors such as initial metal ion concentration, clay dose, pH, contact time, and temperature on the adsorption process. The results have dictated that, the adsorption efficiency of the natural clay was significantly high at pH = 4. Maximum metal ion uptake capacity of clay has been obtained from batch studies was 99.24, 98.21, 77.76 and 57.94% for Th(IV), Ce(IV), La(III) and Sr(II), respectively. The thermodynamic parameters (H o , S o and G o ) have been calculated from the temperature dependent adsorption isotherms. Furthermore, separation factors () have been calculated in order to separate these elements from each other at pH = 4. Adsorption Natural clay Separation factor Radioactive waste Batch experiments Thermodynamic parameters

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The titration of clay minerals

Cited by 113 publications

References 24 publications

The titration of clay minerals

The titration of clay minerals

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Study on adsorption behavior and separation efficiency of naturally occurring clay for some elements by batch experiments

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