| In this work,8series,29kinds nano Fe3O4magnetic polymers (NMPs), in which,21were thiol-functionalized NMPs (SH-Fe3O4-NMPs),4were amino-functionalized NMPs (NH2-Fe3O4-NMPs) and4were amino-thiol-bifunctionalized NMPs (NH2-SH-Fe304-NMPs), have been prepared via improved chemical co-precipitation method, followed by suspension polymerization, substitution and ring-opening reactions. SH-Fe3O4-NMPs were synthesized by varying the episulfide agents, episulfide time, usage amount of Fe3O4and the monomers,i. e., glycidylmethacrylate (GMA), divinylbenzene (DVB) and methyl methacrylate (MMA). The morphologies, magnetic properties, contents and structures of SH-Fe3O4-NMPs have been characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), elementary analysis (EA), thermogravimetry analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that SH-Fe3O4-NMPs were multidispersed, with an average diameter of around250-350um, well responded to magnetic fields and thermodynamic stabilized. The effects of the removal of Hg(Ⅱ) from aqueous solution by SH-Fe3O4-NMPs were investigated via batch tests. The effects of some important factors, i.e., the effects of pH value, the initial concentration of Hg(Ⅱ), contacting time, contacting temperature and coexisted anion ions were intensively investigated. Presumed mechanism of Hg(Ⅱ) adsorbing onto SH-Fe3O4-NMPs was discussed by investigating the VSM, XRD, and XPS of SH-Fe3O4-NMPs before and after adsorption of Hg(Ⅱ). The results showed that the adsorption properties of SH-Fe3O4-NMPs were highly pH dependent. The adsorption efficiency of Hg(Ⅱ) increased with the increase of the pH value of the aqueous solution and reached a plateau at pH above4.0. The adsorption of Hg(Ⅱ) reached equilibrium in10～90mins and the kinetic data were well fitted to pseudo-second-order model; Thermodynamic studies indicated that the process of the Hg(Ⅱ) adsorbing onto SH-Fe3O4-NMPs was endothermic and entropy favored in nature; The adsorption data were found to be well correlated with Langmuir isotherm model; The effectiveness of SH-Fe3O4-NMPs for the removal of Hg(Ⅱ) could be restrained by the coexisted Cl". The results of VSM, XRD, and XRD indicated that Hg(Ⅱ) ions had been successfully adsorbed onto SH-Fe3O4-NMPs via coordination interactions, and Hg(Ⅱ) might be partially reduced to through solid state redox reaction via charge transport from Fe(II) on the surface of the SH-Fe3O4-NMPs. |
PDF Full Text Request