Light-Induced Advanced Oxidation Processes as PFAS Remediation Methods: A Review

Abstract

PFAS substances, which have been under investigation in recent years, are certainly some of the most critical emerging contaminants. Their presence in drinking water, correlated with diseases, is consistently being confirmed by scientific studies in the academic and health sectors. With the aim of developing new technologies to mitigate the water contamination problem, research activity based on advanced oxidation processes for PFAS dealkylation and subsequent mineralization is active. While UV radiation could be directly employed for decontamination, there are nevertheless considerable problems regarding its use, even from a large-scale perspective. In contrast, the use of cheap, robust, and green photocatalytic materials active under near UV-visible radiation shows interesting prospects. In this paper we take stock of the health problems related to PFAS, and then provide an update on strategies based on the use of photocatalysts and the latest findings regarding reaction mechanisms. Finally, we detail some brief considerations in relation to the economic aspects of possible solutions.

Nanomaterial-Based Advanced Oxidation/Reduction Processes for the Degradation of PFAS

“…The direct degradation of PFOA by 254 nm UV lamp is, as expected, limited [52][53][54][55][56]. Relatively high degradation rates (89% degradation and 33% defluorination yields) were only observed with relatively high power xenon-mercury lamp (200 W) and for a relatively high exposition time (72 h) [56].…”

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

“…Recently, a few research groups developed a new approach of metal ion activated external oxidants (Peroxymonosulfate: PMS, Persulfate: PS) in generating reactive radical species (i.e., sulfate radicals) for remediating various organic contaminants (e.g., estrogenic compounds) [53,54]. A recent article on reviewing the light-induced advanced oxidation processes (AOPs) as PFAS remediation methods are detailed elsewhere [32], whereas the present work focuses on light-induced, electrochemical supported [electro-oxidation] AOPs in addition to the electro-kinetic/coagulation-sorption. The analysis and the sensing part, in addition to the modeling aspects of these emerging contaminants, are also receiving more extensive attention from the peers considering the global concern [55][56][57][58][59].…”

“…[11,[26][27][28][29][30], and ii) Degradation techniques (catalysis, sonochemical, advanced oxidation/reduction processes, electrochemical oxidation, photocatalysis, thermal/plasma-degradation, bio-degradation, etc.) [31][32][33][34][35][36][37][38][39][40][41]. Both the non-degradation and degradation technologies are of equal concern and, in general, are being discussed in a combined manner to address the efficacious and economical treatment technologies for PFAS remediation on different platforms [42][43][44][45][46][47].…”

Strategies to Enhance ZnO Photocatalyst's Performance for Water Treatment: A Comprehensive Review

“…This method can be broadly divided into two categories: (i) degradation of pollutant species occurs in a single phase, also known as the homogeneous system; (ii) degradation of pollutant species occurs in multiple phases, also known as the heterogeneous system. [18,19] Zinc oxide (ZnO) is widely used in many applications such as gas sensors, solar cells, photocatalysis, medicines, lightemitting diodes, laser diodes, chemical and biosensors. [20][21][22][23] ZnO is one of the most studied photocatalyst due to its low cost, high photosensitivity, non-toxic nature, environmentally friendly features, and suitable conduction band and valence band positions with enough redox potential for the production of hydroxyl * OH and * O 2 free radicals.…”

“…The use of conventional mirrors can block the reflection of UV portion and this can reduce the yield of reactions depending on the material properties absorbing UV. This method can be broadly divided into two categories: (i) degradation of pollutant species occurs in a single phase, also known as the homogeneous system; (ii) degradation of pollutant species occurs in multiple phases, also known as the heterogeneous system [18,19] …”