Wieser, MichaelBirks, JeanKruschel, Courtney2021-09-152021-09-152021-09Kruschel, C. (2021). Measurements of the stable isotopic composition of molybdenum as a tracer for petroleum coke interactions with water (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/113874This thesis reports on the measurement of molybdenum (Mo) stable isotopic compositions of natural surface and groundwaters, fluid petroleum coke (PC), PC leachates, and waters from PC column experiments. Samples were from the Athabasca oil sands region (AOSR). PC is identified as an environmental concern due to high concentrations of metals, including Mo. The goal was to evaluate whether Mo stable isotopic compositions could be used to identify Mo originating from PC to better understand the processes that occur in PC interactions within an aqueous environment. An analytical method was developed for measurements of Mo isotopic composition of samples with concentrations as low as 0.66 µg/L. The isotopic composition of whole PC and PC leachate were determined, the δ^(98/95) Mo of whole PC ranged from 0.53 to 0.94 ± 0.14 ‰ (k = 2) and the δ^(98/95) Mo of PC leachates ranged from 0.2 to 1.31 ± 0.14 ‰ (k = 2). Measurements were completed on water samples from column experiments to investigate the release of Mo from PC when exposed to different input waters expected in an oil sands closure landscape (e.g. meteoric water and Oil Sands Process Water (OSPW)). For the meteoric water samples, the δ^(98/95) Mo values became enriched in the heavier isotopes over the course of the experiment. These data along with pH data suggest that the adsorption of molybdate to the surface of the PC was likely occurring in the meteoric water samples. The δ^(98/95) Mo values of the OSPW column did not become enriched in the heavier isotopes suggesting that the process of adsorption by molybdate to the surface of the PC was not occurring. The variations in Mo isotopic composition on these same samples agreed with the results from the pH and concentration analysis. The results from this thesis demonstrate that Mo stable isotopic composition can help elucidate the mechanisms of Mo release during PC interactions with the aqueous environment and add to the previously measured data on Mo stable isotopic compositions throughout the AOSR.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Stable IsotopesMass SpectrometryMolybdenumPetroleum CokeEnvironmental SciencesPhysics--Atomicmaster thesis10.11575/PRISM/39200