The cation exchange capacity of a sandy soil in southern Brazil: an estimation of permanent and pH-dependent charges

2005 ◽  
Vol 57 (3) ◽  
pp. 356-364 ◽  
Author(s):  
E. C. Bortoluzzi ◽  
D. Tessier ◽  
D. S. Rheinheimer ◽  
J. L. Julien
1977 ◽  
Vol 57 (3) ◽  
pp. 233-247 ◽  
Author(s):  
ROGER W. BARIL ◽  
THI SEN TRAN

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.


1968 ◽  
Vol 48 (1) ◽  
pp. 53-63 ◽  
Author(s):  
J. S. Clark ◽  
W. E. Nichol

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.


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

Clay Minerals ◽  
1972 ◽  
Vol 9 (4) ◽  
pp. 425-433
Author(s):  
B. S. Kapoor

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.


2019 ◽  
Vol 38 (1) ◽  
pp. 147-156
Author(s):  
Cesar Augusto MOREIRA ◽  
José Ricardo Melges BORTOLIN ◽  
Walter MALAGUTTI FILHO ◽  
João Carlos DOURADO

The sugar and alcohol sector represents one of the most profitable economic activities in Brazil, being ethanol one of the main products. Among the residues related to the production of ethanol, it is highlighted the stillage, a liquid substance generated in the approximate proportion of 13 liters for each liter of ethanol produced. This paper presents the results of a stillage infiltration experiment, in various proportions, through trenches in sandy soil, with the aim to evaluate possible alterations in electrical properties in the geological materials, in individual experiments, with 60L, 300L and 900L of effluent. The initial proportion was defined based on a standard stipulated by the Environmental Agency of the State of São Paulo, which considers the cation exchange capacity of the soil, while the other quantities were defined from ratios of 4 and 15 times higher than those defined by legislation. The experiment was monitored by means of electrical resistivity measurements by indirect means through the geophysical method of Electroresistivity. The data indicate the absence of alterations in electrical properties in the soil below the point of infiltration in the experiment for 60L of stillage. The data for infiltrations with 300L and 900L revealed a zone of low resistivity below the infiltration point, basically limited to the 1m layer of sandy soil and with tendency for lateral flow supported by the soil/rock interface. The results demonstrate that the infiltration of inorganic solutions, in a proportion inferior to the cation exchange capacity of the soil, does not perceptibly alter its electrical properties in studies using the geophysical method of Electro resistivity, whereas proportions that exceed natural absorption capacity are characterized by the geoelectric signature of low resistivity.


2018 ◽  
Vol 28 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Krzysztof Gondek ◽  
Monika Mierzwa-Hersztek ◽  
Michał Kopeć ◽  
Jakub Sikora ◽  
Tomasz Głąb ◽  
...  

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 373-383 ◽  
Author(s):  
Nia Gray ◽  
David G. Lumsdon ◽  
Stephen Hillier

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.


1987 ◽  
Vol 67 (1) ◽  
pp. 175-185 ◽  
Author(s):  
MARTIN DUQUETTE ◽  
WILLIAM H. HENDERSHOT

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


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