Functionalized magnetic nanoparticles supported on activated carbon for adsorption of Pb(II) and Cr(VI) ions from saline solutions

Adsorption ability of prepared magnetic nanoparticles supported on activated carbon (AC-MNPs) was evaluated to synthesize an efficient and a low cost adsorbent for removal of Pb(II) and Cr(VI) ions from single and binary component aqueous solutions in the presence of salinity. Magnetic adsorbent was prepared by co-precipitation over activated carbon derived from almond shell by physical activation method. AC-MNPs was modified by oxygen containing functional groups to enhance the adsorption capacity of adsorbent. XRD, XPS, BET, Boehm, TEM, FT-IR, DLS and XRF were used to characterize the AC@Fe3O4@SiO2-NH2-COOH. Characterization analyses indicated the high dispersion of Fe3O4 crystallites on the activated carbon. TEM, XRD and DLS results revealed that size of Fe3O4 crystallites were below 17 nm. XPS results of the adsorbents before and after Pb(II) and Cr(VI) ions adsorption indicated that these metal ions successfully adsorbed. There were found from operating experiments that Cr(VI) ions have a negligible effect on adsorption of Pb(II) ions in binary solutions. However, removal efficiency of metal ions was reduced which were reached 80% and 53% for Pb(II) and Cr(VI), respectively. Results also illustrated that the effect of salinity on the adsorption of metal ions at pH > 7 was negligible.