Abstract Nano-sized magnetic sorbents can be promising candidate materials for treatment of low-level effluents resulting in effective decontamination and very high volume reduction of radioactive wastes. Preparation of magnetite-hexacyanoferrate composite was based upon wet-dispersion and in situ precipitation for synthesizing coatings on magnetite. Superior magnetic properties were rendered to potassium nickel (II) hexacyanoferrate (II), a sorbent with high specificity for cesium uptake, by loading to magnetite. The magnetic complex showed same apparent sorption capability for cesium as potassium nickel (II) hexacyanoferrate (II). Transmission electron microscope revealed a particle size distribution of 8–30 nm for these magnetic particles. Large moment possessed by particles was responsible for high uptake of magnetic separator column at low background magnetic field. Low residual magnetism favored magnetic filter regeneration parameter requirement.