The nanoparticles of Fe3O4 were prepared by chemical co-precipitation method. In order to improve the photocatalytic activity and preparation of magnetic separable ZnO from aqueous phase, nano ZnO was immobilized on Fe3O4 as magnetically separable visible-light-driven photocatalyst. For this purpose, the prepared Fe3O4 nanoparticles (2.00g) were dispersed by ultrasonic into 150 mL of deionized distilled water by ultrasonic irradiation for 30 min in 25°C. Then, 1.00 g of zinc nitrate was added to the formed suspension of Fe3O4 with mechanical stirring continued for 2h. This solution was precipitated by NaOH solution (5M) with continuous stirring by mechanical stirrer and the suspension subsequently was sonicated in air for 1hto produce nano ZnO immobilized on Fe3O4. The characterization of prepared magnetic nanocomposite was analyzed by XRD, EDX and scanning electron microscopy (SEM). The efficiency of magnetic photocatalyst was investigated by degradation of acid orange 7 (AO7) from aqueous solution in the presence of visible light. The results showed that the prepared magnetic photocatalyst has suitable efficiency under visible light compared with ZnO powder in same conditions. Also, photocatalyst can be separated easily from the aqueous phase by a magnet. The result showed the photodegradation followed pseudo first order kinetic and the activation energy of reaction was 2.24 KJ.mol-1
