ORCID Identifier(s)

0000-0003-4337-2915

Graduation Semester and Year

2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

Hyeok Choi

Abstract

Perfluorinated alkyl substances (PFASs) are highly persistent organic contaminants that have become a global health concern. Few studies so far have demonstrated successful decomposition of PFASs under ambient condition. As a result, this feasibility study aimed to quickly examine whether or not zerovalent iron (ZVI)-based materials, in particular palladium-doped nanoscale ZVI (so-called nZVI/Pd) known to dehalogenate many halogenated chemicals, can remove perfluorooctanoic acid (PFOA) in water, one of the most widely used PFASs. Batch experiments were performed to evaluate the effects of various operating parameters including reaction pH, nZVI/Pd dose, and PFOA concentration, and thus to find best treatment options for PFOA. Significant removal of PFOA was observed at low pH and high nZVI/Pd dosage while nZVI/Pd was superior to micron-size ZVI and nZVI without Pd. However, decrease in total organic carbon was very similar to PFOA removal, negligible amounts of fluoride ions were detected in water, and mass spectrometry analysis indicated no significant formation of reaction intermediates. The results implied that the observed PFOA removal was more closely associated with adsorption than reaction (i.e., defluorination). Kinetic models and adsorption isotherm models were employed to explain the PFOA removal and obtain insights on the physicochemical processes around nZVI/Pd interacting with PFOA.

Keywords

PFOA, PFOS, PFASs, nZVI, Adsorption

Disciplines

Earth Sciences | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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