Efficient Photocatalytic PFOA Degradation over Boron Nitride

Abstract

Concern over water contamination by per/polyfluoroalkyl substances (PFAS) has highlighted the lack of effective treatment approaches. Photocatalysis offers advantages of using ambient conditions for reaction, air as the oxidant, and light as the energy source, but identifying photoactive materials is challenging. Herein, we report that boron nitride (BN) degrades PFOA upon irradiation with 254 nm light. The ability of BN to degrade PFOA photocatalytically has previously been unreported and is unexpected, because its band gap is too large for light absorption. On the basis of scavenger results, we suggest that PFOA degrades in the presence of BN via a hole-initiated reaction pathway similar to the TiO 2 case and involves superoxide/hydroperoxyl and hydroxyl radicals. We surmised that defects allow BN to absorb in the UVC range and to photogenerate reactive oxygen species. Sealed batch studies indicated BN was ∼2 and ∼4 times more active than TiO 2 , before and after ball milling the material, respectively. BN can be reused, showing no decrease in activity over three cycles. BN was active for the photocatalytic degradation of GenX, another PFAS of concern. These findings present fresh opportunities for materials design and for the re-evaluation of other wide band gap semiconductors for PFAS photocatalytic degradation.

Challenges in the PFAS Remediation of Soil and Landfill Leachate: A Review

“…In contrast, commercial β-Ga2O3 degraded only 38% of the PFOA in 3 h (which was still two times higher than the rate obtained with P25 TiO2) [114]. On the other hand, boron nitride (BN) was found to be quite an efficient catalyst, being 2 to 4 times more active than TiO2 [115]. Duan et al [115] showed that low concentrations of PFOA were detected after 240 min of photolytic degradation using BN [115].…”

“…On the other hand, boron nitride (BN) was found to be quite an efficient catalyst, being 2 to 4 times more active than TiO2 [115]. Duan et al [115] showed that low concentrations of PFOA were detected after 240 min of photolytic degradation using BN [115].…”

Aqueous‐Phase Photocatalytic Degradation of Emerging Forever Chemical Contaminants

“…Ong et al [59] examined the photocatalytic degradation of PFOA and dye using ZnO/rGO nanocomposite (NCs) photocatalyst and found similar behaviors as for titania [57] in an analogous composite. Duan et al [60] photocatalytically degraded PFOA with boron nitride using 254 nm irradiation. Defects were proposed to allow the adsorption of light in the UVC range and the photogeneration of reactive oxygen species.…”

“…The photocatalytic performance of boron nitride was reported as ∼ 4x greater than that of P25 TiO 2 . [60] Sahu et al [61] demonstrated PFOA degradation using BiPO 4 wide and Bi 3 O(OH)(PO 4 ) 2 (BOHP) composition under UV irradiation as being better than BiPO 4 and a β-Ga 2 O 3 catalysts. The authors postulated that the better performance is due to PFOAs surface charge, leading to stronger adsorption of deprotonated PFOA to the hydroxylated BOHP surface, and favorable redox potentials of BOHP charge carriers.…”

Reductive Defluorination and Mechanochemical Decomposition of Per- and Polyfluoroalkyl Substances (PFASs): From Present Knowledge to Future Remediation Concepts

“…While the majority of the reviewed processes seem both reliable and reproduceable, most of them require extreme reaction conditions. The latter range from high-demanding physical conditions (hydrothermal treatments) [ 78 , 80 , 131 ], over sensitive reactants and equipment (photochemical treatment) [ 62 , 67 , 90 , 91 , 132 , 133 ], up to very long reaction times (biological and bio-inorganic catalysis) [ 83 , 85 , 86 ].…”