Activation of peroxymonosulfate to degrade the Orange II dye by nitrogen-doped cyanobacterial carbon

ABSTRACT The activated cyanobacterial carbon (ACC) prepared from Chaohu Lake cyanobacteria was used as a carrier for nitrogen doping to synthesize nitrogen-doped activated cyanobacterial carbon (N@ACC), a highly efficient activation material. N@ACC was found to be an effective catalyst for the degradation of Orange II (OII) dye by activating peroxymonosulfate (PMS). Characterization of N@ACC showed that it had a larger specific surface area (159.12 m 1 /g) than ACC and an average particle size of 3.28 nm. N@ACC also contained various functional groups such as C=O, C=N, and –OH. To optimize the degradation of OII, the reaction conditions of the N@ACC activated PMS system were adjusted. The N@ACC activated PMS system was able to achieve a degradation rate of 98.8% for OII (100 mg/L) within 35 min, which was significantly higher than the rate achieved by the ACC activated PMS system (19.5%). The degradation reaction followed first-order kinetics and indicated a combined free radical mechanism. Compared to ACC, N@ACC contained a higher content of nitrogen, specifically pyridinic and graphitic nitrogen. The results showed that introducing nitrogen would refactor the structure of raw carbon, regulate its properties, and create new active sites for the degradation of pollutants. Moreover, N@ACC does not need metallic elements to improve PMS degradation efficiency. Therefore, the synthesis of N@ACC could be used as a new way to activate PMS.