Showing 01 - 12 of 139 Results

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Measurements on Cation Exchange Capacity of Bentonite in

exchangeable cations is also the cause of the bentonite swelling, which is one of the bases for using it as a buffer in nuclear waste disposal. The cation exchange capacity of bentonite has two origins. The first type is the permanent negative charge caused by isomorphous substitution in the tetrahedral and octahedral sheets of montmorillonite,

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(PDF) Interlaboratory CEC and Exchangeable Cation Study of

Interlaboratory CEC and Exchangeable Cation Study of Bentonite Buffer Materials: II. Alternative Methods Article (PDF Available) in Clays and Clay Minerals 60(2) · April 2012 with 130 Reads

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Cation exchange and adsorption on clays and clay minerals

Cation exchange and adsorption on clays and clay minerals Dissertation Submitted for the degree “Dr. rer. nat.” of the faculty of mathematics and natural sciences Christian-Albrechts-Universität Kiel Submitted by Lars Ammann Kiel 2003

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PAPER OPEN ACCESS Related content Determination of CEC

the bentonite component and cation exchange mode which may cause an increase or decrease in the concentration of cation index [4]. Indonesia is one of the exporting countries of natural materials in form of bentonite which is quite calculated in the world. Indonesia's bentonite reserves are abundant, amounting to approximately 380

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(PDF) Interlaboratory CEC and Exchangeable Cation Study of

Interlaboratory CEC and Exchangeable Cation Study of Bentonite Buffer Materials: I. Cu(II)-triethylenetetramine Method Article (PDF Available) in Clays and Clay Minerals 60(2) · April 2012 with

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Bentonite Resistance to Cation Exchange-Tech Note

Bentonite Resistance to Cation Exchange for Geomembrane Supported GCL Products the soils contained a mix of ions, illustrating that bentonite will preferentially adsorb calcium even in situations with a mix of ions in the permeating water. In all three cases, the hydraulic conductivity of the bentonite increased one to two

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Cation exchange capacity of bentonite in a saline

Cation exchange capacity (CEC) is one of the basic characteristics of clays and clay minerals. Accessory minerals, such as carbonates, can influence the measured value of the CEC because of their

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Cation Exchange Capacity an overview ScienceDirect Topics

The cation exchange capacity of rocks refers to the mmol value of cation exchanged by 100 g clay when the pH value is 7, expressed as Cation Exchange Capacity (CEC). As the types of clay minerals in rocks differ, there is a great difference in the CEC. Bentonite buffer. Martin Birgersson, Anders Sjöland, in Geological Repository

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Recommended Buffers for Cation Exchange Chromatography

Recommended Buffers for Cation Exchange Chromatography Recommended buffer substances for anion exchange chromatography. According to Amersham Biosciences catalogue

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Characteristics for the Copper Exchange Reaction by

The bentonite, a buffer material, is essential for the deep geological disposal of HLW (high-level radioactive waste), and it is important to know its characteristic long-term evolution in the

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Cation Exchange Chromatography LSR Bio-Rad

Cation exchange chromatography is a form of ion exchange chromatography (IEX), which is used to separate molecules based on their net surface charge.Cation exchange chromatography, more specifically, uses a negatively charged ion exchange resin with an affinity for molecules having net positive surface charges.

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Selectivity coefficient for Ca/Na ion exchange in highly

The basic aim with the present work was therefore to determine selectivity coefficients for sodium/calcium exchange in bentonite with low water-to-solid ratios, and thereby give a reliable base for calculating the cation distribution in a confined bentonite buffer with a relatively high density.

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Ion Exchange Chromatography Troubleshooting Sigma-Aldrich

Ensure that buffers are in the correct containers. Reduce ionic strength of sample by desalting, page 156, or dilution with start buffer. For an anion exchanger, increase buffer pH, for a cation exchanger, decrease buffer pH. If proteins still do not bind at any pH, it is possible that the column has been contaminated by detergent.

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Cation-exchange chromatography of monoclonal antibodies

Jul 01, 2011· Cation-exchange chromatography of monoclonal antibodies. A novel cation-exchange resin, Eshmuno™ S, was compared to Fractogel All buffers were prepared both without sodium chloride (buffer A) as described above and with additional 1 M NaCl (buffer B). Salt concentrations between 0 and 1 M NaCl could be prepared by mixing these two

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EP2215117A1 Antibody purification by cation exchange

A method for purifying an antibody by cation exchange chromatography is described in which a high pH wash step is used to remove of contaminants prior to eluting the desired antibody using an elution buffer with increased conductivity.

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Determination of the cation exchange capacity and the

ELSEVIER Applied Clay Science 9 (1995) 327-336 Determination of the cation exchange capacity and the surface area of bentonite, illite and kaolinite by methylene blue adsorption G. Kahr, F.T. Madsen Laboramry Jbr Clay Mineralogy, Division t~Geotechnical Engineering, Swiss Federal Institute of Technology, Sonneggstrasse 5, CH-8092 Zi~'rich, Switzerland Received 30 March 1994; accepted

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Lot A2 test, THC modelling of the bentonite buffer

TOUGHREACT was used to model a test known as the long-term test of buffer material adverse-2, which was conducted at the Äspö hard rock laboratory in Sweden. The results on the evolution of cation-exchange equilibria, bentonite porewater chemistry, mineralogy, and saturation of the buffer are presented and discussed.

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Using COMSOL for the Transport Modelling of Some Special

Cation exchange capacity CEC (eq/kg) is the fixed charge content (negatively charged sites occupied by cations) of the solid. Concentration of CEC per pore volume is given by . CEC d 1 c CEC f r f u (5) 2.2 Cation exchange and aqueous reactions . We started the chemical modelling of bentonite-water with this system: sodium (Na), calcium

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Activation of a Ca-bentonite as buffer material

The corresponding mechanism refers to exchange of cations and breakdown of quasi-crystal, which results in ion exchange hysteresis of Ca-bentonite. Due to the ion exchange hysteresis, activated bentonite shows a post-rise time-swell relationship different than the sigmoid-shaped time-swell curves of typical bentonites.

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Long-Term Stability of Bentonite Posiva

The exchangeable cation composition of the buffer bentonite is expected to equilibrate with the surrounding groundwater during and after saturation. This process is expected to lead towards Ca-dominant exchangeable cation composition within the mont-morillonite interlayer spaces in the buffer. In general it seems that the transformation

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BENTONITE AND ITS USES JNJ Resources

The cation exchange capacity of bentonite buffers (neutralises) the effect of lactic acid and thereby prevents ruminal acidosis. Bentonite is typically mixed with the grain and other mineral supplements at about 4% for starter rations and 2% for finisher rations.

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Bentonite buffer: Macroscopic performance from nanoscale

12.1.3.4. Cation exchange capacity. The cation exchange capacity (CEC, eq/kg) reveals the molar charge of exchangeable ions, which is of importance for the swelling characteristics of the bentonite. The CEC is relatively easy to determine with high accuracy by use of, e.g., the Cu-trien method described by Meier and Kahr (1999).

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Cation Exchange and Mineral Reactions Observed in MX 80

In the present study, chemical and mineralogical alteration processes of the bentonite MX 80 after an 8 y heating period were investigated. The water content of all samples increased following inflowing Na-Ca-Cl-type granitic groundwater causing cation exchange in the bentonite buffer materials.

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Mineralogical investigations of the first package of the

behaviour in bentonite is cation exchange’’. Montes H et al. (2005), for example, confirmed this. Field experiments the intermediate scale Plo¨tze et al. (2007) studied the stability of a bentonite buffer (Almeria, Spain) in a small-scale heater experiment which was carried out at the underground laboratory in Mont Terri, Switzerland.

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BENTONITE AND ITS USES JNJ Resources

The cation exchange capacity of bentonite buffers (neutralises) the effect of lactic acid and thereby prevents ruminal acidosis. Bentonite is typically mixed with the grain and other mineral supplements at about 4% for starter rations and 2% for finisher rations.

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Bentonite buffer: Macroscopic performance from nanoscale

12.1.3.4. Cation exchange capacity. The cation exchange capacity (CEC, eq/kg) reveals the molar charge of exchangeable ions, which is of importance for the swelling characteristics of the bentonite. The CEC is relatively easy to determine with high accuracy by use of, e.g., the Cu-trien method described by Meier and Kahr (1999).

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Mineralogical investigations of the first package of the

behaviour in bentonite is cation exchange’’. Montes H et al. (2005), for example, confirmed this. Field experiments the intermediate scale Plo¨tze et al. (2007) studied the stability of a bentonite buffer (Almeria, Spain) in a small-scale heater experiment which was carried out at the underground laboratory in Mont Terri, Switzerland.

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DELIVERABLE D2.6 Microbial diversity in bentonite buffer

bentonite [2]. Montmorillonite carries a negative charge that is balanced by cations, which exchange readily with other cations in the external solution. In the worst case, the exchange of cations can cause the montmorillonite structure to collapse and the hydraulic conductivity to increase markedly.

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CATION EXCHANGE AND MINERAL REACTIONS OBSERVED IN

Bentonites are candidate materials for high-level radioactive waste (HLRW) repositories and, therefore, are investigated with respect to long-term stability. In order to identify

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Recommended Buffers for Cation Exchange Chromatography

Recommended Buffers for Cation Exchange Chromatography *. To use the calculator, enter the buffer's concentration and temperature, then click on the corresponding = button. The following are the implicit rules of the calculator:

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(PDF) Determination of CEC value ( Cation Exchange

Research on determination of value CEC (Cation Exchange Capacity) Bentonite North Aceh and Bener Meriah with three methods has been studied. The purpose of this study was to determine the value of

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Cation Exchange and Mineral Reactions Observed in MX 80

In the present study, chemical and mineralogical alteration processes of the bentonite MX 80 after an 8 y heating period were investigated. The water content of all samples increased following inflowing Na-Ca-Cl-type granitic groundwater causing cation exchange in the bentonite buffer materials.

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Ion Exchange Chromatography Selection Guide

Ion Exchange Chromatography Selection Guide. use anionic (negatively-charged) buffers for cation exchange (Mustang S membrane), and cationic (positively-charged) buffers for anion exchange (Mustang contaminants that have also bound to the ion exchange matrix. Ions of

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Characterization of the Second Package of the Alternative

Apr 11, 2017· In the ‘Alternative Buffer Material’ (ABM) test in the hard rock laboratory in Äspö, Sweden, six packages of eleven different buffer materials (mainly bentonites) with various exchangeable cation populations were packed vertically with an iron tube used as a heater in the center.

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Chemical and mineralogical characterization of the

the bentonite buffer, these cations may change significantly over time, mainly depending on the chemical evolution of the surrounding groundwater. Specific favorable properties of a particular charge compensating cation can consequently not be taken into account, and the specification of the bentonite buffer has in principle to be based on the

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Interlaboratory CEC and Exchangeable Cation Study of

The cation exchange capacity (CEC) has proven to be one of the most sensitive parameters for detecting changes in mineral properties in bentonite-alteration experiments. An interlaboratory study of CECs and exchangeable cations for three reference bentonite buffer materials that were used in the Alternative Buffer Material test (ABM) project in

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VTT PUBLICATIONS 721

Keywords THC, temperature dependence, modelling, cation exchange, heat formation, heat transport, bentonite, porewater, montmorillonite Abstract Finnish spent nuclear fuel disposal is planned to be based on the KBS-3V concept. Within this concept, the role of the bentonite buffer

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Cation-exchange capacity Wikipedia

Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the

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Chemical and mineralogical characterization of the

the bentonite buffer, these cations may change significantly over time, mainly depending on the chemical evolution of the surrounding groundwater. Specific favorable properties of a particular charge compensating cation can consequently not be taken into account, and the specification of the bentonite buffer has in principle to be based on the

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VTT PUBLICATIONS 721

Keywords THC, temperature dependence, modelling, cation exchange, heat formation, heat transport, bentonite, porewater, montmorillonite Abstract Finnish spent nuclear fuel disposal is planned to be based on the KBS-3V concept. Within this concept, the role of the bentonite buffer

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Interlaboratory CEC and Exchangeable Cation Study of

Based on the measured precision, greater measured differences in Cu-trien CEC and exchangeable cation values of bentonite buffer samples, before and after an experiment, might be actual differences. Great care must be taken when interpreting measured CEC differences, and analytical characterization of any structural changes may be needed.

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Recommended Buffers for Anion Exchange Chromatography

The best buffers for cation-exchange (white background): for concentrations 1 to 200mM, the Debye-Hückel model is used, and the resulting pKa is presented in brown font. for concentrations 201 to 500mM, the Davies model is used, and the resulting pKa is presented in blue font. Less suitable buffers for cation-exchange (light brown background):

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Bentonite Clay: Sodium vs Calcium Dispelling the Myths

Sep 14, 2014· Some clays can have buffers and fillers. If taking it internally it must be stated on the label that it is food quality/edible. The Bentonite clay we offer at Australian Healing Clay is a unique sodium/ magnesium Bentonite that is volcanic clay having a cation exchange of 90/meq.

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Modelling of geochemical reactions and experimental

Modelling of geochemical reactions and experimental cation exchange in MX80 bentonite G. Montes-Ha,*, B. Fritza, A. Clementa, bentonite-to-Ca-bentonite exchange there is a small decrease in the amount of adsorbed water and the swelling potential. characteristics of the buffer material are expected to fill up

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Cation-exchange capacity Wikipedia

Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the

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INTERLABORATORY CEC AND EXCHANGEABLE CATION STUDY

The cation exchange capacity (CEC) has proven to be one of the most sensitive parameters for detecting changes in mineral properties in bentonite-alteration experiments. An interlaboratory study of CECs and exchangeable cations for three reference bentonite buffer materials that were used in the Alternative Buffer Material test (ABM) project in

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Practical Considerations for IEX Separation Sigma-Aldrich

Buffer selection and preparation. Buffer ions. Buffering ions should have the same charge as the functional groups on the IEX medium (buffering ions that carry a charge opposite to that of the functional groups will take part in the ion exchange process and can cause significant pH fluctuations during elution) and, preferably, a pKa value within 0.6 pH units of the working pH.

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Characterization of the Second Package of the Alternative

Apr 11, 2017· In the ‘Alternative Buffer Material’ (ABM) test in the hard rock laboratory in Äspö, Sweden, six packages of eleven different buffer materials (mainly bentonites) with various exchangeable cation populations were packed vertically with an iron tube used as a heater in the center.

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Interactions of bentonite with metal and concrete from the

This phenomenon probably led to gradients in the exchangeable cation population at various locations within the bentonite buffer. The cement (shotcrete) bentonite interface of one block was characterized by a thin (0.1–1.0 mm) reaction zone in which bentonite constituents, carbonates and sulfates occurred. Cation exchange and a slight

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CO2 effect on the pH of compacted bentonite buffer on the

CO 2 effect on the pH of compacted bentonite buffer on the laboratory scale The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The model included cation exchange, surface complexation and mineral equilibrium of calcite and gypsum. The relevant reactions in this

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Sodium Bentonite in Ruminant Rations

magnesium ions. The remaining positive charge needed to balance the structure is provided by sodium or calcium ions which are loosely held in the outer silica layers of the lattice structure. In water, the exchange ions dissociate at varying rates creating a negative charge on the platelet surface. The ion exchange potential of bentonite is

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Cation Exchange Resins Thermo Fisher Scientific US

Cation exchange chromatography is a form of ion exchange chromatography in which a positively charged biomolecule binds to a negatively charged resin. Request information POROS CEX resins are designed for high dynamic binding capacity over a range of pH and conductivity conditions, thereby