Verduzco, RafaelWong, Michael S2022-09-262023-05-012022-052022-04-21May 2022Rogers, Tanya K. "Development of Nanocatalytic-Enabled Systems for Treatment of Anthropogenic Water Contaminants." (2022) Diss., Rice University. <a href="https://hdl.handle.net/1911/113368">https://hdl.handle.net/1911/113368</a>.https://hdl.handle.net/1911/113368Versatile and easily implemented methods for water treatment capable of removing and degrading toxic anthropogenic contaminants (e.g., nitrate (NO3-) and perfluoroalkyl substances (PFAS)) are lacking, motivating the need for novel technologies. Nanocatalytic particles offer favorable properties for remediation, including high capacity, excellent kinetics, and selective chemical transformations. However, prior efforts have not effectively implemented these catalysts approaches for continuous water treatment. In this work, we develop novel systems using nanocatalytic materials and new device architectures for water treatment. We developed a new approach termed Catalytic Capacitive Deionization (CCDI) for adsorption and selective reduction of nitrate (NO3-) to innocuous dinitrogen (N2) via indium deposited on palladium (In-on-pd) nanoparticles. We demonstrate that CCDI can convert 91% of aqueous nitrate to N2 with lower electrical energy per order (EEO) compared to alternative treatment methods. We further investigated CCDI for treatment of per- and polyfluoroalkyl (PFAS), enabled by titanium (IV) oxide (TiO2) nanoclusters. Degradation experiments showed successful decomposition of perfluorooctanoic acid (“C8” - PFOA) to shorter-chain products (“C7” – “C3”) under an applied potential energy (Eapp) great than TiO2 band gap energy (Ebg). Density functional theory (DFT) calculations and hydroxyl radical (•OH) indicator experiments provided insight to the critical roles of energy input and reactive oxygen species (ROS). Lastly, we first report the use of covalent organic frameworks (COFS) as nanocatalysts for photodegradation of PFAS. Three conjugated-COF scaffolds were selected based on density functional theory (DFT) calculations of building block monomers HOMO/LUMO levels. Thiophene-linkers exhibited the best degradation performance during photocatalytic experiments, revealing the photo-oxidation catalytic performance of COFs is primarily governed by the oxidizing ability of monomer photo-generated holes (i.e., the HOMO energy level of thiophene monomer (TTDA) was the most positive). This study shows a new application for COF materials and provides important guidelines on designing COFs with optimal photocatalytic performance for per- and polyfluoroalkyl (PFAS) substances. In summary, we developed three new nanocatalytic-enabled water system architectures for treatment of anthropogenic contaminants.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.nanotechnologycatalysiswater treatmentThesis2022-09-26