The exploration in the use of nanomaterials for a multitude of different applications has grown within the last few years. This is largely due to the vast number of features exhibited by nanoscale materials when compared to their bulk counterparts. The use of nanomaterials in environmental applications can come in different facets, such as, the production of clean energy in solar cells and the application of nanotechnologies in coatings for building exterior surfaces.
The first section of the thesis focuses on the use of nanomaterials for water remediation, since purified groundwater is still not globally accessible. Chapter 2 focuses on the use of Pd nanoparticles supported on TiO₂ (Pd@TiO₂) to photo-generate H₂ while using bacterial cells as sacrificial electron donors (SEDs) rather than chemical reagents. Different conditions were examined to investigate the photo-destruction of gram negative bacteria, E. coli, which is a microbial pollutant often found in a number of different water sources. Samples containing photocatalyst in solution were irradiated using a solar simulator, which is a light source that is similar to the solar spectrum, for applications in a flow system. Chapter 3 is a project in collaboration with Dr. Edith Amuhaya and her research group in Nairobi, Kenya exploring the use of porphyrins, an organic compound, supported on glass wool for water treatment in a flow system. Porphyrins are photosensitizers that generate reactive oxygen species (ROS) when exposed to light and oxygen. However, their high solubility in aqueous media makes it difficult to use them for water remediation and can add an extra step in the process of water purification. Therefore, we suggest attaching the porphyrins to glass wool, which is an inexpensive and inert support that can easily be removed from a flow system. Here, we explore the use of glass wool as a support for a series of different conjugated porphyrins and metalloporphyrins. We have synthesized different porphyrins bearing carboxylic group substituents to enable ease of deposition onto the amino-functionalized glass surface (glass surface modified with (3-Aminopropyl) triethoxysilane, APTES). The characterization of the materials suggests some of the porphyrins retain the ability to absorb solar light and generate reactive oxygen species upon irradiation. Antimicrobial activity and degradation of selected pollutants were also explored.
The last section of the thesis discusses a different approach regarding nanoparticles. Typically, nanoparticles are used for their reactivity when they absorb light, often producing a high number of free radicals in the process. However, this high reactivity can become an issue when these free radicals cause unintended damage to biological environments. This is the case for TiO₂ used for photo-protection sunscreens, where there has been some concern regarding the free radical damage to skin. Previously, the group has synthesized TiO₂ particles in a thin shell of lignin, a natural biopolymer. Lignin is an antioxidant that can scavenge the radicals produced by the photo-excited TiO₂ and prevent them from being released into the surrounding media. Here, we further characterize and investigate the properties of the lignin on TiO₂ nanoparticles and attempt to scale up the production of the particles.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/42101 |
| Date | 10 May 2021 |
| Creators | Fournier, Kelsey |
| Contributors | Scaiano, Juan |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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