Activation of peroxymonosulfate by cobalt doped graphitic carbon nitride for ammonia removal in chloride-containing wastewater

Abstract

• The Co-g-C 3 N 4 /PMS/Cl process is an effective method for ammonia removal. • Cl • is proved to play a major role in ammonia removal. • Ammonia is mainly converted to nitrogen gas. • The Co-g-C 3 N 4 catalyst exhibits a great stability and reusability. Ammonia is one of the main nitrogen pollutants in water, and a low concentration of ammonia in water is relatively difficult to remove. The catalytic system activating peroxymonosulfate (PMS) by the cobalt doped graphitic carbon nitride (Co-g-C 3 N 4 ) was established for the oxidation of ammonia. The high removal efficiency of 98.3% for ammonia can be achieved, and total nitrogen removal efficiency was approximately 76.1% in the Co-g-C 3 N 4 /PMS/Cl process. Sulfate radical (SO 4 •− ) was generated during the Co-g-C 3 N 4 /PMS process, reacting with chloride ions to produce chloride radical (Cl • ), which was identified as the main radical species for the transformation of ammonia to nitrogen gas. Moreover, Co-g-C 3 N 4 had a good stability and can be recycled and reused owing to the Co-N bond. The results demonstrated the Co-g-C 3 N 4 /PMS/Cl process was an efficient and promising method for the removal of ammonia in chloride-containing wastewater under ambient conditions.