Experimental and Theoretical Insight of Perfluorooctanoic Acid Destruction by Alkaline Hydrothermal Treatment Enhanced with Zero-Valent Iron in Biochar

Yang, M; Du, Z; Bao, H; Zhang, X; Liu, Q; Guo, W; Ngo, HH; Nghiem, LD

Experimental and Theoretical Insight of Perfluorooctanoic Acid Destruction by Alkaline Hydrothermal Treatment Enhanced with Zero-Valent Iron in Biochar

Yang, M Du, Z Bao, H Zhang, X Liu, Q Guo, W

Ngo, HH Nghiem, LD

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Publisher:: AMER CHEMICAL SOC
Publication Type:: Journal Article
Citation:: ACS ES and T Water, 2023, 3, (5), pp. 1286-1293
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Yang, M
dc.contributor.author	Du, Z
dc.contributor.author	Bao, H
dc.contributor.author	Zhang, X
dc.contributor.author	Liu, Q
dc.contributor.author	Guo, W https://orcid.org/0000-0001-5542-2858
dc.contributor.author	Ngo, HH
dc.contributor.author	Nghiem, LD
dc.date.accessioned	2024-01-08T12:04:53Z
dc.date.available	2024-01-08T12:04:53Z
dc.date.issued	2023
dc.identifier.citation	ACS ES and T Water, 2023, 3, (5), pp. 1286-1293
dc.identifier.issn	2690-0637
dc.identifier.issn	2690-0637
dc.identifier.uri	http://hdl.handle.net/10453/174108
dc.description.abstract	This study demonstrates the complementarity between alkaline-thermal treatment and zero-valent iron immobilized in biochar (BC-ZVI) for enhanced degradation of perfluorooctanoic acid (PFOA). New and complementary research techniques, including 19F-NMR and density functional theory (DFT) analysis were used to evaluate defluorination efficiency and elucidate possible degradation mechanisms. The defluorination of PFOA was governed primarily by alkaline strength while BC-ZVI could enhance reaction kinetics by 2.4 times. Adsorption of the intermediates to BC-ZVI resulted in near-complete removal of all fluorinated compounds (with the exception of perfluoracetic acid) in the aqueous phase within 15 min of reaction. After 4 h of alkaline hydrothermal treatment (240 °C and 250 mM NaOH) with BC-ZVI, defluorination efficiency of PFOA of 99.7% was observed. Perfluoracetic acid was the only persistent byproduct but accounted only for less than 1% of the initial PFOA. DFT analysis also showed that strong alkaline conditions could decrease the reaction energy barrier by 73.9% due to the decarboxylation of PFOA via nucleophilic substitution. In addition to Kolbe decarboxylation, the profile of intermediate products and DFT analysis results suggest that PFOA was degraded by other mechanisms leading to near-complete and effective defluorination.
dc.language	English
dc.publisher	AMER CHEMICAL SOC
dc.relation.ispartof	ACS ES and T Water
dc.relation.isbasedon	10.1021/acsestwater.2c00614
dc.rights	info:eu-repo/semantics/closedAccess
dc.title	Experimental and Theoretical Insight of Perfluorooctanoic Acid Destruction by Alkaline Hydrothermal Treatment Enhanced with Zero-Valent Iron in Biochar
dc.type	Journal Article
utslib.citation.volume	3
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	/University of Technology Sydney/Strength - CTWW - Centre for Technology in Water and Wastewater Treatment
utslib.copyright.status	closed_access	*
pubs.consider-herdc	false
dc.date.updated	2024-01-08T12:04:48Z
pubs.issue	5
pubs.publication-status	Published
pubs.volume	3
utslib.citation.issue	5

Abstract:

This study demonstrates the complementarity between alkaline-thermal treatment and zero-valent iron immobilized in biochar (BC-ZVI) for enhanced degradation of perfluorooctanoic acid (PFOA). New and complementary research techniques, including 19F-NMR and density functional theory (DFT) analysis were used to evaluate defluorination efficiency and elucidate possible degradation mechanisms. The defluorination of PFOA was governed primarily by alkaline strength while BC-ZVI could enhance reaction kinetics by 2.4 times. Adsorption of the intermediates to BC-ZVI resulted in near-complete removal of all fluorinated compounds (with the exception of perfluoracetic acid) in the aqueous phase within 15 min of reaction. After 4 h of alkaline hydrothermal treatment (240 °C and 250 mM NaOH) with BC-ZVI, defluorination efficiency of PFOA of 99.7% was observed. Perfluoracetic acid was the only persistent byproduct but accounted only for less than 1% of the initial PFOA. DFT analysis also showed that strong alkaline conditions could decrease the reaction energy barrier by 73.9% due to the decarboxylation of PFOA via nucleophilic substitution. In addition to Kolbe decarboxylation, the profile of intermediate products and DFT analysis results suggest that PFOA was degraded by other mechanisms leading to near-complete and effective defluorination.

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http://hdl.handle.net/10453/174108