Photocatalytic degradation of perfluorooctanoic acid (PFOA) by metal organic framework MIL-177-HT: New insights into the role of specific surface area, charge separation and dimensionality

• Published in: Separation and purification technology 2025-02, Vol.354, p.128877, Article 128877
• Main Authors: Wen, Yinghao, Kirchon, Angelo, Day, Gregory S., Lin, Hengyu, Smith, Mallory F., Boehme, Anne, Ozdemir, Ray Osman K., Sharma, Virender K., Ma, Xingmao, Zhou, Hong-Cai
• Format: Article
• Language: English
• Subjects: Defluorination; Hydrated electron; Metal–organic framework; Perfluorooctanoic acid; Photocatalytic degradation
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.128877

[Display omitted] •MIL-177-HT photocatalytically degrade and defluorinate PFOA.•Photo-generated hydrated electron is the primary reactive species for PFOA degradation.•H-F exchange and chain shortening are two dominant processes causing PFOA degradation.•MOF ligand hydrophobicity and dimensionality are crucial for effective PFAS removal.•Reducing the bandgap of MIL-177-HT can further enhance its photoactivity. Per- and polyfluoroalkyl substances (PFAS) are known to cause severe adverse health effects. Therefore, their prevalent detection in drinking water calls for rapid development of effective destruction technologies. This paper presents restuls on the degradation and defluorination of perfluorooctanoic acid (PFOA) by a photocatalytic titanium-based metal–organic framework (MOF), MIL-177-HT. This MOF achieved about 83 % PFOA removal and 32 % defluorination within 24 h, The results suggested that additional characteristics of MOF were also critical for efficient PFOA degradation. A comprehensive comparison of the adsorption capacity and degradation efficiency of different MOFs applied to remove PFOA in the literature indicated that the ligand hydrophobicity, dimensionality and corresponding band gaps of MOFs are likely key factors governing the adsorption and the degradation of PFOA. These newly obtained insights markedly advance our knowledge in synthesizing novel MOF structures to degrade PFAS efficiently.