Date of Award
Bachelor of Science
Laura Ann MacManus Spencer
PFAAs, PFOA, Perfluorinated Alkyl Acids, Drinking Water
Perfluoroalkyl Acids (PFAAs), a family of industrial chemicals, are found in household products such as pizza boxes, microwave popcorn bags, and non-stick pans. PFAAs of different carbon chain lengths and ionic head groups exist, such as PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid). Used without regulation in industry for decades, PFAAs only recently became recognized as contaminants of emerging concern, since they are bioaccumulative in organisms, persistent in the environment, and toxic. PFAAs are known to accumulate in the blood, liver and kidneys, and drinking water contaminated with PFAAs has been linked to certain types of cancer. Therefore, it is highly desirable and necessary that drinking water in PFAA contaminated areas be effectively filtered. Previous research has focused on testing granulated activated charcoal and ion exchange resins on water contaminated with only certain PFAAs. Recently, a montmorillonite material was modified with a specialized surfactant and was demonstrated to selectively adsorb PFOA and PFOS in the presence of other organic contaminants in water. The aim of this work is to expand upon the previous research using hectorite clay and more commonplace and inexpensive surfactants to target PFAAs of all chain lengths and ionic head group type. The modified hectorite materials are synthesized by a simple, aqueous method using various cationic quaternary ammonium salts of different size. These materials are then exposed to different environmentally-relevant concentrations of PFAAs in water, and the resultant aqueous PFAA concentrations are quantified via liquid chromatographytandem mass spectrometry. Multiple modified Hectorite materials have been synthesized and characterized via infrared spectroscopy and X-ray powder diffraction. Preliminary evidence has shown that hectorite modified with dodecyltrimethyl ammonium bromide is successful at adsorbing PFOA from water. Ongoing work is focused on more extensive testing of this and other modified hectorite materials with other PFAAs, mixtures of PFAAs and real contaminated drinking water samples.
Pagano, Alexandra, "Synthesis and Characterization of Organically Modified Hectorites for Sequestration of PFAAs from Contaminated Drinking Water" (2018). Honors Theses. 1588.