Comparison of the adsorption preference using superparamagnetic Fe3O4-SH nanoparticles to remove aqueous heavy metal contaminants.

In this study, thiolated magnetic iron oxide nanoparticles (Fe 3 O 4 -SH) were prepared and characterized in detail, which exhibited benign superparamagnetism and magnetic recoverability. And the adsorption and desorption processes for various heavy metals, including Pb 2+ , Ni 2+ , Zn 2+ and Cu 2+ , had been investigated comprehensively both in single and mixed systems using the Fe 3 O 4 -SH nanoparticles as adsorbents. The results showed that heavy metal ions could be removed rapidly depending on the complexation with the SH-groups on the Fe 3 O 4 -SH surface. Besides, the adsorption was all sensitive to pH and ionic strength while the nano-adsorbents had the highest adsorption capacity and rate for Ni 2+ according to the adsorption kinetics and thermodynamics. In addition, the corresponding competitive adsorption processes and desorption experiments reflected that Fe 3 O 4 -SH had the strongest affinity and adsorption selectivity for Pb 2+ , followed by Ni 2+ and finally by Cu 2+ and Zn 2+ . Generally, the present study might provide a serviceable direction for the future efforts towards the application of Fe 3 O 4 -SH nano-adsorbents in industrial wastewater treatments involving multiple heavy metal contaminants. [ABSTRACT FROM AUTHOR]