Abstract
Magnetic ferrite nanoparticles were synthesized through the microwave-assisted combustion method. X-ray diffraction analysis confirmed the formation of a single spinet cubic structure with a mean crystallite size of 40-60 nm. Scanning electron microscopy observations revealed spherical-particles at the nanoscale with a tendency to agglomeration. Magnetic measurements indicated a ferromagnetic order with a saturation magnetization of 57-61 emu/g. A specially designed miniaturized flow cell was fabricated using a laser cutting machine on polymethyl methacrylate substrate. The flow cell was tailored to incorporate a magnet used to hold the nanoparticles in position while performing the flow experiments. The flow cell containing the nanoparticles was successfully applied for the removal of different heavy metal ions. Several factors affecting the adsorption of metal ions including pH, contact time, and flowrate, were investigated. Maximum adsorption efficiencies of 98%, 94% and 82% were achieved in almost 10 min for Cd(II), Cr(III) and Pb(II), respectively, while adsorption efficiencies of higher than 90% were obtained at around 40 min for Co(II) and Cu(II), and 50 min for Zn(II). The selectivity of nanoparticles for multiple metal ions solution varied in the order of Pb(II) > Cu(II) > Co(II) > Cd(II). Moreover, the synthesized nanoparticles proved their applicability for a real waste sample and their possibility to be regenerated with complete restoration of the adsorption efficiency. The adsorption of selective ions onto magnetic ferrite nanoparticles was found to follow pseudo-second-order kinetics and was well fitted by the Langmuir isotherm. This work provides an efficient method for the removal of heavy metal ions in continuous systems and complex environments, which make it a suitable candidate for industrial applications.