Date of Award:

5-2018

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Advisor/Chair:

Craig Adams

Co-Advisor/Chair:

William J. Doucette

Third Advisor:

David Tarboton

Abstract

Pharmaceuticals and personal care products (PPCPs) are widely used throughout the world. PPCPs are emerging as pollutants of concern and may pose a risk in the future to drinking water supplies. Two such compounds are sulfamethoxazole (SMXL) and fluoxetine (FLX). These ionizable compounds are not readily removed from water by conventional water treatment technologies. Powdered activated carbon (PAC) is a useful material for removing contaminants from water and is currently used in many water treatment applications. PACs may carry either a net positive or negative surface charge depending on the pH of solution. This study examined the hypothesis that the electrostatic interactions between three PACs’ surface charges and the charges of sulfamethoxazole’s and fluoxetine’s ionizable functional groups would lead to greater sorption efficiency than non-electrostatic interactions alone. Samples containing SMXL or FLX, were treated with varying doses of PAC, and mixed for three hours. The pH of samples were adjusted between experiments to determine if interaction between the polar contaminants and charged surface of PAC significantly impacted removal of the contaminant from solution. Analysis of the treated samples showed the effects of pH and varying PACs on the removal of SMXL and FLX from solution. It was observed that pH of the solution did play a significant role in the removal of contaminant in a number of the experiments, but that under other conditions where greater removal was anticipated based on predicted electrostatic interactions, it did not. These conditions included pH conditions where the contaminant existed predominantly in a negatively charged form. While not the initial focus of this study, it was observed that pore size distribution of the PACs may play a more significant role in the removal of ionizable compounds, especially in the case of fluoxetine, than electrostatic interactions.

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