Tantalum-based metal oxides for the photocatalytic degradation of Per- or Polyfluoroalkyl Substances (PFAS) Rachael Matthews, Cameron Shearer Department of Chemistry, The University of Adelaide, South Australia, Australia There is an imminent need to develop degradation pathways for Per- or Polyfluoroalkyl Substances (PFAS) to relieve current global contamination. PFAS are toxic, ubiquitous and consist of the C-F bond which is recalcitrant to current degradation processes. This study considers tantalum-based perovskite metal oxides for the photocatalytic degradation of PFAS molecules. ATaO 3 (A = Li, Na, K) photocatalysts are among the most efficient photocatalysts reported to date. 1 However, their wide band gap (>3.5 eV) requires UV light which renders their use cost-prohibitive in most applications. 1 Since there is no alternative for PFAS remediation, photocatalytic degradation with UV light is a viable option. 2 Furthermore, the wide band gap gives the photocatalyst a large redox potential to drive the reduction/oxidation of the C-F bond. ATaO 3 (A = Li, Na, K) were first synthesised via a solid-state high temperature synthesis with varying La mol% doping, following previous studies. 1 The band gap of the photocatalysts were determined from UV-Vis DRS, the crystal structure was determined by powder XRD, and the morphology and particle size were analyzed by SEM. Degradation reactions with PFAS were conducted in a continuous flow reactor system under UV-LED irradiation. PFAS conversion was monitored by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) and fluoride was quantified using an ion selective electrode. Our results highlight the effect of La doping mol% and the A site element on photocatalytic PFAS conversion efficiency, and selectivity toward producing fluoride. References
1. Kato H, Asakura K and Kudo A. J. Am. Chem. Soc ., 2003, 125 , 3082-3089. 2. Li M, Yu Z, Liu Q, Sun L, Huang. W Chem. Eng. J. , 2016, 286 , 232-238.
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