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- Creators: School of Life Sciences
- Creators: Anderson, Anthony David
- Creators: Close, Emily Charlotte
Description
Within recent years, metal-organic frameworks, or MOF’s, have gained a lot of attention in the materials research community. These micro-porous materials are constructed of a metal oxide core and organic linkers, and have a wide-variety of applications due to their extensive material characteristic possibilities. The focus of this study is the MOF-5 material, specifically its chemical stability in air. The MOF-5 material has a large pore size of 8 Å, and aperture sizes of 15 and 12 Å. The pore size, pore functionality, and physically stable structure makes MOF-5 a desirable material. MOF-5 holds applications in gas/liquid separation, catalysis, and gas storage. The main problem with the MOF-5 material, however, is its instability in atmospheric air. This inherent instability is due to the water in air binding to the zinc-oxide core, effectively changing the material and its structure. Because of this material weakness, the MOF-5 material is difficult to be utilized in industrial applications. Through the research efforts proposed by this study, the stability of the MOF-5 powder and membrane were studied. MOF-5 powder and a MOF-5 membrane were synthesized and characterized using XRD analysis. In an attempt to improve the stability of MOF-5 in air, methyl groups were added to the organic linker in order to hinder the interaction of water with the Zn4O core. This was done by replacing the terepthalic acid organic linker with 2,5-dimethyl terephthalic acid in the powder and membrane synthesis steps. The methyl-modified MOF-5 powder was found to be stable after several days of exposure to air while the MOF-5 powder exhibited significant crystalline change. The methyl-modified membrane was found to be unstable when synthesized using the same procedure as the MOF-5 membrane.
ContributorsAnderson, Anthony David (Author) / Lin, Jerry Y.S. (Thesis director) / Ibrahim, Amr (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This paper encompasses part of the complex topic of relationships between consumers, organic products, and advertising in America with a particular focus on Tempe, Arizona. Background research included in this paper includes how the term "organic" was developed and regulated to fit the federal standards that are implied through the use of the USDA organic label that was introduced in October of 2002. Further research considers the factors that have empirically and overwhelmingly contributed to motivations of attitude development and purchasing behaviors of the average organic consumer in America, tracking changes and potential causes over the past several decades. A large proportion of this paper analyzes the results of a survey conducted in Tempe between late 2014 and early 2015. This survey, shown in the appendices, includes responses from 310 Tempe consumers regarding questions of demographics, knowledge and perception of organic products, perceived access to organic products, consumer values, and purchasing behaviors. The results of the survey reflect the values displayed in previous studies on national surveys, with some discrepancies that appear to set Tempe apart from the national average. However, the results of the survey are limited by their exclusion and limited parsing of multiple confounds. Additionally, the respondents of the survey were not proportionate to the actually population of Tempe and therefore cannot be accurately generalized to the Tempe population as a whole. The third and final section of this paper deals with the relationship between advertisers and consumers. This considers how advertising helps to develop product values and perceptions through various methods. Future directions for advertising of organic products is also addressed, as advertisers can potentially become a source of developing scientific information if properly utilized. Further directives and gaps in research are addressed in the final portion of the paper and include how to increase consumer knowledge, the problems faced by organic advocates, what is important about what we already know, and where to go from here.
ContributorsAttanasio, Amber-Leigh Lace (Author) / Brian, Jennifer (Thesis director) / Phillips, Elizabeth Capaldi (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Metal-organic frameworks (MOFs) are a new set of porous materials comprised of metals or metal clusters bonded together in a coordination system by organic linkers. They are becoming popular for gas separations due to their abilities to be tailored toward specific applications. Zirconium MOFs in particular are known for their high stability under standard temperature and pressure due to the strength of the Zirconium-Oxygen coordination bond. However, the acid modulator needed to ensure long range order of the product also prevents complete linker deprotonation. This leads to a powder product that cannot easily be incorporated into continuous MOF membranes. This study therefore implemented a new bi-phase synthesis technique with a deprotonating agent to achieve intergrowth in UiO-66 membranes. Crystal intergrowth will allow for effective gas separations and future permeation testing. During experimentation, successful intergrown UiO-66 membranes were synthesized and characterized. The degree of intergrowth and crystal orientations varied with changing deprotonating agent concentration, modulator concentration, and ligand:modulator ratios. Further studies will focus on achieving the same results on porous substrates.
ContributorsClose, Emily Charlotte (Author) / Mu, Bin (Thesis director) / Shan, Bohan (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
The Effect of ZnS and Other Metal Sulfides on cis-1,2-dimethylcyclohexane at Hydrothermal Conditions
Description
Reactions between minerals and organic compounds in hydrothermal systems (high temperature and presence of H2O) are critical in the Earth’s deep carbon cycle and may have implications in the origins of life. Previous work demonstrated that in the absence of a mineral, hydrothermal reaction of cis- and trans-1,2-dimethylcyclohexane is extremely slow and resulted in the formation of many products. However, in the presence of sphalerite (ZnS), the reaction rate is significantly increased and it results in the formation of one main product, the corresponding stereoisomer. Following similar methods, we demonstrated that the sphalerite used in the reaction of cis-1,2-dimethylcyclohexane to the trans- stereoisomer visually changes structure via SEM. Additionally, we ran the experiments in sealed glass tubes, which unlike previously used gold tubes, do not react with the organics and provides more volume for larger amounts of mineral to be used. Finally, we investigated the role of other metal sulfides (FeS and PbS) in organic transformation reactions and analyzed their resulting physical structure. We found the role of FeS catalysis to be ambiguous and that PbS seemed to have no effect in the transformation reactions. We also found the glass tube data using ZnS to track previously published data with the same reactions in gold tubes. Our reactions were run without pressurizing the reaction vessels and at 300°C indicating pressure is not main factor in product formation (compare 1000 bar and 300°C).
ContributorsMchenry, Austin Ryan (Author) / Gould, Ian (Thesis director) / Johnson, Kristin (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05