Effect of soil properties on sorption and mobility of cadmium in selected aridisols and andisols

Persistent Link:
http://hdl.handle.net/10150/283999
Title:
Effect of soil properties on sorption and mobility of cadmium in selected aridisols and andisols
Author:
Al-Harbi, Saud Sebayle
Issue Date:
1999
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Concern over environmental quality has generated interest in the chemistry of Cd in soils. When Cd sorption and the influence of soil characteristics on the process are better understood, Cd contamination of ground water and plant availability may be assessed more accurately. Therefore, a series of experiments, including laboratory batch studies, soil thin layer chromatography studies and selective ion electrode procedures were conducted to evaluate the effect of soil properties on Cd sorption and mobility by fourteen different Aridisols and Andisols having a range of chemical properties. In addition, surface complexation models were used to model the amount of Cd adsorbed onto each of the humic acid and hydrous ferric oxide surfaces. Sorption isotherms were obtained using batch experiments by in which 25 ml of solution containing a total of 0.8, 1.6, 3.2, 6.4, and 12.8 ppm of Cd²⁺ to 0.5 g were added to soil samples. The results of the batch experiments indicate that in all the soils used the Cd sorption is best described by the Freundlich sorption isotherm. The maxima soil sorption capacities were significantly correlated with the free iron oxides. The Cd activities in the soils varied from 10⁻⁷·⁴⁴ to 10⁻⁴·⁸² M. It increased with increasing total Cd added and were inversely related to the soil pH The Cd mobility retardation factor (Rf) obtained from soil thin layer chromatography ranged from 0.25 to 0.95. It showed that Cd was slightly mobile in 64%, moderately mobile in 29% and very mobile in 7% of the soils. The Cd Rf indicates that Cd mobility would decrease with increasing amounts of iron oxide fractions; silt % and exchangeable Mg²⁺ in the soils. The non electrostatic and diffuse layer models results indicate that humic materials are an important factor in Cd sorption at pH values greater than 3 and hydrous ferric oxide surfaces are important at pH values greater than 7. The ion activity products of Cd(OH)₂ ranged from 2.3 x 10⁻²⁵ M to 5.6 x 10⁻¹⁶ M, while the solid activity coefficients of adsorbed Cd (SACCd2+) ranged from 3.9 x 10⁻⁶ to 4.6. The SAC(Cd₂₊) values were significantly correlated yet negative with silt %, CEC, Ald, Alo, O.C and iron fractions.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture, Soil Science.; Environmental Sciences.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Soil, Water and Environmental Science
Degree Grantor:
University of Arizona
Advisor:
Hendricks, David M.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleEffect of soil properties on sorption and mobility of cadmium in selected aridisols and andisolsen_US
dc.creatorAl-Harbi, Saud Sebayleen_US
dc.contributor.authorAl-Harbi, Saud Sebayleen_US
dc.date.issued1999en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractConcern over environmental quality has generated interest in the chemistry of Cd in soils. When Cd sorption and the influence of soil characteristics on the process are better understood, Cd contamination of ground water and plant availability may be assessed more accurately. Therefore, a series of experiments, including laboratory batch studies, soil thin layer chromatography studies and selective ion electrode procedures were conducted to evaluate the effect of soil properties on Cd sorption and mobility by fourteen different Aridisols and Andisols having a range of chemical properties. In addition, surface complexation models were used to model the amount of Cd adsorbed onto each of the humic acid and hydrous ferric oxide surfaces. Sorption isotherms were obtained using batch experiments by in which 25 ml of solution containing a total of 0.8, 1.6, 3.2, 6.4, and 12.8 ppm of Cd²⁺ to 0.5 g were added to soil samples. The results of the batch experiments indicate that in all the soils used the Cd sorption is best described by the Freundlich sorption isotherm. The maxima soil sorption capacities were significantly correlated with the free iron oxides. The Cd activities in the soils varied from 10⁻⁷·⁴⁴ to 10⁻⁴·⁸² M. It increased with increasing total Cd added and were inversely related to the soil pH The Cd mobility retardation factor (Rf) obtained from soil thin layer chromatography ranged from 0.25 to 0.95. It showed that Cd was slightly mobile in 64%, moderately mobile in 29% and very mobile in 7% of the soils. The Cd Rf indicates that Cd mobility would decrease with increasing amounts of iron oxide fractions; silt % and exchangeable Mg²⁺ in the soils. The non electrostatic and diffuse layer models results indicate that humic materials are an important factor in Cd sorption at pH values greater than 3 and hydrous ferric oxide surfaces are important at pH values greater than 7. The ion activity products of Cd(OH)₂ ranged from 2.3 x 10⁻²⁵ M to 5.6 x 10⁻¹⁶ M, while the solid activity coefficients of adsorbed Cd (SACCd2+) ranged from 3.9 x 10⁻⁶ to 4.6. The SAC(Cd₂₊) values were significantly correlated yet negative with silt %, CEC, Ald, Alo, O.C and iron fractions.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgriculture, Soil Science.en_US
dc.subjectEnvironmental Sciences.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineSoil, Water and Environmental Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHendricks, David M.en_US
dc.identifier.proquest9957937en_US
dc.identifier.bibrecord.b40114570en_US
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