A Comparative Study on Spinel Iron-cobalt Oxide Prepared by Co-precipitation and Hydrothermal Routes

Spinel iron-cobalt oxide was synthetized by coprecipitation and hydrothermal process. The nanostruc-tures of the prepared samples were characterized as functions of the calcination temperature and the hy-drothermal synthesis time, using X-ray powder diffractometry (XRD) and nitrogen adsorption–desorption technique ( BET, BJH ). Using chloride salts as start materials and both of sodium hydroxide and ammo-nia as precipitating agents; The results show that the CoFe2O4 obtained has a mesoporous structure with a pore distribution strongly depending on the experimental conditions. The crystallite size and lattice pa-rameter showed a same variation as function of ( i ) the calcination temperature in the coprecipitation method, ( ii ) the synthesis time in the hydrothermal process. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3509

Late pulmonary metastases of renal cell carcinoma immediately after post-transplantation immunosuppressive treatment: a case report

Introduction We report a case of pulmonary metastatic recurrence of renal adenocarcinoma soon after radical nephrectomy that was followed by renal transplant and immunosuppressive medication. Increased risk of metastatic recurrence of renal cell carcinoma should be considered in the immediate post-transplant period when immunosuppressive medication is administered, even if nephrectomy had been performed many years earlier.Case presentation In 1986 the patient demonstrated renal insufficiency secondary to mesangial glomerulonephritis. In 1992 he underwent left side radical nephrectomy with histopathological diagnosis of clear cell adenocarcinoma. Mesangial glomerulonephritis in the remaining right kidney progressed to end-stage renal failure. In October 2000 he received a kidney transplant from a cadaver and commenced immunosuppressive medication. Two months later, several nodules were found in his lungs, which were identified as metastases from the primary renal tumor that had been removed with the diseased kidney 8 years earlier.Conclusion Recurrence of renal cell carcinoma metastases points to tumor dormancy and reflects a misbalance between effective tumor immune surveillance and immune escape. This case demonstrates that a state of tumor dormancy can be interrupted soon after administration of immunosuppressant medication.This work was partially supported by the Fondo de Investigaciones Sanitarias (PI 02/0175), the plan Andaluz de Investigacion, and the Instituto de Salud Carlos III-Red de centros de Cancer, Spain

Structural and textural study of Ni and/or Co in a common molybdate lattice as catalysts

This work deals with the search for new molybdate catalyst formulations, which are known to be active in light alkane oxidative dehydrogenation, a process which could be replace in the near future the common steam cracking and pure dehydrogenation processes currently used for the production of alkenes. Co, Ni and mixed Ni-Co molybdates of various compositions are prepared by a modified coprecipitation procedure from metal nitrates and ammonium heptamolybdate. Their structural and textural properties were studied by XRD, Raman, B.E.T and XPS. Textural and structural properties of the materials are correlated to the composition

New way for iron introduction in LDH matrix used as catalysts for Friedel–Crafts reactions

The alkylation of toluene, reaction employing benzyl chloride as the alkylating agent over basic hydrotalcite materials: Fe–Mg–Al-LDH prepared by different synthesis methods, including the method of co-precipitation, impregnation and a new method called the method of intercalation by anion exchange in the lamellar space of the host structure LDH. Our prepared solids were characterized by chemical analysis, XRD analysis, BET method and thermogravimetric analysis (TGA) and tested in the alkylation of toluene by benzyl chloride reaction. Fe–Mg–Al-LDH clay without or with calcination (at 773 K) has been investigated. The catalyst derived from the hydrotalcite by its calcination at 773 K shows high catalytic activity for the alkylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the oxides of iron on the catalyst surface

In Situ Regeneration of Alumina-Supported Cobalt–Iron Catalysts for Hydrogen Production by Catalytic Methane Decomposition

A novel approach to the in situ regeneration of a spent alumina-supported cobalt⁻iron catalyst for catalytic methane decomposition is reported in this work. The spent catalyst was obtained after testing fresh catalyst in catalytic methane decomposition reaction during 90 min. The regeneration evaluated the effect of forced periodic cycling; the cycles of regeneration were performed in situ at 700 °C under diluted O2 gasifying agent (10% O2/N2), followed by inert treatment under N2. The obtained regenerated catalysts at different cycles were tested again in catalytic methane decomposition reaction. Fresh, spent, and spent/regenerated materials were characterized using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), laser Raman spectroscopy (LRS), N2-physisorption, H2-temperature programmed reduction (H2-TPR), thermogravimetric analysis (TGA), and atomic absorption spectroscopy (AAS). The comparison of transmission electron microscope and X-ray powder diffraction characterizations of spent and spent/regenerated catalysts showed the formation of a significant amount of carbon on the surface with a densification of catalyst particles after each catalytic methane decomposition reaction preceded by regeneration. The activity results confirm that the methane decomposition after regeneration cycles leads to a permanent deactivation of catalysts certainly provoked by the coke deposition. Indeed, it is likely that some active iron sites cannot be regenerated totally despite the forced periodic cycling

Structure, reactivity and catalytic properties of nanoparticles of nickel ferrite in the dry reforming of methane

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