Investigation of MPTMS-modified magnetic nanoparticles in the removal of lead and cadmium ions from aqueous solution: equilibrium and kinetic studies

Environmental pollution by heavy metals has received much attention in recent years. Therefore, this study aims to remove lead and cadmium ions by using silica-coated magnetic nanoparticles modified with mercaptopropyltrimethoxysilane (MPTMS) from aqueous solutions.
In this study, Fe3O4@SiO2-SH magnetic nanoparticles were synthesized via the simplified co-precipitation method at 80°C. The structure and morphology properties of synthesized nanoparticles were characterized by XRD, FT-IR, SEM and TEM. Finally, the adsorption experiments were performed in aqueous media. All stages of this research were conducted ethically.
According to the results, Fe3O4@SiO2-SH nanoparticles have a uniform distribution with a spherical Fe3O4 core and SiO2 shell, modified by thiol functional groups. The efficiency of synthesized adsorbent in the removal of metal ions was also investigated considering parameters such as pH, adsorbent dose and contact time. The optimum conditions for lead and cadmium removal were obtained at pH 5 to 6, contact time 40 min and absorbent dose 0.8 g/L. The kinetic and isotherm studies underlined that the process of adsorption of both metal ions follows the second-order (R2> 0.98) and Langmuir isotherm (R2>0.98) models.
Based on the results obtained, synthesized Fe3O4@SiO2-SH magnetic nanoparticles can present proper efficiency in the removal of lead and cadmium ions from aqueous media under optimum conditions.