Civil Engineering ETDs

Publication Date

Summer 7-15-2022

Abstract

The goal of this dissertation was to investigate the mechanisms of immobilization of uranium (U) and arsenic (As) in waters nearby to Native American Communities for remediation applications. This work sought to identify the physical or chemical processes affecting the complexation, sorption, and precipitation of U and As with calcium (Ca), carbonates (CO3)2-, and phosphate (PO4)3-. The current knowledge about the mechanisms affecting the reaction of metal mixtures such as U, As, and other co-occurring elements in natural waters with minerals such as limestone1-5 and hydroxyapatite for remediation applications is limited. A better understanding of thermodynamics and kinetics affecting the reaction of metal mixtures is essential for the development of water remediation strategies for the application of natural abundant minerals in the southwestern US and other areas of the world. The research objectives were: 1) Determine the solubility product and thermodynamic variables (Δ𝐺°,Δ𝐻°,Δ𝑆°) for uranyl arsenate solids with the monovalent cations sodium (Na) and potassium (K). 2) Determine the kinetic rate law for dissolution of uranyl arsenate solids at acidic pH. 3) Determine conditions that favor precipitation of U and As with phosphate and limestone at pH 3 and 7 for water remediation. The information gained from this research will be relevant for risk assessment and remediation.

Keywords

URANIUM ARSENIC THERMODYNAMICS SOLUBILITY PRODUCT LIMESTONE

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Committee Member (Chair)

JOSE CERRATO

Second Committee Member

KERRY HOWE

Third Committee Member

JORGE GONZALEZ ESTRELLA

Fourth Committee Member

PETER LICHTNER

Fifth Committee Member

PETER BURNS

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