Challenges Facing Sustainable Visible Light Induced Degradation of Poly- and Perfluoroalkyls (PFA) in Water: A Critical Review

Abstract

Poly-and perfluoroalkyls (PFAs) are now designated as serious threats to the environment. More than 4700 PFAs, along with their precursors, show a high degree of persistence and long-range spreading in soils and waters causing recalcitrant bioaccumulation in plants, fish, birds, and mammals causing health hazards all along the food chain. Visible-light induced degradation of PFA in pure water using photocatalysts, a potentially sustainable advanced oxidation process, showed exciting results in laboratories for both complete and partial mineralization of these toxins. However, none of the methods and materials have been considered so far for upscaling toward practical applications due to several hard-to-resolve challenges. This Review provides a critical analysis of the recent advancements in photocatalytic remediation of aqueous PFA under visible light irradiation and addresses possible future directions to valorize some of the prospective methods and materials to practical applications.

Exploring Solar Energy Solutions for Per‐ and Polyfluoroalkyl Substances Degradation: Advancements and Future Directions in Photocatalytic Processes

“…[ 104 ] There are reports showing PFAS photo‐oxidation with junctions between semiconductor and plasmonic materials with resonance within the excitation spectral range (See paragraph 5 and Table 2). However, the role of the metal plasmonic resonance is usually neither explicitly stated nor investigated [48a,57,107] . Indeed, several materials used as electron‐trapping media can absorb low‐energetic wavelengths to generate mobile excited charges that can recombine or be transferred either into the semiconductor or directly into the pollutant.…”

Computational Design of Sorbent Materials for Per- and Polyfluoroalkyl Substances (PFAS) Remediation

“…However, at the same time, the stable C−F bonds have made the degradation of these substances a challenge. 2 Due to the difficulty of their degradation and destruction, PFAS have earned the nickname "forever chemicals". Moreover, studies have shown that PFAS are environmentally detrimental, and potentially cause a range of health issues including thyroid illness, liver damage, and cancer.…”

“…The desirable properties of PFAS such as amphiphilicity, thermal stability, and resistance to oxidation result from their chemical composition; specifically, the strong C–F bonds, hydrophilic polar headgroup, and hydrophobic tail. However, at the same time, the stable C–F bonds have made the degradation of these substances a challenge . Due to the difficulty of their degradation and destruction, PFAS have earned the nickname “forever chemicals”.…”

Enhanced removal of perfluorooctanoic acid with sequential photocatalysis and fungal treatment

“…In recent research, focused particularly on developing new visible-light active photocatalysts for the degradation of PFAS, bismuth oxyiodide (BiOI)–based semiconductor materials have received greater attention than more traditional titanium-, zinc-, and indium-based photocatalysts (Paul Guin et al 2022 ). The ability to absorb light in the visible region of solar spectrum and an increased mobility of photogenerated charge carriers by the induced dipoles of [Bi 2 O 2 ] 2+ slabs in BiOI increase its photocatalytic performance (Lin et al 2022 ).…”