Understanding PFOS Adsorption on a Pt Electrode for Electrochemical Sensing Applications

Abstract

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.

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

“…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.…”

Laboratory validation of an integrative passive sampler for per- and polyfluoroalkyl substances in water

“…The increased uptake rate may be due to adsorption of these compounds to previously bound PFAS in the pores of the resin. Adsorbate–adsorbate interactions between PFOS at surfaces have been detected with both electrochemical measurements 27 and adsorption isotherms. 28 In contrast, PFBA adsorption may primarily be facilitated by ion exchange interactions with the resin and thus is limited by the number of accessible Cu( ii ) sites.…”

Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications

“…[3c] Furthermore, a low detection limit of 0.1 nM (0.05 ppb) of perfluoro-octane sulfonic acid (PFOS), a PFAS molecule similar to PFOA, has been reported on non-modified poly-crystalline platinum electrodes. [5]…”

“…Li and colleagues measured the adsorption of per-fluorooctane sulfonate (PFOS) on platinum electrodes using differential pulse voltammetry and electrochemical impedance spectroscopy. [5] It was discovered the adsorption of PFOS on Pt electrodes is more substantial than on alumina, and the modes of adsorption change as its bulk concentration changes. While these measurements provide critical data for practical applications, they provide limited details on the configuration of adsorbed molecules on the electrode.…”

“…Currently, research on the adsorption of PFAS molecules on electrodes is limited. Li and colleagues measured the adsorption of per‐fluorooctane sulfonate (PFOS) on platinum electrodes using differential pulse voltammetry and electrochemical impedance spectroscopy [5] . It was discovered the adsorption of PFOS on Pt electrodes is more substantial than on alumina, and the modes of adsorption change as its bulk concentration changes.…”