Keske, Eric

The oil sands industry is producing large volumes of tailings waste reaching 2 billion cubic meters by 2034 In this study, the industrial standard flocculant, high molecular weight PAM, was grafted from the surface of activated carbon (AC). This material was designed to increase the flocculant's hydrophobicity and density. Different molecular weight PAM was grafted from AC with different AC contents and particle sizes (AC-PAMs). The AC-PAMs were synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP). The AC-PAMs achieved molecular weights 107 – 5,600 kg/mol and AC content of 0.2 – 5.8% on <0.1 and 0.1 – 0.5 mm AC particle diameters. AC-PAM achieved higher solids contents up to 51 wt% using AC-PAM with 5.1 wt% AC due to the grafting from a hydrophobic AC core. To summarize, our work shows the successful grafting of PAM from AC and its potential as a flocculant for mature fine tailings.

Author Keywords: activate carbon, atom transfer radical polymization, flocculation, grafting-from, polyacrylamide, surface-initiated polymerization

In an effort to improve upon existing analytical methods, electrochemical sensors offer portable, cost-effective alternatives to traditional lab-based techniques. Recent advances in supramolecular chemistry offer a unique alternative to achieve high selectivity while also benefitting from facile scaling for mass production. Thus, by incorporating host-guest chemistry with electrochemical sensors, the development of simple and selective sensors is possible. To that extent, novel hosts and electroactive ion pairs were investigated for their ability to transduce an electrochemical signal representative of host-guest complexation. Results demonstrated that the upper rim modifications of resorcinarene hosts attenuated their affinity for electroactive probes whilst maintaining structural integrity upon extended cycling. Further work revealed that guests may be directly quantified via their complexation with electroactive hosts. The sensing method was further validated by quantification of surfactant pollutants in the Otonabee River. Through a fundamental understanding of the electrochemical behaviour of host-guest systems a general sensing platform can be developed, where hosts are interchangeable for specificity towards any desired analyte. Therefore, moving away from expensive lab-based methods and significantly reducing the barriers for biological or environmental monitoring.

Author Keywords: Electrochemistry, Ferrocene, Host-Guest, Resorcinarenes, Supramolecular Chemistry, Surfactants