Aminodextran Magnetic Colloidal Particles for Heavy Metals Removal

Submicron aminodextran coated-magnetic poly(divinylbenzene) nanoparticles (AD-MPDVBs) have been prepared as magnetic adsorbents for removal of Cu(II), Pb(II) and Zn(II) ions from aqueous solutions. AD-MPDVBs were prepared in two steps; the first step depends on the encapsulation of magnetic emulsion nanoparticles by the crosslinked poly(divinylbenzene) shell, followed by electrostatic adsorptions of aminodextran on their surface. The successful formation of AD-MPDVBs was evidenced by transmission electron microscope (TEM), zeta potential measurements and thermal gravimetric analysis (TGA). In addition, particle size and size distribution, magnetic content and magnetic properties of AD-MPDVBs were also investigated. The key parameters which can affect metal ions uptake efficiency of AD-MPDVBs including contact time, initial metal ion concentration and pH of the solution has been studied. The obtained results showed that AD-MPDVBs exhibited high and fast adsorption of Cu(II), Pb(II), and Zn(II) ions, and the equilibrium was achieved within 30 min. Furthermore, for equilibrium studies, two isotherm models were used in this study; Freundlich and Langmuir models. The equilibrium studies showed that the adsorption of Cu(II), Pb(II), and Zn(II) follows Langmuir isotherm model and the maximum sorption capacity of AD-MPDVBs was found to be 11.62, 100 and 40 mg/g for Cu2+, Pb2+ and Zn2+, respectively. In addition, the adsorption process could be described by pseudo-second-order kinetic model, and the mechanism of Cu(II), Pb(II), and Zn(II) ions sorption onto AD-MPDVBs was tentatively proposed. Furthermore, a comparison study was carried out between maximum sorption capacity of the prepared AD-MPDVBs and those obtained by using various magnetic/polymer hybrids in the literature. The prepared AD-MPDVBs showed promising results which make them convenient to serve as effective adsorbents for removal of heavy metal ions from wastewater.