Peroxymonosulfate activation by Co@TiO2 for high-efficiency organic removals

Here we demonstrated that the Co doped anatase titanium dioxide (Co@TiO2) prepared by a facile wet chemical method could activate peroxymonosulfate (PMS) for efficiently degrading a wide range of refractory organic pollutants. The characterization results demonstrated that the doped Co replaced partial Ti while did not bring obvious structural change. The Co@TiO2/PMS system can efficiently remove about 100 % chlortetracycline (CTC) within 40 min and 100 % Rhodamine B (RhB) within 15 min. The Co@TiO2/PMS/CTC system maintained a good catalytic performance over a wide pH range from 3 to 11 and the removal efficiency of CTC improved with increasing pH. The Co@TiO2/PMS system had a good anti-interference ability, which was free from interference by inorganic ions (such as H2PO42-, NO3- and SO42-, etc.) and HA, and also in the different real water matrixes and refractory organic pollutants. Quenching experiments and electron spin resonance (EPR) measurements confirmed that the system had a typical radical process as hydroxyl radical (•OH), sulfate radical (SO4•−) and superoxide radical (O2•−) were the main reactive species for the degradation of CTC. Furthermore, the Co@TiO2 also showed excellent stability and low metal leaching during long-term use because of the excellent chemical and physical stability of TiO2.