LAUSR

A magnetically separable Fe3O4/CuO core-shell heterostructure photocatalyst was synthesized by hydrothermal method. The obtained photocatalyst was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-visible diffuse reflectance (UV-DRS). The obtained photocatalyst was used for the degradation of azo dye Direct Red 89 (DR89), under visible light irradiation provided by fluorescent lamp of 100 W in the presence of 7 mL of H2O2 (30%); the results of the photocatalytic activity for Fe3O4/CuO photocatalyst showed that in the presence of 0.75 g dispersed in 250 mL of 40 mg/L of DR89 dye at pH 6 the dye was completely removed after 240 min. Moreover, the photocatalytic activity of the prepared Fe3O4/CuO was enhanced 11 and 9 times compared with the pure Fe3O4 or CuO. The effect of initial dye concentrations on the photocatalytic activity was studied in the range of 20–60 mg/L, and the results showed that the catalyst has a good photocatalytic activity of 89% even at high concentration (60 mg/L). Furthermore, the catalyst maintained its activity after 5 cycles, and its paramagnetic property facilitates its recovery. The excellent photodegradation activity of Fe3O4/CuO was attributed to the low band gap of the catalyst equal to 1.54 eV and the enhancement of light absorption in visible range of 330–780 nm, but also to a better charge carriers separation, due to the presence of Fe3O4 that reduces electron/hole recombination.