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Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta
Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta
Biological and Agricultural Engineering Undergraduate Honors Theses
The purpose of this project is to explore the functionality of carbon nanotubes as a bacterial removal method, specifically towards water-borne bacterial pathogens in wastewater by utilizing its unique magnetic and bacteria-binding properties. The general protocol set for this research follows five steps: 1) Preparation of wastewater media, 2) preparation of CNT culture, 3) preparation of reaction mixture with CNTs for bacterial binding, 4) magnetic separation of bacteria-bound-CNT clusters and, 5) assessment of supernatant. The CNTs effectively removed bacterial contaminants in the wastewater (10%, v/v) after the sand filtration process from the Paul R. Noland Wastewater Facility at Fayetteville, Arkansas. …
Novel Catalysts For The Production Of Co- And Co2-Free Hydrogen And Carbon Nanotubes By Non-Oxidative Dehydrogenation Of Hydrocarbons, Wenqin Shen
University of Kentucky Doctoral Dissertations
Non-oxidative dehydrogenation of hydrocarbons is an attractive alternative route for the production of CO- and CO2-free hydrogen. It will satisfy a major requirement for successful utilization of polymer electrolyte membrane (PEM) fuel cells (< 10 ppm CO) and sequestering carbon as a potentially valuable by-product, carbon nanotubes (CNTs). Due to the deposition of carbon on the surface of catalyst particles during the reaction, catalyst performance, life-time, and purification of the generated carbon product, are significant issues to solve in order to make the process practically feasible. The scope of this thesis includes: the development of novel Fe, Ni, and Fe-Ni catalysts supported on a Mg(Al)O support to achieve improved catalytic performance with easily-purified CNTs; evaluation of catalysts for ethane/methane dehydrogenation at moderate reaction temperatures; and study of activation and deactivation mechanisms by a variety of characterization techniques including TEM, HRTEM, XRD, Mössbauer spectroscopy, and x-ray absorption fine structure (XAFS) spectroscopy. The Mg(Al)O support was prepared by calcination of synthetic MgAl-hydrotalcite with a Mg to Al ratio of 5. The catalysts were prepared either by conventional incipient wetness method or by a novel nanoparticle impregnation method, where the monodisperse catalyst nanoparticles were prepared in advance by thermal decomposition of a metal-organic complex in an organic-phase solution and then dispersed onto the Mg(Al)O support. Dehydrogenation of undiluted methane was conducted in a fix-bed plug-flow reactor. Before reaction, the catalysts were activated by reduction in hydrogen. Fe-based catalysts exhibit a higher hydrogen yield at temperature above 600ºC compared with monometallic Ni catalyst. FeNi-9 nm/Mg(Al)O, Fe-10 nm/Mg(Al)O and Fe-5 nm/ Mg(Al)O nanoparticle catalysts show much improved performance and longer life-times compared with the corresponding FeNi IW/Mg(Al)O and Fe IW/Mg(Al)O catalysts prepared by incipient wetness. 10 nm is the optimum particle size for methane dehydrogenation. Addition of Ni to Fe forming a bimetallic FeNi alloy catalyst enhances the catalytic performance at the temperatures below 650ºC. Metallic Fe, Ni, FeNi alloy and Fe-Ni-C alloy, unstable iron carbide are all catalytically active components. Catalysts deactivation is due to the carbon encapsulation. The carbon products are in the form of stack-cone CNTs (SCNTs) and multi-walled CNTs (MWNTs), depending on the reaction temperature and catalyst composition. The growth of CNTs follows a tip growth mechanism and the purity of cleaned CNTs is more than 99.5%.