Novel Defluorination Pathways of Perfluoroether Compounds (GenX): α‑Fe2O3 Nanoparticle Layer Retains Higher Concentrations of Effective Hydrated Electrons

• Published in: Environmental science & technology Vol. 58; no. 12; pp. 5567 - 5577
• Main Authors: Qi, Yuwen, Yang, Yinbo, Cui, Shengyan, Tang, Xuejiao, Zhang, Peng, Wang, Cuiping, Liang, Yanna, Sun, Hongwen, Ma, Chuanxin, Xing, Baoshan
• Format: Journal Article
• Language: English
• Published: Easton American Chemical Society 26.03.2024
• Subjects: Aerobic conditions; Anaerobic conditions; Bisulfite; Defluorination; Dissolved oxygen; Electrons; Electrostatic properties; Environmental risk; Ferric oxide; Fluorides; Hydrated electrons; Hydrophobicity; Nanoparticles; Oxygen enrichment; Perfluorooctanoic acid; Physico-Chemical Treatment and Resource Recovery; Wastewater treatment; hydrophobic confinement structure; defluorination mechanisms; GenX; degradation pathway; hydrated electrons
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.3c09879

The development of efficient defluorination technology is an important issue because the kind of emerging pollutant of hexafluoropropylene oxide dimer acid (GenX) as an alternative to perfluorooctanoic acid (PFOA) has the higher environmental risks. In the UV/bisulfite system, we first developed a hydrophobic confined α-Fe2O3 nanoparticle layer rich in oxygen vacancies, which accelerated the enrichment of HSO3 – and GenX on the surface and pores through electrostatic attraction and hydrophobic interaction, retaining more hydrated electrons (eaq –) and rapidly destroying GenX under UV excitation. Especially, under anaerobic and aerobic conditions, the degradation percentage of GenX obtain nearly 100%, defluorination of GenX to 88 and 57% respectively. It was amazed to find that the three parallel H/F exchange pathways triggered by the rapid reactions of eaq – and GenX, which were unique to anaerobic conditions, improved the efficiency of fluoride removal and weaken the interference of dissolved oxygen and H+. Therefore, this study provided an available material and mechanism for sustainable fluoride removal from wastewater in aerobic and anaerobic conditions.