Communication Dans Un Congrès Année : 2024

PFOA and PFOS removal using nano-sized palladium spots coated zero-valent iron microparticles (nPd-μZVI)

Dorian Davarzani
Julie Lions

Résumé

Per- and polyfluoroalkyl substances, PFAS, are known to be toxic for human health and represent a major environmental concern. Rodrigues et al.1,2 showed a complete dechlorination of hexachlorobutadiene and hexachloroethane by the reduction of C-Cl bond, facilitated by the generation of highly reactive H° radicals by the galvanic corrosion of well characterised nano-sized palladium spots coated zero-valent iron microparticles (nPd-μZVI). The goal of this study was to apply this successful for C-Cl bond reduction method to reduce the C-F bond into the perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS). The PFOA and PFOS removal were individually investigated in sealed batch at 10 or 50 mg/L in 10 mL CH3COOH/CH3COONa buffer at pH 4, by using 0.1 or 1 g of nPd-μZVI. Experiments were also conducted in the pH range 1-14, using 10 mg/L of PFOA or PFOS and 1 g of nPd-μZVI. For this purpose, HCl (pH 1), CH3COOH/CH3COONa (pH 5), drinking water (pH 7) and NaOH solutions (pH 9, 10, 11 and 14) were used as reactive media. For all experiments, samples were vortexed and placed in a heated ultrasonic bath (45 kHz, 90°C) during 72 hours to pursue the PFAS-nPd-μZVI interaction under homogenised slurries. The liquid reactive media was then withdrawn and centrifuged. All nPd-μZVI solids were washed with 10 mL of methanol to differentiate adsorption from defluorination process. For a better insight, the washing procedure was repeated 5 times. The liquid reactive media and the methanol from the washes were analysed by Ultra-high-Pressure Liquid Chromatograph coupled with Mass Spectrometer (UPLC-MS) to quantify PFOA and PFOS contents. SEM-EDS allowed us to characterize the nPd-μZVI after interaction. Experiments clearly showed the predominance of PFOS and PFOA adsorption process onto nPd-μZVI. It was confirmed by SEM-EDS analysis: adsorbed PFAS films were observed on nPd-μZVI. The PFOS and PFOA adsorption process reached 99% and 80% respectively with 1 g of nPd-μZVI, regardless of the tested concentrations (10 or 50 mg/L) at pH 4. With 0.1 g of nPd-μZVI, it decreased to 80% and 40% respectively for both concentrations. Experiments showed significant effectiveness at pH 1: PFOS and PFOA adsorption reached 99% and over 80% respectively. At pH 5, it decreased to 65% for both pollutants. At pH 7, 9, 10 and 11, the PFOA adsorption decreased between 15 and 4%; it decreased between 40 and 18% for the PFOS. At pH 14, the PFOA adsorption remained at 10%, while it reached 60% for the PFOS. The adsorption processes are driven by the anaerobic galvanic corrosion of nPd-μZVI (AGC-nPd-μZVI). In the pH range 1-4, AGC-nPd-μZVI intensity remains in the same order of magnitude; the massive production of free Fe2+ is responsible for PFAS complexation adsorption process (PFAS-CAP) onto nPd-μZVI. In the pH range 5-11, AGC-nPd-μZVI decreasing kinetic induces PFAS-CAP drop. From pH 8.7 to 11, FeII hydrolyses, as Fe(OH)+, and precipitates, as Fe(OH)2, onto nPd-μZVI that compete with the PFAS-CAP, which drastically decreased. At pH 14, the increase of AGC-nPd-μZVI results in FeII redissolution as FeO22- that should prevent PFAS-CAP, which is not the only occurring sorption phenomenon. The influence of the functional group onto the surprizing adsorption process of PFOS is still under investigation. Acknowledgements: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036449. The authors thank S. Borensztajn for SEM-EDS analyses.
Abstract_MicroFerPd_PFOA_PFOS.pdf (874.79 Ko) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04648688 , version 1 (15-07-2024)

Identifiants

  • HAL Id : hal-04648688 , version 1

Citer

Raphael Tur, Stéphanie Betelu, Romain Rodrigues, Stéfan Colombano, Dorian Davarzani, et al.. PFOA and PFOS removal using nano-sized palladium spots coated zero-valent iron microparticles (nPd-μZVI). 18th International Symposium on Persistent Toxic Substances and Health (ISPTS-2024), ISPTS Organising Committee, Sep 2024, Chania Crete, Greece. ⟨hal-04648688⟩
59 Consultations
10 Téléchargements

Partager

More