Significantly Accelerated Photochemical Perfluorooctanoic Acid Decomposition at the Air–Water Interface of Microdroplets

Li, Kejian; You, Wenbo; Wang, Wei; Gong, Kedong; Liu, Yangyang; Wang, Longqian; Ge, Qiuyue; Ruan, Xuejun; Ao, Jianpeng; Ji, Minbiao; Zhang, Liwu

doi:10.1021/acs.est.3c05470

“…25 min, which is substantially lower than that in the gaseous phase (∼130 days) by >7000 times. The value is longer than that reported in a pioneer study using similar sized microdroplets with additional UV irradiation and Fe(NO 3 ) 3 that can induce photochemical transformation of PFOA. However, more rapid degradation of PFOA was observed (Figure a) for smaller microdroplets (1–50 μm) generated by nebulizing (ca.…”

Section: Results and Discussionmentioning

confidence: 57%

“…In this study, we observed for the first time that perfluorooctanoic acid (PFOA), a widely used and detected PFAS, as well as some other PFASs, can be spontaneously degraded in water microdroplets at room temperature without external energy input. Quenching experiments and ab initio molecular dynamics (AIMD) simulations provided strong evidence for a mixed multicycle two- and one-carbon-shortened degradation pathway on water-microdroplet surfaces, which are ubiquitous in the environment, distinctive from previously reported mechanisms underlying advanced oxidation/reduction processes. − This study extends the current understanding of the environmental fate and chemistry of C–F bond-containing substances and provides insight into aid in the development of effective methods for converting PFASs into environmentally harmless or less toxic species.…”

Section: Introductionmentioning

confidence: 60%

Spontaneous Degradation of the “Forever Chemicals” Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) on Water Droplet Surfaces

Xia,

Zhang,

Ju

et al. 2024

J. Am. Chem. Soc.

2

0

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Because of their innate chemical stability, the ubiquitous perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been dubbed "forever chemicals" and have attracted considerable attention. However, their stability under environmental conditions has not been widely verified. Herein, perfluorooctanoic acid (PFOA), a widely used and detected PFAS, was found to be spontaneously degraded in aqueous microdroplets under room temperature and atmospheric pressure conditions. This unexpected fast degradation occurred via a unique multicycle redox reaction of PFOA with interfacial reactive species on the droplet surface. Similar degradation was observed for other PFASs. This study extends the current understanding of the environmental fate and chemistry of PFASs and provides insight into aid in the development of effective methods for removing PFASs.

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Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Grooms,

Huttner,

Stockwell

et al. 2024

Angewandte Chemie

0

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Non‐thermal plasma discharge produced in the wake of charged microdroplets is found to facilitate catalyst‐free radical mediated hydrazine cross‐coupling reactions without the use of external light source, heat, precious metal complex, or trapping agents. A plasma‐microdroplet fusion platform is utilized for introduction of hydrazine reagent that undergoes homolytic cleavage forming radical intermediate species. The non‐thermal plasma discharge that causes the cleavage originates from a chemically etched silica capillary. The coupling of the radical intermediates gives various products. Plasma‐microdroplet fusion occurs online in a programmable reaction platform allowing direct process optimization and product validation via mass spectrometry. The platform is applied herein with a variety of hydrazine substrates, enabling i) self‐coupling to form secondary amines with identical N‐substitutions, ii) cross‐coupling to afford secondary amine with different N‐substituents, iii) cross‐coupling followed by in‐situ dehydrogenation to give the corresponding aryl‐aldimines with two unique N‐substitutions, and iv) cascade heterocyclic carbazole derivatives formation. These unique reactions were made possible in the charged microdroplet environment through our ability to program conditions such as reagent concentration (i.e., flowrate), microdroplet reactivity (i.e., presence or absence of plasma), and reaction timescale (i.e., operational mode source). The selected program is implemented in a co‐axial spray format.

show abstract

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Grooms,

Huttner,

Stockwell

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

Non‐thermal plasma discharge produced in the wake of charged microdroplets is found to facilitate catalyst‐free radical mediated hydrazine cross‐coupling reactions without the use of external light source, heat, precious metal complex, or trapping agents. A plasma‐microdroplet fusion platform is utilized for introduction of hydrazine reagent that undergoes homolytic cleavage forming radical intermediate species. The non‐thermal plasma discharge that causes the cleavage originates from a chemically etched silica capillary. The coupling of the radical intermediates gives various products. Plasma‐microdroplet fusion occurs online in a programmable reaction platform allowing direct process optimization and product validation via mass spectrometry. The platform is applied herein with a variety of hydrazine substrates, enabling i) self‐coupling to form secondary amines with identical N‐substitutions, ii) cross‐coupling to afford secondary amine with different N‐substituents, iii) cross‐coupling followed by in‐situ dehydrogenation to give the corresponding aryl‐aldimines with two unique N‐substitutions, and iv) cascade heterocyclic carbazole derivatives formation. These unique reactions were made possible in the charged microdroplet environment through our ability to program conditions such as reagent concentration (i.e., flowrate), microdroplet reactivity (i.e., presence or absence of plasma), and reaction timescale (i.e., operational mode source). The selected program is implemented in a co‐axial spray format.

show abstract

Significantly Accelerated Photochemical Perfluorooctanoic Acid Decomposition at the Air–Water Interface of Microdroplets

Cited by 5 publications

References 72 publications

Spontaneous Degradation of the “Forever Chemicals” Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) on Water Droplet Surfaces

Spontaneous Degradation of the “Forever Chemicals” Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) on Water Droplet Surfaces

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

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