<p>Bentonite clays and Fe-reducing bacteria have been independently identified as important geochemical agents possessing the ability to influence metal(loid) mobility in aqueous environments. In the context of metal(loid) immobilization, however, the interactions occurring between Fe-reducing bacteria and bentonite clays remain largely undescribed. This thesis examines the immobilization of Cu<sup>2+</sup>, Cd<sup>2+</sup>, and As<sup>5+</sup> from aqueous solution by natural bentonite clays, and compares sorption to sterile bentonite clays with sorption in the presence of Fe-reducing bacteria. The research questions under investigation in this thesis are: 1) What are the influences of potentially metal-tolerant Fe-reducing bacteria on metal(loid) uptake by bentonite clay sorbents of varying smectite content and on the stability of bentonite clay-sorbed metal(loid)s?; and 2) Are there differences in the influence of Fe-reducing bacteria on Cd<sup>2+</sup> and Cu<sup>2+</sup> sorption to bentonite clays when As<sup>5+</sup>, a reducible, metabolically-available metalloid, is present in solution?</p> <p>While the influence of bacterial augmentation on Cu<sup>2+</sup> sorption was negligible in these experiments, Cd<sup>2+</sup> sorption was enhanced in the presence of Fe-reducing bacteria, and most profoundly, As displayed time-dependent desorption during the experimental timeframe in the presence of Fe-reducing bacteria. These results highlight the existence of potential limitations to the use of bentonite clay sorbents for metal(loid)-contaminated wastewater reclamation, identifying the microbially-vulnerable nature of metal(loid) sorption reactions. Abundant facets concerning clay-bacterial-metal(loid) interactions exist which require further characterization and experimentation to generate deeper understanding of the potential utility of, as well as limitations to, the use of clay mineral-based sorbents for the sequestration of toxic metal(loid)s from aqueous solution.</p> / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/11121 |
| Date | 10 1900 |
| Creators | Holland, Steven P. |
| Contributors | Warren, Lesley A., Luc Bernier, Jim Smith, Luc Bernier, Jim Smith, Earth and Environmental Sciences |
| Source Sets | McMaster University |
| Detected Language | English |
| Type | thesis |
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