Cation and Anion Sorption Capability of Organophilic Bentonite

1997 ◽  
Vol 506 ◽  
Author(s):  
J. Bors ◽  
St. Dultz ◽  
B. Riebe
Keyword(s):  
Cation Exchange ◽  
Surface Charge ◽  
Cation Exchange Capacity ◽  
Particle Surface ◽  
Exchange Capacity ◽  
Negative Particle ◽  
Strontium Ions ◽  
Wyoming Bentonite

ABSTRACTSorption experiments were performed with iodide, cesium and strontium ions on MX-80 Wyoming-bentonite treated with hexadecylpyridinium (HDPy+) in amounts equivalent to 0.2 - 4.0 times the cation exchange capacity (CEC) using 125I- 134Cs+ and 85Sr2+ as tracers. In HDPy-bentonite, iodide exhibited increasing adsorption, while cesium and strontium ions showed decreasing adsorption with increasing organophilicity. It was also found that the Cs+affinity to original and HDPy-bentonite was considerably higher than that of Sr2+ ions. HDPy+ uptake in increasing concentrations resulted in a pronounced expansion of the basal spacings (d002 reflex at 2.78 nm) and in a change of the negative particle surface charge to positive values.

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.

Reaction of mixed magnesium–aluminum and calcium–aluminum hydroxides with Wyoming bentonite

1969 ◽  
Vol 6 (1) ◽  
pp. 47-53
Author(s):  
J. S. Clark ◽  
G. J. Ross
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Marked Reduction ◽  
Exchange Capacity ◽  
Reaction Products ◽  
Aluminum Hydroxides ◽  
Wyoming Bentonite

Excess AlCl3 was reacted with Mg(OH)2 and Ca(OH)2 in suspensions of Wyoming bentonite and the nature of the reaction products formed and their effect on the cation-exchange capacity (CEC) of the clay was determined. Reaction of Mg(OH)2 and AlCl3 with the clay produced marked decreases of the CEC in the bentonite, whereas much smaller decreases were observed in the Ca–Al–clay preparations. The decreases in the CEC were attributed to the formation of mixed Mg–Al and Ca–Al hydroxide clay complexes. The greater stability of the mixed Mg–Al hydroxide complexes with the clay appeared to account for the marked reduction of CEC in these systems.

scholarly journals Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

2016 ◽  
Vol 30 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Kamil Skic ◽  
Patrycja Boguta ◽  
Zofia Sokołowska
Keyword(s):  
Specific Surface ◽  
Cation Exchange ◽  
Surface Charge ◽  
Surface Area ◽  
Water Vapour ◽  
Potentiometric Titration ◽  
Specific Surface Area ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Sorption Properties

Abstract Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g−1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=−0.736; α = 0.05) as well as ash content (R=−0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g−1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

scholarly journals SOME PROPERTIES OF ALUMINUM HYDROXIDE PRECIPITATED IN THE PRESENCE OF CLAYS

1965 ◽  
Vol 45 (3) ◽  
pp. 331-336 ◽  
Author(s):  
R. C. Turner
Keyword(s):  
Cation Exchange ◽  
Aluminum Hydroxide ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
The Other ◽  
Wyoming Bentonite

With Arizona bentonite, Wyoming bentonite, Fithian illite, and Georgia kaolin it was found that the OH/Al ratio of the aluminum hydroxide precipitated was about 2.7, providing the initial OH/Al ratio was not greater than 2.7. When the initial OH/Al ratio was increased to 3.0 the OH/Al ratio of the precipitate also increased to 3.0. The decrease in cation exchange capacity of the clays per milliequivalent of Al in the precipitate was independent of the initial OH/Al ratio when the ratio was varied from 1.0 to 2.7. When this ratio was increased beyond 2.7, however, inactivation of the exchange sites decreased, until with an initial OH/Al ratio of 3.0 there was very little decrease in exchange capacity. It required less precipitated Al to decrease the exchange capacity of Arizona bentonite than it did for the other three clays.

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 Quantification of permanent and variable charges in reference soils of the State of Pernambuco, Brazil

2014 ◽  
Vol 38 (4) ◽  
pp. 1162-1169 ◽  
Author(s):  
Jailson Cavalcante Cunha ◽  
Hugo Alberto Ruiz ◽  
Maria Betânia Galvão dos Santos Freire ◽  
Víctor Hugo Alvarez V. ◽  
Raphael Bragança Alves Fernandes
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Chloride Solution ◽  
Particle Surface ◽  
Cesium Chloride ◽  
Exchange Capacity ◽  
The State ◽  
Isomorphic Substitution ◽  
Do So

The electrical charges in soil particles are divided into structural or permanent charges and variable charges. Permanent charges develop on the soil particle surface by isomorphic substitution. Variable charges arise from dissociation and association of protons (H+), protonation or deprotonation, and specific adsorption of cations and anions. The aim of this study was to quantify the permanent charges and variable charges of Reference Soils of the State of Pernambuco, Brazil. To do so, 24 subsurface profiles from different regions (nine in the Zona da Mata, eight in the Agreste, and seven in the Sertão) were sampled, representing approximately 80 % of the total area of the state. Measurements were performed using cesium chloride solution. Determination was made of the permanent charges and the charges in regard to the hydroxyl functional groups through selective ion exchange of Cs+ by Li+ and Cs+ by NH4+, respectively. All the soils analyzed exhibited variable cation exchange capacity, with proportions from 0.16 to 0.60 and an average of 0.40 when related to total cation exchange capacity.

Surface charge characteristics and lime requirements of soils derived from basaltic, granite and metamorphic rocks in high rainfall tropical Queensland

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 173 ◽  
Author(s):  
GP Gillman ◽  
EA Sumpter
Keyword(s):  
Cation Exchange ◽  
Surface Charge ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Exchange Method ◽  
High Rainfall ◽  
Exchangeable Al ◽  
Basaltic Soils ◽  
Highly Weathered Soils

The cation and anion exchange capacities of a large number of soils formed on basaltic, granitic, and metamorphic parent materials in the high rainfall area (approximately 4000 mm) of tropical north Queensland have been examined. Aspects studied included the changes in CEC and AEC between pH 4 and pH 6, the relative amounts of permanent and variable charge over this pH range, and the lime requirements of these highly weathered soils. A distinction is made between the Total Cation Exchange Capacity (CECT), defined as the Ca + Al adsorbed, and the Basic Cation Exchange Capacity (CECB), which is the Ca adsorbed. At low pH, CECB may be much less than CECT. The CEC, increase with pH in the highly oxidic basaltic soils is largely due to changes in surface charge, while in the granitic and metamorphic soils, increasing occupation of exchange sites by Al as pH decreases is the factor responsible for the increase in CECB. A good estimation of CECB at soil pH is obtained with a previously described compulsive exchange method, and there is high correlation between CECT at soil pH and the Effective Cation Exchange Capacity (= Ca + Mg + K + Na + Al). The amount of lime required to raise soil pH to pH 5.5 in the granitic and metamorphic soils was equivalent to the amount of exchangeable Al, but in the basaltic soils the lime requirement was two to three times greater than the amount of exchangeable Al.

REACTIONS OF PHOSPHATE WITH ALUMINUM AND WYOMING BENTONITE

1969 ◽  
Vol 49 (2) ◽  
pp. 231-240 ◽  
Author(s):  
M. D. Webber ◽  
J. S. Clark
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Major Part ◽  
Aluminum Phosphate ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Complexes ◽  
Phosphate Phase ◽  
Wyoming Bentonite

Reactions between phosphate, Al and Wyoming bentonite in aqueous suspensions were studied under two conditions: (1) H3PO4 was added after interlayer hydroxy aluminum complexes had been formed by the addition of Ca(OH)2 to AlCl3 + bentonite suspensions; and (2) H3PO4 was added to AlCl3 + bentonite suspensions before the addition of Ca(OH)2. The suspensions were aerated and maintained at 25 °C.When H3PO4 was added after the formation of hydroxy aluminum complexes, the results were not significantly different from those when Ca(OH)2 was added to suspensions containing both AlCl3 and H3PO4. Phosphate was removed from solution and an interlayer hydrous aluminum phosphate was formed which increased the d(001) spacings of the bentonite. The amount of phosphate removed from solution increased to a maximum with increasing amounts of H3PO4 added and over this range there was no change in cation exchange capacity (CEC). Large amounts of H3PO4 increased the CEC of the bentonite. A major part of the reaction was completed within 24 hours and the values of pH changed only slightly from 1 to 120 days.Values of the (Al) (OH)2(H2PO4) ion product measured after aging for 14 days were larger than would have been maintained by crystalline variscite, but X-ray diffraction studies showed no evidence for formation of a separate crystalline phosphate phase.

scholarly journals Chemical attributes of a remineralized Oxisol

2017 ◽  
Vol 47 (11) ◽  
Author(s):  
Rafael Cipriano da Silva ◽  
Marina Elias Cury ◽  
João José Cardinali Ieda ◽  
Renata Alcarde Sermarini ◽  
Antonio Carlos de Azevedo
Keyword(s):  
Cation Exchange ◽  
Surface Charge ◽  
Cation Exchange Capacity ◽  
Amorphous Solids ◽  
Mechanisms Of Action ◽  
Exchange Capacity ◽  
Agricultural Fields ◽  
Chemical Attributes ◽  
Crystal Volume

ABSTRACT: Remineralizers are comminuted rocks that are applied to soil, and their use as an agricultural amendment was regulated in Brazil in 2013. However, mechanisms of action of these materials must be better known to enable them to be best used in agricultural fields. Soil chemical attributes of an Oxisol were monitored after the application of a diabase remineralizer. The increase in exchangeable Na observed was associated with the dissolution of the border of the plagioclase crystals where this element is highly concentrated (albite). Therefore, it was inferred that the time since the application of the remineralizer (1 to 2 years depending on the treatment) was not sufficient to exhaust this crystal volume. Unfortunately, the presence of several sources of Ca-containing minerals in the remineralizer did not allow to infer if the calcic nuclei was dissolving. An increase in effective cation exchange capacity was observed without the concurrent increase in the pH of the soil. The two non-exclusive hypotheses proposed to explain this result were that an extra surface charge has originated on the surface of the newly precipitated oxidic phases and/or from the dissolution of the remineralizer grains. Rapid precipitation of amorphous solids (as measured by the increase in Alo and Feo) would also explain the lack of increase in exchangeable Fe and Al despite the large amount of Al2O3 (11.90%) and Fe2O3 (14.45%) in the remineralizer.

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