Heavy metals are major pollutants in the environmen due to their bioaccumulation in living cells and their non-biodegradable nature. The objectives of this research were synthesing the magnetite nanoparticles (Fe 3 O 4 ) and determining their efficiency inthe removal of heavy metal ions from aqueous solutions.In this study, magnetic nano-adsorbent has been synthesized by the covalent immobilization of poly (acrylic acid) (PAA) and 4-phenyl-3-thiosemicarbazide (TSC) as a complexing agent on the surface of Fe 3 O 4 nanoparticles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), FT-IR spectroscopy, X-ray diffraction and vibration samplemagnetometer (VSM) were used for characterization of the synthesized magnetite nanoparticles.Atomic absorption spectroscopy (AAS) was used for determination of heavy metal ions in the solution befor and after treatment with adsorbent. The ability of the Fe 3 O 4 @PAA@TSC M for removing heavy metal ions Pb 2+ , Cd 2+ , Co 2+ , Cu 2+ and Zn 2+ from aqueous solution was studied and the effects of pH, contact time, metal ion concentration and background electrolytes on heavy metal ions removal efficiency were investigated in batch system. SEM results showed that the diameter of the particles is in the rang of 40-60 nm. Results also showed that the optimum pH value for adsorption is 5. The kinetic data were properly fitted by the pseudo-second-order model.The assumption that the metal ions adsorption is due to complex formation between active sites of the adsorbent and the heavy metal ions was further confirmed by investigating the adsorption isotherms and kinetics.The equilibrium time of 45 min and 0.050 g used of adsorbent for the volume 50.0 mL of wastewater solution.Finally, adsorption process was investigated with Langmuir and Freundlich isotherms. The experimental adsorption equilibrium data were fitted to Langmuir adsorption and the maximum adsorption capacities of Pb 2+ , Cd 2+ , Co 2+ , Cu 2+ and Zn 2+ were found to be 181.1, 125.0, 86.2, 67.1 and 57.8 mg g -1 , respectively.The adsorption capacity increased and the adsorption efficiency decreased with increasing the concentration of heavy metal ions and reducing the amount of adsorbent.The desorption experiments under batch conditions revealed that the Fe 3 O 4 @PAA@TSC M are reusable adsorbent for practical removal of the heavy metal ions. The ability of the prepared nanoparticles for removal of heavy metal ions from industrial samples was evaluated by using different industrial wastewaters from Moham industrial complex, Raad plating company and Iran Aircraft Manufacturing Industrial Company (HESA) and obtained optimum conditions is adsorbent concentration 1.0 gL -1 , contact time 45 minutes, solution pH=5.0, solution valume 50.0 mL and stirrer speed 300 round per minutes that is applied to real samples.Excellent adsorption capacity of the modified nano-adsorbent together with other advantages such as reusability, easy synthesis, easy separation and more specially freedom of interferences of alkaline earth metal ions make them suitable alternatives to the well-known adsorbents for removal of heavy metal ions from industrial wastewaters. Key Words Heavy Metal; Magnetic Nanoparticle; Poly Acrylic Acid; 4-Phenyl-3-Thiosemicarbazide; Magnetite; Fe 3 O 4 .