Hyperbranched amino modified magnetic nanoparticles for simultaneous removal of heavy metal ions from aqueous solutions

Functionalized magnetic nanoparticles (MNPs) are gaining considerable interest to remove heavy metal ions (HMIs) from polluted water. However, simultaneous removal of coexisting HMIs remains a challenge due to the competition between different HMIs to bind the limited number of adsorption sites of the adsorbent. To address this, abundant adsorption sites were provided by increasing the density of functional groups on the surface of MNPs using the second-generation of a hyperbranched polyamidoamine (PAMAM) dendrimer. For dendritic modification, a novel approach was used to remove the surfactant coating on the as-prepared MNPs synthesized by the thermal decomposition. The magnetic nanoadsorbents were extensively characterized by XRD, TEM, FTIR, zeta potentials, XPS, SQUID-VSM, and BET. The MNP-PAMAM nanoadsorbents were utilized for the simultaneous removal of model HMIs Pb(II), Ni(II), and Cd(II) from aqueous solutions by batch adsorption experiment. Pb(II), Ni(II), and Cd(II) were found to have maximum adsorption capacities (qm) of 37.00, 31.92, and 24.94 mg/g, respectively, in the ternary system and 92.82, 80.10, and 57.72 mg/g, respectively in single systems. The adsorption kinetics and isotherm follow Langmuir and pseudo-second-order models, respectively. MNP-PAMAM nanoformulation developed in this study can also be useful in other applications such as biomedical, sensors, and nanocatalysis.