Carbon supported/modified adsorptive Photocatalysts for concentrating and destructing per- and Polyfluoroalkyl...

Per- and polyfluoroalkyl substances (PFAS) have emerged as a major water contamination concern due to their widespread presence, high persistence, and adverse health impacts. While cost-effective treatment technologies remain lacking, it has come a long way over the last several years due to intensive research and development efforts. Of the numerous treatment technologies reported so far, photocatalytic degradation of PFAS using adsorptive photocatalysts appeared promising. Adsorptive photocatalysts take advantage of the synergy between an adsorbent (e.g., a carbonaceous material) and a photocatalyst to achieve effective concentration and degradation of trace levels of PFAS in water under mild conditions. Yet, a systematic review has been lacking on adsorptive photocatalysts in the context of a novel concentrate-and-destroy strategy for treating PFAS. In this regard, this review paper focused on the following tasks: 1) Overviewing the type, preparation, and effectiveness of various adsorptive photocatalysts that have been tested for degradation of PFAS, 2) Elucidating the reaction mechanisms with the emphasis on understanding the roles of various carbonaceous materials, such as activated carbon, carbon spheres, carbon nanotubes, and variants of graphene, in the adsorption and photocatalysis of PFAS, 3) Introducing and assessing the concentrate-and-destroy or trap-&-zap strategy, and 4) Identifying major bottlenecks and research needs in adsorptive photocatalysis. The information is useful for guiding future development and optimization of adsorptive photocatalysts for enhanced degradation of PFAS and other persistent organic pollutants in water.