Abstract
A new type of magnetic chelating resin (MIDA) beads bearing iminodiacetate groups derived from acrylamide N,N'-methylenebis(acrylamide) copolymer was synthesized in the presence of Fe3O4 nanoparticles and tested for the removal of Cu(II), Pb(II), Zn(II), and Cd(II) from aqueous solution. The prepared Fe3O4 nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM)-energy dispersive X-ray, transmission elelctron microscopy, and X-ray diffraction (XRD). The obtained MIDA was characterized by FTIR, SEM, Brunauer-Emmett-Teller analysis, XRD, thermal analysis, and water regain (W%). Different factors affecting the adsorption process such as pH of solution, initial concentration of the metal ions, shaking time, and temperature of solution, were investigated by batch technique. The maximum adsorption capacities were 4.1, 3.6, 2.4, and 2.2 mmol.g(-1) for Cu(II), Pb(II), Zn(II), and Cd(II), respectively. Langmuir isotherm and pseudo-second-order equation could adequately describe the adsorption process of all metal ions. Thermodynamic parameters revealed that the adsorption process is endothermic, spontaneous in nature, and entropy driven. Additionally, the removal of Cu(II) was tested using the fixed-bed column technique. The effect of significant column parameters such as bed height, flow rate, and Cu(II) concentration on the performance of the column were examined. The breakthrough curves obtained were analyzed by Thomas and Yoon-Nelson kinetic models. The regeneration of the exhausted column bed was conducted with 0.1 M HNO3 solution, and MIDA was found to maintain its high adsorption capacity up to six cycles.