Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Surface Soils ◽  
Ph Values ◽  
Variable Charge ◽  
Effects Of Ph ◽  
Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

Zinc and cadmium mobility in sand: effects of pH, speciation, Cation Exchange Capacity (CEC), humic acid and metal ions

Chemosphere ◽  
1998 ◽  
Vol 36 (10) ◽  
pp. 2283-2290 ◽  
Author(s):  
P. Warwick ◽  
A. Hall ◽  
V. Pashley ◽  
J. Van der Lee ◽  
A. Maes
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Effects Of Ph

scholarly journals Adsorption Potentials of Alfisol on Glyphosate and Cadmium Contaminants

2020 ◽  
pp. 25-33
Author(s):  
F. B. Okanlawon ◽  
O. O. Awotoye ◽  
P. O. Ogunbamowo
Keyword(s):  
Ionic Strength ◽  
Organic Carbon ◽  
Cation Exchange ◽  
Soil Sample ◽  
Adsorption Capacity ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Initial Concentration ◽  
University Of Ibadan ◽  
Ibadan Nigeria

Aims: This study aimed at demonstrating the adsorption capacity as well as the removal of glyphosate and cadmium unto Alfisols. Place and Duration of Study: Research was carried out in Analytical Laboratory of Department of Chemistry, University of Ibadan, Nigeria. The soil sample was collected from an undisturbed forest land, University of Ibadan, Nigeria. Methodology: The soil sample was air dried for 72 hours under ambient temperature and allowed to pass through 2 mm sieve before use. All solutions and soil dispersions were prepared using de-ionised water. The pH, organic carbon, particle size, exchangeable cations, cation exchange capacity, available phosphorus and soil total nitrogen were all analysed for in the soil sample following the standard procedures likewise the cadmium and glyphosate adsorption/adsorbent studied. Results: The pH of the soil is slightly acidic with high total organic carbon, while the cation exchange capacity is on the lower side. The textural class of the soil greatly influences its water retention capacity, thus the soil under study is predominantly sandy. A decrease in the equilibrium adsorption capacity was observed when the adsorbent dose was increased from 0.2 – 0.8 g however, with a sharp increase at a dose of 1 g. An increase in the percentage cadmium removal was observed with increase in pH from 48.80% to a maximum of 91.10% at neutral pH. The result also indicates that increasing the initial concentration of the cadmium ions and glyphosate lead to an increase in the uptake capacity of the soil for both adsorbate. At higher ionic strength of 0.1 M, the peak removal was obtained at initial concentration of 10 ppm which eventually attains equilibrium at other concentration level. Conclusion: Alfisol can therefore concluded to be an adsorbent provided some conditions like a low cadmium concentration, a neutral pH and a higher adsorbent dosage are adhere too. While glyphosate removal, a pH of 5 and higher ionic strength of KNO3. is required.

Differential effect of pasture species on the pH and cation exchange capacity of a subsequently cultivated soil

1970 ◽  
Vol 74 (3) ◽  
pp. 453-456 ◽  
Author(s):  
A. J. Rixon
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Differential Effect ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Lower Percentage ◽  
Ph Values ◽  
Cultivated Soil ◽  
The Difference ◽  
Inorganic Fraction

SUMMARYHigher pH values had been established under grass than under clover pastures during a prior pasture phase. The differential effect of pasture species on the pH of the subsequently cultivated soil was reduced in time, but continued to be significant after 4 years.There was greater cation exchange capacity and lower percentage base saturation after clovers than after grasses. The cation exchange capacity of the inorganic fraction of the soil was not affected by the type of pasture and did not change with time. The difference in cation exchange capacity for the cultivated soil was, therefore, due to the difference in the cation exchange capacity of organic matter residual from the clover and grass pastures.

A proposed method for the measurement of exchange properties of highly weathered soils

Soil Research ◽  
1979 ◽  
Vol 17 (1) ◽  
pp. 129 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Barium Chloride ◽  
Exchange Capacity ◽  
Potential Surfaces ◽  
Exchange Method ◽  
Barium Chloride Solution ◽  
Highly Weathered Soils ◽  
Basic Cations

The 'compulsive exchange' method of Bascomb has been modified to allow the determination of cation exchange capacity and anion exchange capacity of soils containing significant quantities of constant potential surfaces. The soil is equilibrated with unbuffered barium chloride solution at an ionic strength approximating that of the soil solution, so that the conditions under which determinations are made are similar to those found in the field. Barium on the exchange complex is then replaced by magnesium when the latter is added as magnesium sulfate, and this is accomplished without altering the solution ionic strength. If desired, exchangeable basic cations can be determined as an additional step in the procedure. Results obtained by the proposed method are compared with other commonly used procedures for determining cation exchange capacity and exchangeable basic cations.

Prediction of K-Ca-Mg ternary exchange from binary isotherms in volcanic soils using the Rothmund-Kornfeld approach

Soil Research ◽  
2002 ◽  
Vol 40 (5) ◽  
pp. 781 ◽  
Author(s):  
M. Escudey ◽  
P. Diaz ◽  
J. E. Förster ◽  
G. Galindo ◽  
C. Pizarro ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Surface Charge ◽  
Cation Exchange Capacity ◽  
Binary Data ◽  
Exchange Capacity ◽  
Volcanic Soils ◽  
Experimental Conditions ◽  
Equivalent Fractions ◽  
Variable Surface

The Gaines-Thomas formulation of the Rothmund-Kornfeld equation was used to predict the K-Ca-Mg exchange in variable surface charge soils. Binary and ternary equilibria were carried out at 25°C and at constant ionic strength of 0.050 mol/L. The selectivity sequence K > Ca > Mg was observed in binary isotherms. The experimental ternary isotherms are well described from binary data. When experimental v. calculated equivalent fractions were plotted, slopes between 0.901 and 1.051, and correlations between 0.970 and 0.986, were obtained. The design used assures in volcanic soils that no, or minor, changes in surface charge, cation exchange capacity, and selectivity occur, but the predicted ternary values are restricted to the same binary experimental conditions employed.

scholarly journals Uranium(VI) adsorption on surfactant modified heulandite/clinoptilolite rich tuff

2006 ◽  
Vol 71 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
Srdjan Matijasevic ◽  
Aleksandra Dakovic ◽  
Magdalena Tomasevic-Canovic ◽  
Mirjana Stojanovic ◽  
Deana Iles
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Adsorption Isotherms ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Zeolitic Tuff ◽  
Zeolite Surface ◽  
Inorganic Cations ◽  
Maximal Amount ◽  
Ph Values

The adsorption of uranium(VI) on heulandite/clinoptilolite rich zeolitic tuff modified with different amounts (2, 5 and 10 meq/100 g) of hexadecyltrimethyl ammonium (HDTMA) ion was investigated. The organozeolites were prepared by ion exchange of inorganic cations at the zeolite surface with HDTMA ions, and the three prepared samples were denoted as OA-2, OA-5 and OA-10. The maximal amount of HDTMAin the organozeolite OA-10 (10 meq/100 g) was equal to the external cation exchange capacity of the starting material. The results showed that uranium( VI) adsorption on unmodified zeolitic tuff was low (0.34 mg uranium(VI)/g adsorbent), while for the organozeolites, the adsorption increased with increasing amount of HDTMA at the zeolitic surface. The highest adsorption indexes were achieved for the organozeolite OA-10, in which all the surface inorganic cations had been replaced with HDTMA. An investigation of the adsorption of uranium(VI) ions onto organozeolite OA-10 at different pH values (3, 6 and 8) showed that the adsorption index increased with increasing amount of adsorbent in the suspension. Since uranium(VI) speciation is highly dependent on pH, from the adsorption isotherms, it can be seen that uranium(VI) adsorption on organozeolite OA-10 at pH 6 and 8 is well described by a Langmuir type of isotherm, while at pH 3, it corresponds to a Type III isotherm. .

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