Use of tar pitch as a binding and reductant of BFD waste to produce reactive materials for environmental applications

In this work, a new approach is presented for the modification of the hazardous steel industry waste BFD (Blast Furnace Dust) into a versatile material for application in environmental remediation processes. Tar pitch, another waste, was used to agglomerate the very fine (submicrometric) dust particles to produce a compact and robust pelletized material that under simple thermal treatment produces notably reactive reduced Fe phases. SEM, TG/DTA, Mössbauer, XRD, Raman, BET and elemental analyses indicated that the tar/BFD composite (1:1 wt ratio) pellets treated at 400, 600 and 800 °C lead to tar decomposition to form a carbon binding coat concomitant with the reduction of the Fe oxides to produce primarily Fe3O4 (magnetite), FeO (wüstite) and Fe0. Preliminary reactivity studies indicated that these treated composites, especially at 800 °C, are active for the reduction of Cr(VI)aq and for the elimination of textile dye via reduction and the Fenton reaction

Magnetic carbon nanofiber networks as support for ionic liquid based catalyst

In this work, the ionic liquid (IL) 1-hexyl-3-methyl-imidazolium bromide (HMIm.Br) containing Pd suspended nanoparticles was supported on a nanostructured magnetically recoverable carbon nanofiber network. The magnetic material was prepared by a simple reaction of ethanol directly with a nanostructured hematite. SEM, XRD, Mössbauer, Raman, TG/DTA, BET surface area and magnetization analyses suggested that the network is based on carbon nanofibers with carbon coated magnetic Fe nanoparticles. These magnetic networks offer a high exposed carbon fiber area, which has a good interaction with the IL to form a thin layer. Preliminary studies with a Pd dispersed in supported IL as catalyst for the hydrogenation of 1,5-cyclooctadiene showed a membrane effect, which leads to an important increase on the selective hydrogenation of 1,5-cyclooctadiene to cyclooctene

Catalytic oxidation of aqueous sulfide in the presence of ferrites (MFe2O4, M = Fe, Cu, Co)

In this work, the spinel structured iron oxides, MFe2O4 (M = Cu2+ and Co2+), magnetite (Fe3O4) and maghemite (γ-Fe2O3) were investigated as catalyst for the sulfide oxidation in aqueous medium. XRD, Mössbauer, BET, TPR, SEM/EDS and XPS analyses suggest the formation of the spinel phase with surface areas varying from 75 to 105 m2 g-1 and the metal ions Cu2+ and Co2+ located in the octahedral and tetrahedral sites. It was observed that the presence of Co and especially Cu strongly increased the catalytic activity for the oxidation of sulfide to polysulfides, i.e. Sx 2- (x = 1-4) and other S-O species. The strong effect of Cu2+ is discussed in terms of thermodynamically favorable processes comprising a strong surface interaction of S2--Cu2+, an electron transfer from sulfide to produce Cu1+ followed by an electron transfer from Cu1+ to Fe3+ bulk.Fil: Cunha, Igor T.. Universidade Federal de Minas Gerais; BrasilFil: Teixeira, Ivo F.. University of Oxford; Reino UnidoFil: Albuquerque, Adriana S.. Centro de Desenvolvimento da Tecnologia Nuclear; BrasilFil: Ardisson, José D.. Centro de Desenvolvimento da Tecnologia Nuclear; BrasilFil: Macedo, Waldemar A. A.. Centro de Desenvolvimento da Tecnologia Nuclear; BrasilFil: Oliveira, Henrique S.. Universidade Federal de Minas Gerais; BrasilFil: Tristão, Juliana C.. Universidade Federal de Viçosa; BrasilFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada ; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Lago, Rochel M.. Universidade Federal de Minas Gerais; Brasi