Electro-enhanced activation of peroxymonosulfate by a novel perovskite-Ti4O7 composite anode with ultra-high efficiency and low energy consumption: The generation and dominant role of singlet oxygen

Abstract

Traditional free radicals-dominated electrochemical advanced oxidation processes (EAOPs) and sulfate radical-based advanced oxidation processes (SR-AOPs) are limited by pH dependence and weak reusability, respectively. To overcome these shortcomings, electro-enhanced activation of peroxymonosulfate (PMS) on a novel perovskite-Ti4O7 composite anode (E-PTi-PMS system) was proposed. It achieved an ultra-efficient removal rate (k = 0.467 min-1) of carbamazepine (CBZ), approximately 36 and 8 times of the E-PTi and PTi-PMS systems. Singlet oxygen (1O2) played a dominant role in the E-PTi-PMS system and transformed from SO4•−, O2•−, •OH and oxygen vacancy (Vo••). The electric field expedited the decomposition and utilization of PMS, promoting the generation of radicals and expanding the formation pathway of 1O2. The E-PTi-PMS system presented superiorities over wide pH (3–10) and less dosage of PMS (1 mM), expanding the pH adaptability and reducing the cost of EAOPs. Simultaneously, the excellent reusability (30 cycles) solved the bottleneck of recycling catalysts in SR-AOPs via an ultra-low energy (0.025 kWh/m3-log). This work provides a promising alternative towards high-efficiency and low-cost treatment of polluted waters.