The disclosure provides a TiO.sub.2-CQDs nanoflower photocatalyst, a photocatalytic thin film and an application, belonging to a technical field of photocatalyst for food processing. The TiO.sub.2-CQDs nanoflower photocatalyst includes TiO.sub.2 and CQDs doped with TiO.sub.2. the CQDs is derived from aloe extract. According to the disclosure, the extract obtained from natural aloe is used as a carbon source to provide CQDs, and TiO.sub.2 is modified to obtain the nanoflower photocatalyst and the photocatalytic thin film for catalytic degradation of polycyclic aromatic hydrocarbons (PAHs).

Systems and methods are provided for degrading PFAS in a semi-solid sample. The semi-solid sample includes PFAS molecules in a partially liquid solution. An electron donor, and optionally a surfactant, are introduced into the mixture, forming micelles. An electron donor associates with the micelle surface and releases hydrated electrons upon exposure to UV light to initiate the reductive defluorination reaction, resulting in fluoride, water, and simple carbon compounds.

Systems and methods are provided for degrading PFAS in a semi-solid sample. The semi-solid sample includes PFAS molecules in a partially liquid solution. An electron donor, and optionally a surfactant, are introduced into the mixture, forming micelles. An electron donor associates with the micelle surface and releases hydrated electrons upon exposure to UV light to initiate the reductive defluorination reaction, resulting in fluoride, water, and simple carbon compounds.