Synthesis of an oxidized mesoporous carbon-based magnetic composite and its application for heavy metal removal from aqueous solutions

Abstract

The aim of this study was to synthesize and consider an oxidized mesoporous carbon-based magnetic composite (M-O-MC) for heavy metal removal from aqueous solutions. The M-O-MC used was a black powdery particle that was attracted to external magnets and thus separated from aqueous solutions. The M-O-MC had an average particle size of 232 ± 63 nm, with a BET specific surface area of 179 m2/g and a total pore volume of 0.18 cm3/g. The X-ray diffractometer pattern of the M-O-MC showed characteristic peaks related to maghemite due to the impregnation of iron oxide nanoparticles. Fourier-transform infrared spectra showed that carboxylic and Fe-O bonds were assigned on the M-O-MC due to surface functionalization. The X-ray photoelectron spectra showed that carboxyl functional groups on the surface of the M-O-MC were involved in the adsorption of Cu(II). Batch tests were performed using Cu(II) as a target heavy metal. The Cu(II) adsorption to the M-O-MC was influenced by solution pH and other cations. In the four cycles of adsorption–desorption testing, the M-O-MC was successfully regenerated and reused, maintaining its magnetic property. The equilibrium time for the Cu(II) adsorption was 3 h, whereas the maximum adsorption capacity was 51.4 mg/g. The Cu(II) adsorption was endothermic, increasing with a rise in temperature from 15 °C to 45 °C. In batch tests with plating wastewater containing various metal ions (Cu(II), total Cr, Ni(II), Zn(II), etc.), the M-O-MC was applied as an adsorbent for the removal of heavy metal ions.