Suchergebnisse

In this study, magnetic nanocomposites were developed and used as adsorbents for lead and copper from aqueous media. Structural, surface, magnetic and textural properties of functionalized maghemite nanoparticles synthesized by alkaline co-precipitation were studied. The surfaces of the iron oxide nanoparticles (Nps) were modified with different chemical agents such as fatty and amino acids, silica (SiO2), mesoporous silica (SBA-15), hydroxyapatite, multiwall carbon nanotubes (MWCNTs) and ethylenediaminetetraacetic acid (EDTA), obtaining NPs with mean particle sizes ranging from 7 to 16 nm according to Rietveld refinement and TEM images analysis. The physicochemical surface properties of the functionalized materials were studied via zeta potential (zeta) and Fourier transform infrared (FTIR) spectroscopy. Mossbauer spectroscopy (MS) as a function of temperature and DC magnetometry were used to study the magnetic properties. The superparamagnetic relaxation was studied by MS. The resolved spectra at 20 K confirm the presence of nanomaghemite phase. Besides, the saturation magnetization varies from 12 to 62 emu g(-1). A nitrogen adsorption-desorption technique was used to determine the specific surface area and to study the porous structure. The functionalized gamma-Fe2O3 Nps exhibited a Brunauer-Emmett-Teller (BET) specific surface area ranging from 74 to 214 m(2) g(-1) and revealed remarkable uptake capacities to remove Cu(II) and Pb(II) species from aqueous solutions. ; National Council of Science, Technology and Technological Innovation (CONCYTEC/Cienciactiva-Peru) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; DAAD ; Ministerio de Economia y Competitividad of Spanish Government ; Natl Univ San Marcos, Fac Phys Sci, POB 14-0149, Lima 14, Peru ; Tech Univ Carolo Wilhelmina Braunschweig, Inst Phys Kondensierten Mat, D-38110 Braunschweig, Germany ; Univ Fed Sao Paulo, Inst Ciencia & Tecnol, Ave Cesare Mansueto Giulio Lattes 1201, BR-12247014 Sao Jose Dos Campos, SP, Brazil ; Brazilian Ctr Res Phys CBPF, BR-22290180 Rio De Janeiro, RJ, Brazil ; Univ Fed Rio Grande do Norte, Dept Fis Teor & Expt, BR-59078970 Natal, RN, Brazil ; Univ Rey Juan Carlos, Environm & Chem Engn Grp, C Tulipan S-N, Madrid, Spain ; Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, Av. Cesare Mansueto Giulio Lattes, 1201, São José dos Campos, Brazil ; CNPq: 305748/2015-7 ; Ministerio de Economia y Competitividad of Spanish Government: CTM2015-69246-R ; Web of Science