Highly-efficient Peroxymonosulfate Activation for Sulfacetamide Degradation over Nitrogen-functionalized Graphene: the Effect of Thermal Annealing Temperature on Reactive Functional Groups

Abstract

Nitrogen-doped graphene (NG) prepared through thermal annealing of graphene oxide (GO) and urea was employed as a peroxymonosulfate (PMS) activator to degrade sulfacetamide (SAM). The fine tuning of the concentrations of functionalities and catalytic performance of NG was realized via tweaking thermal annealing temperature. NG600 (NG prepared at 600 °C) with the controlled N bonding configurations (a high N doping level (16.0 wt%) and a most optimum amount of pyridinic N (38.4 %N), pyrrolic N (31.8 %N), graphitic N (25.9 %N)) performed best as PMS activator. Quenching experiments disclosed that radical pathway contributed more to SAM degradation than non-radical pathway. SO₄^•- was the key reactive species for the SAM degradation in the NG/PMS system.
Key words: metal-free catalysis, nitrogen-doped graphene, peroxymonosulfate, sulfacetamide, sulfate ra