Per-/Poly-fluoroalkyl Substances (PFASs) Treatment and Mechanistic Insights: Photo-catalyst and Photo-Electro-catalyst Materials Application

The PFASs contamination (Per-/Poly-fluoroalkyl Substances ~ 4000 compounds) is influencing the humane through soil and aquifers contamination, resulting in the endocrine-disrupting symptoms (EDS). PFASs decontamination involves both (i) Capture/non-degradation techniques and (ii) Degradation techniques. In the present work, a detailed discussion on various photo-catalytic/electrocatalytic electrode materials (Fe/Ti/Zn/Bi/C etc.) over PFASs degradation is provided. The authors have focused onto the recent literature published in the last couple of years for citing research outputs and schematic figures. The analysis of both radical species (e.g., hydroxyl/sulphate species) and direct electron transfer (DET) mechanisms are given. An insightful discussion of the impact on various degradation mechanisms (decarboxylation, and hydrodefluorination) onto various PFASs has been provided. A different set of examples are provided in describing both electron (e-) based oxidation and hole (h+) based oxidation phenomenon. The state-of-the-art novel inventions towards pilot-scale studies and field-level applications are discussed with explaining the possible limitations (e.g., light source etc.). The factors influencing the degradation process (i.e., Electrode potential, Current density, Impact of dosage, pH, Radical species, Competing ions, Temperature and light source) are also detailed prior to the future perspective and conclusions.