CoN_x@TiO_x degradation of levofloxacin by highly activated PMS with nanorods

Heterogeneous Fenton catalytic oxidation is a promising method for removing organic pollutants. In this work, a simple ethylene glycol assisted method was used to prepare rod-shaped porous materials CoN_x@TiO_x catalyzer. The catalyst was characterized and tested by XRD, SEM, TEM, HRTEM, and XPS to further investigate its performance in activating peroxymonosulfate (PMS) to degrade levofloxacin (Levo), and the catalytic mechanism was studied in detail. The results showed that the degradation rate of Levo (20 mg/L) by CoN_x@TiO_x reached about 90% within 10.5 min. Further exploration was conducted on the effects of environmental parameters such as PMS dosage, catalyst dosage, Levo concentration, water quality, pollutant types, anion types, pH value, etc. on Levo degradation. The results of the cyclic experiment showed that within approximately 16 h of operation of the cyclic equipment, the degradation rate of Levo remained at around 85% of the catalyst, achieving sustained and efficient treatment of Levo. This is mainly because the precursor formed a carbon film in the high temperature nitriding process, which was wrapped on the surface of CoN_x@TiO_x, making the catalyst with excellent stability and repeatability. Electrochemical tests and free radical quenching experiments showed that the hole and non-free radical (¹O₂ and electron transfer) played the main role in the process of Levo degradation in CoN_x@TiO_x/PMS system.