Adsorption of Cu(II), Pb(II), and Cd(II) Ions from Acidic Aqueous Solutions by Diethylenetriaminepentaacetic Acid-Modified Magnetic Graphene Oxide
文摘
In this study, diethylenetriaminepentaacetic acid (DTPA)-modified magnetic graphene oxide (MGO) was synthesized for removal of Cu(II), Pb(II), and Cd(II) ions from acidic aqueous solutions. The prepared DTPA/MGO composites were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared and X-ray photoelectron spectroscopies, and zeta potential. The results showed that DTPA successfully functionalized MGO. Adsorption experiments indicated that DTPA/MGO composites exhibited excellent adsorption property in acidic aqueous solutions. The adsorption processes were applicable for the Langmuir adsorption isotherm and the pseudo-second-order model. The maximum adsorption capacities at pH 3.0 for Cu(II), Pb(II), and Cd(II) ions were 131.4, 387.6, and 286.5 mg/g, respectively. The thermodynamic studies demonstrated that adsorption processes were endothermic and spontaneous. Moreover, the DTPA/MGO composites could selectively adsorb Pb(II) from multimetal mixed systems. Adsorption–desorption results showed that the DTPA/MGO composites exhibited excellent reusability. These results suggested that DTPA/MGO composites have great potential in removing heavy metals from acidic wastewater, especially for Pb(II).
