scholarly journals Cd2+Exchange for Na+and K+in the Interlayer of Montmorillonite: Experiment and Molecular Simulation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Lefu Mei ◽  
Huashang Tao ◽  
Chao He ◽  
Xuebing Xin ◽  
Libing Liao ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Interlayer Space ◽  
Molecular Simulations ◽  
Exchange Interactions ◽  
Exchange Capacity ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations ◽  
Cation Exchange Reaction ◽  
High Cation Exchange Capacity

Montmorillonite (Mt) has high cation exchange capacity and thus has been studied extensively for its cation exchange interactions with other cations. However, molecular simulations for the forces governing the cation exchange on Mt surfaces or in the interlayer spaces were limited. In this study, Mt with K+and Na+in the interlayer spaces was tested for its cation exchange with Cd2+in solution and the forces driving the cation exchange reaction were simulated by molecular simulations. The experimental results showed that Na+in Na + Mt was completely exchanged by Cd2+, while only 50% of K+in K + Mt was exchanged by Cd2+. A largerd-value was noticed for Na + Mt in comparison to K + Mt, suggesting that the interlayer space is more hydrated with Na+as the interlayer space cation. Molecular dynamic simulations revealed a larger energy decrease when Cd2+substitutes K+. However, the nice fit of the K+into the 12-coordinated interlayer space sites may restrict its hydration and thus reduce its interlayer space cation exchange capability by Cd2+.

Ionic composition of a disordered kaolinite

Clay Minerals ◽  
1966 ◽  
Vol 6 (4) ◽  
pp. 341-344 ◽  
Author(s):  
W. E. Worrall ◽  
A. E. Cooper
Keyword(s):  
Cation Exchange ◽  
Clay Mineral ◽  
Cation Exchange Capacity ◽  
Ionic Composition ◽  
Exchange Capacity ◽  
Plastic Clay ◽  
High Cation Exchange Capacity

AbstractA white-burning, highly-plastic clay from Jamaica, containing mainly disordered kaolinite, was examined recently. It was unusual in that it was practically free from fine mica, and therefore could be purified readily by standard sedimentation techniques.The cation exchange capacity was abnormally high, and the purified clay mineral, on analysis and calculation of the ionic composition, was found to be deficient in aluminium, but contained magnesium and iron.The results confirmed the view, previously expressed, that disorder in kaolinites is associated with a high cation exchange capacity and a substituted lattice.

scholarly journals Biochar Surface Oxygenation by Ozonization for Super High Cation Exchange Capacity

2019 ◽  
Vol 7 (19) ◽  
pp. 16410-16418 ◽  
Author(s):  
Gyanendra Kharel ◽  
Oumar Sacko ◽  
Xu Feng ◽  
John R. Morris ◽  
Claire L. Phillips ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
High Cation Exchange Capacity

Effect of extensive drying on the cation exchange capacity of bentonites

Clay Minerals ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 441-448 ◽  
Author(s):  
S. Kaufhold ◽  
R. Dohrmann
Keyword(s):  
Radioactive Waste ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Interlayer Space ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Interlayer Cation ◽  
Smectite Clay ◽  
Radioactive Waste Repositories ◽  
Waste Repositories

AbstractExtensive drying of smectites can cause the interlayer space to break down (collapse). This can affect the properties of bentonites as geotechnical barriers of HLRW (highly radioactive waste) repositories. If and to what extent the collapse occurs depends strongly on the type of interlayer cation. In particular K is known to lead to ready dehydration, in contrast to Ca and Mg. In the present study, various bentonites and one illite/smectite clay were dried/heated at 90ºC for 1.5 a and in a different experiment at 120ºC for 4.5 a and investigated with respect to mineralogical and geochemical changes of the smectite.Smectite alteration after extensive drying was restricted to changes of the exchangeable cations. The CEC decreased by 9% (90ºC test) and 14% (120ºC test). A slight decrease of exchangeable Na+ was observed following the 90ºC test. No significant further decrease was observed after the 120ºC test. In contrast, the larger cation exchange capacity (CEC) decrease after the 120ºC test could be explained by increased Ca/Mg fixation. A possible mechanism for the observations is presented.

scholarly journals Synthesis of granular zeolitic materials with high cation exchange capacity from agglomerated coal fly ash

Fuel ◽  
2007 ◽  
Vol 86 (12-13) ◽  
pp. 1811-1821 ◽  
Author(s):  
Roberto Juan ◽  
Susana Hernández ◽  
José Manuel Andrés ◽  
Carmen Ruiz
Keyword(s):  
Fly Ash ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Coal Fly Ash ◽  
Exchange Capacity ◽  
Zeolitic Materials ◽  
High Cation Exchange Capacity

scholarly journals Heavy-metal uptake by a high cation-exchange-capacity montmorillonite: the role of permanent charge sites

2013 ◽  
Vol 12 (3) ◽  
pp. 248-255
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Metal Uptake ◽  
Exchange Capacity ◽  
Point Of Zero Charge ◽  
Heavy Metal Uptake ◽  
Smectite Clays ◽  
Analysis Scheme ◽  
High Cation Exchange Capacity

A High Cation Exchange Capacity (HCM) montmorillonite clay has been prepared by acetate treatment of Zenith clay. The HCM has been evaluated for metal-uptake from aqueous solutions. The present data show that the cation exchange sites can play a significant role in the adsorption of metals in smectite clays. A theoretical analysis scheme has been developed which shows that permanent-charge sites can become dominant in metal-uptake by clays. In addition, it was shown that the permanent charge can influence the ionic-strength sensitivity of the Point of Zero Charge of the clay.

scholarly journals Synthesis of Zeolitic Material with High Cation Exchange Capacity from Paper Sludge Ash Using EDTA

2021 ◽  
Vol 11 (23) ◽  
pp. 11231
Author(s):  
Takaaki Wajima
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Ethylenediaminetetraacetic Acid ◽  
Exchange Capacity ◽  
Paper Sludge ◽  
Zeolite Synthesis ◽  
Zeolite A ◽  
Paper Sludge Ash ◽  
Sludge Ash ◽  
High Cation Exchange Capacity

Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content because of the presence of calcite fillers, which interfere with the zeolitic conversion of PSA. Ca-masking with ethylenediaminetetraacetic acid (EDTA) was used to reduce Ca interference during zeolite synthesis so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Hydroxysodalite, zeolite-P, hydroxycancrinite, tobermorite, and zeolite-A can be synthesized from PSA by an alkali reaction with EDTA. With the addition of EDTA, calcium ions in the solution were trapped by chelation, and the number of zeolitic crystals with low Si/Al (Si/Al = 1), zeolite-A, increased owing to the promotion of the synthesis reaction. A product with a high CEC that has a high zeolite-A content was obtained. The chelating agent can inhibit Ca interference for zeolite synthesis by Ca-masking, and a product with a high zeolite-A content can be obtained from PSA using EDTA.

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