Electrochemical degradation of perfluoroalkyl acids by titanium suboxide anodes

• Published in: Environmental science water research & technology 2020-01, Vol.6 (1), p.144-152
• Main Authors: Wang, Yaye, Pierce, Randall "David", Shi, Huanhuan, Li, Chenguang, Huang, Qingguo
• Format: Article
• Language: English
• Subjects: Acids; Anodes; Anodizing; Aqueous solutions; Constants; Degradation; Density functional theory; Design optimization; Electrochemistry; Groundwater; Groundwater pollution; Organic chemistry; Oxidation; Perfluoroalkyl & polyfluoroalkyl substances; Rate constants; Scaling; Stockpiling; Titanium; Wastewater; Wastewater pollution
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/c9ew00759h

Our recent findings indicate effective electrochemical degradation of perfluoroalkyl acids (PFAAs) in aqueous solutions using novel titanium suboxide (TSO) anodes. This provides a potentially promising technology to treat per- and polyfluoroalkyl substances (PFASs) in legacy AFFF stockpiles or in wastewater and contaminated groundwater. The degradation of PFAAs in TSO-based electrooxidation was evaluated with solutions of different compositions containing eight PFAAs either individually or in a mixture and under a range of operation conditions. Surface area normalized pseudo-first order rate constants were obtained and interpreted in terms of PFAA degradation behaviors and mechanisms. The PFAA degradation rates were further correlated to the molecular and electronic descriptors of the chemicals calculated based on density functional theory. The results of this study further the understanding of PFAS degradation in TSO-based anodic oxidation and provide a basis for process optimization, design and scaling. Effective degradation of eight perfluoroalkyl acids by electrooxidation on titanium suboxide anodes is correlated to their respective molecular structures, offering insight into their degradation behaviors.