Degradation of atrazine by N-doped graphitic carbon encapsulated Nickel-iron alloy via heterogeneous activation of peroxymonosulfate

Abstract

Heterogeneous magnetic catalysts for peroxymonosulfate (PMS) activation that are used to degrade pollutants have attracted growing attention, and bimetallic alloy catalysts have excellent catalytic performance. In this study, nitrogen-doped graphite carbon encapsulated NiFe (NiFe@NC) alloy catalysts were synthesized using nickel-iron Prussian blue analog precursors to remove atrazine (ATZ) via the activation of PMS. The effects of various operating parameters (NiFe@NC dosage, PMS concentration, initial solution pH, and reaction temperature), and the effects of co-existing components were investigated. The synergistic catalysis of Ni and Fe gives NiFe@NC good catalytic properties. The NiFe@NC/PMS system achieved 100% removal of 10 mg L−1 ATZ was achieved in 30 min with an initial pH of 5.9; the TOF was 4.33 min−1, and the system exhibited resistance to interference from many co-existing substances. The graphite-carbon core-shell structure of NiFe@NC slowed down the leaching rate of metal ions and had good stability. Redox cycles in the system were achieved by facilitating the interaction between the transition metal and HSO5-, ensuring the continuous generation of reactive oxygen species. Ecotoxicity assessment showed that the toxicity level was significantly reduced after treatment. The total treatment cost of treating 1 m3 wastewater was lower than that of Fenton sludge catalyst. A continuous flow reactor was constructed to achieve continuous degradation of ATZ for long periods. This study expanded the application of PMS advanced oxidation technology by synthesizing an economical and recyclable magnetic catalyst and provided new insights for the removal of refractory organic matter.