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.

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Volatile properties of copper(II) complexes of the general formula [Cu 2 ( t BuNH 2 ) 2 (m-O 2 CR) 4 ] (R ¼ C n F 2nþ1 , n ¼ 1-6) (1-6), and their potential application as CVD precursors are discussed. These compounds do not require special storage and handling conditions, and they are sources of metallated species between 435 and 473 K. Analysis of variable temperature infrared (IR) spectra of vapors prove the formation of the volatile and stable copper(I) carboxylate and copper(II) amine carboxylate species. Results of CVD experiments prove the usefulness of the Cu II complexes studied in the production of metallic copper layers, between 673 K and 743 K, on silicon (Si (111)), Si-SiO 2 , titanium, and Ti-TiO 2 substrates. Film morphologies are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The structure and purity of copper layers are studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and selected area electron diffraction (SAED).