Synthesis and Characterization of Magnetite-Alginate Nanoparticles for Enhancement of Nickel and Cobalt Ion Adsorption from Wastewater

Superparamagnetic magnetite-alginate nanoparticles (M-AlgNPs) were synthesized utilizing a coprecipitation method. Then, the prepared M-AlgNPs were characterized via Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD) to affirm the formation and the crystallinity of this composite. In addition, the surface morphology of the prepared nanoparticles was inspected by transmission electron microscopy (TEM) which revealed well-dispersed nanoparticles of Fe3O4 into alginate. The adsorption characteristics of the synthesized nanoparticles for removing Ni+2 and Co+2 from wastewater were evaluated via atomic absorption measurements (AAS). The elimination efficiency of the M-AlgNPs was detected at pH=7 in 100 ppm (initial concentration) of Ni+2 and Co+2, separately. The M-AlgNPs provided the maximum equilibrium uptake percentage for Ni+2 and Co+2 of 97.88 and 95.01%, respectively. The adsorption of Ni+2 and Co+2 onto the M-AlgNP surface was found to fit the Langmuir model with R2 values higher than that obtained from the Freundlich model for both metal ions. Moreover, RL “separating factor” for the adsorption process was assessed and found to be less than unity; this expresses the higher ability of the investigated metal ions to be adsorbed onto the M-AlgNP surface. The adsorption method was discovered to be pH-dependent and well-suited to the isothermal equations of Langmuir and Freundlich. For regeneration studies, M-AlgNPs have been investigated and results confirmed that it could be reused with effective sorption capacity over three cycles.