224 research outputs found

    Sustainable Recycling of Insoluble Rust Waste for the Synthesis of Iron-Containing Perovskite-Type Catalysts

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    Insoluble rust waste from the scraping of rusted iron-containing materials represents a cheap, eco-friendly, and available source of iron. LaFeO3 perovskite-type powders were successfully prepared by solution combustion synthesis using rust waste from an electricity transmission tower manufacturer. Solution combustion synthesis enabled introduction of this insoluble iron precursor directly into the final product, bypassing complex extraction procedures. Catalytic activity in the propylene oxidation of the waste-derived LaFeO3 with stoichiometric Fe/La ratio was almost identical to the commercial iron nitrate-derived LaFeO3 , thus demonstrating the viability of this recycling solution. The amount of waste iron precursor was varied and its effect on the powder properties was investigated. A lesser stoichiometric amount of precursor produced a LaFeO3 -La2O3 binary system, whereas a higher stoichiometric amount led to a LaFeO3 -Fe2O3 binary system. Catalytic activity of iron-rich compositions in the propylene oxidation was only slightly lower than the stoichiometric one, whereas iron-poor compositions were much less active. This eco-friendly methodology can be easily extended to other iron perovskites with different chemical compositions and to other iron-containing compounds

    Interpretation of the Metamorphic Processes in Various Rock Types Using the Chemistry of Garnets (Selecka Mountain, Macedonia)

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    The garnets from the complex of Selecka Mountain could be divided in two groups on the basis of their chemical composition and zoning. The garnets from muscovite-schist and amphibole-schist show characteristics typical for a growth in prograde metamorphic conditions up to the medium metamorphic grade. Characteristics of the other garnets (from aplite granite, aplite veins and metabasite) suggest their formation in anatectic or highly metasomatic conditions. The inversion in chemical zoning, observed in some of them, is discussed and related to possible processes of growth

    Compositional Zoning in Amphibole from Amphibole Bearing Parageneses of West Psunj (Croatia): Evidence for Progressive Metamorphism?

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    Amphibole bearing parageneses from the western part of Mt. Psunj (Croatia) record evidence of prograding metamorphism. Optical and microprobe analyses, together with thermobarometric evaluations on amphibole bearing parageneses, show a zonation with Si- and Mg-concentrations decreasing from core to rim along with increasing Al-, Na-, and Ti-content. Changes in the chemical composition of amphibole grains are interpreted through coupled substitutions, and reactions with co-existing minerals during an increase in metamorphic conditions from greenschist to amphibolite facies. The change in P-T conditions recorded in the growth of amphibole grains (general prograding pattern) together with changes in the modal compositions in related parageneses could be interpreted in a model of a subduction zone

    Dehydration of fructose to 5-HMF over acidic TiO2 catalysts

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    Different solid sulfonic titania-based catalysts were investigated for the hydrothermal dehydration of fructose to 5-hydroxymethylfurfural (5-HMF). The catalytic behavior of the materials was evaluated in terms of fructose conversion and selectivity to 5-HMF. The surface and structural properties of the catalysts were investigated by means of X-ray diffraction (XRD), N2 adsorption isotherms, thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and acid capacity measurements. Special attention was focused on the reaction conditions, both in terms of 5-HMF selectivity and the sustainability of the process, choosing water as the solvent. Among the various process condition studied, TiO2-SO3H catalyzed a complete conversion (99%) of 1.1M fructose and 5-HMF selectivity (50%) and yield (50%) at 165 °C. An important improvement of the HMF selectivity (71%) was achieved when the reaction was carried out by using a lower fructose concentration (0.1M) and lower temperature (140 °C). The catalytic activities of the materials were related to their acid capacities as much as their textural properties. In particular, a counterbalance between the acidity and the structure of the pores in which the catalytic sites are located, results in the key issue for switch the selectivity towards the achievement of 5-HMF

    Photocatalytic CO2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO2 Supported or Cu-Loaded TiO2 Samples

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    Both commercial and home prepared (HP) TiO2 samples have been tested for the photocatalytic reduction of CO2. (HP) TiO2 powders were prepared by using TiCl4 or Ti(OC4H9)4 as the precursors to obtain HP1 and HP2 samples, respectively. Also HP Cu-loaded and SiO2 supported TiO2 powders were prepared. The HP samples were more active than the commercial ones for the photoreduction of CO2 with and without water vapour. HP1 produced mainly formaldehyde, HP2 principally methane. Acetaldehyde was found to be the primary product obtained when HP1 was supported on SiO2. The addition of Cu increased the photocatalytic reactivity either of bulk and SiO2-supported HP1. In particular, 1 wt % of Cu improved the formaldehyde yield obtained with the bare HP1 by one order of magnitude. Differently, the presence of Cu or SiO2 in the HP2 samples markedly reduced the production of methane

    A Rare Cause for Acute Cor Pulmonale

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    A number of diseases may cause right atrial mass. Primary cardiac tumors range from 0.002 to 0.25%. Intracardiac manifestation and pulmonary embolism of hepatocellular carcinoma (HCC) is a very rare finding and uncommon even at autopsy. Here we describe the case of a 32-year-old Asian man who was referred for shortness of breath lasting for a month, along with unproductive cough. He was a manual laborer with a history of diabetes, alcoholism, and smoking. Clinically he was diagnosed as having pulmonary embolism. Echocardiogram showed a mass in the right atrium. Magnetic resonance imaging showed that he had a large mass in the right atrium extending down into the inferior vena cava. Further evaluation showed that he had chronic liver disease with portal hypertension and was hepatitis B surface antigen-positive, indicating hepatitis B infection. He underwent excision of the mass, and the pathological report showed metastasis of HCC with multiple vascular emboli in the lungs. As this is the second reported case of this kind in the literature, we highlight the need of screening at least 6-monthly all patients with chronic liver disease, hepatitis B and C virus infection for the early detection of HCC
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