Advances in inorganic NiFe2O4/g-C3N4 composite catalysts: Synthesis, characterization, and application in peroxymonosulfate activation for antibiotic degradation

The fabrication of exceptionally effective and reusable heterogeneous catalysts for the activation of peroxymonosulfate (PMS) to eliminate the enduring contamination by antibiotic drugs, particularly Tetracycline (TC), in aquatic systems continues to pose a considerable challenge. Herein, we present a unique and efficient magnetic composite catalyst developed by anchoring nickel ferrite over graphitic carbon nitride (NiFe₂O₄/g-C₃N₄) through a sol-gel method that can easily activate PMS to effectively degrade TC. Evidently, the NiFe₂O₄/g-C₃N₄/PMS achieved a maximum TC removal effectiveness of 97.54 % in 42 min, surpassing NiFe₂O₄/PMS (72.65 %), respectively, under optimized parameters ([catalyst] = 0.4 g/L, [PMS] = 24 mM, [TC] = 18 mg/L, [pH] = 3.0). The catalytic efficacy of NiFe₂O₄/g-C₃N₄ composites surpassed that of the alone NiFe₂O₄ or g-C₃N₄, attributable to the cyclic interactions of Ni²⁺/Ni³⁺ and Fe³⁺/Fe²⁺ at the interfaces of NiFe₂O₄/g-C₃N₄. The radical trapping experiments and EPR analyses revealed that SO₄^•−, ^•OH, and ¹O₂ were the principal reactive species accountable for the mineralization of TC. Additionally, a potential mechanism for the TC degradation process was put forward. The magnetic NiFe₂O₄/g-C₃N₄ composites have shown remarkable recycling ability and versatility. Ultimately, this work presents an effective, rapid, and eco-friendly PMS activation approach that offers sustainable technological support for the remediation of antibiotic drug contaminants in water.