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On surfaces and within interfaces occur some of the most important reactions in chemistry, from world changing industrial reactions to critical environmental processes. It is even hypothesized that the chiral nature of life arose from reactions occurring on chiral mineral surfaces. In any case adsorption typically plays a key role. Adsorption can occur on rapid time scales, particularly in catalytic systems, and it can be the precursor to highly stable surface interaction mechanisms such as surface precipitation. Surface adsorption can have a dramatic affect on the resulting surface increasing or decreasing the propensity for further reactivity or adsorption. In order to understand the processes occurring on a surface both the surface and the adsorbate must be understood. This includes a surface with any prior adsorbates. This is why many catalytic studies are done in UHV environments where clean surfaces are prepared for each experiment. The same is true with environmental surfaces, but obtaining pristine surfaces can be problematic, and systems are often extremely complicated involving organic, inorganic, and biological components. Often research is focused on just one component. A significant portion of this dissertation is focused on the adsorption of organic and inorganic species on pristine mineral surfaces. While there is significant research done on environmental surfaces, often times the surface used in studies is not well characterized. In essence lesser attention is paid to the substrate then the adsorbate. This is particularly true of infrared studies similar to the type presented in chapter 5 where carbonate is shown to exist in significant quantity on all ferrihydrite surfaces. Furthermore, chapter 4 highlights the potential for ion mobility on calcite surfaces under ambient conditions and the effect the adsorbates in chapter 3 have on the mobility process. The principal of this dissertation is to characterize fundamental surface processes which occur on calcite and ferrihydrite surfaces under ambient conditions. The hope is that this can lay the ground work for future studies where native adsorption and restructuring is taken into account on mineral surfaces during experimental studies. / Chemistry

Lateral flow biosensors are analytical devices that detect biomaterials with physicochemical signals, such as optical signals. Unlike other biosensors, lateral flow biosensors are based on porous membranes, which use capillary force to transport biomaterials spontaneously. However, lateral flow biosensors are fabricated in batch mode, which means that membranes need to be cut from the rolls, pretreated, and assembled using a step-by-step process. Thus, there is a need for a more efficient manufacturing process. This thesis aims to accelerate the fabrication process by developing a method wherein the whole device is printed directly, including the printable substrates, as well as by developing a clog-free process for depositing expensive reagents. These novel printable porous media were developed using printing inks that contained various pigments and polymer binders. To this end, candidate formulations were screened from nine hundred inks formulations via wicking experiments. The results of these tests showed that the most promising formulations were based on calcium carbonates and latex polymers. This formulation was then used to develop printable porous media that can easily be printed into complex patterns, with changeable wicking speeds within each pattern. In addition, a bio- colorimetric assay of alkaline phosphates conducted on these porous media showed strong color signals that were comparable to the traditional membrane-based lateral flow strips. Clog-free printing processes were investigated by using a piezoelectric inkjet printer to print silica sols and six nanoparticle inks. The results of these tests showed that the vibration of the piezoelectric layer and the deposition of particles on the printhead surfaces induced clogging issues. Over time, the silica sols formed multilayer deposits on the print head surface, which subsequently detached due to the vibration of the piezoelectric layer. Consequently, these large sheets of silica clogged the nozzles during printing. This clogging issue was eliminated by adjusting the pH value of the silica sol inks to 3.1. The hydrophobic cationic polystyrene nanoparticles form a sub-monolayer on the printhead surface, which causes air entrainment and promotes air bubble adhesion into the interior of the print head surface when the piezoelectric layer deforms. Thus, alternate surface chemistries for the print head and ink particle surfaces may be required in order to print hydrophobic ink materials. Overall, this enhanced understanding of these clogging mechanisms helps to explain why printer performance varies when different particles are used. / Thesis / Doctor of Philosophy (PhD) / Many devices in our day-to-day lives incorporate lateral flow biosensors, for example, home pregnancy test kits. These tests allow users to obtain results within 30 minutes by simply applying a few droplets of urine onto a test strip. However, these biosensors are largely manufactured using manual processes: workers cut strips (also called substrates) from sheets, deposit reagents onto the strips, and then assemble the pretreated strips into devices. As such, these processes are time consuming and less productive. To accelerate the manufacturing process, we developed printable porous substrates and a clog-free printing process for depositing expensive reagents onto the substrates. Novel porous media can be flexibly printed into complex patterns using pigment- based inks. Moreover, the use of different pigments within the designed patterns enables these porous media to control wicking velocity. In addition to printable porous substrates, the research in this thesis shows that the manufacturing process can be improved by using piezoelectric inkjet printers. The use of these printers not only allows the expensive reagents to be precisely deposited onto the substrates, but it also offers a more cost-effective method of doing so. Finally, in order to ensure the printing process remained clog-free, we systematically investigated clogging mechanisms by printing with different polymers and nanoparticles.

Nitrocellulose is currently the most common porous material used in commercially available lateral flow assays. It is, however, unsafe to manufacture and time consuming to incorporate into multi-component assay devices. Precipitated calcium carbonate is a material produced from naturally occurring lime that can be suspended in a binder and extruded onto a surface. This extruded suspension forms a porous coating through which a solution can be wicked. The physical characteristics of three different types of calcium carbonate types were investigated to determine differences that may yield better lateral flow. The capillary flow rate through the coating was found to be largely affected by the calcium carbonate type used, the binder concentration and whether any post-printing treatment was applied, specifically heating the print. Calcium carbonate has a high specific surface area, which results in a high protein binding capacity. To prevent protein binding, pre-treating calcium carbonate particles prior to forming the suspension in a binder was attempted. Pre-treatment with bovine serum albumin, casein or methoxy-PEG phosphate did not show prevention of protein binding. Furthermore, by treating the calcium carbonate particles with a protein before suspension formulation, the wicking rate after printing was found to be diminished. / Thesis / Master of Applied Science (MASc)

The low ambient air temperatures, together with the low annual rainfall and complete lack of vegetation in the Canadian High Arctic, results in a breakdown of the carbonate rock material by mechanical means. The importance of chemical decomposition, soil formation and transport of ionic material in solution is negligible, when compared with the role played by these same processes in more temperate climates. The purpose of this thesis is to investigate certain aspects of the alkali, alkaline earth and heavy metal geochemistry of selected components of the weathering cycle. The discussion will deal with concentration levels of these parameters in stream waters and, to a lesser extent, soils and stream sediments. Analytical results show that element distributions in the streams resemble those of more temperate carbonate terrains. However, the solute levels are, in general, lower, indicating that a greater proportion of the metals is travelling in colloidal form and/or adsorbed to siltsized material carried by the streams. These findings confirm the belief that chemical weathering and transport in solution are of little importance in the area studied. / Thesis / Master of Science (MSc)

Nutrient accumulation in vegetable crops is declining. New varieties, selected for high yield, may be subject to a dilution effect of nutrient concentration. Alternatively, soil fertility may be to blame. Here, we investigate how nitrogen fertilization can enhance or suppress calcium and potassium content in two lettuce varieties already known to accumulate high or low amounts of these nutrients. Effects of varying the ammonium:nitrate ratio and effects of calcium carbonate buffering on plant growth by mass and on uptake and accumulation of potassium and calcium in two lettuce (Lactuca sativa L.) cultivars, Two Star and Red Deer Tongue, were investigated in three greenhouse hydroponic experiments in which ammonium supplied none, 6%, 12%, 25%, 50%, 75% or all of the nitrogen. Ammonium, supplied as the sole nitrogen source (15 mM), was toxic under buffered or unbuffered conditions. It limited growth and concentrations of potassium and calcium in lettuce leaves. Proportions of ammonium-N greater than 50% of total N nutrition severely curtailed growth and nutrient accumulation for both cultivars. For both cultivars, optima for all three variables occurred in treatments that contained less than 50% NH4+-N in the total N supply. Application of calcium carbonate buffer did not result in improved maxima for growth and shoot potassium or shoot calcium concentrations compared to the best responses in unbuffered solutions. However, supplying calcium carbonate buffer did raise the minima for growth and shoot potassium and shoot calcium concentration. Both cultivars in buffered solutions compared to unbuffered solutions had significantly greater values for growth and for shoot potassium or shoot calcium concentration in treatments that contained 50% ammonium-N or greater in the total N supply. Although buffering relieved symptoms of ammonium toxicity, it did not eliminate symptoms, confirming the work of other researchers that ammonium toxicity is not due solely to acidification of the root-zone and that buffering has an effect on the capacity of plants to tolerate ammonium nutrition. Supplying nitrogen with ammonium:nitrate ratios in which nitrate predominates enhances yield and accumulation of calcium and potassium in lettuce. Two Star, the modern variety, is more ammonium-sensitive than Red Deer Tongue, the heirloom variety, if calcium carbonate buffering is not provided.

Organisms have evolved a remarkable ability to mineralize complex skeletons and functional biomaterials. These structures are nucleated and grown in close associaiton with macromolecular assemblages of proteins and polysaccharides that are implicated in regulating all stagees of mineralization. Because of this intimate association of organic with inorgaic components, many studies have investigated the effects of particular organic species on mineral morphology, phase, and growth rate. However, the diversity and species-specific nature of the organic assemblages associated with biominerals across a wide variety of taxa, has limited our understanding of how organisms use biomolecules to regulate skeletal formation. It is clear that a mechanistic picture of biomolecular controls on mineralization requires molecular-level investigations of the interplay between organic and inorganic components at all stages of crystallizaiton. This dissertation presents the findings from theoretical and experimental studies of the physical mechanisms that underlie biomolecule controls on mineral formation. Molecular dynamics simulations probe the effects of acidic molecules on the hydration of alkaline earth cations. After first calculating baseline hydration properties for magnesium, calcium, strontium, and barium, I determine the effects of carboxylate-containing molecules on cation hydration state as well as the kinetics and thermodynamics of water exchange. Experimental work utilizes self-assembled monolayers as proxies for matrix macromolecules in order to understand their effects on CaCO3 nucleation kinetics and thermodynamics. Estimates of nucleation rates and barriers are made from optical microscopy data and correlated with measurements of crystal – substrate rupture force from dynamic force microscopy. These investigations show that an important function of biomolecules in directing mineralization lies in their ability to modulate cation hydration. Both chemical functionality and molecular conformation are influential in regulating the kinetics and thermodynamics of mineral nucleation, and these effects may be predicted by the strength of interaction between organic and inorganic components. These findings contribute to a mechanistic understanding of how organic matrices act to regulate biomineral formation. They demonstrate a plausible physical basis for how carboxyl-rich biomolecules accelerate the kinetics of biomineral growth and suggest roles for organic species in the nucleation and pre-nucleation stages of mineralization. / Ph. D.