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- All Subjects: environment
- Creators: School of Sustainability
one’s self-reported measure of well-being and is thought of as having a high level of positive affect, low level of negative affect, and high degree of life satisfaction (Diener, 1984).
This study was conducted to assess the interrelationships between affective experiences, SWB, and usage of campus outdoor spaces in order to learn how outdoor spaces on the Arizona State University (ASU) Tempe campus can be enhanced to increase SWB and usage. In total, 832 students completed a survey questionnaire 1,140 times for six campus outdoor spaces. The results showed that students experience the greatest amount of happiness in the Secret Garden
and James Turrell ASU Skyspace, relaxation/restoration is the affective experience most strongly related to SWB, and SWB is negatively correlated with frequency of visits but positively link with duration of visits. To improve student happiness and usage of outdoor spaces on campuses, planners and designers should work on increasing the relaxing/restorative qualities of existing
locations, creating new spaces for relaxation/restoration around campus, reducing the perception of crowding and noise in large spaces, increasing fun/excitement by adding stimuli and/or opportunities for activity and entertainment, and adding equipment necessary for students to perform the activities they want. In addition to the ASU Tempe campus, the methodology and
findings of this research could be used to improve outdoor spaces on other college and university campuses and other types of outdoor environments.
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
A large section of United States citizens live far away from supermarkets and do not have an easy way to get to one. This portion of the population lives in an area called a food desert. Food deserts are geographic areas in which access to affordable, healthy food, such as fresh produce, is limited or completely nonexistent due to the absence of convenient grocery stores. Individuals living in food deserts are left to rely on convenience store snacks and fast food for their meals because they do not have access to a grocery store with fresh produce in their area. Unhealthy foods also lead to health issues, as people living in food deserts are typically at a higher risk of diet-related conditions, such as obesity, diabetes, and cardiovascular disease. Harvest, a sustainable farming network, is a smartphone application that teaches and guides people living in small spaces through the process of growing fresh, nutritious produce in their own homes. The app will guide users through the entire process of gardening, from seed to harvest. Harvest would give individuals living in food deserts an opportunity to access fresh produce that they currently can’t access. An overwhelming response based on our user discussion and market analysis revealed that our platform was in demand. Development of a target market, brand guide, and full-lifecycle were beneficial during the second semester as Harvest moved forward. Through the development of a website, social media platform, and smartphone application, Harvest grew traction for our platform. Our social media accounts saw a 1700% growth rate, and this wider audience was able to provide helpful feedback.
Soiled: An Environmental Podcast is a six episode series where common environmental topics are discussed and misconceptions surrounding these topics are debunked.