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Sustainability 2022, 14, x FOR PEER REVIEW 2 of 37

stability and usage in the industries but there are certain disadvantages which are limiting 31

their usage. The source of PFAS are wastewater, groundwater, surface water, coastal water 32

and the drinking water of the countries which are producing PFAS [4-6]. 33

The major entry point for PFAS in our water system is from the industries which produce it. 34

It enters as a waste into the waste water treatment plant and leads to negative impact on the 35

environment, humans and aquatic lives [7]. The exposure of PFAS can occur through various 36

pathways but its impact depends on the source exposure, concentration of the source and the 37

source frequency. In recent study, it was found that PFAS does not degrade easily due to its 38
thermal stability. Hence, conventional technologies to be replaced by new and advanced 39

techniques. The main goal of this review is to provide details about its structure, occurrence, 40

properties and the various new methods which can be utilised for the treatment of PFAS from 41

wastewater. Also, the effect of the exposure to PFAS are explained in details. 42

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2. Sources, Occurrence and Properties of PFAS in environment 45

They are feasible to employ as coatings for carpet, textiles, and leather paper because of the 46
hydrophobic and lipophobic qualities that their distinctive chemical structure affords. These materials 47

are the best for use in products with great adaptability, strength, resilience, and durability because to 48
their dielectric qualities, resistance to heat and chemical agents, and low surface energy. For instance, 49

they have been used in food processing, cosmetics, inks, oil production, mining, pesticide formulation, 50

firefighting foams, wiring insulation for telecommunications, aircraft, defence, electronics (insulators), 51
and semiconductors. They have also been utilised in medicinal applications [8]. 52
2.1 Properties of PFAS: 53

PFAS are synthetic releases from man-made anthropogenic activities. Their unique characteristic as 54

mentioned is due to a strong C-F bond which confers various physical and chemical characteristics, 55
some of these are as mentioned: 56

• High transport potential due to its high-water solubility and certain hydrocarbons' solubility, as 57

well as its lipophobic (oil-hating) surfactant properties. 58
• high resistance to the fluorine-carbon bonds deteriorating 59

• Possibility of adhering to surfaces through sorption of both the polar and non-polar ends of the 60
surfactant-like structure's linear carbon chain. 61