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Morphological Effects of Water Soluble Polymer Flocculants Synthesized by Controlled Reversible-Deactivation Radical Polymerization for Treatment of Mature Fine Tailings
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- Author / Creator
- Nguyen, Benjamin
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The bitumen reserves in Northern Alberta are a valuable asset, but extracting bitumen from oil sands via the Clark hot water process produces undesirable waste tailings. These tailings are transported to tailings ponds where the sand and clay particles are left to settle slowly, creating a long-term environmental problem. The most troublesome component of oil sands tailings is the mature fine tailings (MFT) component. Without additional treatment, the fine clay particles that are part of MFT may never settle completely, remaining in a mud-like suspension that endangers the environment. One of the methods to treat these tailings is to add water-soluble polymer flocculants to create large flocs that settle to the bottom of the ponds, allowing the supernatant water to be recovered and reused in the oil extraction process. Poly((vinylbenzyl)trimethylammonium chloride), PVB, a cationic and partially hydrophobic polymer, is the focus of this thesis. Its positive charges make it adsorb strongly on the negatively-charged clay particles, and its partial hydrophobicity produces flocs that retain less water. This thesis investigates how the configuration of PVB (linear, 3-arm, and 4-arm star) affects its MFT flocculation and dewatering performance. Atom transfer radical polymerization
was used to make PVB with precisely controlled morphologies. The 3-arm star polymer outperformed its linear counterpart at every polymer dosage in initial settling rate tests, while the 4-arm star polymer performed well only at high dosages. In general, higher dosages led to slightly greater turbidities than lower dosages, but it should be noted that suspensions obtained at all dosages were very clear. Dewaterability was measured by comparing capillary suction times of the flocculated suspensions and the settled sediments. All polymers performed virtually the same in this test. Similarly, all polymers produced sediments with similar solids contents. The 4-arm star polymer at low dosages, however, had the worst performance in terms of settling time, relative turbidity, and capillary suction time. -
- Graduation date
- Fall 2020
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.