Boosting Hydroxyl Radical Yield via Synergistic Activation of Electrogenerated HOCl/H 2 O 2 in Electro-Fenton-like Degradation of Contaminants under Chloride Conditions.

Hydroxyl radical production via catalytic activation of HOCl is a new type of Fenton-like process. However, metal-chlorocomplex formation under high chloride conditions could deactivate the catalyst and reduce the process efficiency. Herein, electrogenerated HOCl was activated to OH via a metal-free, B/N-codoped carbon nanofiber cathode for the first time to degrade contaminant under high chloride condition. The results show 98% degradation of rhodamine B (RhB) within 120 min ( = 0.036 min) under sulfate conditions, while complete degradation ( = 0.188 min) was obtained in only 30 min under chloride conditions. An enhanced degradation mechanism consists of an , wherein adsorption concentrates the pollutants at the cathode surface and they are subsequently oxidized by the large amount of OH produced via activation of HOCl and HO at the cathode. Density functional theory calculations verify the pyridinic N as the active site for the activation of HOCl and HO. The process efficiency was also evaluated by treating tetracycline and bisphenol A as well as high chloride-containing real secondary effluents from a pesticide manufacturing plant. High yields of OH and HOCl allow continuous regeneration of the cathode for several cycles, limiting its fast deactivation, which is promising for real application.