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Towards Rational and Sustainable Design of Graphitic Carbon Nitride for Antibacterial Applications

Aquino de Carvalho, Nathalia (2022) Towards Rational and Sustainable Design of Graphitic Carbon Nitride for Antibacterial Applications. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Graphitic carbon nitride (g-C3N4) is an emerging visible-light-responsive photocatalyst with desirable antimicrobial activity. Considering synthesis choices that lead to competitive performance and minimize environmental and human health impacts is critical for developing g-C3N4 as an effective and sustainable disinfection alternative. This dissertation demonstrates the ability to rationally design g-C3N4 by chemical composition manipulations during synthesis, enabling control of g-C3N4 photocatalytic antibacterial response. Further, a life cycle assessment (LCA) of g-C3N4 syntheses offers concrete opportunities for the reduction of synthesis related impacts.
g-C3N4 properties that influence photocatalytic bacterial inactivation (i.e., band gap, intermediate defect states, dispersed surface area, absorbance in suspension, and charge separation) are compared across six samples modified using different synthesis temperature and carbon-doping. The effect of altering these material properties on the production of reactive oxygen species is investigated and linked to the ability to inactivate Escherichia coli bacteria. Results indicate that C-doping is an effective avenue to modulating g-C3N4 properties, and it induces variable levels of bacterial inactivation. C-doping is also successful in expanding g-C3N4 visible light range from 449 nm to 588 nm while maintaining a level of antibacterial activity.
To evaluate the sustainability of g-C3N4, a LCA is completed for predominant synthesis routes, and their environmental impacts are benchmarked to a competitive photocatalyst alternative, titanium dioxide nanoparticles (nano-TiO2). Results reveal energy demand during synthesis as the major contributor to the environmental impacts, highlighting opportunities to reduce the impacts through several suggested synthesis process modifications. The sustainability claim of g-C3N4 is found to depend on the particular synthesis route and underlying assumptions of the comparison to nano-TiO2. Expanding the analysis of g-C3N4 to the use-stage shows benefits from activating g-C3N4 with visible wavelength light emitting diodes instead of ultraviolet (UV) wavelengths for nano-TiO2. Given g-C3N4 high embodied resource footprint, any mass of g-C3N4 used for disinfecting drinking water to viral load reduction standards results in greater impact than UV disinfection.
Collectively, the research in this dissertation provides novel findings contributing to further development of g-C3N4 as a competitive sustainable antimicrobial, supporting rational design through synthesis modifications to control disinfection performance and reduce synthesis associated environmental impacts.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Aquino de Carvalho, Nathalianaa71@pitt.edunaa710000-0002-9568-5350
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairGilbertson, Leanne Mleanne.gilbertson@pitt.eduleanne.gilbertson0000-0003-3396-4204
Committee MemberBibby, Kylekbibby@nd.edu0000-0003-3142-6090
Committee MemberNg,
Committee MemberKhanna, Vikaskhannav@pitt.edukhannav0000-0002-7211-5195
Date: 6 September 2022
Date Type: Publication
Defense Date: 14 December 2021
Approval Date: 6 September 2022
Submission Date: 14 February 2022
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 230
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Civil and Environmental Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Nanotechnology, Microbiology, Disinfection, Photocatalysis
Date Deposited: 06 Sep 2022 16:40
Last Modified: 06 Sep 2023 05:15


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