Quantification of the environmental impact of titanium dioxide photocatalytic pavements for air pollution remediation
Doctor of Philosophy (PhD)
Engineering Science (Interdepartmental Program)
Photocatalytic concrete pavements are a promising technology for mobile source air pollution remediation, however before widespread application of this technology is realized many unanswered questions remain regarding its overall environmental impact. In response to these questions, the goal of this study was to increase the understanding of the environmental impact of photocatalytic concrete pavement highways. To achieve this goal, the objectives of this study were to (A) construct a model that evaluates the nitrogen oxides (NOx) reduction from photocatalytic pavements, (B) quantify the nitrates released from the photocatalytic degradation of NOx, and (C) identify and characterize pathways for TiO2 nanoparticle exposure. To achieve objective A, a field study was conducted to evaluate the NOx reduction. Results showed evidence of minimal photocatalytic reductions with large variability due to many unknown and known parameters. As a result, this study also investigated the use of laboratory results to better understand the significance of the NOx reduction through the creation of a theoretical mass balance Lavoisier box model. Laboratory results indicated that the nitrogen monoxide (NO) oxidation rate is reaction rate mass transfer controlled following the Langmuir- Hinshelwood (L-H) model. A parametric study was completed to evaluate the L-H constants under different environmental conditions and statistical model was created to describe the NO oxidation rate. Incorporating the resulting NO oxidation rate into a Lavoisier box model the mass transfer mechanisms were compared and objective A was achieved. Objectives B and C of the project deal with evaluating potential unintended consequences resulting from implementation of photocatalytic concretes. To complete objective B, nitrates and TiO2 nanoparticles released to water were quantified. Lastly, TiO2 nanoparticles released to the air during construction activities were quantified and characterized to achieve objective C.
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Dylla, Heather Lee, "Quantification of the environmental impact of titanium dioxide photocatalytic pavements for air pollution remediation" (2013). LSU Doctoral Dissertations. 2658.