Cobalt-based catalyst to activate PMS for selective ammonium oxidation in PMS/chloridion system

The efficient elimination of ammonia nitrogen (NH4+-N) from the specific wastewater and selective oxidation to nitrogen gas are the most desirable purposes of wastewater treatment, but still remains a challenge. Herein, we presented a cobalt-based catalyst (Co-VB12-C) as a novel heterogeneous catalyst, which was fabricated via the co-pyrolysis of poly (2,6-diaminopyridine) and vitamin B12. Co-VB12-C were successfully prepared to construct a facile heterogeneous Co-VB12-C/PMS/Cl system and achieve effective removal of NH4+-N and high selectivity to nitrogen gas in acidic and neutral pH. Co-VB12-C had superior catalytic capability, reusability, and stability. The role of catalyst, PMS, Cl-, and pH value was investigated and the corresponding mechanism was proposed, which revealed that Cl•-mediated oxidation reactions made predominant contribution to NH4+-N transformation. This system is a facile alternative technology for removing ammonium from high saline wastewater.