Fe3O4 nanoparticles functionalized with poly (ethylene glycol) for selective separation and enrichment of Au (III)
Magnetic nanoparticles with surface containing multiform heteroatoms have great potential for metal-ion recovery with a high throughput. In this paper, a novel adsorbent (Fe3O4@CPTES@PEG) developed to adsorb Au (III) from aqueous solution has been synthesized by functionalizing Fe3O4 magnetic nanoparticles with poly (ethylene glycol) via simple two-step reactions. Various techniques including fourier transform infrared spectrometer (FT-IR), thermal gravimetric analyzer (TGA), vibrating Sample Magnetometer (VSM), transmission electron microscope (TEM) and X-ray diffraction spectrum (XRD) were used to characterize the adsorbent, demonstrating that poly (ethylene glycol) was successfully grafted onto Fe3O4 magnetic nanoparticles. Batch experiments were applied to investigate the effects of initial concentration of Au (III), contact time and coexist ions on the absorption of Au (III) from aqueous solution at pH=1.0. Simultaneously, the adsorption process was fitted well with the Langmuir and pseudo-second-order models. The synthesized core–shell structured Fe3O4@CPTES@PEG showed high performance towards Au (III) adsorption and the maximum adsorption capacity was about 83 mg/g. Significantly, the material exhibited highly selective adsorption toward Au (III) versus coexist ions (Fe(III), Mn(II), Pb(II), Cd(II), Cu(II), Cr(III), Al(III), Mg(II), Zn(II) and Au (III)). And also, the material could be regenerated electively by ferrous sulfate, and exhibited an excellent reutilization at least three times without significant loss of adsorption capacity after simple post-treatment. Therefore, the proposed method shows an enormous potential for practical applications in selective separation and enrichment of Au (III) from aqueous solution at pH=1.0.