Efficient degradation and defluorination of perfluorobutyric acid under UV irradiation in the presence of persulfate

Wang, Mingran; Wang, Qianyu; Cai, Yanping; Yuan, Rongfang; Wang, Fei; Yu, Qian; Chen, Zhongbing; Zhou, Beihai; Chen, Huilun

doi:10.1016/j.jclepro.2021.129472

Cited by 19 publications

(7 citation statements)

References 42 publications

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“…The k of C7 HFPO-TA was 0.011 min –1 in the UV/PS process, indicating the oxidative degradation could be induced by the decarboxylation through one electron transfer to SO 4 • – (Table S9). The total decay and defluorination of C7 HFPO-TA increased with the PS concentration in the UV/PS process (Figure S2), which was due to the generation of more SO 4 • – . However, the improvement on the total decay and defluorination in the UV/PS process was negligible compared to the VUV process, implying the limited oxidation ability of SO 4 • – (2.5–3.1 V) .…”

Section: Resultsmentioning

confidence: 98%

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange

Gu,

Liu,

et al. 2023

Environ. Sci. Technol.

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C7 HFPO-TA is a newly identified alternative to PFOA, which possesses a unique structure fragment (CF 3 O−CF(CF 3 )−). In this study, we evaluated the chemical reactivity of C7 HFPO-TA in advanced oxidation and reduction processes for the first time, which revealed a series of unexpected transformation mechanisms. The results showed that reductive degradation based on hydrated electrons (e aq − ) was more feasible for the degradation of C7 HFPO-TA. For oxidative degradation, the branched −CF 3 at the α-position carbon posed as the spatial hindrance, shielding the attack of SO 4•− to −COO − . The synergistic effects of HO • /e aq − and direct photolysis led to deeper defluorination and mineralization of C7 HFPO-TA in the vacuum UV/ sulfite (VUV/SF) process. We identified a unique H/OCF 3 exchange that converted the CF 3 O−CF(CF 3 )-into H−CF(CF 3 )-directly, and the SO 3•− involved mechanism of C7 HFPO-TA for the first time. We revealed the branched −CF 3 connected to the same carbon next to the CF 3 O-group affected the C−O bond cleavage site, preferring the H/OCF 3 exchange pathway. The defluorination of C7 HFPO-TA was compared with PFOA and three PFECAs in the VUV/SF process, which was highly dependent on structures. Degradation kinetics, theoretical calculations, and products' analysis provided an in-depth perspective on the degradation mechanisms and pathways of C7 HFPO-TA.

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Section: Resultsmentioning

confidence: 98%

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange

Gu,

Liu,

et al. 2023

Environ. Sci. Technol.

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“…The PFBA concentration, however, increased by 24% in 1 h. Ultrashort-chain PFAA (TFA and triflate) concentrations remained constant in the first hour of the plasma treatment (Figure c), whereas PFPA concentration experienced a slight increase. This chain-length-dependent removal of PFAAs over the first hour in the absence of CTAB is consistent with the lab-prepared water and our previous findings. , The increase of PFBA and PFPA concentrations and the constant TFA and triflate concentrations were due to the formation of degradation byproducts of unidentified PFAA precursors and longer-chain PFAAs and their inability to accumulate at the gas–liquid interface. , …”

Section: Resultsmentioning

confidence: 99%

“…22,42 The increase of PFBA and PFPA concentrations and the constant TFA and triflate concentrations were due to the formation of degradation byproducts of unidentified PFAA precursors and longer-chain PFAAs and their inability to accumulate at the gas−liquid interface. 43,45 The rate constants of long-and short-chain PFAAs (except PFPeA) in the RO reject are generally higher than those in the lab-prepared water (Table S6). For instance, the pseudo-firstorder rate constant for PFOA and PFOS removal was 0.40 min −1 in the RO reject and 0.25 min −1 in the lab-prepared water.…”

Section: Chain-length-dependent Removal Of Pfaasmentioning

confidence: 99%

PFAS–CTAB Complexation and Its Role on the Removal of PFAS from a Lab-Prepared Water and a Reverse Osmosis Reject Water Using a Plasma Reactor

Li,

Isowamwen,

Ross

et al. 2023

Environ. Sci. Technol.

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Electrical discharge plasma reactors with argon bubbling can effectively treat long-chain perfluoroalkyl acids (PFAAs) in contaminated water, and the addition of a cationic surfactant cetrimonium bromide (CTAB) is known to enhance the removal of short-chain PFAAs. However, the roles of PFAA chain length, functional group, and water matrix properties on PFAA–CTAB complexation are largely unknown. This work investigated the bulk liquid removal of different PFAAs by CTAB in the absence of plasma. Stepwise addition of CTAB was subsequently used to efficiently treat PFAAs in a lab-prepared water and a reverse osmosis (RO) reject water using an enhanced contact plasma reactor. The results show that CTAB inhibited the bulk liquid removal of long-chain PFAAs in the absence of plasma likely due to the formation of hydrophilic CTAB-PFAA mixed micelles and competition for interfacial access between long-chain PFAAs and CTAB. On the contrary, CTAB enhanced the removal of short- and ultrashort-chain PFAAs by forming hydrophobic complexes. After 6 h of treatment in the plasma reactor with CTAB, PFAAs were 86 to >99% removed from the lab-prepared water and 29 to >99% removed from the RO reject water. This study provides important insights for overcoming mass transfer limitations for PFAA treatment technologies.

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“…Sulfate radicals can be generated from peroxymonosulfate (PMS) or peroxydisulfate (PDS) through various activation methods, including alkali, 10 UV, 11 ultrasound, 12 and transition metal catalysts. 13 Among these methods, alkali activation poses challenges for UPW production due to the neutralization process caused by pH changes.…”

Section: Introductionmentioning

confidence: 99%

Powdered Activated Carbon (Pac)-Assisted Peroxymonosulfate Activation for Efficient Urea Elimination in Ultrapure Water Production from Reclaimed Water

Kim,

Yoo,

Lee

et al. 2023

Preprint

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Efficient degradation and defluorination of perfluorobutyric acid under UV irradiation in the presence of persulfate

Cited by 19 publications

References 42 publications

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange

PFAS–CTAB Complexation and Its Role on the Removal of PFAS from a Lab-Prepared Water and a Reverse Osmosis Reject Water Using a Plasma Reactor

Powdered Activated Carbon (Pac)-Assisted Peroxymonosulfate Activation for Efficient Urea Elimination in Ultrapure Water Production from Reclaimed Water

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Efficient degradation and defluorination of perfluorobutyric acid under UV irradiation in the presence of persulfate

Cited by 19 publications

References 42 publications

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF3 Exchange

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF3 Exchange

PFAS–CTAB Complexation and Its Role on the Removal of PFAS from a Lab-Prepared Water and a Reverse Osmosis Reject Water Using a Plasma Reactor

Powdered Activated Carbon (Pac)-Assisted Peroxymonosulfate Activation for Efficient Urea Elimination in Ultrapure Water Production from Reclaimed Water

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Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange

Deeper Defluorination and Mineralization of a Novel PFECA (C7 HFPO-TA) in Vacuum UV/Sulfite: Unique Mechanism of H/OCF₃ Exchange