Photocatalytic Degradation of Perfluorooctanoic Acid in Water by Free and Immobilised ZnO, g-C3N4 and Their Composite under UV and Visible Light Irradiation

Navidpour, Amir Hossein

Photocatalytic Degradation of Perfluorooctanoic Acid in Water by Free and Immobilised ZnO, g-C3N4 and Their Composite under UV and Visible Light Irradiation

Navidpour, Amir Hossein

Permalink

Publication Type:: Thesis
Issue Date:: 2023

Open Access

Copyright Clearance Process

Recently Added
In Progress
Open Access

This item is open access.

Adobe PDF

Download thesisAdobe PDF (15.35 MB)

View statistics

Full metadata record

Field	Value	Language
dc.contributor.author	Navidpour, Amir Hossein
dc.date.accessioned	2024-04-11T03:32:30Z
dc.date.available	2024-04-11T03:32:30Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/177716
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	Perfluorooctanoic acid (PFOA) is among perfluoroalkyl and polyfluoroalkyl substances (PFAS) that is widely detected in the environment. ZnO and graphitic carbon nitride are among the most economical semiconductors which have not been widely used for PFOA decomposition. Therefore, ZnO could be an alternative to In₂O₃, as a benchmark photocatalyst for PFOA degradation, under ultraviolet (UV) irradiation. More interestingly, suspended ZnO nanoparticles showed promising for PFOA degradation under visible light irradiation (unlike In₂O₃ nanoparticles). The probable production of sulphate radicals by the addition of peroxymonosulfate (PMS) up to ~0.53 g/L significantly improved PFOA decomposition to ~70% within 2 h (~53 mg/L PFOA concentration, ~0.53 g/L ZnO nanoparticles, 254 nm UV). More importantly, the same amount of PMS improved PFOA degradation under visible light illumination (source of light: 300W xenon lamp), while ZnO with its wide band gap energy is not usually considered a visible light activated semiconductor. Electrophoretic deposition was effectively used for the immobilisation of ZnO nanoparticles on FTO plate. Notably, the addition of PMS (~0.27 g/L) improved the apparent rate constant of PFOA decomposition under both UV and visible light irradiation, clarifying the crucial role of sulphate radicals in PFOA decomposition. The optimal ZnO coating was also used as the photoanode for the degradation of PFOA using photoelectrocatalysis (at V = 0) where the apparent rate constant of 0.331 h⁻¹ was obtained under UV irradiation and ~53 mg/L PFOA concentration. Citric acid was effectively used to modify g-C₃N₄ with increasing the photo-absorption ability and lowering the recombination rate of charge carriers. Hence, ZnO@citric acid-modified carbon nitride nanocomposites were successfully produced by ball milling and effectively used for PFOA decomposition. Although citric acid-modified was not effective for PFOA degradation, ZnO@citric acid-modified carbon nitride (5 wt%) nanocomposite showed superior efficiency than initial ZnO nanoparticles under UV irradiation (0.406 h⁻¹ against 0.103 h⁻¹) in 2 h (~53 mg/L PFOA concentration, ~0.53 g/L catalysts). The optimal nanocomposite also showed extremely higher proficiency than pure ball-milled ZnO nanoparticles (control) under visible light irradiation.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/177716/3/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Amir Hossein Navidpour
dc.rights	au.edu.uts.lib/cph
dc.title	Photocatalytic Degradation of Perfluorooctanoic Acid in Water by Free and Immobilised ZnO, g-C3N4 and Their Composite under UV and Visible Light Irradiation	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Perfluorooctanoic acid (PFOA) is among perfluoroalkyl and polyfluoroalkyl substances (PFAS) that is widely detected in the environment. ZnO and graphitic carbon nitride are among the most economical semiconductors which have not been widely used for PFOA decomposition. Therefore, ZnO could be an alternative to In₂O₃, as a benchmark photocatalyst for PFOA degradation, under ultraviolet (UV) irradiation. More interestingly, suspended ZnO nanoparticles showed promising for PFOA degradation under visible light irradiation (unlike In₂O₃ nanoparticles). The probable production of sulphate radicals by the addition of peroxymonosulfate (PMS) up to ~0.53 g/L significantly improved PFOA decomposition to ~70% within 2 h (~53 mg/L PFOA concentration, ~0.53 g/L ZnO nanoparticles, 254 nm UV). More importantly, the same amount of PMS improved PFOA degradation under visible light illumination (source of light: 300W xenon lamp), while ZnO with its wide band gap energy is not usually considered a visible light activated semiconductor. Electrophoretic deposition was effectively used for the immobilisation of ZnO nanoparticles on FTO plate. Notably, the addition of PMS (~0.27 g/L) improved the apparent rate constant of PFOA decomposition under both UV and visible light irradiation, clarifying the crucial role of sulphate radicals in PFOA decomposition. The optimal ZnO coating was also used as the photoanode for the degradation of PFOA using photoelectrocatalysis (at V = 0) where the apparent rate constant of 0.331 h⁻¹ was obtained under UV irradiation and ~53 mg/L PFOA concentration. Citric acid was effectively used to modify g-C₃N₄ with increasing the photo-absorption ability and lowering the recombination rate of charge carriers. Hence, ZnO@citric acid-modified carbon nitride nanocomposites were successfully produced by ball milling and effectively used for PFOA decomposition. Although citric acid-modified was not effective for PFOA degradation, ZnO@citric acid-modified carbon nitride (5 wt%) nanocomposite showed superior efficiency than initial ZnO nanoparticles under UV irradiation (0.406 h⁻¹ against 0.103 h⁻¹) in 2 h (~53 mg/L PFOA concentration, ~0.53 g/L catalysts). The optimal nanocomposite also showed extremely higher proficiency than pure ball-milled ZnO nanoparticles (control) under visible light irradiation.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/177716