Matching Items (9)

Filtering by

Clear all filters

Heterogeneous Catalysis for Organic Reactions

Description

This honors thesis is focused on two separate catalysis projects conducted under the mentorship of Dr. Javier Pérez-Ramírez at ETH Zürich. The first project explored ethylene oxychlorination over supported europium oxychloride catalysts. The second project investigated alkyne semihydrogenation over nickel

This honors thesis is focused on two separate catalysis projects conducted under the mentorship of Dr. Javier Pérez-Ramírez at ETH Zürich. The first project explored ethylene oxychlorination over supported europium oxychloride catalysts. The second project investigated alkyne semihydrogenation over nickel phosphide catalysts. This work is the subject of a publication of which I am a co-author, as cited below.

Project 1 Abstract: Ethylene Oxychlorination
The current two-step process for the industrial process of vinyl chloride production involves CuCl2 catalyzed ethylene oxychlorination to ethylene dichloride followed by thermal cracking of the latter to vinyl chloride. To date, no industrial application of a one-step process is available. To close this gap, this work evaluates a wide range of self-prepared supported CeO2 and EuOCl catalysts for one-step production of vinyl chloride from ethylene in a fixed-bed reactor at 623 773 K and 1 bar using feed ratios of C2H4:HCl:O2:Ar:He = 3:3 6:1.5 6:3:82 89.5. Among all studied systems, CeO2/ZrO2 and CeO2/Zeolite MS show the highest activity but suffer from severe combustion of ethylene, forming COx, while 20 wt.% EuOCl/γ-Al2O3 leads to the best vinyl chloride selectivity of 87% at 15.6% C2H4 conversion with complete suppression of CO2 formation and only 4% selectivity to CO conversion for over 100 h on stream. Characterization by XRD and EDX mapping reveals that much of the Eu is present in non-active phases such as Al2Eu or EuAl4, indicating that alternative synthesis methods could be employed to better utilize the metal. A linear relationship between conversion and metal loading is found for this catalyst, indicating that always part of the used Eu is available as EuOCl, while the rest forms inactive europium aluminate species. Zeolite-supported EuOCl slightly outperforms EuOCl/γ Al2O3 in terms of total yield, but is prone to significant coking and is unstable. Even though a lot of Eu seems locked in inactive species on EuOCl/γ Al2O3, these results indicate possible savings of nearly 16,000 USD per kg of catalyst compared to a bulk EuOCl catalyst. These very promising findings constitute a crucial step for process intensification of polyvinyl chloride production and exploring the potential of supported EuOCl catalysts in industrially-relevant reactions.

Project 2 Abstract: Alkyne Semihydrogenation
Despite strongly suffering from poor noble metal utilization and a highly toxic selectivity modifier (Pb), the archetypal catalyst applied for the three-phase alkyne semihydrogenation, the Pb-doped Pd/CaCO3 (Lindlar catalyst), is still being utilized at industrial level. Inspired by the very recent strategies involving the modification of Pd with p-block elements (i.e., S), this work extrapolates the concept by preparing crystalline metal phosphides with controlled stoichiometry. To develop an affordable and environmentally-friendly alternative to traditional hydrogenation catalysts, nickel, a metal belonging to the same group as Pd and capable of splitting molecular hydrogen has been selected. Herein, a simple two-step synthesis procedure involving nontoxic precursors was used to synthesize bulk nickel phosphides with different stoichiometries (Ni2P, Ni5P4, and Ni12P5) by controlling the P:Ni ratios. To uncover structural and surface features, this catalyst family is characterized with an array of methods including X-ray diffraction (XRD), 31P magic-angle nuclear magnetic resonance (MAS-NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Bulk-sensitive techniques prove the successful preparation of pure phases while XPS analysis unravels the facile passivation occurring at the NixPy surface that persists even after reductive treatment. To assess the characteristic surface fingerprints of these materials, Ar sputtering was carried out at different penetration depths, reveling the presence of Ni+ and P-species. Continuous-flow three-phase hydrogenations of short-chain acetylenic compounds display that the oxidized layer covering the surface is reduced under reaction conditions, as evidenced by the induction period before reaching the steady state performance. To assess the impact of the phosphidation treatment on catalytic performance, the catalysts were benchmarked against a commercial Ni/SiO2-Al2O3 sample. While Ni/SiO2-Al2O3 presents very low selectivity to the alkene (the selectivity is about 10% at full conversion) attributed to the well-known tendency of naked nickel nanoparticles to form hydrides, the performance of nickel phosphides is highly selective and independent of P:Ni ratio. In line with previous findings on PdxS, kinetic tests indicate the occurrence of a dual-site mechanism where the alkyne and hydrogen do not compete for the same site.

This work is the subject of a publication of which I am a co-author, as cited below.

D. Albani; K. Karajovic; B. Tata; Q. Li; S. Mitchell; N. López; J. Pérez-Ramírez. Ensemble Design in Nickel Phosphide Catalysts for Alkyne Semi-Hydrogenation. ChemCatChem 2019. doi.org/10.1002/cctc.201801430

Contributors

Agent

Created

Date Created
2019-05

134548-Thumbnail Image.png

We Are Resilient Arizona

Description

This creative project is a collection of profiles focused on Arizona nonprofits and refugees. The profiles share stories of refugees, volunteers, employees and others involved in the community serving refugees. Nonprofits are a vital resource for refugee resettlement. These organizations

This creative project is a collection of profiles focused on Arizona nonprofits and refugees. The profiles share stories of refugees, volunteers, employees and others involved in the community serving refugees. Nonprofits are a vital resource for refugee resettlement. These organizations offer services to support refugees as they transition into new communities. Some services include: housing, English language learning, cultural orientation, job placement, medical treatment, education, and farming. Each of these programs support resiliency for refugees and for the communities in which they live. We Are Resilient was created first, to show the important role nonprofits have in serving refugees. Second, to connect people to a few of the stories and experiences within the Arizona refugee community. And third, to build understanding of the strength refugees bring to communities of Arizona and by extension the country. Visit weareresilientaz.com to learn more.

Contributors

Created

Date Created
2017-05

Vida Sin Agua: Vanishing Water in the Valley of the Sun

Description

The Colorado River is the lifeblood for seven Basin States including Colorado, Utah, Wyoming, New Mexico, Arizona, California and Nevada. This water source aided westward expansion and allowed the arid Southwest to grow. Today, the river is over-allocated resulting in

The Colorado River is the lifeblood for seven Basin States including Colorado, Utah, Wyoming, New Mexico, Arizona, California and Nevada. This water source aided westward expansion and allowed the arid Southwest to grow. Today, the river is over-allocated resulting in reduced flows. This could lead to water challenges in Arizona and the other Basin states. This river is the single largest entity from which Arizona receives water. Despite this, Arizona is still better situated for water cutbacks than other states like California. Arizona has more than nine million acre-feet of banked underground water and access to other water sources including the Salt and Verde rivers. Government officials are making decisions now that will affect water usage in Arizona for decades and generations to come. Digital media, such as iPad magazines are a good way to reach this technologically savvy generation and engage them concerning important issues. Designing for digital platforms presents unique opportunities. This platform requires solid content and visually appealing design to attract a Millennial audience born between the years 1981 and 1996, according to Pew Research Center. Digital magazines currently present a small segment of the media market, however this segment is growing exponentially. A study by Pew Research Center reports that this slice of the population is interested in consuming the news and emerging technologies such as digital magazines. These are good ways to reach and interest a digitally engaged readership. Reaching this age group is important because the Millennial generation will need to determine the future of the Colorado River and water use in Arizona. To ensure the future of water in the West, this generation needs to "learn about the reality of our water supply, what our real water challenges are and then get engaged and have a voice in what we do about our water planning for the future" (Porter, 2015). DISCLAIMER: The digital magazine was created in InDesign with interactive PDFs, which are best viewed on tablets. Screenshots of the magazine are included to demonstrate the magazine.

Contributors

Created

Date Created
2016-05

135417-Thumbnail Image.png

Arizona State Senate: First Hand Accounts of the Female Political Experience in Arizona

Description

In Arizona's early history, Females garnered more independence than most other women in the United States because they were forced to build a completely new life in settlements with little to no infrastructure. Now, Arizona has achieved a level of

In Arizona's early history, Females garnered more independence than most other women in the United States because they were forced to build a completely new life in settlements with little to no infrastructure. Now, Arizona has achieved a level of equality that no other state has yet to achieve in regard to gender representation. Yet, we have yet to achieve total equity. This paper looks to analyze responses that female senators from the Arizona State Legislature gave while being interviewed by the author. With questions derived from previous research conducted on women in politics at the state and federal level, this paper will delve into the personal experiences of six female senators. Although their personal narratives differ, their stories seem to reflect a collective tie that unites the female members together, beyond party allegiance. Each of the responses given by the senators had some aspects that showed trends supporting the majority of the hypotheses. Moving forward, in order to achieve 50% equality, two more senators would need to be elected and replace male senators.

Contributors

Agent

Created

Date Created
2016-05

136954-Thumbnail Image.jpg

Creating Shared Economic Value for Arizonans by Proliferating Solar through the Hyperloop Project

Description

Each year the United States' interstates and roadways become increasingly congested, with little development of useful mass transit. Elon Musk released a whitepaper titled Hyperloop Alpha in order to generate conversation around a potential "fifth mode of transportation" as an

Each year the United States' interstates and roadways become increasingly congested, with little development of useful mass transit. Elon Musk released a whitepaper titled Hyperloop Alpha in order to generate conversation around a potential "fifth mode of transportation" as an alternative to current high-speed rail technologies. This case study analyzes the implications of implementing the Hyperloop along the 120-mile Phoenix-Tucson route in terms of the State's geographic, economic, political, and environmental advantages for the Hyperloop design. This case study was not meant to investigate the engineering aspects of an untested technology, but rather to generate conversation and elicit enthusiasm in the State of Arizona in order to bring the project in-house. Through comparison of the California context of the Hyperloop and other megaregions this report proposes that given Arizona's solar power production potential, short, flat, undeveloped route, explosive population growth, urban density distribution, recognized need for HSR, and strong research institutions make it the ideal site and premiere candidate for initial Hyperloop testing and construction.

Contributors

Agent

Created

Date Created
2014-05

135913-Thumbnail Image.png

Sustainability Competencies in Middle-School Curriculum: Educating Students About Water Systems and Drought

Description

Current literature on sustainability education and its core competencies (systems thinking, normative, interpersonal, strategic, and future thinking) has yet to acknowledge the K-12 level, concentrating instead on higher-level institutions. To initiate study at the critical K-12 level, a curriculum module

Current literature on sustainability education and its core competencies (systems thinking, normative, interpersonal, strategic, and future thinking) has yet to acknowledge the K-12 level, concentrating instead on higher-level institutions. To initiate study at the critical K-12 level, a curriculum module composed of four lessons to address the wicked sustainability problem of drought in the Sonoran Desert was developed, piloted, and evaluated. The framework of each lesson combined the core competencies and the 5Es pedagogy (engage, explore, explain, elaborate, and evaluate). Two lessons were successfully piloted in two seventh grade middle-school science classes in Phoenix, Arizona. Topics addressed were the water cycle, types of drought, water systems, and mitigation methods. Evaluation determined a high level of student engagement. Post-pilot teacher questionnaires revealed a high degree of support for inclusion of sustainability education and core competencies addressing drought in future opportunities. It is concluded that lessons in the future can adopt the core competences of sustainability with the support of educators in Arizona.

Contributors

Agent

Created

Date Created
2015-12

136089-Thumbnail Image.png

Water: Are We Using it Wisely? A comparative analysis of water demand management trend and strategies in Phoenix and Tucson, Arizona

Description

As Arizona enters its fifteenth year of drought and Lake Mead hits historic lows, water management and policy planning will become increasingly important to ensure future water security in the Southwestern region of the United States. This thesis compares water

As Arizona enters its fifteenth year of drought and Lake Mead hits historic lows, water management and policy planning will become increasingly important to ensure future water security in the Southwestern region of the United States. This thesis compares water demand trends and policies at the municipal level in Phoenix and Tucson, Arizona over the time period from 1980-2010. By analyzing gallons per capita per day (GPCD) trends for each city in the context of population growth, drought, and major state and local policies over the twenty year period, reasons for declines in per capita water demand were explored. Despite differences in their available water sources and political cultures, both the City of Phoenix and the City of Tucson have successfully reduced their per capita water consumption levels between 1980 and 2010. However, this study suggests that each city's measured success at reducing GPCD has been more a result of external events (supply augmentation, drought, and differing development trends) rather than conservation and demand reduction regulations adopted under the auspices of the Groundwater Management Act.

Contributors

Created

Date Created
2015-05

132064-Thumbnail Image.png

A White Paper on the Methods to Prevent Fracking in Arizona

Description

When the Bureau of Land Management (BLM) auctioned off federal lands in the Holbrook Basin area in Arizona, this action set off a furor among concerned residents and groups in Arizona. Under new rules, the BLM did not have to

When the Bureau of Land Management (BLM) auctioned off federal lands in the Holbrook Basin area in Arizona, this action set off a furor among concerned residents and groups in Arizona. Under new rules, the BLM did not have to conduct a public input or environmental analysis before the lease auction. Furthermore, evidence suggests that oil and gas companies may use techniques similar to fracking to obtain helium gas from the Holbrook Basin. Through the analysis of the history of fracking in the United States (U.S.) and Arizona as well as fracking bans in four key states, New York, Pennsylvania, Colorado, and Florida, this paper will illustrate some of the ways Arizona can go about preventing fracking. These case studies suggest that the best way to do this is to focus on the local level, specifically zoning regulations, and then move to the state level.

Contributors

Agent

Created

Date Created
2019-12

134716-Thumbnail Image.png

History and Overview of Dual Language Immersion Programs

Description

Dual Language Immersion programs have been growing exponentially as a result of an urgent need for globally competent, bilingual or multilingual citizens. The US is currently facing a language deficit, which negatively affects national security, international relations and even the

Dual Language Immersion programs have been growing exponentially as a result of an urgent need for globally competent, bilingual or multilingual citizens. The US is currently facing a language deficit, which negatively affects national security, international relations and even the economy. If America wants to stay in contention as one of the strongest world powers, the US needs to foster more interest in learning foreign languages earlier and invest in the development of foreign language education. The purpose of this paper is to provide an overview of the history and implementation of different Dual Language Immersion program models. The geographical scope of the paper will cover historical background in Canada and the current implementation of Dual Language Immersion models in three Southwestern states: California, Utah and Arizona. The paper also outlines challenges related to the implementation of these dual language immersion programs.

Contributors

Agent

Created

Date Created
2016-12