Title: Soil Dynamics and Earthquake Engineering

Title: Soil Phosphorus

? Larson, S. (1967), Soil Phosphorus, Academic Press, New York.

Title: Soil Physical Chemistry

White, G.N. and Zelazny, L.W. (1986), Charge properties of soil colloids. in Soil Physical Chemistry, (Edited by Sparks, D.L.), CRC Press, Boca Raton, Florida, 39-81.

Sparks, D.L. (1986), Kinetics of reaction in pure and mixed systems. in Soil Physical Chemistry, (Edited by Sparks, D.L.), CRC Press, Boca Raton, Florida, 83-145.

Title: Soil Science

ISO Abbreviated Title: Soil Sci.

JCR Abbreviated Title: Soil Sci

ISSN: 0038-075X

Issues/Year: 12

Journal Country United States

Language: English

Publisher: Lippincott Williams & Wilkins

Publisher Address: 530 Walnut St, Philadelphia, PA 19106-3621

Subject Categories:

Agriculture, Soil Science: Impact Factor 0.923, 13/29 (2000)

? Wolkoff, M.I. (1918), Effect of ammonium sulfate in nutrient solution on the growth of soybeans in sand cultures. Soil Science, 5 (2), 123-150.

Full Text: -1959\Soi Sci5, 123.pdf

Keywords: Growth, Sand, SCI, Soil, Solution, Sulfate, USA

Kerr, H.W. (1928), The identification and composition of the soil alumino-silicate active in base exchange and soil acidity. Soil Science, 26 (5), 385-398.

Full Text: -1959\Soi Sci26, 385.pdf

? DeTurk, E.E., Wood, L.K. and Bray, R.H. (1943), Potash fixation in corn belt soils. Soil Science, 55 (1), 1-12.

Full Text: -1959\Soi Sci55, 1.pdf

Liebig, Jr., C.F., Vanselow, A.P. and Chapman, H.D. (1943), The suitability of water purified by synthetic ion-exchange resins for the growing of plants in controlled nutrient cultures. Soil Science, 55 (5), 371-376.

Full Text: -1959\Soi Sci55, 371.pdf

Broadbent, F.E. and Bradford, G.R. (1952), Cation-exchange groupings in the soil organic fraction. Soil Science, 74 (6), 447-457.

Full Text: -1959\Soi Sci74, 447.pdf

Fried, M., Hagen, C.E., Saiz Del Rio, J.F. and Leggett, J.E. (1957), Kinetics of phosphate uptake in the soil-plant system. Soil Science, 84 (6), 427-437.

Full Text: -1959\Soi Sci84, 427.pdf

Schnitzer, M. and Skinner, S.I.M. (1966), Organo-metallic interactions in soils: 5. Stability constants of Cu²⁺-, Fe²⁺- and Zn²⁺-fulvic acid complexes. Soil Science, 102 (6), 361-365.

Full Text: 1960-80\Soi Sci102, 361.pdf

Kuo, S. and Lotse, E.G. (1973), Kinetics of phosphate adsorption and desorption by hematite and gibbsite. Soil Science, 116 (6), 400-406.

Full Text: 1960-80\Soi Sci116, 400.pdf

Abstract: The phosphate adsorption by hematite and gibbsite conformed to the Freundlich equation. The rate of phosphate adsorption was rapid initially and decreased with prolonged reaction time. A two-constant rate equation was developed which successfully described the rate of phosphate adsorption. The low activation energy of phosphate adsorption indicated that the adsorption was a diffusion controlled process. The highly complexing agent, EDTA=, was more effective than oxalate, hydroxyl, and fluoride anions in releasing adsorbed phosphate. The rate of phosphate release was similar to the rate of phosphate adsorption and could be described by the proposed two-constant rate equation. (C) Williams & Wilkins 1973. All Rights Reserved.

Evans, R.L. and Jurinak, J.J. (1976), Kinetics of phosphate release from a desert soil. Soil Science, 121 (4), 205-211.

Full Text: 1960-80\Soi Sci121, 205.pdf

Abstract: The kinetics of indigenous phosphorus release from the surface and subsoil of Thiokol silt loam, a typic calciorthid, was studied at 11°, 25°, and 40°C. The anion-resin technique was used to obtain the P-release data. The P-release data from the two samples over a period of 5 days could be described by three simultaneous first-order-rate expressions. Three reactions are proposed which could account for the kinetic data. The calculated specific rate constants for any given reaction were similar in both the surface and subsurface soil, suggesting the same reactions were occurring. However, there was a marked difference noted in the total amount of phosphorus released by the soil from the two depths. The effect of temperature on the phosphorus release kinetics was small resulting in activation energies with values between 2 and 3 kcal/m. Thus, the release of phosphorus from this desert soil is not a major energy-consuming process. The parabolic diffusion expression defined P release from the surface and subsoil for only the initial 16 min of reaction. (C) Williams & Wilkins 1976. All Rights Reserved.

Moreale, A. and van Bladel, R. (1979), Soil interactions of herbicide-derivated aniline residue: A thermodynamic approach. Soil Science, 127 (1), 1-9.

Full Text: 1960-80\Soi Sci127, 1.pdf

Abstract: Interactions between soil and aniline residues increase with temperature. Exothermic values of free energy change point out the higher affinity of the Soignies soil colloids for p-chloroaniline, in comparison to aniline, with increasing temperature. The magnitude of adsorption of these aniline residues was inversely related to their water solubilities. The temperature coefficient of the thermodynamic equilibrium constant, expressed per unit of organic matter, emphasizes the greater reactivity of Soignies soil organic matter. The net increase in entropy change, calculated for that substrate, indicates higher stability of these amine-soil colloids complexes. Results of the thermodynamic study suggest that diffusion processes of p-chloroaniline within a porous adsorbent, like Soignies soil organic matter, must play a leading part in the overall energetic process of the adsorption reaction. This view is further supported by values of adsorption rate constant derived from the rates of adsorption of p-chloroaniline by the two soil types. (C) Williams & Wilkins 1979. All Rights Reserved.

? Dalal, R.C. (1979), Application of Dubinin-Radushkevich adsorption-isotherm for phosphorus sorption by soils. Soil Science, 128 (2), 65-69.

Full Text: 1960-80\Soi Sci128, 65.pdf

Abstract: The Dubinin-Radushkevich (DR) adsorption isotherm, using Polanyi’s potential for sparingly soluble solutes, was applied to phosphorus sorption by 20 soils. The DR isotherm is where [epsilon], the Polanyi potential, is X is the amount of phosphorus adsorbed, Xm is the adsorption maximum, and C is the equilibrium phosphorus concentration. B is a constant and is related to the mean energy of adsorption, R is a gas constant, and T is absolute temperature. The DR isotherm was obeyed so long as phosphorus sorption occurred within the single phase of sparingly soluble phosphorus compounds. The adsorption maxima obtained by the DR isotherm and the Langmuir isotherm were essentially similar. The mean energy of adsorption indicated that diffusion (or anion exchange) controlled the process of phosphorus sorption by soils. (C) Williams & Wilkins 1979. All Rights Reserved.

Notes: highly cited

? Ghosh, K. and Schnitzer, M. (1980), Macromolecular structures of humic substances. Soil Science, 129 (5), 266-276.

Full Text: 1960-80\Soi Sci129, 266.pdf

Abstract: We investigated humic substances by surface pressure and viscosity measurements at different pHs and neutral salt concentrations to elucidate their macromolecular configurations. We observed that such configurations were not unique, they varied with the changes in the medium. The controlling parameters were sample concentration, pH of the system, and the ionic strength of the medium. Model macromolecular structures are proposed on the basis of our investigation and of data published in the literature. With the aid of these models, we were able to resolve the contradictions between the so-called rigid “spherocolloid” and flexible “linear molecule” concepts. Our work shows that humic and fulvic acids behave like rigid spherocolloids at high sample concentrations, low pH, or in the presence of sufficient amounts of neutral electrolytes, but they are flexible linear colloids at low sample concentrations, provided that the pH is not too low or that the ionic strength is relatively low, conditions that normally prevail in soils. (C) Williams & Wilkins 1980. All Rights Reserved.

Ou, L.T. (1984), 2,4-D degradation and 2,4-D degrading, microorganisms in soils. Soil Science, 137 (2), 100-107.

Full Text: 1984\Soi Sci137, 100.pdf

Abstract: In laboratory studies on Cecil loamy sand and Webster sandy clay loam, I examined the influence of soil-water tension and soil temperature on 14C-2,4-D degradation and the formation of nonextractable 14C-residues, and I correlated the degradation rate with the growth rate of 2,4-D degrading microorganisms. 14C-2,4-D rapidly mineralized in the two soils maintained at 0.1 and 0.33 bar of soil-water tension. Because the total amounts of metabolites in the solvent extracts never exceeded 5% of the total 14C activity, the disappearance rate of extractable 14C essentially represented the disappearance rate of extractable 14C-2,4-D. Extractable 14C in the 14C-2,4-D treated soils maintained at 1 bar and below disappeared rapidly, and at the same time nonextractable 14C rapidly formed, whereas extractable 14C in soils maintained at 15 bars disappeared at much slower rates, and the formation of nonextractable 14C was also slower. After 14 d of slow disappearance, however, extractable 14C in the Cecil soil held at 15 bars started disappearing at a constant rate of 3.6% of applied 14C per day. The disappearance rates in soils incubated at 35°C were generally smaller than those incubated at 25°C. Even though the initial most probable number (MPN) of 2,4-D degrading microorganisms in the Cecil soil was one fourth of that in the Webster soil, the organisms propagated more rapidly in the moist Cecil soil (0.33 bar) than in the moist Webster soil in response to the application of 10 g 2,4-D/g of soil. As a result, 2,4-D in the Cecil soil degraded at a faster rate. The growth rates of 2,4-D degrading organisms in dry soils (15 bars) were small, in spite of the rapid degradation occurring in the Cecil soil after 14 d of incubation. In addition to forming nonextractable 14C residues in humus components, as much as 4.2% of applied 14C could be associated with microbial mass. (C) Williams & Wilkins 1984. All Rights Reserved.

Body, S.A. and King, R. (1984), Adsorption of labile organic compounds by soil. Soil Science, 137 (2), 115-119.

Full Text: 1984\Soi Sci137, 115.pdf

Abstract: Rapid degradation of p-cresol in aerobic soil prohibited measurement of adsorption by the batch technique. Degradation of p-cresol was not observed under anaerobic conditions over a period of 96 h. Adsorption of p-cresol measured using the batch technique and soil incubated anaerobically demonstrated that adsorption equilibrium was attained within 24 h and that the Freundlich K values (K = 1.1) remained essentially constant for 96 h. Adsorption of 2,3-dichlorophenol and 2,4-dichlorophenol by aerobic, anaerobic, and autoclaved soil was compared. Freundlich K values describing adsorption of 2,3-dichlorophenol and 2-4 dichlorophenol by aerobic and anaerobic soil were similar. Freundlich K values obtained using autoclaved soil were significantly higher. These results indicated that an accurate measurement of adsorption of labile organic compounds can be achieved by using anerobic conditions to prohibit degradative losses. (C) Williams & Wilkins 1984. All Rights Reserved.

Sparks, D.L. and Jardine, P.M. (1984), Comparison of kinetic equations to describe potassium-calcium exchange in pure and in mixed systems. Soil Science, 138 (2), 115-122.

Full Text: 1984\Soi Sci138, 115.pdf

Abstract: We used first-order, Elovich, parabolic diffusion, and zero-order equations to describe the kinetics of K-Ca exchange in kaolinite, montmorillonite, vermiculite and soils of the Atlantic Coastal Plain Region. The first-order equation was the best of the various kinetic equations studied to describe the reaction rate of K adsorption in the clay minerals and soils, as evidenced by the highest simple correlation coefficients (r) and the lowest values of the standard error of the estimate (SE). The parabolic diffusion law described K adsorption best on vermiculite and soils dominated by vermiculitic clay minerals. The parabolic diffusion law did not describe K adsorption well on kaolinite and soils high in kaolinite. These differences were related to the kinds of binding sites present in the pure and mixed systems. The Elovich and zero-order equations did not satisfactorily describe K adsorption in the soils and clays. Apparent potassium adsorption rate coefficients (ka/) were 0.23, 0.58, and 2.65 h^-1 for vermiculite, montmorillonite, and kaolinite, respectively. The ka/ values for the soils ranged from 0.84 to 1.86 h^-1, and their magnitude was related to the type and quantity of clay minerals present. (C) Williams & Wilkins 1984. All Rights Reserved.

? Singh, M.V. and Abrol, I.P. (1985), Solubility and absorption of zinc in sodic soil. Soil Science, 140 (6), 406-411.

Full Text: 1985\Soi Sci140, 406.pdf

Abstract: Zinc solubility at pH higher than 7.9 was controlled by precipitation of Zn as Zn(OH)₂ or ZnCO₃ in sodic soils. In the pH range of 6.0 to 7.9, Zn solubility was highly pH dependent, and the chemisorption reactions controlled the Zn concentration of the equilibrium solution. At low pH, 4.2 to 6.0, a reduction in the adsorption of Zn may be attributed to an increase in concentration of competing cations, such as Al, Mn, Fe, and Ca, and to the partial dissolution of soil mineral carbonates. -from Authors [Journal, In English]

? Buchter, B., Davidoff, B., Amacher, M.C., Hinz, C., Iskandar, I.K. and Selim, H.M. (1989), Correlation of freundlich Kd and n retention parameters with soils and elements. Soil Science, 148 (5), 370-379.

Full Text: 1989\Soi Sci148, 370.pdf

Abstract: We studied the retention of 15 elements by 11 soils from 10 soil orders to determine the effects of element and soil properties on the magnitude of the Freundlich parameters Kd and n. The magnitude of Kd and n was related to both soil and element properties. Strongly retained elements, such as Cu, Hg, Pb, V, and P had the highest Kd values. The transition metal cations Co and Ni had similar Kd and n values, as did the group IIB elements Zn and Cd. Oxyanion species tended to have lower n values than did cation species. Soil pH and CEC were significantly correlated with log Kd values for cation species. High pH and high CEC soils retained greater quantities of the cation species than did low pH and low CEC soils. A significant negative correlation between soil pH and the Freundlich parameter n was observed for cation species, whereas a significant positive correlation between soil pH and n for Cr(VI) was found. Greater quantities of anion species were retained by soils with high amounts of amorphous iron oxides, aluminum oxides, and amorphous material than were retained by soils with low amounts of these minerals. Several anion species were not retained by high pH soils. Despite the facts that element retention by soils is the result of many interacting processes and that many factors influence retention, significant relationships among retention parameters and soil and element properties exist even among soils with greatly different characteristics. (C) Williams & Wilkins 1989. All Rights Reserved.

Cancela, G.D., Taboada, E.R. and Sanchezrasero, F. (1990), Adsorption of cyanazine on peat and montmorillonite clay surfaces. Soil Science, 150 (6), 836-843.

Full Text: 1990\Soi Sci150, 836.pdf

Abstract: The adsorption of cyanazine by peat and montmorillonite is studied as a function of the crystal chemical characteristics of exchangeable cations and temperature. The adsorption kinetics of cyanazine on peat shows that the adsorption equilibrium is reached within 1 h. The values of the rate constants of the reaction seem to indicate that the adsorption rate of cyanazine by peat is mainly controlled by the diffusion process. The order of adsorption of cyanazine by peat is as follows: H⁺-peat > Cu²⁺-peat > Ca²⁺-peat > Co²⁺-peat > Mg²⁺-peat > K⁺-peat. The thermodynamic parameters seem to point to an adsorption mechanism by hydrogen bonds, although in the acidic and Cu²⁺ samples a protonation process and adsorption of the protonated species is also likely. The values of the adsorption rate constant of cyanazine by montmorillonite is ten times higher than that for peat. The adsorption of cyanazine by montmorillonite follows this order: Cu²⁺-mont > Co²⁺-mont > H⁺-mont, the adsorption on Cu²⁺-mont is five times greater than on the other samples. For the Cu²⁺ samples, the thermodynamic parameters seem to point to a mechanism of direct coordination cyanazine-Cu²⁺. The most probable mechanism for the adsorption of cyanazine by the Co²⁺ sample is by physical bonding. For the H⁺ sample there is a physical adsorption and an ionic one according to the following reaction: H⁺-mont + cyanazine -> mont - H⁺-cyanazine. (C) Williams & Wilkins 1990. All Rights Reserved.

? Fu, G.M., Allen, H.E. and Cowan, C.E. (1991), Adsorption of cadmium and copper by manganese oxide. Soil Science, 152 (2), 72-81.

Full Text: 1991\Soi Sci152, 72.pdf

Abstract: Cadmium and copper adsorption by delta-MnO₂ was investigated by potentiometric titration over a range of pH. Adsorption increased with increasing pH because of hydrolysis of metal cations and/or variable charge sites on delta-MnO₂. The surface acidity constant for delta-MnO₂ was determined using the Triple Layer Model to be pK(int, a2) = 5.34. The data from titrations with pH as master variable were analyzed to determine the Triple Layer Model intrinsic stability constants, p*K(int, Cd²⁺) = 0.81, p*K(int, CdOH)⁺ = 6.89, p*K(int, Cu²⁺) = 1.66, and p*K(int, CuOH⁺) = 3.79 for cadmium and copper adsorption onto delta-MnO₂. Titrations with metal ion as the master variable were performed at constant pH to estimate the adsorption capacities. The data conformed to a Langmuir isotherm and could be modeled with the Triple Layer Model constants. For cadmium, at pH 5.5, 7.0, and 8.0, the adsorption capacity is 0.434, 1.08, and 1.92 mmol/g, respectively. The affinity of delta-MnO₂ for Cu, 1.54 mmol/g at pH 5.5, is greater than that for cadmium. The results show delta-MnO₂ has high adsorption capacities and high adsorption affinities for cadmium and copper even in acidic conditions.

Keywords: Interface, Ligands

? Aharoni, C., Pasricha, N.S. and Sparks, D.L. (1993), Adsorption and desorption-kinetics of cesium in an organic matter-rich soil saturated with different cations. Soil Science, 156 (4), 233-239.

Full Text: 1992\Soi Sci156, 233.pdf

Abstract: Samples of soils made homoionic with K, Na, or Ca were reacted with solutions containing Cs ions, and the quantities of Cs sorbed and the rates of exchange were measured. The samples were then reacted with solutions containing K, Na, or Ca, and the quantities of Cs desorbed and the rates of exchange were again measured. Samples made homoionic with Na had a greater ion exchange capacity than samples made homoionic with K, and, in both cases, the ion exchange capacity increased with the organic matter content of the soil. For samples pretreated with Ca, the ion exchange capacity is not related in a simple way to the organic matter content. The kinetics were assessed by plotting the rate of exchange vs. the time and vs. the quantity exchanged. A first-order equation was obeyed during most of the run in Cs desorption experiments and during a limited part of the run in Cs adsorption experiments. An increase in the rate of Cs exchange was observed at the beginning of the experiments especially for Cs adsorption. This increase is presumably due to an increase of the ionic strength of the liquid phase during the exchange process.

Keywords: Calcareous Soils, Diffusion, Equations, Exchange, Mathematical-Models, Miscible Displacement, Potassium Release Kinetics, Sorption, Systems

? Amalfitano, C., Quezada, R.A., Wilson, M.A. and Hanna, J.V. (1995), Chemical-composition of humic acids: A comparison with precursor light fraction litter from different vegetations using spectroscopic techniques. Soil Science, 159 (6), 391-401.

Full Text: 1995\Soi Sci159, 391.pdf

Abstract: Humic acids from a range of Italian soils and the residual suspended organic material (light fraction litter) associated with them have been studied by pyrolysis gas chromatography mass spectrometry, solid state nuclear magnetic resonance spectroscopy, and infra-red spectroscopy. Although the major vegetation types on the soils differ considerably, spectra of humic acids from soils with different major vegetation types were similar. Because no relationship between humic acid structure and major vegetation type was observed, gross assumptions about humic acid structure should not be drawn from a knowledge of macro-vegetation types on soils. Light fraction litter in the soils from minor vegetation may be more significant in affecting the eventual structure of the humic acids. (C) Williams & Wilkins 1995. All Rights Reserved.

Jin, X., Bailey, G.W., Yu, Y.S. and Lynch, A.T. (1996), Kinetics of single and multiple metal ion sorption processes on humic substances. Soil Science, 161 (8), 509-520.

Full Text: 1996\Soi Sci161, 509.pdf

Abstract: Single and multiple metal ion reaction processes were studied on humic acids (HA) from various sources, A sequential sampling method (samples periodically removed from the bulk reaction volume) was used. Experimental parameters studied included pH, temperature, HA and peat sources, metal type and concentration, The Langmuir-Hinshelwood (LH) kinetics approach was used to describe the sorption kinetics of metal ions onto HA. Great differences were found among the metals in the extent of reaction and sorption kinetics, The extent of reaction was Cr(III) > Pb(II) > Cu(II) > Ag(I) > Cd(II) = Co(II) = Li(I) for single metal adsorption and Cr(III) >> Pb(II) > Cu(II) = Ag(I) = Cd(II) = Co(II) Li(I) for multiple metal adsorption on Humic Acid No. 1. The multiple ion sorption kinetics were similar between HA from different sources, For peat reactions, the extent of multiple metal ion sorption was Cr(III) > Pb(II) > Cu(II) > Ag(I) > Co(II) = Cd(II) = Li(I).

The sorption rates of all metal ions on HA were very rapid, Most adsorption occurred within 2 minutes, but sorption did not reach equilibrium in 1 day under competitive conditions, The presence of Cr(III) greatly decreased the adsorption of all other metals to the extent that some were not adsorbed at all, For all metal ions studied, less total sorption of each metal ion occurred in the presence of multiple competing ions than with single metal ions.

Pearson’s Hard Soft Acid Base principles and Klopman’s generalized perturbation theory of chemical reactivity generally predicted the sorption preference between metal ions and humic substances, A nonlinearity concept was used to rationalize the use of the LH kinetic model.

López Piñeiro, A. and Navarro, A.G. (1997), Phosphate sorption in vertisols of southwestern Spain. Soil Science, 162 (1), 69-77.

Full Text: 1997\Soi Sci162, 69.pdf

Abstract: Low phosphorus availability is a critical impediment to agricultural use of Vertisols. Several studies have explored the P sorption characteristics of Vertisols, but few have investigated the relationship between soil physicochemical and the P sorption parameters calculated from uniform-surface and two-surface Langmuir equations, Phosphate sorption was investigated in surface-samples of 19 Vertisols in southwestern Spain. The phosphate sorption maxima (PAM) deduced from the uniform-surface Langmuir equation ranged from 150 to 2566 mg P kg^-1, with a mean value of 1115 mg P kg^-1. The calculated sorption maxima (TPAM) for the two-surface Langmuir model ranged from 410 to 15406 mg P kg^-1, and the mean value (4296 mg P kg^-1) increased about 3 times compared with the basic Langmuir equation, The two-surface Langmuir model fit the sorption data better than the uniform layer model, Therefore, an underestimation of the P-sorption was observed when the traditional Langmuir equation was used,Total surface area was highly correlated with sorption maxima: n = 0.708*** for PAM and 0.900*** for TPAM, For the two-surface equation, correlation analysis suggested that the “active” CaCO3 (ACCE) was the most active sorbent of P on the high energy sites, whereas citrate-dithionite-bicarbonate extractable Fe (Fe-d) contributed to P sorption on the low energy sites. The prediction of the PAM and TPAM was improved by combining all or several of following soil properties: Fe-d, ACCE, clay, and total surface area in a multiple-regression analysis. The equations obtained could offer a rapid estimation of P-sorption in Vertisols of southwestern Spain. Moreover, the results obtained from a greenhouse experiment with Agrostis tennuis and two levels of P (0 and 218 mg P kg^-1) showed that the amount of available soil P was a positive function of Fed but a negative function for ACCE.

Keywords: Adsorption, Clay, Equation, Iron, Phosphate Sorption, Soils, Sorption, Two-Surface Langmuir

Ajwa, H.A. and Tabatabai, M.A. (1997), Metal-induced sulfate adsorption by soils: III. Application of Langmuir equations, Soil Science, 162 (3), 169-180.

Full Text: 1997\Soi Sci162, 169.pdf

Keywords: Isotherms, Phosphate Adsorption, Sorption, Two-Surface Langmuir

Houng, K.H. and Lee, D.Y. (1998), Comparisons of linear and nonlinear Langmuir and Freundlich curve-fit in the study of Cu, Cd, and Pb adsorption on Taiwan soils. Soil Science, 163 (2), 115-121.

Full Text: 1998\Soi Sci163, 115.pdf

Abstract: In the Langmuir adsorption equation, q = MbC, (1+bC), the b parameter can be identified as the reciprocal of the concentration, C-1, 2, at which the adsorbent is half-saturated with the adsorbate. If the concentration, C, is scaled in the unit of C-1, 2, and replaced the C’, where C’ = C, C-1, 2, the universal dimensionless Langmuir equation, theta = C’, (1+C’), is obtained, Arbitrary points chosen on segments of the normal Langmuir plot can be fitted to different Freundlich equations with statistical significance. This indicates that the Freundlich equation can be applied to represent a selected range of the adsorption data that also fit the Langmuir equation. Linear and nonlinear least squares methods were applied to fit experimental data of adsorption of a metal ion in the presence of another metal ion, on three Taiwan soils, to Langmuir and Freundlich equations. The goodness-of-fit of the model to the experimental data was compared with the magnitude of the residual root mean square error (RMSE) of the original nonlinear forms of both adsorption isotherms. Results indicate that simple conclusions, based on the R-2 values obtained by the usual linear least squares method applied to the linearly transformed equations, may be in error. Even when the metal ion adsorption on soils appeared to be better represented by the Freundlich equation,judging from the size of the R-2 value, than by the Langmuir equation, there are cases in which the Langmuir equation could better represent the experimental data based on the size of RMSE value,These were examples of experiments conducted in a limited concentration range, Increasing the range of concentration for the adsorption experiments may eventually turn the Freundlich-type adsorption isotherms into the Langmuir type if no complication arises in the more concentrated solutions.

Keywords: Adsorption, Adsorption Isotherms, Curve-Fitting, Estimating Michaelis-Menten, Freundlich Model, H System, Hematite, Isotherm Constants, Langmuir Model, Least-Squares, Phosphate Sorption, Zinc

Sun, X.H. and Doner, H.E. (1998), Adsorption and oxidation of arsenite on goethite. Soil Science, 163 (4), 278-287.

Full Text: S1998\Soi Sci163, 278.pdf

Abstract: Arsenic toxicity, mobility, and bioavailability in soil-water systems are highly dependent on its oxidation states and chemical species. In this study, both indirect (FTIR) and direct (X-ray Absorption Near Edge Structure (XANES)) spectroscopic techniques mere applied to investigate the adsorption and oxidation of As(III) on the surface of goethite, The results indicate that: at low pH, the As(V)/As(III) ratio in the solid phase is higher than in the solution phase. As(III) adsorbed on goethite under air dry conditions was not stable. After 20 days, more than 20% of adsorbed. As(III) was oxidized to As(V), Birnessite was an active oxidant of As(III), both in solutions and on the goethite surface, This study suggests that the adsorption-oxidation system composed of goethite and birnessite map be significant in decreasing arsenic toxicity in terrestrial environments.

Keywords: FTIR, Xanes, Arsenate, Arsenite, Adsorption, Oxidation, Goethite, Birnessite, Deuteration, Amorphous Iron Hydroxide, Arsenate, Birnessite, As(III), Speciation, Manganese, Sediments, Removal, Waters, Oxides

Hinz, C. and Selim, H.M. (1999), Kinetics of Zn sorption-desorption using a thin disk flow method. Soil Science, 164 (2), 92-100.

Full Text: 1999\Soi Sci164, 92.pdf

Abstract: In this study we investigated the kinetics of Zn sorption and desorption using a short column or thin disk method. The method is based on continuous now through a thin soil layer (1 mm) where the effluent was collected using a fraction collector. Two soils were used: a Windsor soil and Mahan soil, Breakthrough results (BTCs) for different now velocities indicated that Zn sorption is instantaneous and equilibrium retention is dominant when a pulse of Zn with a concentration of 2.6210^-5 M is applied. However, based on now interruption, time-dependent Zn sorption-desorption processes were most pronounced when the applied Zn pulse concentration was two orders of magnitude lower (2.5110^-7 M), This confirms earlier findings of concentration-dependent kinetics from batch experiments on Windsor soil (Hinz et al., 1992), The removal of organic matter and iron oxide, based on peroxide and peroxide/dithionite-treatments, resulted in doubling and quadrupling Zn retention, respectively, compared with the untreated Windsor soil. Differences between the untreated, peroxide-, and peroxide/dithionite-treated Windsor soils were most pronounced at low input Zn concentrations, suggesting that more specific sites became available as a result of the different treatments. At high input Zn concentrations, increases of specific sites may not be significant. For the treated soil, stronger sorption and desorption kinetic behavior was exhibited compared with the untreated soil. Diffusion into soil minerals or surface-controlled reactions may cause such behavior.

Keywords: Transport, Heavy Metals, Organic Matter, Iron Oxides, Organic-Matter, Soil, Adsorption, Exchange, Equilibrium, Cadmium, System, Oxide, Zinc, Iron

Zehetner, F. and Wenzel, W.W. (2000), Nickel and copper sorption in acid forest soils. Soil Science, 165 (6), 463-472.

Full Text: 2000\Soi Sci165, 463.pdf

Abstract: Five acid forest soils of eastern Austria were used to study nickel and copper sorption at metal concentrations ranging over five orders of magnitude. Distribution coefficients were calculated, and the Langmuir equation was fitted to the experimental isotherm data.

Exchange for mono- and divalent cations is considered the primary mechanism of Ni sorption, whereas complexation on organic surfaces may contribute significantly to Cu sorption in the studied soils. Organic matter is considered the most effective sorbent in topsoils, while sorption in subsoils may involve primarily Mn-oxide and clay mineral surfaces. The soils studied showed higher affinity for Cu than for Ni, however, at low metal levels, competitive complexation of Cu with soluble organic compounds counteracted sorption in topsoil horizons.

Using the van Bemmelen-Freundlich equation, general sorption density isotherms were developed for the studied soils. For Ni, similar fits were obtained by using specific surface area (SSA) and cation exchange capacity (CEC) as reference quantities, however, the quality of fit was improved when only the proportion of CEC occupied by mono- and divalent cations (CEC²⁺) was used as a reference. For Cu, the surface area-based approach yielded a better fit than the charge-based isotherms. Comparison with independent datasets from the literature showed good agreement with the proposed general sorption density isotherms, suggesting general applicability for acid soils of varying origin and composition.

Keywords: Nickel, Copper, Sorption, Isotherm, Langmuir, Freundlich, Heavy-Metal Deposition, West-Germany, Adsorption, Cadmium, Precipitation, Isotherms, Cobalt, Ions, Peat

Namjesnik-Dejanovic, K., Maurice, P.A., Aiken, G.R., Cabaniss, S., Chin, Y.P. and Pullin, M.J. (2000), Adsorption and fractionation of a muck fulvic acid on kaolinite and goethite at pH 3.7, 6, and 8. Soil Science, 165 (7), 545-559.

Full Text: 2000\Soi Sci165, 545.pdf

Abstract: Molecular weight (MW) of humic materials is a key factor controlling proton and metal binding and organic pollutant partitioning. Several studies have suggested preferential adsorption of higher MLW, more aromatic moieties to mineral surfaces, quantification of such processes is fundamental to development of predictive models, We used high pressure size exclusion chromatography (HPSEC) to quantify MW changes upon adsorption of a muck fulvic acid (MFA) extracted from a peat deposit to kaolinite and goethite, at pH 3.7, 6, and 8 at 22°C, I = 0.01 (NaCl), 24-h reaction time. MFA adsorption affinity was greater for goethite than for kaolinite, At concentrations less than the adsorption maximum (A(max)) for both adsorbents, the weight-average MW (M-w) of MFA remaining in solution decreased by as much as several hundred Daltons relative to control samples, indicating preferential adsorption of the higher MW components, At concentrations more than A(max), M-w of MFA in solution did not change appreciably, Although total adsorption decreased significantly as pH increased, fractionation as measured by change in M-w remained similar, perhaps indicating greater selectivity for higher MW components at higher pH, Absorptivities at lambda = 280 nm normalized to mg C L^-1 (epsilon) suggested preferential adsorption of more aromatic moieties to kaolinite, epsilon could not be used for goethite-reacted samples because high Fe concentrations in the aqueous phase brought about by goethite dissolution interfered with the spectroscopic analysis, Preliminary kinetic experiments suggested that smaller molecules adsorbed first and were replaced by larger molecules whose adsorption was thermodynamically favored.

Keywords: Fulvic Acid, Kaolinite, Goethite, Adsorption, Aquatic Humic Substances, Dissolved Organic-Matter, Atomic-Force Microscopy, Spectroscopic Properties, Molecular-Weight, Polyacrylic-Acid, Water Interface, Surface-Charge, Natural-Waters, Iron-Oxides

? Selim, H.M. and Zhang, H. (2007), Arsenic adsorption in soils: Second-order and multireaction models. Soil Science, 172 (6), 444-458.

Full Text: 2007\Soi Sci165, 444.pdf

Abstract: Arsenic (As) is a toxic element, and the understanding of its retention in the soil environment is a prerequisite in predicting As behavior in the vadose zone. The objective of this study was to quantify the extent of the kinetics of As adsorption in soils over a wide range of concentrations and to investigate the capabilities of multireaction and a second-order modeling (MRM and SOM, respectively) approaches in describing the kinetic behavior of As in soils. Batch kinetic experiments were carried out to determine adsorption of As(V) over a wide range of concentrations by clay, loam, and sandy soils. Adsorption results indicated strongly kinetic behavior where the rate of As(V) retention was rapid initially and was followed by slow retention behavior with time. Sorption isotherms exhibited strong nonlinearity with a Freundlich reaction order much less than 1 for all soils. We tested the MRM and SOM for their capability to predict As concentration with time and found that several model versions fit the data equally well, but the sorption kinetics prediction capability varied among the soils investigated. MRM was superior to SOM, and the use of irreversible reaction into the model formulations was essential. In addition, we found that incorporation of an equilibrium-sorbed phase into the various model versions for As(V) predictions should be avoided.

Keywords: Adsorption, Adsorption-Desorption, Arsenic, As(V), Behavior, Cadmium, Chemistry, Clay, Concentration, Concentrations, Desorption, Environment, Ferrihydrite, Formulations, Freundlich, Goethite, Heavy Metals, Isotherms, Kinetic, Kinetics, Model, Modeling, Models, Multireaction Models, Nonlinearity, Order, Predict, Predicting, Prediction, Predictions, Range, Rate, Reaction, Reaction Order, Retention, Sandy Soils, Second Order, Soil, Soils, Som, Sorption, Sorption Kinetics, Toxic, Toxic Element, Transport, Vadose

? Xu, R.K., Kozak, L.M. and Huang, P.M. (2008), Kinetics of phosphate-induced desorption of arsenate adsorbed on crystalline and amorphous aluminum hydroxides. Soil Science, 173 (10), 683-693.

Full Text: 2008\Soi Sci173, 683.pdf

Abstract: Research on arsenate adsorption by Al hydroxides is common, however, relatively little is known on the kinetics of arsenate desorption from these Al hydroxides. The batch method was used to compare the phosphate-induced desorption kinetics of preadsorbed arsenate from the crystalline and amorphous Al(OH)₃ at pH 5.0, background electrolyte of 0.01 M NaNO₃ at 298 and 318 K. The results showed that both the amount of arsenate adsorbed by the amorphous Al(OH)₃ and the mole fraction of arsenate remaining adsorbed on the amorphous Al(OH)₃ after desorption were substantially greater than those in the crystalline Al(OH)₃ system. The second-order rate equation was chosen to compare the rates of arsenate desorption. The rate constant of arsenate desorption from the crystalline Al(OH)₃ was 3.8 to 15.5 times greater than that from the amorphous Al(OH)₃ in the reaction period, suggesting that, compared with the crystalline Al(OH)₃, the arsenate adsorbed on the amorphous Al(OH)₃ was much more difficult to be desorbed by phosphate. The rate constant of arsenate desorption increased with the increase of phosphate concentration from 0.1 to 1.0 mM and the increasing temperature. Although the activation energy for arsenate desorption from the crystalline Al(OH)₃ in the fast reaction was greater than that from the amorphous Al(OH)₃, the much greater frequency factor for the desorption from the former resulted in a higher desorption rate of arsenate from the crystalline Al(OH)₃. This information is of fundamental significance in understanding the dynamics of remobilization and fate of arsenate in soil and related environments. (Soil Science 2008,173:683-693).

Keywords: Activation, Activation Energy, Adsorption, Arsenate, Arsenite, Batch, Batch Method, Clay-Minerals, Competitive Adsorption, Concentration, Crystalline and Amorphous Al(OH)₃, Desorption, Desorption Kinetics, Dynamics, Energy, Fate, Ferrihydrite, Goethite, Information, Kinetics, Oxide-Water Interface, pH, Phosphate, Rate Constant, Rates, Residence Time, Second Order, Second-Order, Selenite Desorption, Significance, Soil, Soils, Surface-Chemistry, Temperature, Understanding