Identifier

etd-10192013-150711

Degree

Master of Science (MS)

Department

Plant, Environmental Management and Soil Sciences

Document Type

Thesis

Abstract

Transport of heavy metals such as Ag is affected by several rate-limiting processes including adsorption and release reactions in soils. In this study, the objective was to qualify adsorption-desorption behavior and transport of silver in the different soils. This study also investigated the influence of the presence of Zn on Ag retention and transport in soils. Kinetic batch adsorption-desorption and column experiments were carried out to investigate the adsorption-desorption and transport of silver in soils having different properties in the presence of Zn. Transport of Ag was carried out using miscible-displacement experiments in water saturated soil columns. For all soils, results indicated that adsorption isotherms for Ag were highly nonlinear with greater affinity for Webster soil. Moreover, the presence of Zn resulted in reduced Ag sorption indicative of competitive behavior. Measured Ag breakthrough results (BTCs) from the column experiments indicated highest Ag mobility in Olivier soil whereas Webster soil exhibited least mobility. This finding is based on the Ag recovered and the retardation of the arrival of Ag in the effluent solution. Furthermore, the presence of Zn resulted in enhanced mobility of Ag. A multireaction and transport model (MRTM) that accounted for nonlinear reversible kinetics and irreversible reactions was capable of describing both Ag and Zn transport in all soil columns.

Date

2013

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Selim, H. M.

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