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You searched for +publisher:"University of Colorado" +contributor:("Zhiyong Ren"). Showing records 1 – 3 of 3 total matches.

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University of Colorado

1. Haeger, Alexander John. New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment.

Degree: MS, Civil, Environmental & Architectural Engineering, 2015, University of Colorado

Wastewater treatment is a hallmark of advanced society and has evolved throughout history to improve treatment efficiency while reducing harmful effects to humans and surrounding ecosystems. The water-energy nexus is no more apparent than in wastewater treatment and much work is being done currently to reduce the energy footprint of the industry. Anaerobic technologies are at the forefront of this energy revolution because they are capable of producing energy products while performing treatment. One such anaerobic technology is the bioelectrochemical system (BES). Exoelectrogenic bacteria in BESs oxidize organics while producing direct electrical current. While much work has been done in the field, until now, a bottleneck to BES deployment has been the lack of a scalable reactor configuration. In this study a new compact and high performance spiral wound microbial fuel cell (a type of BES) configuration was developed for wastewater treatment. The 3” long configuration showed high power output of 170 W/m3 treated (effective reactor volume), low internal resistances of under 1Ω (ohmic), high electrode surface area to volume ratios of 700 m2/m3, and treatment capacity of 9.01 kgCOD/day. An automated electrolyte feeding system was also developed as a part of this study to maintain the highest possible system performance during experiments. Power output and hydraulic dead space both increased with electrode packing density, which is a new insight for the spiral wound design. The manufacturing methods developed for spiral wound BES modules were successfully applied to microbial capacitive deionization (MCD) for oil and gas produced water treatment. 40” long reactors were built with the aid of a custom machine and maximum power and current outputs of 89 W/m3 and 228mA were achieved while removing over 68% of the COD in real produced water. The large scale reactor removed 10.2 gTDS/day although external power was required for the integrated desalination process due to a design error. Custom monitoring and control systems were also developed for the MCD system with a focus on operational simplification for field deployment. As a part of ongoing work, material and process improvements can be made to improve the energy efficiency of the desalination system. Advisors/Committee Members: Zhiyong Ren, JoAnn Silverstein, Karl Linden.

Subjects/Keywords: automation; microbial capacitive deionization; microbial fuel cell; microcontrollers; self-powered treatment; wastewater treatment; Civil Engineering; Electro-Mechanical Systems; Environmental Engineering

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APA (6th Edition):

Haeger, A. J. (2015). New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/cven_gradetds/177

Chicago Manual of Style (16th Edition):

Haeger, Alexander John. “New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment.” 2015. Masters Thesis, University of Colorado. Accessed December 09, 2019. https://scholar.colorado.edu/cven_gradetds/177.

MLA Handbook (7th Edition):

Haeger, Alexander John. “New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment.” 2015. Web. 09 Dec 2019.

Vancouver:

Haeger AJ. New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment. [Internet] [Masters thesis]. University of Colorado; 2015. [cited 2019 Dec 09]. Available from: https://scholar.colorado.edu/cven_gradetds/177.

Council of Science Editors:

Haeger AJ. New Spiral Wound Bioelectrochemical Systems and Control Automation for Energy Production and Wastewater Treatment. [Masters Thesis]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/cven_gradetds/177


University of Colorado

2. Robinson, Allison M. The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts.

Degree: PhD, Chemical & Biochemical Engineering, 2016, University of Colorado

In this thesis we investigate the role of oxophilic metal modifiers in deoxygenation catalysts, starting with surface science experiments and extending to supported catalyst studies. Carbon-oxygen bond scission is critical for biomass upgrading applications, but these bonds tend to be strong in the aromatic oxygenates that make up a large portion of pyrolysis oil. Bimetallic catalysts containing a noble metal and an oxophilic metal have shown promising activity and selectivity for deoxygenation, but the role of each metal in the overall reaction is unclear. Gaining a fundamental understanding of the roles of oxophilic sites will facilitate a systematic approach to catalyst design. Structure-property relations were investigated under ultra-high vacuum (UHV) using a Pt(111) single crystal modified with sub-monolayer quantities of molybdenum. X-ray photoelectron spectroscopy suggested that when the surface is pretreated in hydrogen the Pt and Mo sites interact, resulting in a significant electronic effect on the Pt atoms. Low energy electron diffraction indicated that the hydrogen-reduced surface is well ordered, with Mo atoms inserted into the Pt lattice. The electronic effect was apparent using temperature-programmed desorption (TPD) experiments; as the coverage of Mo increased the desorption temperatures of carbon monoxide and hydrogen decreased by 10 and 30 K, respectively. In addition, these reduced Pt-Mo sites were shown to allow dissociation of water into hydrogen and surface hydroxyls, a process that does not occur on unmodified Pt(111). This may be important for deoxygenation because surface hydroxyl groups may act as acid sites. Alternatively, when the surface was treated in oxygen, the oxidized Mo formed an inert, disordered surface layer that only served to block active sites. To extend this approach to more complex reactants representative of pyrolysis oil, the surface chemistry of benzyl alcohol was studied using TPD. Pt(111) catalyzed both decarbonylation to form benzene and carbon monoxide as well as complete decomposition to hydrogen and surface carbon. Incorporation of Mo improved the selectivity to hydrogenolysis, forming toluene as the major organic product. Toluene TPD and density functional theory (DFT) calculations suggested that the selectivity improvement may be in part due to reduced adsorption strength of the aromatic ring. These results were extended to alumina-supported Pt and PtMo catalysts. When Mo was incorporated into particles with a large fraction of terrace (111) sites the same shift in reaction pathway was observed as in the UHV results, with increased hydrogenolysis activity to produce toluene and lower activity for decarbonylation. Supported Pt and PtMo catalysts were also studied for deoxygenation of m-cresol, an aromatic oxygenate containing a very strong C-O bond. Incorporation of Mo was found to increase selectivity to the deoxygenated alkane product. DFT calculations suggest this may be due in part to strong binding of the oxygen-containing… Advisors/Committee Members: J. Will Medlin, John L. Falconer, Jennifer N. Cha, Jesse E. Hensley, Zhiyong Ren.

Subjects/Keywords: Bimetallic; Catalysis; Hydrodeoxygenation; Molybdenum; Oxophilic Promoter; Platinum; Catalysis and Reaction Engineering; Chemical Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Robinson, A. M. (2016). The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts. (Doctoral Dissertation). University of Colorado. Retrieved from http://scholar.colorado.edu/chen_gradetds/5

Chicago Manual of Style (16th Edition):

Robinson, Allison M. “The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts.” 2016. Doctoral Dissertation, University of Colorado. Accessed December 09, 2019. http://scholar.colorado.edu/chen_gradetds/5.

MLA Handbook (7th Edition):

Robinson, Allison M. “The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts.” 2016. Web. 09 Dec 2019.

Vancouver:

Robinson AM. The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2019 Dec 09]. Available from: http://scholar.colorado.edu/chen_gradetds/5.

Council of Science Editors:

Robinson AM. The Role of Oxophilic Metal Promoters in Bimetallic Hydrodeoxygenation Catalysts. [Doctoral Dissertation]. University of Colorado; 2016. Available from: http://scholar.colorado.edu/chen_gradetds/5


University of Colorado

3. Gomez, Odessa Mason. Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions.

Degree: PhD, 2016, University of Colorado

Biological aerosols (bioaerosols) constitute a significant portion of airborne particulate matter, both indoors and outdoors; however, the extent to which anthropogenic oxidative air pollutants can modify bioaerosols remains unclear. This work isolated the potential for atmospheric ozone to modify important biopolymers in ubiquitous types of bioaerosols. Independent lines of evidence for ozone-mediated modifications of bioaerosols were obtained from environmentally controlled chamber studies designed to challenge bioaerosols with ozone and humidity conditions relevant to the current US EPA NAAQ standards. Before and during different ozone exposures, intrinsic bioaerosol fluorescence was monitored concurrently with the quantity and activity of significant allergens and enzymes present in pure bioaerosols. Results indicate significant decreases in fluorescence intensity, enzyme activity and specific allergen content with ozone exposure, while liberated water soluble organic carbon (WSOC) concomitantly increased over time in all environmental conditions tested. As judged by real-time intrinsic fluorescence measurements of whole bioaerosols (airborne sporulated <i>Aspergillus spp.</i> and <i>Bacillus subtilis</i>), and the intrinsic fluorescence properties of the liberated bioaerosol WSOC fraction, differences in specific fluorescence began to appear within an hour of bioaerosol exposures to ozone and high humidity. Significant decreases in measureable airborne fungal enzyme activity (beta-N-acetylhexosaminidase) and allergen (Aspf1) content were encountered in response to ozone exposures. On time scales relevant for lower atmosphere environmental ozone bioaerosol exposures, these are the first observations implicating ozone inhibition of key enzymes responsible for fungal spore germination, and antigenic modification of the <i>Aspergillus</i> allergen Asp f 1. Results from these controlled bioaerosol exposure chamber studies were related to actual environmental aerosol samples that had experienced extreme oxidative stress during a local wildfire. The carbon content and intrinsic fluorescence profiles of WSOC from collected wildfire aerosols indicate that distinct fluorescence patterns from the WSOC present in wildfire emissions changed over the course of the wildfire event in both indoor and outdoor locations, further demonstrating the infiltration potential of wildfire emissions into the indoor environment. Results from this work contribute to a limited body of existing observations documenting the potential impacts of oxidative air pollutants on bioaerosols present in both outdoor and indoor environments. Advisors/Committee Members: Mark T. Hernandez, Anne Perring, Zhiyong Ren, Fernando Rosario-Ortiz, Darin Toohey.

Subjects/Keywords: air pollution; allergens; bioaerosols; fungal spores; oxidation; ozone; Environmental Engineering; Environmental Microbiology and Microbial Ecology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gomez, O. M. (2016). Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/cven_gradetds/435

Chicago Manual of Style (16th Edition):

Gomez, Odessa Mason. “Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions.” 2016. Doctoral Dissertation, University of Colorado. Accessed December 09, 2019. https://scholar.colorado.edu/cven_gradetds/435.

MLA Handbook (7th Edition):

Gomez, Odessa Mason. “Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions.” 2016. Web. 09 Dec 2019.

Vancouver:

Gomez OM. Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2019 Dec 09]. Available from: https://scholar.colorado.edu/cven_gradetds/435.

Council of Science Editors:

Gomez OM. Characterizing Responses of Primary Biological Aerosols to Oxidative Atmospheric Conditions. [Doctoral Dissertation]. University of Colorado; 2016. Available from: https://scholar.colorado.edu/cven_gradetds/435

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