Influence of Alkaline Activation over Swelling and Cation Exchange
The performance of the alkaline processes on the properties of cation exchange capacity (CEC) and swelling was studied in three different types of bentonite from Brazil, Argentina and Mozambique.
Cation exchange capacity of bentonite in a saline …
Section snippets Materials. A blended Ca-/Mg-bentonite Calcigel ® that was provided by Clariant (Bavaria, Germany) was used as supplied. This material has been extensively characterized as a potential reference buffer/backfill material in the context of geotechnical barriers and has been reported as either Calcigel or Montigel (Emmerich et …
Cation exchange processes in GCLs
FIGURE 1 GCL panel installed in the bottom liner system of a municipal solid waste landfill. Photo courtesy of Nazli Yesiller Geosynthetic clay liners (GCLs) are multi-component materials …
Modelling of geochemical reactions and experimental cation exchange …
Modelling of geochemical reactions and experimental cation exchange in MX 80 bentonite J Environ Manage. 2005 Oct;77(1):35-46. doi: 10.1016/j.jenvman.2005.03.003. ... In fact, this chemical process appears to be a simple cation exchange into the engineered barrier. The purpose of the present study was two-fold. Firstly, it was hoped to predict ...
Critical issues in the determination of the bentonite cation exchange
The following equation correlates the solid charge coefficient with the bentonite cation exchange capacity, CEC, which should be measured by means of experimental procedures that allow a complete ...
Measurement of Exchangeable Cations in Bentonites
Exchangeable cations and cation exchange capacities of bentonites from the Western United States Amounts of cations extracted from three weights of bentonite samples with successive 25 ml ...
Pressure-induced cation exchange in bentonite/laponite …
Exchangeable cation associations in physical mixtures of bentonite and laponite have been examined using X-ray diffraction and a combination of electron microprobe analysis and multivariate statistical methods. The results suggest that cation exchange can occur in air-dry mixtures when pressure (∼64 kbar) is applied.
Quantification of the Bentonite Content in Diaphragm Wall …
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.
Diffusion and sorption properties of radionuclides in …
1996). It has a cation-exchange capacity of ~60 cmol/kg and a specific surface area of 480 m 2/g. Na+ is the predominant exchangeable cation in the Avonlea bentonite (Oscarson et al., 1994). The characteristic features of compacted bentonite are …
Organoclays Based on Bentonite and Various …
At the same time, the cation exchange capacity increases in the following order: original bentonite, amphoteric modified bentonite, anionic modified amphoteric, and cationic modified amphoteric. The …
Clay-based materials for enhanced water treatment: …
Water treatment is of paramount importance to ensure the availability of clean and safe drinking water. In recent years, clay-based materials have gained significant attention as promising adsorbents for water treatment applications. This review provides a comprehensive analysis of different clay types and their surface adsorption properties …
Modelling of geochemical reactions and experimental cation exchange …
The interactions of a copper canister with bentonite are predicted to be restricted to minor amounts of cation exchange in montmorillonite (Cu for Na), resulting in no changes to safety-relevant ...
Cation selectivity in sodium-calcium, sodium-magnesium, …
Exchange isotherms were prepared for Na in Na—»Ca and Na^Mg exchange reactions, and for Mg in Ca—»Mg exchange reactions, at 298 K on Wyoming bentonite suspended in a 0.05M perchlorate background. These isotherms were essentially congruent with the appropriate thermodynamic nonpreference exchange isotherms. It was concluded from …
Modelling of geochemical reactions and experimental cation exchange …
DOI: 10.1016/J.JENVMAN.2005.03.003 Corpus ID: 35627151; Modelling of geochemical reactions and experimental cation exchange in MX 80 bentonite. @article{MontesH2005ModellingOG, title={Modelling of geochemical reactions and experimental cation exchange in MX 80 bentonite.}, author={G. Montes-H and B. Fritz …
Bentonite in Oman
The fastest growing export markets for Bentonite of Oman between 2021 and 2022 were India ($192k), United Arab Emirates ($94.3k), and Qatar ($37.5k). Imports In 2022, Oman imported $6.63M in Bentonite, becoming the 38th largest importer of Bentonite in the world. At the same year, Bentonite was the 706th most imported product in Oman.
Leaching of60Co and137Cs from spent ion exchange …
The leaching rate of 60Co and 137Cs from the spent cation exchange resins in cement–bentonite matrix has been studied. The solidification matrix was a standard Portland cement mixed with 290–350 (kg/m3) spent cation exchange resins, with or without 2–5% of bentonite clay. The leaching rates from the cement– bentonite matrix …
GEOSYNTHETIC CLAY LINERS, PART SIX: ION EXCHANGE
The ion-exchange capability of bentonite is a natural process and, under typical use conditions and without covering the GCL with a geomembrane, it normally transforms original Na-bentonite into Ca-bentonite. The result is a slight change in the GCL's permeability. ... TRT Terms: Bentonite; Calcium; Cation exchange; Clay minerals; …
Cation exchange capacity of bentonite in a saline …
Cation exchange capacity (CEC) and amounts of leached cations (LC) of bentonite were used to predict the water permeability and swelling property in researches related to bentonite buffer for ...
Swelling and cation exchange capacity relationship for the …
Some clay minerals that have high cation exchange capacity, i.e. montmorillonite and bentonite in principle achieve this effect through ion exchange reaction (Önal 2007, Wigger & Loon 2017. The ...
Effect of extensive drying on the cation exchange capacity of
Interlaboratory CEC and Exchangeable Cation Study of Bentonite Buffer Materials: I. Cu(II)-Triethylenetetramine Method. Clays and Clay Minerals, Vol. 60, Issue. 2, p. 162. …
Critical issues in the determination of the bentonite cation …
The swelling pressure and transport properties of bentonites are controlled by the electric charge density of solid particles, which is commonly estimated from the …
Effect of extensive drying on the cation exchange capacity …
Interlaboratory CEC and Exchangeable Cation Study of Bentonite Buffer Materials: I. Cu(II)-Triethylenetetramine Method. Clays and Clay Minerals, Vol. 60, Issue. 2, p. 162. ... Pitfalls in using the hexaamminecobalt method for cation exchange capacity measurements on clay minerals and clay-rocks: Redox interferences between the …
Full Characterization of Smectites
In addition, properties such as the cation-exchange capacity (CEC), interlayer hydration, and swelling change drastically within the wide layer charge range of each end-member (Grim and Kulbicki, 1961, Christidis and Eberl, 2003, Wolters, 2005). Download: Download full-size image; Figure 2.13.1.
The role of bentonite particle size distribution on …
A calcium bentonite from Kütahya region (Turkey) was activated with Na2CO3 at various ratios (1, 2, 2.5, 5, 10, 15g / 100 g bentonite). Due to ion exchange, the original Ca-bentonite was ...
Thermal and saline effects on the swelling deformation of
It can be inferred that cation exchange efficiency of great important to swelling inhibition of bentonite in low concentration solution. In general, hydration behavior of Mt is a crucial factor that influences the swelling properties of bentonite, while the complexity and variation of this behavior can be attributed to the diverse soil structure.
Characterization of activated bentonite clay mineral and the …
The pH-dependent study confirmed that cation exchange and interlayer complexation between bentonite and CIP molecules were the main sorption mechanism, while kinetic studies exhibited that PSO was the best model to describe CIP sorption process and also chemisorption was the responsible mechanism for CIP removal.
(PDF) Determination of CEC value ( Cation Exchange …
However, the cation exchange capacity value of the raw bentonite was found to be 82.1 meq/100 g while the value was reduced to 67.2 meq/100 g for treated bentonite with high specific surface area.
Thermal activation, characterization and performance …
Bentonite activated for 6 h at 300 °C showed a maximum specific surface area of 81.74 m 2 /g while the raw one showed 57.6 m 2 /g. However, the cation …
Interlaboratory CEC and Exchangeable Cation Study of …
The cation exchange capacity (CEC) and exchange-able cations of soils and clays have been determined since 1852 and a long list of publications proves that cation-exchange data are of great importance but difficult to measure reliab ly. Cation exchange capacity results can be used in agricultural and geotechnical applications.
Interlaboratory CEC and Exchangeable Cation Study of …
The cation exchange capacity (CEC) and exchange-able cations of soils and clays have been determined since 1852 and a long list of publications proves that cation-exchange …