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DEVELOPING AGED AND UNAGED MICRO AND NANOPLASTICS FOR ENVIRONMENTAL TESTING
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- Author / Creator
- Elnaz Kalantar
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Concerns are growing about plastics in the environment. The aging of the plastics in the environment will impact their fate and their interactions with the ecosystems’ constituents. As such, there is a need to improve our understanding of aged plastics and how they differ from their pristine or primary counterparts. Toward this aim, this work details the formation of primary and secondary polystyrene (PS) micro and nanoplastics (MNPs) and their weathering by a combination of UV light, heat, and mechanical abrasion.
Primary MNPs were produced through the dissolution of PS in chloroform followed by anti-solvent precipitation in a 10% polyvinyl alcohol (PVA) solution. Secondary MNPs were produced through mechanical abrasion and shear stresses using a ball mill grinder. Following production, particles were filtered, purified, and concentrated in a deionized water (DI) suspension. Weathering of primary and secondary MNPs was performed by Ultraviolet (UV) light exposure to produce surface oxidation, as confirmed by Fourier transform infrared spectroscopy (FTIR).
Characterization of MNPs was performed by scanning electron microscopy (SEM), Coulter counter, laser diffraction, dynamic light scattering (DLS), electrophoretic mobility, and FTIR analyses. Both primary and secondary MNP suspensions had an average particle size in nano-scale (~ 330 ± 2 nm and 155.7 ± 1.5 nm, respectively), though SEM indicated primary MNPs were spherical while secondary MNPs were irregularly shaped. Chemical characterization of primary and secondary MNPs showed the same PS signature of the parent material, and oxidation due to UV light and heat exposure in weathered MNPs was monitored by FTIR.
Due to changes in morphology and surface chemistry, secondary and weathered MNPs are anticipated to behave differently from primary particles. Comparing primary to secondary and weathered MNPs will determine the dependence of aging on particle behavior and will improve the applicability of lab-scale testing when seeking to understand environmental impacts. -
- Subjects / Keywords
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- Graduation date
- Spring 2024
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.