Cobalt ferrite (CF) nanoparticle was synthesized and modified by (3-aminopropyl) trimethoxy silane. Polyoxometalate (H3PW12O40) was immobilized on the modified cobalt ferrite (MCF) nanoparticle. The immobilized polyoxometalate onto the modified cobalt ferrite (IPMCF) nanoparticle was used as an environmentally friendly magnetic catalyst for photocatalytic dye degradation. The synthesized IPMCF was characterized using FTIR, SEM, AFM and XRD. Acid Orange 95, Acid Red 18, and Direct Red 81 were used as model dyes. The effect of catalyst dosage, dye concentration and salt on dye degradation was studied. Dye degradation increases by catalyst dosage. The results showed that decolorization followed by zero-order kinetic model. (C) 2016 Elsevier Ltd. All rights reserved.