Magnetically recoverable Ni-doped iron oxide/graphitic carbon nitride nanocomposites for the improved photocatalytic degradation of ciprofloxacin: Investigation of degradation pathways

Developing efficient and effective photocatalysts is essential for organic dyes and antibiotic degradation in wastewater. Ni-doped α-Fe₂O₃/g-C₃N₄ (NFGCN) photocatalysts were synthesised through a simple co-precipitation technique and used for the ciprofloxacin (CIP) and methylene blue (MB) degradation through photocatalysis. The XRD data indicated the crystallinity of the synthesised iron oxide and its composites with rhombohedral structures with the nature of high purity. The morphology of the NFGCN composite revealed the construction of Ni-doped α-Fe₂O₃ (NFO) nanoparticles onto the g-C₃N₄ (GCN) sheet surface along with the close interface that induced a Z-scheme heterojunction. The synthesised photocatalysts showed photocatalytic activity with good degradation efficiency of 82.1 % and 92.0 % for CIP and MB, respectively, within 120 min under solar light exposure. The improved photocatalytic degradation efficiency was attained owing to the synthesised composite's enhanced light absorption in the visible range. The narrow band gap energies and interaction between Ni-doped α-Fe₂O₃ and g-C₃N₄ displayed by these materials result in enhanced visible light absorption, effective charge carrier separation and transportation to the pollutants. CIP degradation pathways were investigated utilising the LC-MS analysis. NFGCN composites showed good recyclability (5 cycles), magnetic retrievability, and stability for degrading organic and emerging pollutants from wastewater through photocatalysis.