Three-dimensional N-doped carbon electrodes activate peroxymonosulfate for tetracycline degradation

Transition metal-based materials have been widely used as catalysts in both electrochemical oxidation (E) and peroxomonosulfate (PMS) processes to degrade pollutants in water. However, agglomeration of catalyst particles and leaching of metal ions hinder their practical application in pollutant decomposition. In this study, a novel N-doped carbon material (CPANI/CF) was prepared as a three-dimensional electrode by using low-cost synthesised polyaniline-loaded carbon felt as a precursor to improve the electrochemical oxidation capability and capacity to activate PMS in the electrochemical oxidation process. The constructed three-dimensional electrocatalytic system (E–PMS–CPANI/CF) achieved 90.59% TC degradation within 40 min, and the system still removed more than 80% of TC after repeating the experiment for five cycles. We investigated how different experimental conditions (such as the carbonation temperature of CPANI/CF electrode, voltage, PMS dosage and initial pH) affect the degradation of TC. Through quenching experiments, chemical probe experiments and electron spin resonance (ESR) analyses, we discovered that the 3D electrocatalytic system produced single-linear oxygen (1O2), hydroxyl radical (˙OH) and sulphate radical (SO4˙−), which could effectively degrade the pollutants. The results of this study provide a useful strategy for efficient and cost-effective wastewater treatment.