Adsorption of divalent metal ions from aqueous solutions using graphene oxide

Abstract

The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated. GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR). The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3-7 for Cu(II), 5-8 for Zn(II), 4-8 for Cd(II), 3-7 for Pb(II). The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g(-1), respectively. The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II). Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO. Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions. The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions. After adsorption, the tendency to agglomerate and precipitate is observed. Excellent dispersibility of GO and strong tendency of GO-Me(II) to precipitate open the path to removal of heavy metals from water solution. Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.

N, P, and S Codoped Graphene‐Like Carbon Nanosheets for Ultrafast Uranium (VI) Capture with High Capacity

“…From the kinetic equation, Q e and k were calculated to be 200.4 mg g −1 and 0.231 g mg −1 min −1 , respectively. Previous studies reported pseudo‐second‐order kinetic models for the adsorption of U(VI) by other materials such as GOs,27 amidoximated magnetite/GO composites,28 FeS,29 and melamine‐modified graphene hydrogels 30. The values of k were much higher than those previous references, which confirmed the significant adsorption efficiency of the NPS‐GLCs.…”

Graphene oxide/Fe3O4 as sorbent for magnetic solid-phase extraction coupled with liquid chromatography to determine 2,4,6-trinitrotoluene in water samples

“…The functional groups of GO are capable of forming hydrogen bonds or electrostatic interactions with aromatics and polar compounds or metal ions [ 18,19,20 ]. GO has proved to be an ideal sorbent for SPE [ 21 ] and SPME [ 22 ].…”

Biochar from Chinese herb residues as adsorbent for toxic metals removal

“…The removal rate of Pb 2+ by CHR600 was 97.5% at C 0 of 100 mg/L, significantly greater than that by CHR300 (88.6%), implying that the higher sorption affinity of Pb 2+ onto the biochar produced at high temperature. It [8] and graphene oxide (GO) [9]. The surface oxygen-containing functional groups in these carbonaceous material plays a significant role in the adsorption process of the metal ions by an electrostatic attraction or complexation.…”