On the Behavior of Perfluorinated Persistent Organic Pollutants (POPs) at Environmentally Relevant Aqueous Interfaces: An Interplay of Hydrophobicity and Hydrogen Bonding

Ghosh, Nishith; Roy, Subhadip; Mondal, Jahur A.

doi:10.1021/acs.langmuir.0c00189

Cited by 9 publications

(8 citation statements)

References 59 publications

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“…The variance of EF SSA in the submicron range could be further increased considering the different production mechanism of film droplets and jet droplets. For a mixture of surfactants, different compounds are thought to compete for surface area and the behavior of surfactant mixture is likely to be dominated by the component with the greatest surface activity. , Because of the higher surface-area-to-volume ratio of finer film droplets, there would be a relatively larger total surface area for PFAAs on the film cap to partition to during the droplets formation, which may explain the correlations between EF and 1/d 50 observed for compounds with NPC ≤ 9. However, the mechanism by which submicron film droplets are formed upon bubble bursting remains unclear .…”

Section: Discussionmentioning

confidence: 99%

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

Sha

Johansson

Benskin

et al. 2020

Environ. Sci. Technol.

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Perfluoroalkyl acids (PFAAs) are persistent organic substances that have been widely detected in the global oceans. Previous laboratory experiments have demonstrated effective enrichment of PFAAs in nascent sea spray aerosols (SSA), suggesting that SSA are an important source of PFAAs to the atmosphere. In the present study, the effects of the water concentration of PFAAs on their size-resolved enrichment in SSA were examined using a sea spray simulation chamber. Aerosolization of the target compounds in almost all sizes of SSA revealed a strong linear relationship with their water concentrations ( p < 0.05, r 2 > 0.9). The enrichment factors (EF) of the target compounds showed no correlation with their concentrations in the chamber water, despite the concentrations varying by a factor of 500 (∼0.3 to ∼150 ng L –1 ). The particle surface-area-to-volume ratio appeared to be a key predictor of the enrichment of perfluoroalkyl carboxylic acids (PFCAs) with ≥7 perfluorinated carbons and perfluoroalkanesulfonic acids (PFSAs) with ≥6 perfluorinated carbons in supermicron particles ( p < 0.05, r 2 > 0.8), but not in submicron particles. The different enrichment behaviors of PFAAs in submicron and supermicron particles might be a result of the different production mechanisms of film droplets and jet droplets. The results suggest that the variability in seawater concentrations of PFAAs has little influence on EFs and that modeling studies designed to quantify the source of PFAAs via SSA emissions do not need to consider this factor.

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Section: Discussionmentioning

confidence: 99%

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

Sha

Johansson

Benskin

et al. 2020

Environ. Sci. Technol.

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“…In agreement with this, the surface pressure of the DPPG monolayer/water interface (30 ± 2 mN/m) remains unchanged even after the addition of PFHA. In fact similar results were observed for PFHA at hexadecanol monolayer/water interface . We propose that anionic PFHA – is depleted from the protonated-DPPG interface because of repulsive interaction between their fluoroalkyl and alkyl chains.…”

Section: Resultsmentioning

confidence: 99%

“…However, surface tensiometry along with fluorescence anisotropy and differential scanning calorimetry − have shown that an intermediate chain length PFCA (e.g., perfluorooctanoic acid (C8)) penetrates into DPPC bilayers. Using interface-selective vibrational spectroscopy, we have recently shown that the interaction of perfluoroheptanoic acid (PFHA) with conventional fatty acid and alcohol are governed by their relative hydrophobicity and headgroup-specific interaction . Therefore, the perturbation of different lipid monolayers by an intermediate chain length PFCA (∼ C8) may differ from those of the long chain PFCAs (∼ C12 or higher).…”

Section: Introductionmentioning

confidence: 97%

Headgroup-Specific Interaction of Biological Lipid Monolayer/Water Interface with Perfluorinated Persistent Organic Pollutant (f-POP): As Observed with Interface-Selective Vibrational Spectroscopy

2022

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Perfluoro compounds are widely used in various manufacturing processes, which leads to their bioaccumulation and subsequent adverse effects on human health. Using interface-selective vibrational spectroscopy (heterodyne-detected vibrational sum frequency generation (HD-VSFG)), we have elucidated the molecular mechanism of the perturbation of lipid monolayers on the water surface using a prototype perfluorinated persistent organic pollutant, perfluoroheptanoic acid (PFHA). PFHA disrupts the well-ordered all-trans conformation of a cationic lipid (1,2-dipalmitoyl-3-trimethylammonium propane (DPTAP)) monolayer and reduces the interfacial electric field at the lipid/water interface. In contrast, the hydrophobic packing of an anionic lipid (1,2-dipalmitoyl-sn-glycero-3-phospoglycerol (DPPG)) monolayer remains largely unaffected in the presence of PFHA, though the interfacial electric field is reduced. For a zwitterionic lipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC))/water interface, both alkyl chain ordering and interfacial electric field are fairly perturbed by PFHA. Lipid headgroup-specific interaction of PFHA and the repulsive interaction of oleophobic fluoroalkyl chain with the lipid alkyl chains govern these distinct perturbations of the lipid monolayers on the water surface.

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“…In an ER mechanism, one of the reactants of a bimolecular surface reaction reacts directly from the gas phase, which we suggest could be the gaseous electrons in the anode sheath of the plasma. These electrons can interact with the hydrophobic tail of PFOA, which protrudes upward and away from the water surface . The slight decrease in defluorination rates over time (Figure c) may be the result of transport limitations or the formation of shorter-chain PFAS, which have lower surface activity, thus lowering the surface concentration.…”

Section: Resultsmentioning

confidence: 99%

Rate, Efficiency, and Mechanisms of Electrochemical Perfluorooctanoic Acid Degradation with Boron-Doped Diamond and Plasma Electrodes

et al. 2022

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The removal of per- or polyfluorinated alkyl substances (PFAS) has received increasing attention because of their extreme stability, our increasing awareness of their toxicity at even low levels, and scientific challenges for traditional treatment methods such as separation by activated carbon or destruction by advanced oxidation processes. Here, we performed a direct and systematic comparison of two electrified approaches that have recently shown promise for effective degradation of PFAS: plasma and conventional electrochemical degradation. We tailored a reactor configuration where one of the electrodes could be a plasma or a boron-doped diamond (BDD) electrode and operated both electrodes galvanostatically by continuous direct current. We show that while both methods achieved near-complete degradation of PFAS, the plasma was only effective as the cathode, whereas the BDD was only effective as the anode. Compared to the BDD, plasma required more than an order of magnitude higher voltage but lower current to achieve similar degradation efficiency with more rapid degradation kinetics. All these factors considered, it was noted that plasma or BDD degradation resulted in similar energy efficiencies. The BDD electrode exhibited zero-order kinetics, and thus, PFAS degradation using the conventional electrochemical method was kinetically controlled. On the contrary, analysis using a film model indicated that the plasma degradation kinetics of PFAS using plasma were mass-transfer-controlled because of the fast reaction kinetics. With the help of a simple quantitative model that incorporates mass transport, interfacial reaction, and surface accumulation, we propose that the degradation reaction kinetically follows an Eley–Rideal-type mechanism for the plasma electrode, and an intrinsic rate constant of 2.89 × 108 m4 mol–1 s–1 was obtained accordingly. The investigation shows that to realize the true kinetic potential of plasma degradation for water treatment, mass transfer to the interface must be enhanced.

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On the Behavior of Perfluorinated Persistent Organic Pollutants (POPs) at Environmentally Relevant Aqueous Interfaces: An Interplay of Hydrophobicity and Hydrogen Bonding

Cited by 9 publications

References 59 publications

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols

Headgroup-Specific Interaction of Biological Lipid Monolayer/Water Interface with Perfluorinated Persistent Organic Pollutant (f-POP): As Observed with Interface-Selective Vibrational Spectroscopy

Rate, Efficiency, and Mechanisms of Electrochemical Perfluorooctanoic Acid Degradation with Boron-Doped Diamond and Plasma Electrodes

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