Search results for "chemistry [Water]"
showing 10 items of 2369 documents
Preparation and photoactivity of samarium loaded anatase, brookite and rutile catalysts
2011
Abstract Pure and samarium loaded anatase, brookite and rutile nanopowders were synthesized by thermohydrolysis of TiCl 4 . The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), specific surface area (SSA) determination, UV–vis diffuse reflectance spectroscopy (DRS), atomic force microscopy (AFM), contact angle (CA) measurements and photoluminescence (PL) spectroscopy. The photocatalytic activity of pure and Sm-loaded TiO 2 polymorphs was investigated by employing the photodegradation of 4-nitrophenol as probe reaction in a liquid-solid system. Loading with Sm resulted in an improvement of the photoreactivity of the three TiO 2 polymorphs. The benefi…
Photocatalytic Degradation of 4-nitrophenol in aqueous suspension by using polycristalline TiO2 samples impregnated with a Cu(II)-phthalocyanine
2002
In this paper, the preparation of polycrystalline TiO2 samples impregnated with a modified Cu(II)-phthalocyanine (TiO2–CuPc) is reported along with an investigation on the photocatalytic behavior of this system compared with bare TiO2 (both in the anatase and rutile form) and with TiO2 samples impregnated with not functionalized commercial phthalocyanine (TiO2–CuPc) or with metal free phthalocyanine (TiO2–Pc). The photocatalytic degradation of 4-nitrophenol (4-NP) was studied as a probe reaction. The presence of modified CuPc showed to be beneficial only for TiO2 (anatase) while the commercial not functionalized CuPc also slightly for both TiO2 (anatase) and TiO2 (rutile). The metal free Pc…
Influence of pH on the degradation kinetics of nitrophenol isomers in a heterogeneous photocatalytic system
1993
Abstract The kinetics of photocatalytic degradation of 2-, 3- and 4-nitrophenol in aqueousdispersions containing TiO2 (anatase) has been investigated at different initial values of pH and concentrations of substrate. A pseudo-first order kinetics with respect to the nitrophenol concentration was found to hold; an increase of the substrate concentration and the initial pH was detrimental on the degradation rate.
Photocatalytic oxidation of gaseous toluene on anatase TiO2 catalyst: Mechanistic aspects and FT-IR investigation
1999
Abstract Photo-oxidation of toluene has been carried out in gas–solid regime by using polycrystalline anatase TiO2 as the catalyst. The reacting gaseous mixture was toluene, air and water in various molar ratios. A pyrex fixed-bed continuous photoreactor irradiated by a medium pressure Hg lamp was used for performing the photoreactivity experiments. The main oxidation product was benzaldehyde but benzene, benzyl alcohol and traces of benzoic acid, phenol and unidentified compounds were also detected. The molar conversion to benzaldehyde with respect to the initial amount of toluene was ca. 20% in the best experimental conditions. Benzene was produced only as a transient product during the f…
A new hybrid method to improve the ultra-short-term prediction of LOD
2019
Accurate, short-term predictions of Earth orientation parameters (EOP) are needed for many real-time applications including precise tracking and navigation of interplanetary spacecraft, climate forecasting, and disaster prevention. Out of the EOP, the LOD (length of day), which represents the changes in the Earth’s rotation rate, is the most challenging to predict since it is largely affected by the torques associated with changes in atmospheric circulation. In this study, the combination of Copula-based analysis and singular spectrum analysis (SSA) method is introduced to improve the accuracy of the forecasted LOD. The procedure operates as follows: First, we derive the dependence structur…
Genesis of chlorine and sulphur in fumarolic emissions at Vulcano Island (Italy): assessment of pH and redox conditions in the hydrothermal system
2002
Chlorine- and sulphur-bearing compounds in fumarole discharges of the La Fossa crater at Vulcano Island (Italy) can be modelled by a mixing process between magmatic gases and vapour from a boiling hydrothermal system. This allows estimating the compounds in both endmembers. Magma degassing cannot explain the time variation of sulphur and HCl concentrations in the deep endmember, which are more probably linked to reactions of solid phases at depth, before mixing with the hydrothermal vapours. Based on the P–T conditions and speciation of the boiling hydrothermal system below La Fossa, the HCl and Stot contents in the hydrothermal vapours were used to compute the redox conditions and pH of th…
Zircon ages of the Bayankhongor ophiolite mélange and associated rocks: Time constraints on Neoproterozoic to Cambrian accretionary and collisional o…
2010
Abstract Central Mongolia is geologically characterized by close juxtaposition of an accreted oceanic terrane with an arc-microcontinent collision zone. We present new U–Pb zircon ages and geochemical data for the Bayankhongor ophiolite melange from the oceanic terrane and for a syenite porphyry pluton from the arc-microcontinent zone, providing critical constraints on the regional evolution in late Neoproterozoic to early Cambrian times. An anorthosite (655 ± 4 Ma) associated with layered gabbro, a rodingite (metasomatized layered gabbro) (647 ± 6 Ma), and a high-level isotropic amphibole gabbro (647 ± 7 Ma) yielded the oldest zircon ages for the plutonic part of the ophiolite. A plagiogra…
Antibody Complementarity-Determining Regions (CDRs) Can Display Differential Antimicrobial, Antiviral and Antitumor Activities
2008
9 p. Background: Complementarity-determining regions (CDRs) are immunoglobulin (Ig) hypervariable domains that determine specific antibody (Ab) binding. We have shown that synthetic CDR-related peptides and many decapeptides spanning the variable region of a recombinant yeast killer toxin-like antiidiotypic Ab are candidacidal in vitro. An alanine-substituted decapeptide from the variable region of this Ab displayed increased cytotoxicity in vitro and/or therapeutic effects in vivo against various bacteria, fungi, protozoa and viruses. The possibility that isolated CDRs, represented by short synthetic peptides, may display antimicrobial, antiviral and antitumor activities irrespective of Ab…
Salmon (Salmo salar) side streams as a bioresource to obtain potential antioxidant peptides after applying pressurized liquid extraction (PLE)
2021
The pressurized liquid extraction (PLE) technique was used to obtain protein extracts with antioxidant capacity from salmon muscle remains, heads, viscera, skin, and tailfins. A protein recovery percentage ≈28% was obtained for all samples except for viscera, which was ≈92%. These values represented an increase of 1.5–4.8-fold compared to stirring extraction (control). Different SDS-PAGE profiles in control and PLE extracts revealed that extraction conditions affected the protein molecular weight distribution of the obtained extracts. Both TEAC (Trolox equivalent antioxidant capacity) and ORAC (oxygen radical antioxidant capacity) assays showed an outstanding antioxidant activity for viscer…
Antioxidant Properties of a Supercritical Fluid Extract of the Halophyte Mesembryanthemum nodiflorum L. from Sicilian Coasts: Nutraceutical and Cosme…
2020
The aim of this paper was to obtain different extracts from the aerial parts of Mesembryanthemum nodiflorum, comparing traditional extraction (using solvents with increasing polarity such as hexane, ethanol 80%, acetone 70% and water) with an eco-friendly technique (supercritical fluid extraction (SFE))