In this study, the sol-gel auto-combustion method is employed to synthesize barium hexaferrite (BaFe12O19) using carboxymethyl cellulose as chelating agent. The properties and identity of the synthesized BaFe12O19 nanoparticles were verified with X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS) and vibrating sample magnetometry (VSM). The adsorption efficiency of the prepared nanoparticles toward lead(II) metal ions was estimated using atomic absorption spectroscopy (AAS). The synthesized BaFe12O19 was utilized as an adsorbent for removing lead(II) from the aqueous solution. The utilization enhancement studies of the synthesized nanoparticles were influenced by several factors, which include incubation time, pH of metal ion solutions, adsorbent doses, initial lead(II) metal ion concentration and temperature. Under optimum conditions, when 0.20 g of adsorbent was used with 5 mg/L of lead(II) ion solution at a pH 6, the adsorption percentage was found to be 91.53%. Endothermic adsorption and the Langmuir isotherm models were found to best fit the data of lead(II) adsorption. Notably, the maximum adsorption capacity (qm) for lead adsorption was 4.57 mg/g. These findings demonstrated that the novel single material BaFe12O19 magnetic nanoparticles can function as a highly effective nanosorbent for the treatment of wastewater and they can effectively remove lead(II) ions.