Browsing by Subject "recycling"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Recovery and evaluation of the solid products produced by thermocatalytic decomposition of tire rubber compounds(Texas A&M University, 2007-04-25) Liang, LanA thermal catalytic decomposition process has been developed to recycle used tire rubber. This process enables the recovery of useful products, such as hydrocarbons and carbon blacks. During the catalytic decomposition process, the tire rubber is decomposed into smaller hydrocarbons, which are collected in the process. The solid reaction residue, which normally consists of carbon black, catalysts, other inorganic rubber compound components, and organic carbonaceous deposits, was subjected to a series of treatments with the intention to recover the valuable carbon black and catalyst. The process economics depend strongly on the commercial value of the recovered carbon black and the ability to recover and recycle the catalysts used in the process. Some of the important properties of the recovered carbon black product have been characterized and compared with that of commercial-grade carbon blacks. The composition of the recovered carbon black was analyzed by TGA and EDX, the structure and morphology were studied through transmission electron microscopy (TEM), and the specific surface area was measured by BET nitrogen adsorption. The recovered products possess qualities at least comparable to (or even better than) that of the commercial-grade carbon black N660. Methods for increasing the market value of this recovered carbon black product are discussed. Anhydrous aluminum chloride (AlCl3) was used as the primary catalyst in the process. A catalyst recovery method based on the AlCl3 sublimation and recondensation was studied and found to be non-feasible. It is believed that the catalyst forms an organometallic complex with the decomposed hydrocarbons, such that it becomes chemically bonded to the residue material and hence not removable by evaporation. A scheme for the further study of the catalyst recovery is suggested.Item Syntheses and applications of soluble polyisobutylene (PIB)-supported transition metal catalysts(2009-05-15) Tian, JianhuaSoluble polymer supports facilitate the recovery and recycling of expensive transition metal complexes. Recently, polyisobutylene (PIB) oligomers have been found to be suitable polymer supports for the recovery of a variety of transition metal catalysts using liquid/liquid biphasic separations after a homogeneous reaction. Our work has shown that PIB-supported Ni(II) and Co(II) ?-diketonates prepared from commercially available vinyl terminated PIB oligomers possess catalytic activity like that of their low molecular weight analogs in Mukaiyama epoxidation of olefins. Carboxylic acid terminated PIB derivatives can act as carboxylate ligands for Rh(II) cyclopropanation catalysts. An achiral PIB-supported Rh(II) carboxylate catalyst showed good activity in cyclopropanation of styrene in hydrocarbon solvents, and could be easily recycled nine times by a post reaction extraction. Further application of PIB supports in asymmetric cyclopropanation reactions were investigated using PIBsupported arenesulfonyl Rh(II) prolinates derived from L-proline as examples. The PIBsupported chiral Rh carboxylates demonstrated moderate activity and were recovered and reused for four to five cycles. The prolinate catalyst prepared from PIB-anisole also showed encouraging enantioselectivity and about 8% ee and 13% ee were observed on trans- and cis-cyclopropanation product respectively. Finally, PIB oligomers can be modified in a multi step sequence to prepare PIBsupported chiral bisoxazolines that can in turn be used to prepare active, recyclable PIBsupported Cu(I) bisoxazoline complexes for olefin cyclopropanation. These chiral copper catalysts showed moderate catalytic activity and good stereoselectivity in cyclopropanation of styrene. A chiral ligand prepared from D-phenylglycinol provided the most effective stereo control and gave the trans- and cis-cyclopropanation product in 94% ee and 68% ee respectively. All three PIB-supported chiral bisoxazoline-Cu(I) catalysts could be reused five to six times.Item The Recycling Intentions of Sport Spectators: A Theory of Planned Behavior Approach(2012-07-16) McCullough, Brian PatrickSport organizations have a negative impact on the environment but these organizations have begun environmental initiatives to decrease their impact. Introducing recycling programs not only offers visible environmental effort to decrease the organization?s impact but such programs can provide financial savings for the organization. Thus, my dissertation?s purpose is to understand the recycling intentions of sport spectators by the means of three studies theoretically framed using the theory of planned behavior. Study 1 examined the recycling intentions of individuals after consuming plastic water bottles within a campus environment. Participants were undergraduate students (N = 144) enrolled in physical activity classes at a southwestern university in the United States (males n=83, 57.6 percent, females n=60, 41.7 percent; mostly White n=96, 66.7 percent; age M=19.6, SD=1.33). The results indicate that subjective norms (? = .29, p < .001) and attitudes (? = .14, p < .05) towards recycling significantly predicted intentions to recycle plastic bottles after consumption. Study 2 analyzed the recycling intentions within a sport context. Participants (N=129) were adult spectators attending a weekend long youth baseball tournament in the Southwest United States (women n=85, 65.9 percent, men n=40, 31.0 percent; predominately White n=97, 75.2 percent; age M=44.47 years, SD=10.20). Similar to Study 1, subjective norms (? = .27, p < .01) significantly predicted intentions to recycle. However, unlike Study 1, perceived behavioral controls (? = .21, p < .05) were significant in predicting intentions to recycle. Lastly, Study 3 augmented my investigation to understand the unique context of recycling intentions among sport spectators. I used qualitative research methods to understand recycling intentions of spectators during a large scale-sporting event. Participants (N=16) were adults that regularly attend college football games at a large southwestern university (men n=10, women n=6; age M=37.44). The results indicate that recycling within a sport context is unique considering the game day atmosphere. Collectively, the findings from the three studies are discussed as to influence decision-making policies within sport organizations to improve recycling programs and to decrease the organization?s negative environmental impact. Finally, recommendations are made for future research to understand recycling behaviors of sport spectators.