Aluminous Chlorite Origin of pH-Dependent Cation Exchange Capacity Variations

1967 ◽  
Vol 31 (5) ◽  
pp. 614-619 ◽  
Author(s):  
J. M. de Villiers ◽  
M. L. Jackson
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Ph Dependent

ETUDE SUR LA VALEUR DES CRITERES CHIMIQUES PROPOSES PAR LA COMMISSION PEDOLOGIQUE DU CANADA POUR LA CLASSIFICATION TAXONOMIQUE DES SOLS DU QUEBEC

1977 ◽  
Vol 57 (3) ◽  
pp. 233-247 ◽  
Author(s):  
ROGER W. BARIL ◽  
THI SEN TRAN
Keyword(s):  
Cation Exchange ◽  
Soil Ph ◽  
Classification System ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Taxonomic Classification ◽  
Single Test ◽  
Ph Dependent ◽  
Extractable Al

Correlations were made among chemical criteria used for taxonomic soil classificaton. The compared tests were: oxalate Δ (Fe + Al), pyrophosphate-extractable (Fe + Al), oxalate-extractable Al, pH-dependent cation exchange capacity (ΔCEC), ratios of pyrophosphate-extractable (Fe + Al) over clay or over dithionite-extractable (Fe + Al), and finally soil pH measured in 1 M NaF. Significant correlations were found among various measured parameters. However, no single test was found to be reliable as a single criterion when applied to the taxonomic classification of Quebec soils. The two chemical tests, pyrophosphate-extractable (Fe + Al) and its ratio over clay, combined with morphologic criteria appeared useful for classifying Quebec Podzols. A few soils, which presented discrepancies from chemical criteria were found difficult to classify, thus suggesting the possibility of establishing new sub-groups in the Canadain soil taxonomic classification system.

ESTIMATION OF THE INORGANIC AND ORGANIC pH-DEPENDENT CATION EXCHANGE CAPACITY OF THE B HORIZONS OF PODZOLIC AND BRUNISOLIC SOILS

1968 ◽  
Vol 48 (1) ◽  
pp. 53-63 ◽  
Author(s):  
J. S. Clark ◽  
W. E. Nichol
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Acid Soils ◽  
Exchange Capacity ◽  
Hydrous Oxides ◽  
Before And After ◽  
Ph Dependent ◽  
The Difference ◽  
Wyoming Bentonite

Heating in hydrogen peroxide, dilute oxalic acid, and dilute aluminum oxalate did not change the effective cation exchange capacity (CEC) or the pH-7 CEC of Wyoming bentonite and Alberni clay soil containing excess Al(OH)x. This indicated that treatment of soils with H2O2 to oxidize organic matter and the possible production of oxalates during oxidation did not change the CEC values of the inorganic fraction of soils even if some clay exchange sites were blocked by hydrous oxides of Al.With soils of pH less than approximately 5.4, oxidation of organic matter did not change the effective CECs although the pH-7 CEC values were decreased. Thus, organic matter in acid soils appeared to have little or no effective CEC. Because of this and the negligible effect of H2O2 oxidation on the CEC values of clays, the difference of the pH-7 CEC of soils before and after H2O2 oxidation provided a simple means of estimating the amount of organic pH-dependent CEC in acid soils.The amount of organically derived pH-dependent CEC was determined in a number of soils by means of peroxide oxidation. The technique provided a useful indication of the quantities of sesquioxide–organic matter complexes accumulated in medium- and fine-textured soils.

COMPONENTS OF pH DEPENDENT CATION EXCHANGE CAPACITY

Soil Science ◽  
1970 ◽  
Vol 109 (5) ◽  
pp. 272-278 ◽  
Author(s):  
B. L. SAWHNEY ◽  
C. R. FRINK ◽  
D. E. HILL
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Ph Dependent

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.

Effect of pH on the cation exchange capacity of some halloysite nanotubes

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 373-383 ◽  
Author(s):  
Nia Gray ◽  
David G. Lumsdon ◽  
Stephen Hillier
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Halloysite Nanotubes ◽  
Exchange Capacity ◽  
Average Value ◽  
Two Samples ◽  
Wide Ph Range ◽  
Capacitance Model ◽  
Ph Dependent ◽  
Ph Range

AbstractThe cation exchange capacity (CEC) of seven well characterized halloysite nanotubes (HNTs) in the dehydrated 7 Å form has been measured using a method based on cobalt hexammine exchange. In addition to unbuffered measurements, which varied between 2.9 and 9.3 cmol(+)kg−1, CECs were also determined over a wide pH range and proton titration measurements were conducted on two samples. The data were fitted using a constant capacitance model based on the presence of two sites: permanently charged sites and pH-dependent variable charged sites. Normalization of CEC to the average specific surface area (BET) of the halloysite samples reduces considerably the variation of CEC values for the different samples particularly over the intermediate pH range (5–9) with the average value at pH 7 equal to 8.5 cmol(+)kg−1and a standard deviation of 1.17. Overall the CEC behaviour of the seven samples appears reasonably consistent throughout the set. Calculations based on proton titrations suggest a ratio of variable charge to basal sites for the dehydrated halloysite nanotubes of ∼3:1.

CONTRIBUTION OF EXCHANGEABLE ALUMINUM TO CATION EXCHANGE CAPACITY AT LOW pH

1987 ◽  
Vol 67 (1) ◽  
pp. 175-185 ◽  
Author(s):  
MARTIN DUQUETTE ◽  
WILLIAM H. HENDERSHOT
Keyword(s):  
Cation Exchange ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Low Ph ◽  
Soil Samples ◽  
Maximum Amount ◽  
Exchangeable Al ◽  
Exchangeable Aluminum ◽  
Ph Dependent

The cation and anion exchange capacities (CEC and AEC) as functions of pH were measured for 12 soil samples from various parts of Quebec. In addition to the index cation Ca, Al was measured in the replacing solutions in order to evaluate the contribution of Al to pH-dependent CEC at low pH. Although all of the soils possessed some pH-dependent CEC, the soils with the steepest rise in CEC with pH were those with the largest accumulation of sesquioxides. The effective CEC, measured at the soil pH, ranged from 2.4 to 37.2 cmol(+) kg−1 while the CEC at pH 7 minus the CEC at pH3 varied from 4.4 to 39.9 cmol(+) kg−1. The maximum amount of exchangeable Al was found to correlate very highly with the amount of amorphous inorganic Al in the samples. The inclusion of exchangeable Al in the calculation did not significantly reduce the amount of pH-dependent CEC measured for the soils. Key words: Effective CEC, permanent charge, pH-dependent CEC

Using pH-dependent CEC to determine lime requirement

2006 ◽  
Vol 86 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Edouard Lemire ◽  
Kate M Taillon ◽  
William H. Hendershot
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Cation Exchange ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Soil Analysis ◽  
Organic Matter Content ◽  
Exchange Capacity ◽  
Ph Dependent ◽  
Ph Curve

Controlling soil pH is important to ensure good crop yield. This study was conducted to determine whether the accuracy of the existing Shoemaker-McLean-Pratt (SMP) pH-buffer method could be improved by using the pH-dependent cation exchange capacity curve (CECpd). Soil pH, SMP and CECpd measurements were performed on 18 acid surface horizon soil samples, with textures from sandy loam to clay loam. These soils were incubated with three levels of calcium carbonate for 12 wk, after which the soil pH and the effective cation exchange capacity (CECe) were measured. The correlation coefficient (R2) for the CECpd and CECe curves was 0.96. The main factor affecting the slope of the curves is the soil organic matter content. The increase of CECe in the soil was also found to be directly proportional to the amount of lime applied, regardless of the type of soil. By using the slope of the Qv versus pH curve for each soil and the relationship between CECe and lime application, we were able to determine the lime required to raise the soil pH in water to 6.5. As an alternative to the current practice of using the SMP buffer, we propose that it should be possible to estimate the pH-dependent CEC curve from measurable soil properties (e.g., organic matter) and to estimate the lime requirement as the difference in CECpd between the existing and desired pH values. Once the slope of the Qv/pH relationship has been determined or estimated for a soil, the only measurement necessary for calculating lime requirement in subsequent years would be the soil pH. The proposed method would provide lime requirement estimates while decreasing the annual cost of soil analysis. Key words: Lime requirement, cation exchange capacity, Non-Ideal Competitive Adsorption, soil properties, organic matter, Fe oxides

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