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BIOTEMPLATING OF TITANIUM DIOXIDE NANOPARTICLES FOR THE GREEN PRODUCTION OF PHOTOCHEMICALLY ACTIVE CATALYSTS: SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC EVALUATION
Description:
The ability of different nano-sized materials (NSM) to effectively act as active photo-catalytic surfaces has been described for the mineralization/inactivation of many different aqueous pollutants. The reason for their enhanced ability over larger catalytic surfaces owes much to the intrinsic material properties of NSM. However, current methods for synthesis of NSM involve the use of harsh organic solvents and surfactants or are energy intensive. Material inputs for these conventional processes are diminishing, not benign, and separation techniques to obtain the final NSM represent an unnecessary material input. Thus, conventional production of nanoparticles for use in photo-catalytic water disinfection presents a technical challenge to sustainability.
Use of biotemplating by metal accumulating vegetation for the production of some NSM has been successful; however, little has been done on the production of NSM titanium dioxide (TiO2), which is the most popular catalyst for the photocatalytic destruction of organic pollutants. In this proposed study, living Alfalfa and Morning Glory will be evaluated for their ability to uptake soil-soluble titanium, and subsequently precipitate titanium NSM. TiO2 NSM will be synthesized in this manner, its material properties will be characterized, and its photocatalytic performance will be evaluated for mineralization of organic contaminants in water.
The proposed production mechanism will benefit the planet by demonstrating the potential for recycling titanium resources from 'waste' streams where they are present in appreciable amounts. In addition, the project may lead to new and environmentally green technologies for the production other NSM materials. The implementation of NSM TiO2 in a photocatalytic reactor driven by UV (solar) radiation will benefit the developing world by offering a renewable alternative to chemical water disinfection techniques, and may offer an economically feasible mechanism for the production of reclaimed water in the developed world.
This project will serve as the senior design project for two undergraduate students at the University of Cincinnati and as the basis for a capstone design project and honors thesis for a student at Miami University (Ohio). Certain issues on green engineering, green chemistry and sustainability will be included in current dual level courses in the Environmental Engineering and Science (EES) program at the University of Cincinnati dealing with water treatment by "green" technologies and environmental nanotechnology. The courses will incorporate new concepts concerning a deep understanding of the properties of materials and environmental pollution minimization. The twelve principles of green chemistry and engineering will be taught and introduced in examples of modern environmental engineering and process development. The importance of concepts such as resources conservation, industrial ecology and preservation of biodiversity will also be covered. Biological synthesis of nanomaterials, the synthesis of nanomaterials for environmental applications following the twelve principles of green engineering, and the environmental fate of nanomaterials will be of particular emphasis. Finally, aspects of green engineering for the purification of water and for improving the quality of drinking water will also be included in the courses.