Novel Magnetic Extractants for Removal of Pollutants from Water

This research aims at developing magnetic extractants that can be utilized in conjunction with magnetic filtration devices to efficiently and economically remove a number of pollutants from aqueous solutions and mixtures. Two types of magnetic materials were synthesized, characterized, and used in a variety of environmental applications. The first was based on activated carbon, where raw materials used for the development of high surface area activated carbon were modified to produce novel magnetically-active activated carbons (MAC's). The unique properties and adsorption capacity of these materials allowed their application in the extraction of hydrocarbons from water and in breaking oil in water emulsions. In the second phase of the project, nano-composites of organic-capped magnetite and nickel ferrite were successfully obtained by non-hydrolytic thermal treatment of organometallic precursors. The nanoparticles were characterized using a variety of techniques including transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Finally, an investigation on the ability of the nanoparticulate extractants for the removal of 4,6-dinitro-o-cresol pesticide and arsenate from water was conducted.Findings and Conclusions: Magnetic activated carbons prepared from industrial and household byproducts were effective for the removal of decane, 4,6-dinitro-o-cresol, arsenate, and a number of dyes from aqueous media. Additionally, MAC's were capable of breaking oil in water emulsions. Carboxylate capped magnetic nanoparticles were easily synthesized, and exhibited unique properties such as structural uniformity, small size, and high surface area. These nanoparticles showed remarkable results in the removal of 4,6-dinitro-o-cresol pesticide and arsenate from water. Moreover, magnetic activity exhibited by these extractants allowed for quick separation using magnetic filters. Potential applications include rapid cleanup of oil spills, treatment of waste waters, separation of lipids from serum samples for medical analysis and as an alternative to liquid/liquid extraction in chemical and drug manufacturing.Chemistry Departmen

Seismic assessment and rehabilitation of a historical masonry mosque

In order to assess the structural behaviour and to evaluate the seismic vulnerability of old masonry structures located in Lebanon, a historical masonry mosque was analysed under earthquake loading. A numerical model developed by the finite element method using Abaqus software was elaborated on the basis of previously published experimental studies. It was concluded that the numerical model can predict maximum stresses with reasonable accuracy, allowing control of a full scale wall model. This analysis shows that the stresses generated in the joints between the blocks exceed the ultimate shear stress of the mortar, resulting in cracks in the joints. The choice of an adequate structural rehabilitation method was limited because the mosque is of archaeological importance and its original appearance should not be modified. Therefore, a seismic retrofit solution using internal or external post tensioned tendons was recommended

Self-Aligned Carbon Nanotube Yarns for Multifunctional Optoelectronic Applications

In this work, the morphology and electrocatalytic features of carbon nanotube yarns at the structural level allow for enhanced photoconversion efficiency. The energy conversion of electronhole pairs within the carbon nanotube yarn (CNY) due to the functionalization with nanostructured photoactive TiO₂ phases is remarkable. A well oriented anatase TiO₂ thin layer (approximately 100 nm) forms at the interfaces of CNY and TiO₂ mesoporous film when the sample is precoated and annealed at 350ºC. Field Emission Scanning Electron Microscopy (FESEM) images show the integrity and homogeneity of the TiO₂ surface, which is indicative of the overall durability of the CNY-based dye sensitized solar cell (DSSC); Coating TiO₂ on self-aligned carbon nanotube yarns provides several benefits from their high chemical stability, excellent functionality, nontoxicity and relatively low cost. The maximum photon to current conversion efficiency (ηAM1.5) achieved with prolonged-time stability was 3.1%

An Integrated Multidisciplinary Nanoscience Concentration Certificate Program for STEM Education

Integration of nanoscience and nanotechnology curricula into the College of Science, Mathematics, and Technology (CSMT) at the University of Texas at Brownsville (UTB) is reported. The rationale for the established multidisciplinary Nanoscience Concentration Certificate Program (NCCP) is to: (i) develop nanotechnology-relevant courses within a comprehensive Science, Engineering and Technology curriculum, and, to offer students an opportunity to graduate with a certificate in nanoscience and nanotechnology; (ii) to contribute to students\u27 success in achieving student outcomes across all college\u27s majors, and, improve the breath, depth and quality of science, technology, engineering and mathematics (STEM) graduates\u27 education; (iii) through NCCP, recruit certificate- and associate-degree seeking students into four year programs in engineering and physical sciences. A long-term goal is to develop an ABET accredited bachelor program in nanoscience. This program is expected to reach out to a large group of undergraduate students in a coordinated manner, enhance students\u27 knowledge and skills, as well as facilitate efforts of individual faculty members in STEM education. The UTB NCCP is supported by the NSF NUE program, under which we are developing and offering seven upper-level interdisciplinary undergraduate courses. These courses and program are assessed and evaluated

ZnO Nanowires Synthesized by Vapor Phase Transport Deposition on Transparent Oxide Substrates

Zinc oxide nanowires have been synthesized without using metal catalyst seed layers on fluorine-doped tin oxide (FTO) substrates by a modified vapor phase transport deposition process using a double-tube reactor. The unique reactor configuration creates a Zn-rich vapor environment that facilitates formation and growth of zinc oxide nanoparticles and wires (20–80 nm in diameter, up to 6 μm in length, density <40 nm apart) at substrate temperatures down to 300°C. Electron microscopy and other characterization techniques show nanowires with distinct morphologies when grown under different conditions. The effect of reaction parameters including reaction time, temperature, and carrier gas flow rate on the size, morphology, crystalline structure, and density of ZnO nanowires has been investigated. The nanowires grown by this method have a diameter, length, and density appropriate for use in fabricating hybrid polymer/metal oxide nanostructure solar cells. For example, it is preferable to have nanowires no more than 40 nm apart to minimize exciton recombination in polymer solar cells

Seismic assessment and rehabilitation of a historical masonry mosque

In order to assess the structural behaviour and to evaluate the seismic vulnerability of old masonry structures located in Lebanon, a historical masonry mosque was analysed under earthquake loading. A numerical model developed by the finite element method using Abaqus software was elaborated on the basis of previously published experimental studies. It was concluded that the numerical model can predict maximum stresses with reasonable accuracy, allowing control of a full scale wall model. This analysis shows that the stresses generated in the joints between the blocks exceed the ultimate shear stress of the mortar, resulting in cracks in the joints. The choice of an adequate structural rehabilitation method was limited because the mosque is of archaeological importance and its original appearance should not be modified. Therefore, a seismic retrofit solution using internal or external post tensioned tendons was recommended

Nanostructured functional materials for advanced three-dimensional (3D) solar cells

Advancements in dye-sensitized solar cell (DSSC) technology are occurring at an ever-increasing rate, as the development of novel carbon-based materials, the increasing research into new 3D surface morphologies and cell design, and the focus on the development of new sensitizers and electrolytes have allowed many new possibilities for DSSCs. Solar cells that are three-dimensionally structured offer significant advantages over traditional crystalline / semi-crystalline panels in that they can convert incident photons that strike them at large incident angles, can be flexible / used in applications which require non-rigid materials, and can be substantially cheaper to produce than traditional panels, especially with the replacement of more expensive, traditional electrode materials by carbon materials in the working / counter electrode. The use of carefully selected and engineered sensitizers like quantum dots with these three-dimensionally structured solar cells have seen them achieve ever-increasing power conversion efficiencies, and it\u27s likely that they will soon rival traditional crystalline / semi-crystalline panels for both mass power generation and use in more niche applications such as flexible photovoltaic textile fibers. This review covers DSSCs constructed with several different materials, and the advantages and disadvantages of a variety of cell designs

Low Temperature Deposition of Zinc Oxide Nanoparticles Via Zinc-Rich Vapor Phase Transport and Condensation

ZnO nanoparticles as small as 80 nm were successfully synthesized using a modified vapor phase transport (VPT) process at substrate temperatures as low as 222 degrees C Particle size distribution and morphology were characterized by scanning electron microscopy and atomic force microscopy Energy dispersive X-ray spectroscopy and X-ray diffraction indicate the synthesis of high quality crystalline ZnO structures Low temperature (4 2 K) photoluminescence (PL) spectroscopy was used to characterize the optical quality of the nanoparticles Ultraviolet emission and a nanostructure specific feature at 3 366 eV are strong in the PL spectra The 3 366 eV feature is observed to predominate the spectrum with decrease in particle size This size effect corroborates the luminescence as a nanostructure-specific surface related exciton feature as previously speculated in the literature In addition self-assembled ZnO mesoparticles ( \u3e 100 nm) were realized by increasing the growth time Low growth temperatures of the particles allow for their potential utilization in flexible organic hybrid optoelectronics However this work focuses mainly on the modified synthesis and optical characterization of nanoparticles (C) 2010 Elsevier B V All rights reserve

Low Temperature Deposition of Zinc Oxide Nanoparticles Via Zinc-Rich Vapor Phase Transport and Condensation

ZnO nanoparticles as small as 80 nm were successfully synthesized using a modified vapor phase transport (VPT) process at substrate temperatures as low as 222 degrees C Particle size distribution and morphology were characterized by scanning electron microscopy and atomic force microscopy Energy dispersive X-ray spectroscopy and X-ray diffraction indicate the synthesis of high quality crystalline ZnO structures Low temperature (4 2 K) photoluminescence (PL) spectroscopy was used to characterize the optical quality of the nanoparticles Ultraviolet emission and a nanostructure specific feature at 3 366 eV are strong in the PL spectra The 3 366 eV feature is observed to predominate the spectrum with decrease in particle size This size effect corroborates the luminescence as a nanostructure-specific surface related exciton feature as previously speculated in the literature In addition self-assembled ZnO mesoparticles ( \u3e 100 nm) were realized by increasing the growth time Low growth temperatures of the particles allow for their potential utilization in flexible organic hybrid optoelectronics However this work focuses mainly on the modified synthesis and optical characterization of nanoparticles (C) 2010 Elsevier B V All rights reserve