Conversion of Perfluoroalkyl Substances (PFAS) to Fluoride using Light and Bubbles

Title: Conversion of Perfluoroalkyl Substances (PFAS) to Fluoride using Light and Bubbles

Speaker: Dr Cameron Shearer, Adelaide University\

Abstract: Per- and poly-fluoroalkyl substances (PFAS) constitute a class of persistent organic pollutant that severely affect human health and the environment owing to their persistence, bioaccumulation and resistance to degradation. Photocatalysis is a light-assisted catalysis in which photoexcited electrons and holes are used to drive reduction and oxidation reactions, respectively. In this presentation, I will discuss our progress in the development of materials and processes for the photocatalytic degradation of PFAS. We have found control of pH of reaction is essential to achieve PFAS oxidation. Metal sulfides consisting of d10 transition metals often have high reduction potential. I will present our progress toward sunlight-activated photocatalytic mineralization of PFAS by targeting photo-reduction using various metal sulfide systems. To employ photocatalysts for larger-scale treatment, we have developed a continuous flow reactor system and shown its application in PFAS degradation. The collapse of cavitation bubbles produced by irradiation of PFAS samples with high frequency ultrasound is an attractive method for ‘room temperature’ thermal degradation of PFAS. We have applied ultrasonic degradation to field-derived PFAS samples.I will present our findings on the effect of co-contaminant and our efforts to improve degradation rate by pre-treatment of PFAS solutions prior to ultrasonic degradation.

Biography: Dr. Cameron Shearer is a Senior Lecturer in Chemistry at Adelaide University who uses fundamental chemistry and materials science to find solutions to environmentally relevant problems such as the destruction of pollutants or the generation of renewable fuels. Dr Shearer obtained his PhD in 2012 from Flinders University (with Prof. Joe Shapter, Prof. Amanda Ellis and Prof. Nico Voelcker) and has since worked in Germany (The University of Muenster, 2012-2014), with industry (PMB defence engineering, 2014-2015; Membrane Systems Australia, 2019-2020) and each of the three South Australian Universities (Flinders University, 2012-2018; UniSA 2019-2020, University of Adelaide, 2018-2019 and 2020- present). He has held several Fellowships including the ARC Future Fellowship (2020-2024) and received over $5M in competitive research funding.