Potentiometric Autotitration System for Characterizing Reactivity of Environmental Samples

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Potentiometric titrations are critical in quantifying the surface reactivity of environmental surfaces, such as microbes, minerals, and organic compounds, with the ultimate aim of being able to predict the ability of those surfaces to sorb a range of trace and heavy metals from water. In this NSERC RTI application, we request a state-of-the-art autotitration system, to be housed in a new joint Konhauser-Alessi Geobiology laboratory at the University of Alberta (UofA). At present, our two research groups depend on one aging (13-year old) titrator. This instrument has been key in generating data for a number of previous and on-going research projects, including: (i) quantifying the accumulation of trace metals by marine plankton, and determining what role they might have played in Precambrian ocean nutrient cycling and banded iron formation sedimentation, (ii) evaluating the ability of clays and iron-bearing minerals to bind dissolved/particulate organic carbon (DOC/POC) and trace metals from seawater, (iii) determining whether DOC can compete with microbes in trace metal adsorption, (iv) assessing the ability of activated carbon, biochar, and petroleum coke to sequester toxic metal contaminants from mining and landfill sites, and (v) working in partnership with AREVA Resources Canada to characterize tailings sediment and pond waters from the decommissioned Cluff Lake uranium mine in Saskatchewan with the aim of developing a cost effective and efficient bioremediation process. Despite the promise potentiometric titrations hold for both environmental and applied industry research, several limitations exist with our existing instrument, namely: (1) it is overtaxed and students often wait weeks to perform routine analyses, (2) the minimum volumes of acid/base added to solutions by the instrument are too large for titrating small-volume suspensions, such as those of nanominerals, (3) it cannot perform forward (base) and reverse (acid) titrations without a time-consuming and error inducing reconfiguration of the entire instrument, and (4) it cannot perform conductometric titrations (or others, such as redox or Karl Fisher titrations). Moreover, with the continued growth of our joint laboratories, we currently have 12 HQP that use this equipment, making it impractical to continue this promising line of research without a modern titration system. In addition to our own needs, we will also continue to provide training and access to other research groups at the UofA who have previously used the existing titrator, including Drs. Gingras (EAS), Owttrim (BioSci), Gibbs-Davis (Chemistry), Perez and Liu (Civil Engineering). Accordingly, the purchase of a new state-of-the-art titration system provides not only our lab group, but also the UofA, with tremendous potential to increase efficiency, productivity, and support a number of HQP and NSERC supported research programs.