Synthesis of Magnetite-Graphite Oxide Diatomite
as an Alternative Adsorbent for Heavy Metal Ions
Juliet Q. Dalagan* and Romelisa A. Ibale
Chemistry Department, Xavier University,Corrales Avenue,
Cagayan de Oro City, Philippines, 9000
In this recent work, magnetite-graphite oxide-diatomite (Mag-GO-diatomite) composite was produced and was used to remove heavy metal ions, Cr3+, Cu2+ and Pb2+, in aqueous solution. GO was prepared by modified Hummer’s method and characterized by Fourier Transform Infrared (FTIR) and Scanning Electron microscopy (SEM). Mag-GO-diatomite was synthesized using a facile method and characterized by FTIR and SEM-energy dispersive Xray (EDX). Results of IR analysis revealed presence of Fe-O at 750 cm-1 which indicates strong interaction between iron oxide particles of magnetite with the ester O of GO. This was confirmed by EDX analysis which showed strong signals for Fe and O. SEM images corroborated with the IR and EDX analyses with the occurrence of a rough textural surface indicating the presence of magnetite. Adsorption of the heavy metal ions Cr3+, Cu2+, and Pb2+ on GO-diatomite revealed a greater amount of heavy metals adsorbed on the adsorbent with magnetite than the one without magnetite. Furthermore, the adsorption of the 3 metal ions on Mag-GO-diatomite in the presence of each other was investigated and results showed that there is no significant competitive adsorption between Cu2+ and Pb2+. However, Cr3+ manifested a competitive adsorption behavior with the divalent cations.
Water contamination by hazardous metal ions is a worldwide concern. Recent studies have been conducted to eliminate organic and inorganic pollutants. Some commonly used techniques for reducing level of contamination include chemical precipitation by controlling pH (Ito et al. 2000), chemical oxidation, chemical reduction, ion exchange (Mier et al. 2001), membrane ﬁltration using coagulants, electrochemical treatment, evaporation, constructed wetland, and adsorption (Tchobanoglous et al. 2003; Mouflih et al. 2005). Among these methods, the use of novel adsorbents has been widely studied due to its fast adsorption rate, large adsorption capacity, and high adsorption selectivity for hazardous metal ions. Numerous adsorbents such as activated carbon (Sekar et al. 2004), synthetic resin (Demirbas et al. 2005), . . . . read more