Pb2+Removal from Aqueous Solutions Using Montmorillonite and Magnetite-Modified Nanostructures

This study explores the effectiveness of Pb²⁺ ion adsorption from aqueous solutions utilizing two different adsorbents: montmorillonite clay (Mt) and a synthesized magnetic nano organo-composite (MagMt-H). The MagMt-H composite was developed by modifying Mt with the cationic surfactant Hexadecyltrimethylammonium bromide (HDTMA) and incorporating magnetite (Fe₃O₄) nanoparticles. The synthesized composite was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The effect of initial Pb²⁺ concentration on adsorption performance was systematically examined for both adsorbents. Different isotherm and kinetic models—pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion—were applied to better understand how the adsorption process takes place. Pb²⁺ adsorption onto MagMt-H conformed to the Langmuir isotherm and pseudo-second-order kinetic model, achieving a maximum adsorption capacity of 73.58 mg g^-1 at 30 °C, significantly higher than that of Mt (49.54 mg g^-1). Furthermore, the initial adsorption rate (h) for MagMt-H was 18.809 mg g^-1 min^-1, compared to 0.948 mg g^-1 min^-1 for Mt, indicating superior Pb²⁺ removal efficiency of the composite. These findings demonstrate that MagMt-H is not only facile to synthesize but also provides additional adsorption sites, presenting a promising candidate for effective Pb²⁺ remediation from aqueous environments. Future research should investigate the regeneration and reusability of MagMt-H, as well as its performance in complex real wastewater systems.