Table 2. Treatment of a Concentrated PFAS Mixture in NaCl Brine by UV/S + I^a.

PFAS category	compound	PFAS concentration (μg L–1)	total fluorine in C–F bonds (μg L–1)	residual PFAS after 24 h (μg L–1)b	parent PFAS removal ratio (%)
FTSAs	4:2 FTS	131	68	63	51.9
	6:2 FTS	27,950	16,124	296	98.9
	8:2 FTS	875	535	<53	>93.9
PFCAs	PFBA	1950	1212	<5	>99.7
	PFPeA	5872	3803	<13	>99.7
	PFHxA	16,433	10,936	<8	>99.9
	PFHpA	7492	5083	<9	>99.8
	PFOA	101,550	69,896	<10	>99.9
	PFNA	228	159	<12	>94.7
PFSAs	PFBS	4988	2522	279	94.4
	PFHxS	72,550	40,893	<88	>99.8
	PFOS	86,950	56,155	<100	>99.8
sum		327.0 mg L–1	207.4 mg L–1 (10.9 mM)	<0.9 mg L–1	>99.7

^aReaction conditions: the 3% NaCl brine with the tabulated components was diluted with 1:1 DI water, Na₂SO₃ (10 mM), KI (2 mM), NaHCO₃ (5 mM), pH 12.0, 254 nm irradiation (an 18 W low-pressure Hg lamp in 600 mL solution), and 20 °C.

^bConcentrations without a definitive value indicate the limit of quantitation by the HRMS instrument in our study. These values are the HRMS-detected concentration multiplied by 2 (due to the 1:1 dilution before treatment). Solid-phase extraction for accurate quantitation in low concentration ranges (e.g., the prevalent 70 ng L^–1 reference for drinking water) was not used in this proof-of-concept study.