The magnetically modified composites for Cd(II), Pb(II) and Zn(II) ions removal from aqueous solution were synthetized. Montmorillonite/FexOy composites were successfully prepared using ferrofluid. The presence of FexOy nanoparticles (NPs) on the clay surface did not influence its chemical composition and did not lead to the release of clay elements to the solution. Moreover, the FexOy NPs enhanced the sorption properties of the clays and – due to the magnetic properties of composites – they could be easily removed by external magnetic field after the sorption. The influence of initial pH of the aqueous solution containing Cd(II), Pb(II) and Zn(II) ions on sorption capacity of montmorillonite/FexOy composites was studied. The accompanying elements released from clays to final extracts were observed as well. Results show that the initial pH of aqueous solution affected the sorption capacity of the observed elements and the release of the elements from montmorillonite originated from Ivančice (M) and magnetically montmorillonite (MM). The maximum sorption capacity was determined in the acid area of pH (3–4). After the sorption, FexOy NPs were determined in final extracts at low concentrations and are, therefore, fixed onto MM strongly. However, FexOy NPs are not fixed onto magnetically modified Smecta (SM) as strongly as onto MM because they leached to the final extracts more than from MM. Due to the aforementioned results of FexOy leaching, both studied composites were still magnetic after sorption experiments. The prepared composites are functional sorbents and are stable in pH 3–7.Keywords: Montmorillonite, magnetically composite, iron oxide nanoparticles, stability, sorption
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