Kinetics of ion exchange in soil organic matter V. Differential ion exchange reactions of Cu2+‐, Cd2+‐, Zn2+‐ and Ca2+‐ons in humic acid

Bunzl, K.; Wolf, A.; Sansoni, B.

doi:10.1002/jpln.19761390409

Cited by 14 publications

(9 citation statements)

References 9 publications

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“…An elevated affinity of copper to SOM was observed. The order of metal sorption (mass concentrations) obtained in the present study (Cu > Cd > Zn > Ni) conforms to that obtained by Bunzl et al (1976) for humic acids of soils (Cu > Cd > Zn). The same order for these three metals was also observed for soils with high contents of organic matter by Elliott et al (1986).…”

Section: Effect Of Soil Organic Matter Content On the Hm Sorptionsupporting

confidence: 86%

The Adsorption Properties of Agricultural and Forest Soils Towards Heavy Metal Ions (Ni, Cu, Zn, and Cd)

Sprynskyy

Kowalkowski

Tutu

et al. 2010

Soil and Sediment Contamination: An International Journal

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and Zn in single and multi-metal solutions by agricultural and forest soils was investigated in batch sorption experiments. The results showed significant differences in sorption capacities of the studied soils. The selectivity order was as follows: agricultural soil top forest soil > bottom forest soil. The adsorption sequence Cu > Zn > Ni > Cd was established for the agricultural and bottom forest soil, while the order for the top forest soil was Cu > Ni > Zn > Cd. The experimental isotherms for the metal sorption were described satisfactorily by the Freundlich and Langmuir models. The competitive adsorption experiment indicated a reduction in the amount of metals adsorbed by the soils from the multi-metal solution compared to the single metal solution. Properties of the soils, such as pH, content of clay and organic matter, exchangeable bases and hydrolytic acidity, showed a significant influence on adsorption capacities of the studied soils.

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Section: Effect Of Soil Organic Matter Content On the Hm Sorptionsupporting

confidence: 86%

The Adsorption Properties of Agricultural and Forest Soils Towards Heavy Metal Ions (Ni, Cu, Zn, and Cd)

Sprynskyy

Kowalkowski

Tutu

et al. 2010

Soil and Sediment Contamination: An International Journal

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“…In a batch experiment to study the sorption kinetics, film diffusion may partially or completely be the rate determining step. This was demonstrated e. g. for the sorption of Pb 2+ -ions by peat or humic acid particles [15] or river mud [16], K + by kaolinite, vermiculite and loamy soils [17], or Sr-ions by natural sediments [8]. In such a case anomalous ion exchange kinetics will be observed, if in an excess of the material is used to remove the trace ion from the solution almost completely.…”

Section: Implications For the Kinetics Of Ion Sorption By Soilsmentioning

confidence: 95%

Anomalous Kinetics of Ion Exchange in Heterogenous Systems — A Computer Simulation

Bunzl

1992

Radiochimica Acta

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The kinetics of ion exchange in heterogenous mixtures in a well stirred batch system, where film diffusion is the rate determining step was investigated by a computer simulation. Heterogeneity of the different ion exchanger particles in the mixture with respect to their diameters, their ion exchange capacities and their separation factors was considered. The distribution of these properties was assumed to be given by a normal frequency distribution. If sufficient ion exchanger is added to the solution to remove a given counter ion species almost completely, each type of the above heterogeneities will produce an anomalous kinetic behaviour of the system. The faster reacting particles overshoot their equilibrium values initially considerably and have to release subsequently part of these ions in favor of the slower reacting particles. This redistribution of the counterions between the particles via the solution phase, is however, extremely slow and balanced in such a way that the concentration of the counterions in solution remains during this time period constant and exhibits already its final equilibrium value. The kinetic behaviour of such systems can, therefore, not be characterized completely by monitoring only the solution concentration as a function of time. The implications of this effect for sorption measurements involving soils are discussed.counterfoil species almost completely [11]. In this case the smaller and thus faster reaction particles will take up initially an excess of ions at the expense of the large particles. After a relatively short time, however, the smaller particles have to release this excess in favor of the larger particles (redistribution phase), because in equilibrium the equivalent fraction of the ions has to be the same in all size fractions of the otherwise homogenous ion exchanger. During this redistribution phase, however, which lasts orders of magnitude longer than the initial phase, the concentrations of the ions in solution remains all the time constant and corresponds almost exactly to the equilibrium concentration.The purpose of the present investigation was to apply the theory of the kinetics of ion exchangers given earlier [11] also to systems involving particles which exhibit a distribution of their diameters, their ion exchange capacities or their separation factors. In the following we will solve the corresponding rate equations numerically, explain the effect of various parameters on the presence of an anomalous kinetic behaviour, and discuss possible implications on the sorption kinetics in soil systems.

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“…The heterogeneous nature of humic and fulvic materials makes it impossible to assign a molecular weight to these compounds (Buffle & Deladoey, 1982). Also, the heterogeneous nature of these materials makes it difficult to define the types of metal binding sites (Buffle, 1980;Bunzl et al, 1976;Gamble et al, 1980). Therefore, the exact number of sites (stoichiometry) and strength of affinity for metals (stability or formation constants) cannot be known, and direct application of theoretical thermodynamics is not appropriate.…”

Section: Introductionmentioning

confidence: 99%

“…A number of discrete and continuous models have been proposed to describe the different sites available for binding of metals to humic and fulvic substances (Giesy etal., 1986a & b;McKnight etal., 1983;Buffle, 1980;Gamble etal., 1980;Sanders & Bloomfield, 1980;Bloom & McBride, 1979;Chopping & Kullberg, 1978;Buffle etal., 1977;Zunino etal., 1977;Bunzl et al, 1976). Sposito (1981) has suggested the use of a quasiparticle model of metal speciation to represent a simplification of the complex metal-humic interactions in surface waters.…”

Section: Introductionmentioning

confidence: 99%

Conditional stability constants and binding capacities for copper (II) by ultrafilterable material isolated from six surface waters of Wyoming, USA

Giesy

Alberts

1989

Hydrobiologia

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Ultrafilterable material < 0.15 #m was collected from six Wyoming surface waters, for which the chemical limnology had also been determined. The material was separated into four nominal size-fractions and the binding capacity of each for copper was determined by a hyperbolic, site-saturation model. The conditional, overall, thermodynamic stability constants (K') for binding of copper were determined by two discrete models: The one-and two-component Scatchard functions, and two continuous multiligand models; The one-and three-component Gaussian Scatchard functions. The accuracy of the stability constants to predict the speciation of Cu(II) in the titration of the isolated fractions and of whole waters was evaluated by comparing the predictions of the thermodynamic, geochemical simulation model, GEOCHEM to those measured by selective ion electrode. The Cu-binding capacity of material retained by ultrafilters was positively correlated with the hardness and alkalinity of the surface waters, from which they were isolated as well as the percent ash content of the ultrafilter-retained material. The magnitude of the conditional stability constant (Ki') decreased as the ratio of the total Cu concentration to total concentration of Cu-binding sites increased. The cumulative frequency distribution of K,' was lognormally distributed. All four of the models used to estimate the conditional stability constants gave reasonable prediction of the speciation of Cu for both fractionated and whole waters but, depending on the situation, the one-or two-component Scatchard estimate generally gave the best predictions of the proportion of copper, which would be expected to be bound.

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Kinetics of ion exchange in soil organic matter V. Differential ion exchange reactions of Cu²⁺‐, Cd²⁺‐, Zn²⁺‐ and Ca²⁺‐ons in humic acid

Cited by 14 publications

References 9 publications

The Adsorption Properties of Agricultural and Forest Soils Towards Heavy Metal Ions (Ni, Cu, Zn, and Cd)

The Adsorption Properties of Agricultural and Forest Soils Towards Heavy Metal Ions (Ni, Cu, Zn, and Cd)

Anomalous Kinetics of Ion Exchange in Heterogenous Systems — A Computer Simulation

Conditional stability constants and binding capacities for copper (II) by ultrafilterable material isolated from six surface waters of Wyoming, USA

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