Construction of flower-like MnO2 decorated by SrCuFe2O4 as a magnetic nanocomposite for the photocatalytic degradation of methylene blue under visible light

A novel magnetizable nanocomposite (NC) photocatalyst SrCuFe2O4@MnO2-f, consisting of SrCuFe2O4 loaded onto flower-like manganese oxide, was synthesized using a simple template-free method. A hydrothermal route using KMnO4 was employed to produce and control the shape of the MnO2-f nanoparticles, while the SrCuFe2O4 nanoparticles (NPs) were created by a sol-gel method from the nitrates of strontium, copper and iron. The physicochemical properties of the synthesized nanomaterials were characterized by FTIR, FE-SEM with EDAX, XRD, VSM, TGA/DTA, BET, and TEM techniques. The effects of experimental variables on the visible light- induced photocatalytic activity of SrCuFe2O4@MnO2-f for methylene blue (MB) dye degradation were studied. The results showed that the photocatalyst achieved superior photocatalytic performance i.e. 98.3 % MB photolysis within 56 min using 3 mg catalyst dose per 50 mL of 10 ppm MB concentration at pH 10, compared to 58.5 % and 49.51 % for MnO2-f and SrCuFe2O4, individually. The degradation kinetics fitted a pseudo-first order kinetics model with a rate constant of 0.06246 min-1 . The enhanced photocatalytic efficiency, was assigned to better light absorption, more effective separation of electron-hole pairs and faster transfer of charge carriers within the SrCuFe2O4/MnO2-f structure. Moreover, the as-prepared photocatalyst achieved 89.7 % MB degradation efficiency after 4 times recyclability, making it potentially valuable for large scale polluted water purification systems.