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of NTP treatment. PFAS had been mineralized with OM using NTP technology to achieve high degradation 287

rates. This shows that the dissolved OM can compete with reactive species produced by NTP, slowing down 288

their overall rate of transition into other pollutants. Previous research on the relationship between pH and 289

PFAS decomposition reveals various outcomes. Some studies have shown that in acidic circumstances, 290

oxidative species production led to more effective responses. Additionally, the treatment of PFAS with plasma 291

results in acidic treated water; hence, the ensuing low pH must be corrected before use. Finally, the mechanism 292

by which the plasma technique mineralizes PFAS is yet unknown, and various route ideas on its process are 293

employed in the literature. It is frequently noted that shorter-chain PFAS develop. The experimental settings 294

determine the conversion rate and the type of by-products that are produced [75]. As a result, outdoor 295

demonstration tests are only possible with small-scale reactors. 296

3.6 Photocatalysis 297

Photocatalysis is a process in which a material is activated when a photon is absorbed in the presence of a 298

photocatalyst, speeding up the destruction reaction. Generally, these photocatalysts are semiconductors. Due 299

to their uses in solar energy conversion and environmental purification, photocatalyst usage has increased. 300

They may also be used to clean up organic pollutants in the air and water [81]. As an advanced oxidation 301
process (AOP), photocatalysis technology may be used to oxidise a variety of organic pollutants. 302

Heterogeneous photocatalytic materials have demonstrated broad applicability due to their effectiveness in 303

degrading recalcitrant organic compounds, which are similar to PFASs in their characteristics [81]. These 304

catalysts include Fe2O, ZnO, Ga2O3, TiO2, In2O3, and CdS, to name a few. Presently, titanium dioxide (TiO2) 305

is a compound that has been extensively experimented with because of its application in degrading organic 306

pollutants and achieving satisfactory mineralization at a relatively lower cost compared to other technologies 307
[82]. 308

It is difficult to break the Carbon-Fluorine bond by direct photolysis, however photodegradation 309

is offered over a broad range of wavelengths [83, 84]. However, when photocatalysts absorb light energy, 310

it produces negatively charged electrons and positively charged hole pairs, which migrate to the surface and 311

react with the absorbed PFAS [85]. The first cycle, as seen in the cycle, eliminates two fluorine atoms and one 312

carbon atom; after that, it will keep shortening the chain until the PFAS molecule is completely broken down. 313

It was found that adding carbon materials expands the photocatalysts' range of absorbable frequencies, making 314