Piezo-Catalytic Degradation of PFASs: Emerging Trends, Mechanistic Insights, and Future Directions

Per- and polyfluoroalkyl substances (PFAS) are organic materials that are extensively used in various industries due to stability, hydrophobicity, and other physicochemical properties. Their highly chemically stable structure and resistance to degradation make them ubiquitous in the environment and cause adverse health effects upon bioaccumulation. The inefficiency of conventional wastewater treatment in degrading this permanent chemical leads to the use of advanced oxidation processes for the degradation/mineralization. In this article, we have discussed the recent advances of PFAS degradation by piezocatalysis, one of the widely studied advanced oxidation processes in recent years. The key mechanism of piezocatalytic reactive oxygen species generation and destruction of the PFAS chain by C-F bond cleavage is discussed herein. The enhancement of the degradation efficiency by modulating the piezocrystal synthesis techniques and composite formation has also been discussed. Furthermore, the review identified the challenges in piezocatalytic PFAS degradation, such as low degradation efficiency, limited scalability, and minimal defluorination, which are the main drawbacks in real-world applications. Future research direction by forming co-catalysts and integrating other catalytic modalities like photocatalysis, electrocatalysis, and tribocatalysis for the synergistic degradation efficiency has also been discussed. This article delves into piezoelectric materials-based mechanical stress-assisted (piezodynamic) PFAS degradation and the mechanistic pathway, which may serve the new generation of researchers and stakeholders who are working with environmental remediation and sustainable degradation of PFAS from water.