Anodic activation of persulfate by V-mediated Ti4O7: Improved stability and ROS generation

A novel eco-friendly vanadium-mediated Magnéli phase titanium suboxide (V@Ti 4 O 7 ) was fabricated via ball-milling-vacuum sintering method. The presence of V improved the stability and electrochemical performance of Ti 4 O 7 , which significantly promoted the activation of persulfate (PS) for superior degradation of organic pollutant ciprofloxacin (CIP). The results show that V doping significantly facilitated the electron transfer process and enhanced the oxygen evolution potential. The redox cycle of V 3+ /V 4+ and V 4+ /V 5+ endows the electrode with high stability and enriched catalytic active sites for PS activation , which allows for 89.11% CIP removal after the 8 th reuse. Scavenging experiments and electron paramagnetic resonance (EPR) results revealed the contribution of reactive oxidant species (i.e., SO 4 − , OH and 1 O 2 ) for efficient CIP degradation in the E-V@Ti 4 O 7 -PS system, in which, OH was the dominant reactive species accounting for 53.09 % of CIP removal, resulting in efficient CIP mineralization (TOC > 86.51%). The results of this study provide a better understanding of the relationship between the nature of anode and electro-activation of PS, which can facilitate the electrode design and optimization of E-PS reactors.