Reversible adsorption and desorption of PFAS on inexpensive graphite adsorbents <i>via</i> alternating electric field

Shrestha, Bishwash; Ezazi, Mohammadamin; Ajayan, Sanjay; Kwon, Gibum

doi:10.1039/d1ra04821j

Cited by 14 publications

(14 citation statements)

References 66 publications

(89 reference statements)

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“…A second experiment with varying PFOS concentration at 100 mV vs. open circuit potential during the incubation period exhibit similar concentration dependent behaviors, indicating a surface saturation has not been reached yet. Since the adsorption of PFOS molecule is electrostatic in nature, the potential dependent adsorption observed here is consistent with previous literature [13c,19] …”

Section: Resultssupporting

confidence: 92%

Understanding PFOS Adsorption on a Pt Electrode for Electrochemical Sensing Applications

Gogoi

Yao

2022

ChemElectroChem

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Per-and polyfluroalkyl substances (PFAS) are drawing increasing attention in the research community due to their wide spread applications and their toxicity to animals and humans. Effective early detection method of PFAS chemicals in aqueous environment is important to reduce exposure and mitigate the potential toxic effects. This study focuses on the electrochemical detection of per-fluoro octane sulfonate (PFOS) with differential pulse voltammetry and electrochemical impedance spectroscopy on a bare platinum electrode. We observe three distinct regions of adsorption behaviors with respect to PFOS concentration from 0-1000 nM, reflecting changes in the modes of adsorption due to different adsorbate-adsorbate interactions on a bare electrode. The adsorption isotherm constant for PFOS adsorption on a Pt electrode is calculated to be 1.6 × 10 12 cm 3 mol À 1 from fitting the electrochemical data with a modified Langmuir isotherm model.

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Section: Resultssupporting

confidence: 92%

Understanding PFOS Adsorption on a Pt Electrode for Electrochemical Sensing Applications

Gogoi

Yao

2022

ChemElectroChem

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“…Electrosorption of PFAS can be promoted when an anode or cathode exhibits a high specific capacitance (i.e., capacitance per unit mass). , Figure a,b presents the cyclic voltammetry (CV) data of the different MXenes for PFOA and PFBA at a fixed scan rate of 10 mV·s –1 with a voltage window of −1.0–1.0 V (vs Ag/AgCl). The PFOA electrochemical capacitance of O–MXene is obviously larger than those of F–MXene and Cl–MXene, as calculated using eq S4 in the following section.…”

Section: Resultsmentioning

confidence: 99%

Electrosorption, Desorption, and Oxidation of Perfluoroalkyl Carboxylic Acids (PFCAs) via MXene-Based Electrocatalytic Membranes

Gao

Moussa

et al. 2023

ACS Appl. Mater. Interfaces

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MXenes exhibit excellent conductivity, tunable surface chemistry, and high surface area. Particularly, the surface reactivity of MXenes strongly depends on surface exposed atoms or terminated groups. This study examines three types of MXenes with oxygen, fluorine, and chlorine as respective terminal atoms and evaluates their electrosorption, desorption, and oxidative properties. Two perfluorocarboxylic acids (PFCAs), perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) are used as model persistent micropollutants for the tests. The experimental results reveal that O-terminated MXene achieves a significantly higher adsorption capacity of 215.9 mg·g–1 and an oxidation rate constant of 3.9 × 10–2 min–1 for PFOA compared to those with F and Cl terminations. Electrochemical oxidation of the two PFCAs (1 ppm) with an applied potential of +6 V in a 0.1 M Na2SO4 solution yields >99% removal in 3 h. Moreover, PFOA degrades about 20% faster than PFBA on O-terminated MXene. The density functional theory (DFT) calculations reveal that the O-terminated MXene surface yielded the highest PFOA and PFBA adsorption energy and the most favorable degradation pathway, suggesting the high potential of MXenes as highly reactive and adsorptive electrocatalysts for environmental remediation.

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“…This finding means that the internal diffusion of PFAS in WA10 would be easier than in other resins. For the remaining three selected resins, lower porosity was probably not favorable to remove PFAS with a longer backbone due to the steric effects [ 53 ]. There was no significant difference in the adsorption capacity between PFCA and PFSA with the same C-F skeleton.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Understanding of Adsorption Behaviors of Legacy and Emerging Per- and Polyfluoroalkyl Substances (PFASs) on Various Anion-Exchange Resins

Tan

Pan

Yin

et al. 2023

Toxics

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Per- and polyfluoroalkyl substances (PFASs) have received extensive attention due to their various harmful effects. In this study, the adsorptive removal of 10 legacy and emerging PFASs by four anion-exchange resins (including gel and macroreticular resins) were systematically investigated. Our results showed that the capacities of resins absorbing PFASs were ranked in the following order: gel strong base HPR4700 (297~300 μg/g) ≈ macroreticular strong base S6368 (294~300 μg/g) ≈ macroreticular weak base A111S (289~300 μg/g) > gel weak base WA10 (233~297 μg/g). Adsorption kinetic results indicated that the adsorption process might involve chemical and Henry regime adsorption or reaction control. Intraparticle diffusion was probably the major removal step. Co-existing fulvic acid (0.5, 1, 5 mg/L) and inorganic anions (5 mg/L of sulfate, carbonate, bicarbonate) would hinder the PFAS removal by resins with WA10 showing the highest inhibition rate of 17% and 71%, respectively. The adsorption capacities of PFBA decreased from 233 μg/g to 194 μg/g, and from 233 μg/g to 67 μg/g in the presence of fulvic acid and inorganic anions, respectively. PFASs were more easily removed by HPR4700, S6368, and A111S under neutral and alkaline environment. Moreover, WA10 was not able to remove PFASs under an alkaline medium. This study offered theoretical support for removing PFASs from aqueous phases with various resins.

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Reversible adsorption and desorption of PFAS on inexpensive graphite adsorbents via alternating electric field

Abstract: In this study, a reversible adsorption and desorption upon alternating electric field for per- and polyfluoroalkyl substances (PFAS) using inexpensive graphite is reported.

Cited by 14 publications

References 66 publications

Understanding PFOS Adsorption on a Pt Electrode for Electrochemical Sensing Applications

Understanding PFOS Adsorption on a Pt Electrode for Electrochemical Sensing Applications

Electrosorption, Desorption, and Oxidation of Perfluoroalkyl Carboxylic Acids (PFCAs) via MXene-Based Electrocatalytic Membranes

Insights into the Understanding of Adsorption Behaviors of Legacy and Emerging Per- and Polyfluoroalkyl Substances (PFASs) on Various Anion-Exchange Resins

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