In this research, a one step and facile approach was used for the synthesis of magnetic multiwalled carbon nanotubes on the surface of diatomite earth as a substrate by chemical vapor deposition (CVD) of methane. The prepared composite was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), N-2 adsorption - desorption measurement (BET) and Raman spectroscopy analyses. This new material combines the advantages of carbon nanotubes and diatomite in one material. The composite exhibited superparamagnetic properties and was used as a magnetic separable sorbent for adsorption of metal ions from aqueous media. The acid activated sorbent showed fast adsorption kinetic within 10 min and maximum Langmuir monolayer capacity of 60 mg g(-1) for lead ions. The thermodynamic parameters, Delta H, Delta S and Delta G were calculated from temperature-dependent adsorption data indicating adsorption of Pb2+ ions onto the composite material is a spontaneous process. The results suggest that this sorbent is a suitable material for the removal and solidification of metal ions from polluted environmental samples. (C) 2014 Elsevier B.V. All rights reserved.