Date of Completion

Spring 5-1-2015

Thesis Advisor(s)

Chad Johnston

Honors Major

Environmental Engineering

Disciplines

Engineering

Abstract

In soils, the spread of toxic organic anions through groundwater can be partially mitigated by the formation of inner- and outer-sphere complexes with aluminum (hydr)oxides. In current practice, a constant soil-water partition coefficient is used to describe the relative quantity of sorbed compound to that in solution. However this method is empirical and site-specific. In order to establish a thermodynamically relevant sorption model, sorption reactions between many mineral phases and organic compounds must be characterized. While there exists a wealth of research quantifying the sorption potential of ferric oxide mineral phases, there remains a gap in knowledge of these parameters for aluminum oxides. In this study, the energy of outer-sphere complexation reactions will be calculated based on electrostatic and van der Waals interactions between gibbsite (Al(OH)$_3$) and the benzoate compounds using LAMMPS molecular dynamics software. To achieve this objective, adsorption energies have been calculated for benzoate ions with the follwing para-substituted functional groups: nitro-, chloro-, methoxy-, methyl-, and amine-. This research is an advancement of an ongoing effort to develop a thermodynamically relevant adsorption model.

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Engineering Commons

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