Degree

Doctor of Philosophy (PhD)

Department

Chemical Engineering

Document Type

Dissertation

Abstract

Freshwater scarcity poses a growing threat to human welfare and society, with 4 billion people experiencing severe shortages at least one month of the year and half a billion affected year-round. Rising demand from population growth and development combined with the impacts of climate change on water supplies further intensifies this crisis, underscoring the need for improved water reclamation and treatment technologies. Photocatalytic advanced oxidation processes have great potential for chemical-free, energy-efficient degradation of waterborne pollutants, provided long-standing issues including poor light management, mass transfer limitations, and high charge carrier recombination rates are addressed.

Here, we report the development of a dual-porous titanium dioxide photocatalyst designed to overcome these challenges. The immobilized catalyst achieves a surface area-to-volume ratio of 940,000 m2/m3—surpassing even suspension-based systems—which enhances mass transport while eliminating the need for a filtration step. The use of a UV-transparent quartz fiber support further improves performance by preventing parasitic photon absorption.

This photocatalytic system enables efficient degradation of diverse pollutant classes, including dyes, chlorohydrocarbons, alcohols, viral contaminants, and hydrogen sulfide (H2S). For organic pollutants, electrical energy per order (EEO) values remain within the practical benchmark of less than 10 kWh/m3. Viral contamination undergoes a 2-log reduction in a single pass with an EEO of 0.1 kWh/m3. H2S removal is particularly efficient due to the autocatalytic effect of the oxidation product, sulfate. The presence of sulfate improves charge carrier separation, giving an EEO for H2S oxidation of 0.1 kWh/m3 and a photonic efficiency of over 30% under kinetically-limited conditions. Finally, we present preliminary in situ XANES spectroscopic evidence of the photocatalytic reduction of hexavalent chromium to trivalent chromium, highlighting the system’s versatility for treating a broad range of contaminants.

Date

11-4-2025

Committee Chair

McPeak, Kevin M.

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Available for download on Friday, October 30, 2026

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