52 research outputs found

    The Role of Water in the Photocatalytic Degradation of Acetonitrile and Toluene in Gas-Solid and Liquid-Solid Regimes

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    Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercial TiO2 samples ( Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene was CO2 with small amounts of benzaldehyde. In the presence of water vapour, the activity of TiO2 Merck remained stable but greatly decreased if water was absent. TiO2 Degussa P25 continuously deactivated, even in the presence of water vapour. With both catalysts, the photodegradation products of acetonitrile were CO2 and HCN; the activity was stable and was independent of the presence of water vapour in the reacting mixture. The production of HCN represents a drawback of acetonitrile photocatalytic degradation but the elimination of HCN is not actually a problem. In liquid-solid regime, the main intermediates of toluene photodegradation were p-cresol and benzaldehyde; traces of pyrogallol and benzyl alcohol were also found. Benzoic acid, hydroquinone, and trans, trans muconic acid were detected only when TiO2 Merck was used. The photodegradation products of acetonitrile were cyanide, cyanate, formate, nitrate, and carbonate ions

    The STRIP instrument of the Large Scale Polarization Explorer: microwave eyes to map the Galactic polarized foregrounds

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    In this paper we discuss the latest developments of the STRIP instrument of the "Large Scale Polarization Explorer" (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the "B-modes" of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the "Observatorio del Teide" in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.Comment: 17 pages, 15 figures, proceedings of the SPIE Astronomical Telescopes + Instrumentation conference "Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX", on June 15th, 2018, Austin (TX

    Preparation and photoactivity of nanostructured anatase, rutile and brookite TiO2 thin films

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    Photoactive films consisting of pure anatase, brookite or rutile TiO2 were prepared by dip coating from water dispersions obtained by using TiCl4 as the precursor under similar mild experimental condition

    Preparation of photocatalytic brookite thin films

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    Pure brookite films were deposited from a brookite dispersion obtained by peptizing a mixture brookite–rutile prepared by thermolysis of TiCl4 in a HCl solution. The films were characterised by X-ray diffraction and Raman spectroscopy. The photoactivity of the samples was tested by using the photo-oxidation of 2-propanol in gas–solid regime as a probe reaction. The brookite films efficiently degraded 2-propanol under UV illumination
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