Ethylene glycol and glycerol complexes of smectites and vermiculites

Clay Minerals ◽  
1966 ◽  
Vol 6 (4) ◽  
pp. 237-259 ◽  
Author(s):  
G. W. Brindley
Keyword(s):  
Chemical Analysis ◽  
Ethylene Glycol ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Layer Charge ◽  
Silicate Layers

The complexes formed by ethylene glycol, HOCH2.CH2OH, and by glycerol, HOCH2.CHOH.CH2OH, with smectites (montmorillonite-saponite group), and vermiculites have received more attention than any other group of organo-silicate complexes. This interest arose in the first place from their use for identification purposes as proposed by MacEwan (1944, 1946) and by Bradley (1945b). Over the years, increasing attention has been given to the manner in which these complexes vary with the nature of the mineral, the magnitude and source of the charge on the silicate layers, and the number and kind of the exchangeable cations between the layers. The layer charge is determined most reliably from the full chemical analysis of a mineral, but more commonly is estimated from a measurement of cation exchange capacity.

Collaborative Study of the Cation Exchange Capacity of Peat Materials

1973 ◽  
Vol 56 (1) ◽  
pp. 154-157 ◽  
Author(s):  
Virginia A Thorpe
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Collaborative Study ◽  
Statistical Treatment ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Satisfactory Degree ◽  
Modified Method ◽  
Precision And Accuracy

Abstract To provide a measure of the total amount of exchangeable cations that can be held by peat expressed as mequiv./100 g air-dried peat, the modified method of Puustjärvi for cation exchange capacity has been proposed and studied collaboratively. The statistical treatment of the collaborators’ results indicate a satisfactory degree of precision and accuracy for the 3 products considered, moss, humus, and reed-sedge. The method for cation exchange capacity of peat materials, with the description of the transfer technique included, has been adopted as official first action. The 7 ASTM methods have been adopted as procedures.

Dehydration of the montmorillonite minerals

1955 ◽  
Vol 30 (228) ◽  
pp. 604-615 ◽  
Author(s):  
R. Greene-Kelly
Keyword(s):  
Charge Density ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
The Other ◽  
Hydration Energy ◽  
Interlayer Cations ◽  
Potassium Fixation ◽  
Exchange Cations ◽  
Silicate Layers

Studies of the effect of dehydration at temperatures greater than 150° on sorption by montmorillonites have shown that small interlayer cations such as lithium and magnesium promote an irreversible decrease in the amount of interlamellar sorption and a consequent marked fall in the cation exchange capacity as measured by conventional methods (1, 2, 3, 4). The other minerals of the group do not show this property (4), which is quite distinct from the supposed 'potassium fixation' reported in these minerals (5). This latter effect, which is small for montmorillonite, refers to the decreased rate of exchange of potassium as compared with smaller exchange cations especially after the potassium-saturated mineral has been dried at ]00° C., and has been shown to be much more marked in mica-like minerals with silicate layers of higher charge density (e.g. illites and vermiculites (6)). The amount of water sorbed by potassium-saturated montmorillonite is not significantly affected by drying at temperatures below 400° C. although it is less than that of most other montmorilIonites (3), due probably to the low hydration energy of the potassium ion (7).

scholarly journals Influence of clay minerals and exchangeable cations on the formation of humic-like substances (melanoidins) from D-glucose and L-tyrosine

Clay Minerals ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 487-497 ◽  
Author(s):  
P. Arfaioli ◽  
O. L. Pantani ◽  
M. Bosetto ◽  
G. G. Ristori
Keyword(s):  
Cation Exchange ◽  
Clay Minerals ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Reaction Conditions ◽  
Polymeric Compounds

AbstractThe ability to produce humic-like polymeric compounds, with D-glucose and L-tyrosine as starting materials, was evaluated in different mineral systems: (1) Ca-, Al- and Cu(II)-saturated montmorillonite; (2) Ca-, Al- and Cu(II)-saturated kaolinite; (3) quartz in the presence of two different amounts of the same cations (according to the cation exchange capacity of the clays); and (4) untreated quartz (as control). All systems proved to be effective in the formation of humic-like compounds, particularly quartz, in the presence of cations. The effectiveness in promoting humification reactions was strictly related to the amounts of added cations. In the reaction conditions considered, the humification appears to be due more to the cations than to the type of clay minerals. The clayey systems synthesized more complex (aromatic) substances than the quartz ones.

Acid character of nontronite: permanent and pH-dependent charge components of cation exchange capacity

Clay Minerals ◽  
1972 ◽  
Vol 9 (4) ◽  
pp. 425-433
Author(s):  
B. S. Kapoor
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Dependent Component ◽  
Ph Dependent ◽  
The Difference ◽  
The Cost ◽  
Fe Ions ◽  
Acid Character

AbstractThe cation exchange capacity (C.E.C.) of nontronite was determined by titrating the acid clay, prepared by the action of H-resin on nontronite, in water and some nonaqueous solvents. The base-titratable acidities of the acid nontronite, freshly prepared as well as aged, were found to be greater than the acidities extractable with 1 N NaCl; the difference was attributed to the non-exchangeable pH-dependent component of C.E.C. In the freshly prepared sample, H+ and Fe3+ ions were the only exchangeable cations. Ageing produced basic Fe ions which were exchangeable and whose amount increased at the cost of H− and Fe3+ ions. Whatever the age, the total quantity of these exchangeable cations corresponding to the total isomorphous charge, remained constant. The amount of the pH-dependent acidity also remained unchanged. A likely mechanism to account for the observed pH-dependent component of the C.E.C, of nontronite is suggested.

scholarly journals A comparison between three methods for the determination of cation exchange capacity and exchangeable cations in soils

Agronomie ◽  
1997 ◽  
Vol 17 (1) ◽  
pp. 9-16 ◽  
Author(s):  
H. Ciesielski ◽  
T. Sterckeman ◽  
M. Santerne ◽  
J. P. Willery
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchangeable Cations
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