Matching Items (3)
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- All Subjects: Separations
- All Subjects: energy
- Creators: Lind, Mary Laura
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
The recovery of biofuels permits renewable alternatives to present day fossil fuels that cause devastating effects on the planet. Pervaporation is a separation process that shows promise for the separation of ethanol from biologically fermentation broths. The performance of thin film composite membranes of polydimethylsiloxane (PDMS) and zeolite imidazolate frameworks (ZIF-71) dip coated onto a porous substrate are analyzed. Pervaporation performance factors of flux, separation factor and selectivity are measured for varying ZIF-71 loadings of pure PDMS, 5 wt%, 12.5 wt% and 25 wt% at 60 oC with a 2 wt% ethanol/water feed. The increase in ZIF-71 loadings increased the performance of PDMS to produce higher flux, higher separation factor and high selectivity than pure polymeric films.
ContributorsLau, Ching Yan (Author) / Lind, Mary Laura (Thesis director) / Durgun, Pinar Cay (Committee member) / Lively, Ryan (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / Chemical Engineering Program (Contributor)
Created2014-05
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
Description
Styrene, a component of many rubber products, is currently synthesized from petroleum in a highly energy-intensive process. The Nielsen Laboratory at Arizona State has demonstrated a biochemical pathway by which E. coli can be engineered to produce styrene from the amino acid phenylalanine, which E. coli naturally synthesizes from glucose. However, styrene becomes toxic to E. coli above concentrations of 300 mg/L, severely limiting the large-scale applicability of the pathway. Thus, styrene must somehow be continuously removed from the system to facilitate higher yields and for the purposes of scale-up. The separation methods of pervaporation and solvent extraction were investigated to this end. Furthermore, the styrene pathway was extended by one step to produce styrene oxide, which is less volatile than styrene and theoretically simpler to recover. Adsorption of styrene oxide using the hydrophobic resin L-493 was attempted in order to improve the yield of styrene oxide and to provide additional proof of concept that the flux through the styrene pathway can be increased. The maximum styrene titer achieved was 1.2 g/L using the method of solvent extraction, but this yield was only possible when additional phenylalanine was supplemented to the system.
ContributorsMcDaniel, Matthew Cary (Author) / Nielsen, David (Thesis director) / Lind, Mary Laura (Committee member) / McKenna, Rebekah (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Chemical Engineering Program (Contributor)
Created2013-05