Digital Commons Network^™

Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq

Theses and Dissertations (Comprehensive)

Numerous studies have been conducted on the removal of inorganic phosphorus (P) from wastewater, but a push towards lower effluent targets necessitates the additional removal of organic phosphorus as well. This study tested the ability of manganese oxide nanoparticles and iron oxide as potential catalysts for conversion of organic P into more readily removable inorganic forms, as well as the role of iron(III) chloride as coagulant to subsequently allow P to be removed by solids/liquid separation. Removals of 99-101% were obtained for model compounds at pH 5-7, 0.05-0.5 M H₂O₂, and Fe:P molar ratio of 5:1. …

Sm And Dy Interaction With Dissolved Organic Matter (Dom) In Freshwater Measured By Ion-Selective Electrode And Fluorescence Quenching Analytical Techniques, Alexandra Carvajal

Theses and Dissertations (Comprehensive)

With the increased demand for lanthanide metals in various industries, companies are looking into mining of these metals in Northern Canada. The release of these metals into the environment may have adverse effect on aquatic ecosystems; thus, it is important to understand potential toxicological effects of lanthanides on aquatic organisms. One way to predict these effects is by using a Biotic Ligand Model (BLM). Although incorporation of lanthanides into the model will require a substantial amount of future research, initial studies into speciation and toxicity can provide a useful basis for future reference. There are two main objectives to this …

Phosphorus Removal Using Titanium Dioxide Nanoparticles In Wastewater Treatment, Suyoung Choi Mr.

Theses and Dissertations (Comprehensive)

Due to eutrophication caused by nutrients such as phosphorus (P), local surface water near military garrisons and camps has been deteriorated for several years in the Republic of Korea. Thus, in order to remove excessive P in local fresh water, various size of titanium dioxide (TiO₂) were used.

In the first investigation, TiO₂ mixed bulk powder (particle size > 5µm) showed maximum P removal with pH dependence (higher pH shows lower P removal), that was approximately 27%. To determine adsorption isotherms, Langmuir and Freudlich models were used. The experimental data was better fit by a Langmuir model compared …

The Role Of Organic Matter In The Surface Chemistry Of Arsenic Compounds On Iron−(Oxyhydr)Oxides Studied By Atr-Ftir, Arthur Situm

Theses and Dissertations (Comprehensive)

The interaction of organic matter with the interfaces of active soil components such as iron oxides is ubiquitous within soil environments. The presence of organics at these interfaces may have implications for other soil constituents whose mobility is controlled by their ability to bind to active soil components. Most of the studies performed to date which look at these interactions are bulk/batch studies performed ex-situ. Attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was utilized within this work to study interactions between select model organics (citrate, oxalate and pyrocatechol) and iron−(oxyhydr)oxides, as well as their effect on the surface …

Comparing The Regio- And Enantioselectivity Of Inverting Versus Retaining Epoxide Hydrolases, Mark A. Aliwalas

Theses and Dissertations (Comprehensive)

Epoxide hydrolases (EHs) are enzymes that catalyze the ring opening of an epoxide, yielding a vicinal diol. This exciting class of enzymes is often associated with natural product and small molecule biosynthesis. One interesting class of natural products that epoxide hydrolases are involved in the biosynthesis of is the enediynes. Previously, 5 enediyne-associated epoxide hydrolases have been characterized, revealing an inverting-versus-retaining paradigm for enediyne epoxide hydrolases. The work described herein sets the table for future studies involving the probing of the α/β-epoxide hydrolase mechanism for styrene oxide. Kinetic and regioselectivity characterization of the enediyne-associated CynF and SghF has determined that …

Seasonal Evolution Of Active Layer Formation In Subarctic Peat Plateaux And Implications For Dissolved Organic Matter Composition And Transfer, Jennifer L. Hickman

Theses and Dissertations (Comprehensive)

Peat-accumulating wetlands are ecosystems whose rate of photosynthetic production of organic matter is greater than that of its decomposition, resulting in a build up of soil organic matter that may take centuries to fully decompose. Carbon (C) stocks within these ecosystems are a function of inputs from photosynthesis, and losses from heterotrophic decomposition. Due to the short growing season and overall cold climate of boreal and tundra regions, C has been accumulating within these landscapes, mostly in soil organic matter, since the last glaciation. Climate change, predicted to result in rising temperatures and increased precipitation, has begun to degrade the …