Photocatalytic degradation of methylene blue with hematite nanoparticles synthesized by thermal decomposition of fluoroquinolones oxalato-iron(III) complexes

[Fe(C₂O₄)(FQ)(H₂O)₂] complexes (H-FQ = ciprofloxacin (1), lomefloxacin (2) and norfloxacin (3)) were synthesized and characterized using a variety of analytical and spectral techniques such as elemental analysis, infrared spectroscopy, thermogravimetric analysis, ultraviolet-visible spectroscopy, magnetic and conductance measurements. The experimental studies were complemented by quantum chemical calculations in terms of geometry optimization, natural bond orbital analysis and molecular electrostatic potential maps. Electronic structures were discussed by TD-DFT. Hematite (α-Fe₂O₃) nanoparticles, as promising materials for different catalytic applications, were prepared in air via the controlled thermal decomposition of 1-3. Powder X-ray diffraction was used to identify the polymorph of iron oxide. The morphology of nano-hematite was investigated by a field emission scanning electron microscope coupled to energy-dispersive X-ray spectroscopy for surface analysis. The catalytic degradation of methylene-blue (MB), as an industrial pollutant, exposed to UV radiation in the presence of nano-α-Fe₂O₃ as a catalyst and hydrogen peroxide as the oxidant was studied at room temperature in water.