Doctor of Philosophy, University of Akron, 2018, Integrated Bioscience

Most caves form in limestone via water-mediated dissolution and mass transport; however, increasing numbers of caves are being identified that do not fit this model, including the iron formation caves (IFCs) found in the iron mining regions of Brazil. IFCs occur predominantly at the interface of banded iron formations (BIFs; alternating hematite and silica laminae) and a cap rock composed of fragmented BIF in an amorphous Fe(III) matrix, called canga. Despite low erosional rates and insolubility of both BIF and canga, there are >3,000 IFCs in Brazil. There is currently no mechanism that adequately accounts for the growth or formation of IFCs; however, the reductive dissolution of Fe(III) by Fe(III) reducing microorganisms (FeRM) could provide a microbiological mechanism for their formation. To test this hypothesis we first evaluated the susceptibility of Fe(III) phases associated with these caves to reduction by the FeRM Shewanella oneidensis MR-1. Canga (being the least crystalline of the Fe(III) phases tested) was susceptible to reduction, and to a larger degree than the Fe(III) (predominantly hematite) associated with BIF. We then analyzed the microbial communities within the IFCs to determine if FeRM were present. While the caves were dominated by Chloroflexi, Acidobacteria and the Alpha- Beta- and Gammaproteobacteria (all containing lineages capable of FeRM activity), active Fe(III) reducing enrichment cultures from IFCs indicated the predominance of Firmicutes and Enterobacteriaceae, which coupled fermentation to Fe reduction; indicating that IFCs do contain microorganisms capable of reducing Fe(III). To test whether FeRM were actively reducing Fe(III) within the IFCs, we analyzed IFC host rock and discovered that the cave walls had undergone structural weakening. Upon further investigation, we identified an unconsolidated iron depleted (as compared to the surrounding canga) material in the walls of the IFCs. This material contained robust microbial population (open full item for complete abstract)

Bachelor of Science, Ashland University, 2016, Biology/Toxicology

Iron deficiency anemia is the most common nutritional disorder in the world and is a condition in which the concentration of iron in the blood is significantly lowered. Iron plays an important role in the delivery of oxygen to tissues for cellular respiration. One consequence of iron deficiency anemia is a shift toward carbohydrate metabolism, which can be measured through the respiratory exchange ratio (RER), or the ratio of carbon dioxide production to oxygen consumption. This project's objective was to determine the metabolic implications of diets with low iron and high fat levels as measured through RER. Five populations containing three mice each were provided diets with varying levels of fat and iron: a high-fat high-iron diet, a low-fat low-iron diet, a high-fat low-iron diet, a positive control diet, and a negative control diet. Mice were evaluated biweekly using an iWorx metabolic chamber and a GA-200 gas analyzer to assess changes in the ratio of carbon dioxide exhalation to oxygen inspiration. Data was analyzed with correlation tests, ANOVAs, and MANOVAs using R v. 3.2.3 software. Results indicate that iron plays a significant role in allowing the body to continue carbohydrate metabolism under respiratory stress. A side project seeking to quantify iron in saliva as a means of verifying the success of the research diet was completed but iron concentrations were found to be below detection limits of the procedure. The results of this study suggest some key physiological differences in iron deficient mice, which significantly impact the understanding and treatment of iron deficiency anemia.

Doctor of Philosophy (PhD), Ohio University, 2023, Chemical Engineering (Engineering and Technology)

Internal corrosion of transmission tubulars is a huge concern in the oil and gas industry. Corrosion inhibitors (CIs) are often considered the first step in mitigating internal corrosion due to their high efficiency and cost-effectiveness. Yet, predicting the efficiency of corrosion inhibitors, developed and tested in a laboratory environment, in operating field conditions is very challenging. In addition, the presence of corrosion residues or corrosion products on the internal surface of tubular steels can significantly affect the inhibition performance of organic corrosion inhibitors. This aspect is only rarely considered when characterizing the performance of corrosion inhibitors. Therefore, understanding their effects on corrosion inhibition is of great benefit in applying corrosion inhibitors to tackle internal corrosion issues, particularly in aging pipelines. This work mainly focuses on evaluating the corrosion inhibition and revealing the inhibition mechanisms in the absence and presence of various corrosion residues or products, commonly found in oil and gas production. The first half of this work (Chapter 5 and 6) presents a methodology for the characterization of corrosion inhibitors and proposes several innovations to an inhibition prediction model, originally based on the work of Dominguez, et al.. An inhibitor model compound, i.e., tetradecyl phosphate ester (PE-C14), was synthesized in-house and characterized to obtain necessary parameter values required as inputs for the inhibition model. The updated inhibition model could predict steady state and transient corrosion inhibition behaviors with good accuracy. The second half of the presented work (Chapter 7, 8, and 9) focuses on the effects of corrosion residue (Fe3C) and products (FeCO3 and FeS) on corrosion inhibition and advances the understanding of the associated inhibition mechanisms. The galvanic effect caused by residual Fe3C on corrosion rate and inhibition efficiency was quantitatively (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 2023, Chemistry and Biochemistry (Arts and Sciences)

In biological systems, O2 interaction with iron centers in enzyme structure occurs during respiration and the metabolic process. To fully understand the interaction mechanism, each step of the O2 reduction process is important and needs to be characterized. To this goal, we have synthesized and characterized a series of cationic five-coordinate iron complexes, [FeII(L)(L')]+ where L is TpMe, Me = hydrotris{3,5-dimethylpyrazol-1-yl}borate; TpPh, Me = hydrotris{3-phenyl-5-methylpyrazol-1-yl}borate; L'= 2,2'-bipyridine; 4,4'-dimethoxy-2,2'-bipyridine; 4,4'-dimethyl-2,2'-bipyridine; 4,4′-bis(trifluoromethyl)-2,2′-bipyridine; 4,4'-dibromo-2,2'-bipyridine. These complexes were utilized to activate O2 to isolate iron-oxygen intermediate species. The electronic spectra indicate intense absorption at 390 nm consisting of O2 binding to the mononuclear iron complex that generates an iron oxygen intermediate. In addition, the effect of the ligand on the stability of the potential intermediate was studied by altering the ligand substitute. We also treated the high-spin iron(II) reaction with CO to generate the corresponding adduct of low-spin iron(II). 1HNMR analysis reveals a diamagnetic complex arising from a spin-state change from S = 2 to S = 0. Furthermore, infrared spectroscopy has been used to support CO binding empirically. In chapter 3, my research studies nitrene chemistry. Nitrenes are chemically analogous to a single oxygen atom (i.e., NR vs. O). Therefore, nitrene can insert into other chemical bonds. Such reactivity can install synthetically valuable carbon-nitrogen bonds into hydrocarbon substrate. Affording shorter routes to high-value commodity chemicals. However, free nitrenes are generated with difficulty and often display rapid and unselective reactivity. Some degree of control can be achieved through the coordination of nitrene within the ligand field of a metal complex. Structural and electronic modifications affect nitrene reactivity and enable (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2018, Chemical Engineering

Electroless Deposition of Amorphous Iron-Alloy Coatings Abstract by Jacob K. Blickensderfer Amorphous iron alloys are a potentially benign alternative for replacing nickel-phosphorus films commonly used in electronics and surface finishing applications. In addition to being environmentally friendly, the amorphous iron alloys provide excellent corrosion resistance, solderability and micro hardness. In this work, electroless deposition of two such iron alloys, i.e., iron boron (FeB) and iron phosphorus (FeP), is investigated. A process for electroless deposition of FeB without the use of substrate activation is developed. Mixed potential behavior and polarization behavior of individual half-reactions occurring during electroless FeB deposition are characterized, and then used to elucidate the process conditions necessary for activation-free electroless FeB deposition. Corrosion resistance of amorphous FeB films deposited using this newly developed process is tested and the corrosion current is determined to be 31.1 µA/cm2, which is an order of magnitude lower than that typical of crystalline Fe deposits. Unlike FeB deposition, electroless FeP plating critically needs substrate activation by palladium (Pd). The role of substrate (Cu) activation by Pd in enabling electroless FeP deposition is studied in depth. Specifically, it is demonstrated that a critical Pd surface coverage of 10.6% is essential for spontaneous electroless FeP deposition to commence. Below this critical Pd coverage, the surface is catalytically inactive for FeP deposition. A mechanistic model that incorporates surface heterogeneity due to partial Pd coverage of Cu and the effect of this heterogeneity on electrocatalysis of the reductant oxidation reaction during electroless deposition is presented. Model predictions are compared to experimental observations of the electroless surface mixed potential to gain insights into the mechanism by which Pd catalyzes electroless FeP deposition. (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2017, Chemical Engineering

For grid-scale energy storage applications, iron-based hybrid flow batteries have advantages of safety, sustainability and low-cost. Still, several challenges such as device lifetime and efficiency have limited their development. In this work, a new type of hydrogen-ferric ion recombination reactor based on catalyzed, three-dimensional felt is proposed in order to maintain chemical balance in the electrolytes and hence improve the battery stability and lifetime. Cyclic voltammetry (CV) and electrochem- ical impedance spectroscopy (EIS) were used to identify a diffusion-limited hydrogen oxidation current near 0.3 psig of hydrogen partial pressure and show that the perfor- mance can be improved with increasing hydrogen pressure up to about P H 2 = 10 psig. Also, pressure-based measurements showed that high rates of hydrogen recombina- tion (greater than 20 mA cm -2 based on the geometric area and greater than 100 mA cm -2 based on the cross-sectional area) were possible using a floating, membrane-less reactor design. A flow battery model that incorporates the hydrogen evolution side-reactions and chemical rebalancing was developed using a system of differential and algebraic equations (DAE). A good agreement between simulated and measured pressure profiles was obtained for an all-iron flow battery operating at ±100 mA cm -2 . Effects of separator porosity and thickness were simulated, showing how increased thickness and reduced porosity can cause higher pH in the negative electrolyte and hence reduced hydrogen generation. Lastly, a new hybrid flow battery based on mixed, lightly acidic electrolytes was investigated. By using the anomalous codeposition (ACD) phenomenon, it was possible to electrodeposit nearly pure zinc from mixed ZnCl 2 -FeCl 2 electrolytes. The cell was shown to provide 17 % higher voltaic efficiency and 40 % higher power density compared to an all-iron battery operating under the same conditions. A zinc-iron chloride flow battery (open full item for complete abstract)

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2006, Biological Sciences

Low Fe availability constrains algal primary production in numerous oceanic provinces. Although not numerically abundant, the diatom microplankton (> 20 micro m) are important contributors to new production in these regions. To better understand the contributions made to new production by diatoms in Fe-depleted waters, this dissertation work addressed the Fe-specific physiological and biochemical autecology of this group. A field component consisted of two research cruises in 2002 and 2003 along a transect at 29 degrees North spanning the eastern half of the Central North Pacific (CNP) gyre, and focused on the vertically migrating bouyant giant diatom genera Rhizosolenia spp. and Ethmodiscus spp. The lab component examined physiological, biochemical and growth responses of large open-ocean and coastal diatom isolates to perturbations of Fe in the growth medium. Whereas mats of Rhizosolenias howed elevated values (ca. 0.61, n = 88) of Fv/Fm, a measure of photochemical energy conversion efficiency, along the easterly transect from Hawaii to San Diego, a clear decline in this parameter measured at locations west of 165 degrees West provided physiological evidence of nutrient limitation. By contrast, cells of Ethmodiscus showed consistently near maximal values of Fv/Fm (ca.0.7, n = 70). The higher Fv/Fmassociated with Ethmodiscus was supported in part by an enhanced Ferredoxin Index (Fd Index), a common biochemical measure for Fe status. By comparison, the Fd Index for Rhizosolenia along the western reaches of the transect was consistently depressed. Cellular Fe quotas of both diatoms rinsed with oxalate, a reagent used to reduce cell surface adsorbed Fe facilitating its removal from the cell surface, demonstrated comparable low Fe:C stoichiometry (means of 5.41 SE 4.76 and 9.21 SE 5.10) (micro mol:mol) for Ethmodiscus and Rhizosolenia, respectively. This was consistent with the presumed low dissolved Fe content of these ultraoligotrophic waters. These cellular Fe quota (open full item for complete abstract)

Master of Arts in History, Youngstown State University, 2013, Department of Humanities

The study of the merchant iron industry presents a unique representation of the growth of both the Mahoning Valley and its industrial fortitude into the twentieth century. Known as the Steel Valley throughout the 1930s to the 1970s, the region's principal industry began in the first half of the nineteenth century in the form of pig iron production to serve local pioneer life and other industries throughout Youngstown and Pittsburgh. As steel manufacture flourished at the turn of the century, extensive steel production supplanted many of these former merchant iron producers, as large-scale manufacturing centralized in Youngstown. Those former merchant iron producers and their furnaces that remained portray distinctive methods of business practice and significant development in iron making technology and work. Relative hesitation of local industrialists to convert from iron to steel production allowed some former independent merchant iron producers to remain in operation or become part of a larger corporate entity into the twentieth century. This thesis looks at the furnaces in Hubbard, Struthers (Anna furnace) and Lowellville, Ohio (Mary furnace) and how their transition into the twentieth century presented various changes and adaptation in blast furnace technology, and how reliance on wrought iron manufacture presented a regional disadvantage as steel overtook iron production. One of the primary sources used are photographs, which allow the best look at changing technology within the industry when other documentation from these companies are relatively non-existent. Other information such as industry periodicals, newspapers, personal accounts and local histories help construct an extensive study of an industry that developed the Mahoning Valley into one of the largest iron and steel centers in the United States.

Doctor of Philosophy, Miami University, 2013, Microbiology

Acinetobacter baumannii is an important opportunistic human pathogen that causes severe nosocomial infections. The bacterium must overcome iron starvation and oxidative stress conditions imposed by the host in order to propagate and cause disease. This work further investigates the transport and utilization of iron by A. baumannii, and their involvement in virulence. The transport of iron is an active process and requires energy; A. baumannii ATCC 19606T contains and expresses three gene loci encoding functions in the TonB energy-transducing complex to provide the energy needed for iron transport. Transformation of Escherichia coli KP1344 with plasmids harboring the TonB components of these A. baumannii TonB systems promoted cell growth under iron-chelated conditions, which shows that these systems provide the necessary energy needed for iron acquisition. Inactivation of tonB1 and tonB2 in A. baumannii resulted in growth restriction under iron-chelation, indicating these genes are involved in iron transport. The Galleria mellonella infection model showed that TonB1 and TonB2 are involved, but are not essential for bacterial virulence, indicating A. baumannii carries redundant functional TonBs. Furthermore, TonB2 plays an additional role in the interaction with A549 human alveolar cells. Inactivation of dppA1A2 and dppBC, components of an inner membrane ABC transporter, did not affect growth under iron-chelation, suggesting alternative transport functions. However, inactivation of cirA, which codes for an iron-regulated outer membrane receptor resulted in reduced growth under iron-chelated conditions, indicating CirA has a role in iron transport. Furthermore, A. baumannii expresses hemin utilization functions independent of production and transport of acinetobactin-siderophore. Following transport, iron must be integrated into the intracellular iron pool. NfuA, a [Fe-S] cluster carrier protein was found to be involved in the ability of cells to respond to (open full item for complete abstract)

Master of Science, The Ohio State University, 2007, Graduate School

Master of Science, The Ohio State University, 2007, Graduate School

Master of Science (MS), Ohio University, 2024, Civil Engineering (Engineering and Technology)

Practical considerations for the design of an AMD treatment plant located in the Sunday Creek watershed were investigated. A mixed culture of bacteria originally from and AMD site located at Wolf Run, Noble County, OH, was enriched under various conditions in AMD from the Sunday Creek site. Following the work of Almomani (2023), the effects of inoculum size (1%, 2%, 5%, and 10%), nutrient enrichment conditions (reagent-grade ammonium and phosphate, no nutrient addition, and commercially available fertilizers), and temperature (8 °C, room temperature, and 32 °C) on the iron-oxidation kinetics of this culture were investigated. Inoculum size had no statistically significant effect on oxidation rates, although the oxidation rate at 5% and 10% inoculum (0.175 and 0.171 h^-1 , respectively) were observed to be nearly twice the oxidation rate at 1% inoculum (0.107 h^- 1 ). There was no significant difference between the oxidation rates of samples containing 0.1 M ammonium sulfate and 5 mM potassium phosphate (0.156 h^-1 ) and samples containing only inoculum (0.108 h^-1 ), and commercial fertilizer was observed to decrease iron oxidation rates (0.0547 h^-1 ), although the total time from inoculation to total iron oxidation was similar to that of the samples containing only inoculum. Iron oxidation rates increased with temperature, and the oxidation kinetics were fitted using the Arrhenius model yielding an activation energy of 70.1 kJ mol^-1 °K^-1 and a pre-exponential factor of 2.21 ∙ 10^11 h^-1 . A pilot-scale batch reaction experiment was conducted in field conditions at the Sunday Creek site in a 1250 gal clarifier. Oxidation rates were observed to be 0.012 h^-1 after the second subculturing, which was lower than any rate observed in the laboratory experiments. This was explained by a combination of suboptimal factors, including low temperatures and inclusion of commercial fertilizer as a secondary nutrient source. Finally, a process optimiz (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2024, Geological Sciences

Little is understood about the chemical evolution of banded iron formations (BIFs) subducted into the mantle during the Precambrian era. In general, the mantle becomes more reducing with increasing depth, with much of the deep mantle thought to be below the iron-wustite (IW) buffer. At equilibrium, under shallower mantle conditions, the hematite and magnetite in subducted BIFs would reduce wustite. In more deeply subducted BIFs, where the oxygen fugacity buffer is below IW, the wustite would reduce to iron metal. A key question is how rapidly iron oxide reduction reactions proceed at mantle pressures and temperatures. Fast reaction rate would imply that large amounts of wustite and/or metal may have precipitated in the deep mantle. BIFs that reduced to wustite and resisted further reduction could exist in the form of ULVZs (ulta-low velocity zones), as suggested by Dobson and Brodholt (2005). BIFs that fully reduced to iron metal could have produced large volume iron diapirs which would have been capable of sinking into the core and providing an inner core nucleation substrate, as suggested by Huguet et al. (2018). The studies reported here seek to answer these questions by determining the high-pressure, high-temperature reduction rates of iron oxides under mantle conditions. Chapter one describes the various approaches used to recreate banded iron formation subduction at high-pressures and high temperatures. Experiments explore temperatures from 600-1200 oC and pressures from 1.5-15 GPa. Chapter two addresses the first step of BIF reduction—the reduction of hematite and magnetite to wustite in the upper mantle. Experiments explore 14 temperatures from 600-1400 oC and pressures between 2-14 GPa. Chapter three addresses the final step in BIF reduction—the reduction of wustite to iron metal in the lower mantle.

Master of Science (MS), Ohio University, 2024, Civil Engineering (Engineering and Technology)

The goal of this thesis is to compare the current methods to generate pigment from AMD, test the pigments for their chemical and elemental compositions, and determine whether the pigments generated meet ASTM and market standards. The pigments were also evaluated to find their associated color numbers and compared to existing pigments collected from pigment companies. Iron oxide sludge was generated and collected from Truetown, OH by oxidizing and settling AMD. This sludge was tested for quality with the intent of making pigments from dried iron oxide. The sludge was dewatered or washed to represent potential treatment methods, then dried and ground into a fine powder. The powder was tested for iron oxide, sulfates, lead, organic coloring matter, moisture content, and ignition loss using ASTM standard methods. It was tested for its X-ray patterns using X-ray diffraction and for 31 elements using X-ray fluorescence. It was finally tested for its performance as an oil paint and its color spectrophotometry. These experiments were repeated for several examples of pigments from existing industry, including artistry and concrete dyeing. The results of these experiments showed that AMD pigments are generally lower in impurities than artist pigments, but higher than expected in sulfates. They are also amorphous but contain no toxic levels of metals. The experiments consistently showed that pressing was more effective than washing for removing impurities. The AMD pigments were also determined to be a different color than any of the collected pigments on the market, and would need to be identified as its own, separate color. Based on these conclusions and its derivation from AMD, it is suspected to be the iron oxide mineral known as Shwertmannite.

PHD, Kent State University, 2023, College of Arts and Sciences / Department of Biological Sciences

Climate change is exerting profound and far-reaching impacts on ecosystems worldwide, encompassing both aquatic and terrestrial environments. The evolving precipitation patterns and shifting temperature regimes impact fluctuations in hydrology, resulting in shifts in redox conditions which can impact the availability of nutrients like phosphorus (P). Phosphate, the bioavailable form of P, is only present in small amounts within soils, making the biological demand greater than soil phosphate availability. The majority of soil P is present in non-labile forms including organic P and phosphate sorbed to metal oxides like iron (Fe). Microorganisms must content with geochemical and other abiotic factors to access phosphate from these non-labile sources through the use of various strategies including the secretion of enzymes, the production of phosphate solubilizing acids, as well as indirect mechanisms associated with the reduction of Fe oxides. The primary goal of this dissertation was to advance our understanding of how microorganisms access both labile and non-labile forms of P in the presence of changing hydrologic and redox conditions which impact the speciation of Fe that is present, altering phosphate availability. Specifically, I investigated 1) how phosphate availability changes across a permafrost thaw gradient (palsa, bog, and fen) in the presence of iron oxides, 2) how microorganisms access and mobilize chemically diverse phosphorus sources under contrasting redox conditions, and 3) how changes in hydrology, redox, iron mineralogy, and phosphate availability drive shifts in microbial community composition, specifically iron oxidizers, reducers, and phosphate solubilizers. In our first study assessing microbial phosphate accessibility across a permafrost thaw gradient, we found that near surface redox conditions changed as a function of permafrost thaw which impacted phosphate availability. Reducing conditions in the bog promoted the dissolution of Fe oxides, (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2023, Nutrition Program, The Ohio State University

Iron deficiency anemia is a world-wide problem and affects 2 billion people, especially children, women, and vegetarians. Currently, inorganic iron fortified foods and iron supplements are used to prevent or treat iron deficiency, and some governments mandate iron fortification of staple crops. However, inorganic iron in grains and vegetables has limited bioavailability (1-10%), compared to heme iron (10-35%) in red meat. Since red meat consumption is resource intensive, we proposed a more sustainable plant-based iron delivery method. Iron chlorophyll derivatives (ICDs) are structurally analogous to heme containing a chlorophyll backbone with Fe replacing Mg. We tested if moderate electric field (MEF) could increase iron concentration in kales (iron fortification of vegetables), and proposed iron chlorophyllin can be produced in a green vegetable matrix following MEF treatment. The hypothesis was that ICDs can be produced in a green vegetable following MEF treatment. The results show MEF processing increased iron concentration 160 times more than control, indicating MEF increased mass transfer from solution to vegetable matrix. MEF did not produce ICDs, but increased heme isomer concentrations and total chlorophyll derivatives in MEF treated kale, possibly via increasing heme synthesis, reduced degradation, or increased extractability. We have also determined if ICDs are bioaccessible and deliver iron to Caco-2 human intestinal cells after in vitro digestion, better than ferrous sulfate. The results show that ICDs have poorer bioaccessibility relative to FeSO4 and hemoglobin. However, ICDs are better than FeSO4, but not hemoglobin, at increasing the ferritin concentration within Caco-2 cells, a marker of cell iron uptake and concentrations. ICDs facilitated greater ferritin synthesis when co-digested and incubated with albumin and ascorbic acid. This work also evaluated the capacity of ICDs to bind common toxins in food and water, i.e. aflatoxin B1 (AFB1), 1, 2 (open full item for complete abstract)

Master of Science (MS), Ohio University, 2023, Civil Engineering (Engineering and Technology)

The effects of pH, nutrients, and organic carbon on iron oxidation rates by mixed cultures of iron-oxidizing bacteria collected from three different extremely acidic AMD sites were investigated for the possibility of remediating the Truetown AMD at the Sunday creek, OH. Four values of pH (2.0, 2.5, 3.0, and 4.0), four concentrations of ammonium (0.01 M, 0.05 M, 0.1 M, and 0.5 M), five concentrations of phosphate (0.1 mM, 0.5 mM, 1.0 mM, 5.0 mM, and 10.0 mM), and three concentrations of glucose (0.05 M, 0.1 M, and 0.2 M) were tested. The best pH, ammonium concentration, and phosphate concentration were found to be 2.5, 0.1 M, and 5.0 mM, respectively, resulting in an iron oxidation rate of 0.570 hr-1, while the organic carbon resulted in approximately 52% inhibition after only one subculture. The iron oxidation rates achieved in this study surpassed the maximum iron oxidation rate achieved in most studies reported in the literature except for two studies where they adopted significantly different operation conditions. The best culture was found to be the one collected from Wolf Run site of predominantly A. ferrooxidans. Applying these results to Truetown AMD achieved a 12-fold increase in biotic iron oxidation rates, and a 1327-fold increase compared to the abiotic iron oxidation rates at Truetown site. In conclusion, iron-oxidizing bacteria, and nutrient addition significantly enhanced iron oxidation rates at very low pH. With further economical and operational optimization, AMD remediation by microorganisms can become a fast, sustainable, and low-cost treatment method exceeding other available AMD remediation techniques.

Master of Science (MS), Ohio University, 2023, Civil Engineering (Engineering and Technology)

Remediation of acid mine drainage (AMD) is an expensive process. Iron sediment from AMD treatment can be industrially significant and sold as pigment which can mitigate the remediation cost. An AMD treatment plant in Millfield, Ohio is being constructed for this purpose with the goal of selling commercial grade iron pigment while restoring an impaired stream. The ferrous iron in the AMD is oxidized, and then the hydrolyzed ferric iron is settled. However, to produce high-quality pigment, the pH must be kept at 4.5 or lower, posing a challenge for adequate settling. In this research, ten different commercial polymers were evaluated to increase the settling rates of the iron particles at low pH. The jar test was implemented to select the best polymer and optimize the dose to reduce the turbidity of the sample. The polymers NS-6650 and 6050 from Neo-Solutions, Inc. (Beaver, PA) removed more than 99% turbidity at 0.2 mg/L dosage, making them the best flocculants tested. In terms of calculated flocculent contamination, this flocculant dose yielded 99.95% pigment purity. The flocculants and dose were further tested for sedimentation, which resulted in iron settling rate of 0.15-0.25 ft/min. A clarifier design rise rate of 0.5-0.9 gpm/ft2 (700-1250 gpd/ft2) and diameter of 35-50 ft was recommended for the approximate Truetown seep flowrate of 2 cfs expecting 3-3.5% clarifier underflow solids content. For dewatering this sludge produced at low pH, vacuum filtration and filter press were evaluated in this research. The vacuum filtration did not appear as a suitable option because of longer cake formation time and high suspended solids content in the filtrate. However, the filter press showed feasible performance producing filter cakes with 20-25% solids content and indicating further improvement up to 30% cake solids with water effluent TSS <1 mg/L. As a viable dewatering process option, a single filter press equipment with 250-350 ft3 capacity was recommended to meet the (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2022, Geology

The Western Lake Erie Basin (WLEB) has been experiencing harmful algal blooms due to increases in dissolved reactive phosphorous (DRP) from agricultural land in the Maumee River watershed. Agricultural best management practices (BMPs) can be useful to mitigate the DRP loads; nevertheless, DRP is not always fully removed by in-field BMPs. Phosphorous (P) removal structures can be filled with phosphorus sorption materials (PSM) such as iron and aluminum oxides and can be placed at the junction of runoff and subsurface drainage to trap DRP from tile drainage. However, dissolved organic matter (DOM) from the agricultural farmland might compete with phosphate ions (PO43-) at the adsorption sites in the media, reducing its lifetime and efficiency. Therefore, laboratory flow-through column experiments were conducted to determine whether DOM is affecting P sorption onto iron enhanced activated alumina media (Alcan). The experiments were informed by field data collected from a regional farm. Alcan (Al/ Fe (hydro) oxides) media was efficient in removing PO43- coming into the filtering system and thereby, flow-through column experiments were able to determine a discrete P removal percentage efficiency of 83.32%, 68.26%, 66.54%, 57.16% and 41.27% by the end of treatment I (5mg L-1 PO43- only), treatment II (5mg L-1 PO43- and 5 mg L-1 DOM), treatment III (5mg L-1 PO43- and 10 mg L-1 DOM), treatment IV (5mg L-1 PO43- and 20 mg L-1 DOM), and treatment V (10mg L-1 PO43- and 20 mg L-1 DOM), respectively. Moreover, from exponential regression analysis of P removal curves for each treatment, it was measured that a total cumulative of 231.45 gm, 92.65 gm, 92.06 gm, 65.998 gm and 91.476 gm of P per kg PSM can be added to treatment I, II, III, IV and V, respectively, until the media gets fully saturated, i.e., concentration of influent PO43- would be equal to the effluent PO43- concentrations. It is evident that DOM is competing with PO43- decreasing PO43- sorption onto the Alcan media. (open full item for complete abstract)

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2022, Photochemical Sciences

Nature provides a wide range of biopolymers that have been used over the years to create different materials with different properties. Among these biopolymers, we used polysaccharides to develop sustainable materials with unique properties. To enhance their properties, we tried recreating the hierarchal assemblies found in nature between soft organic and hard inorganic components. In other words, our approach was to use metal coordination to ligand groups present in the polysaccharides to make materials with unique mechanical properties and water stability. We also wanted to be able to use light to modify the properties of these materials or degrade them. We chose to work with Fe(III) and V(V) metal ions because these two metals ions showed photoreactivity with different ligands such as carboxylate-containing polyuronates such as alginate and pectin, and other polysaccharides such as chitosan and cellulose and small hydroxy acids such as tartaric acid. First, we studied the photoreactivity of V(V) with two polysaccharides, alginate and chitosan in aqueous solution. In both solutions, a decrease in viscosity was observed with light irradiation accompanied by a change in color from an initial yellow color to a blue color corresponding to the photochemical reduction of V(V) to V(IV) according to previous studies. Second, we made solid films from pectin and chitosan and improved their properties using V(V) ion coordination. V(V)-coordinated films showed increased strength and water stability compared to V(V)-free films. The photochemical reaction observed in solution was also observed in solid state. Finally, to further understand the photochemical reaction in solid state, we made films by blending two of the three polysaccharides, either pectin and chitosan or pectin and ᴋ-carrageenan with different Fe-species. We learned that rheological properties and photochemical properties can be tuned by changing the blend of polysaccharide (open full item for complete abstract)