Competitive Adsorption of Metals onto Magnetic Graphene Oxide: Comparison with Other Carbonaceous Adsorbents

Abstract

Competitive adsorption isotherms of Cu(II), Pb(II), and Cd(II) were examined on a magnetic graphene oxide (GO), multiwalled carbon nanotubes (MWCNTs), and powered activated carbon (PAC). A series of analyses confirmed the successful synthesis of the magnetic GO based on a simple ultrasonification method. Irrespective of the adsorbents, the adsorption was highly dependent on pH, and the adsorption was well described by the Langmuir isotherm model. The maximum adsorption capacities of the adsorbents were generally higher in the order of Pb(II) > Cu(II) > Cd(II), which is the same as the degree of the electronegativity and the hydrated radius of the metals, suggesting that the metal adsorption may be governed by an ion exchange between positively charged metals and negatively charged surfaces, as well as diffusion of metals into the surface layer. The adsorption of each metal was mostly lower for multi- versus single-metal systems. The antagonistic effects were influenced by solution pH as well as the type of metals, and they were higher in the order of the magnetic GO > MWCNT > PAC. Dissolved HS played a greater role than HS adsorbed onto the adsorbents, competing with the adsorption sites for metal complexation.

Sorption of radionuclides and metals to graphene oxide and magnetic graphene oxide

“…Impressive adsorption capacities have been reported for the GO composites, e.g., sorption capacity of GO decorated with Fe 3 O 4 , sorption capacity of sulfonated magnetic GO composite and magnetic mn-doped Fe(III) oxide nanoparticle implanted graphene for Cu(II) varied from 18.3 to 129.7 mg g -1 , while for Pb(II) it ranged from 274.7 to 673 mg g -1 [33][34][35][36][37]. The reported maximum adsorption capacity at pH of 7 of magnetic GO composite for Cu(II) was 59.44 mg g -1 and for Pb(II) was 151.17 mg g -1 were lower than that obtained in this study [38]. Thus, the sinthesized sorbents showed a similar or higher adsorption capacity as compared to the values reported in the recent publications with the exeption of the GO adsorption capacity for Pb.…”

Preparation and characterization of magnetic graphene oxide nanocomposite (GO-Fe3O4) for removal of strontium and cesium from aqueous solutions

“…111. 8 m 2 /g, 49.9 m 2 /g, respectively [23,24] . The results obtained in this study are consistent with the literature.…”

Heavy metals removal by EDTA-functionalized chitosan graphene oxide nanocomposites

“…Among these, adsorption is the preferred technology because of its simplicity, effectiveness, and low cost in the removal of toxic heavy metals from water/ wastewater. 10 Moreover, the simple operation, time efficiency, and large-scale applicability of the adsorption method are considered promising for the development of wastewater treatment technologies. In recent years, carbonaceous nanomaterials such as graphene oxide (GO), a two-or threedimensional nanosheet, have attracted the attention of researchers because of their unique properties and large composition diversity.…”