Search results for "SILICA"

showing 10 items of 1092 documents

Nano- to Global-Scale Uncertainties in Terrestrial Enhanced Weathering.

2022

Enhanced weathering (EW) is one of the most promising negative emissions technologies urgently needed to limit global warming to at least below 2 °C, a goal recently reaffirmed at the UN Global Climate Change conference (i.e., COP26). EW relies on the accelerated dissolution of crushed silicate rocks applied to soils and is considered a sustainable solution requiring limited technology. While EW has a high theoretical potential of sequestering CO2, research is still needed to provide accurate estimates of carbon (C) sequestration when applying different silicate materials across distinct climates and major soil types in combination with a variety of plants. Here we elaborate on fundamental …

SoilCarbon SequestrationClimate change negative emissions technology global warming carbon sequestration enhanced weathering concrete recyclingClimate ChangeSilicatesSettore ICAR/02 - Costruzioni Idrauliche E Marittime E IdrologiaEnvironmental ChemistryGeneral ChemistryCarbon DioxideWeatherEnvironmental sciencetechnology
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A new class of heterogeneous Pd catalysts for synthetic organic chemistry

2011

A new series of leach-proof nanostructured Pd(0) catalysts able to catalyze a number of fundamental organic transformations including C–C bond formation has been developed. Reactions in general proceed with high yield and often at completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry trademarked SiliaCat Pd0 Hydrogel.

Sol gel chemistryChemistryYield (chemistry)fine chemistryOrganic chemistryheterogeneous catalysiorganically modified silica (ORMOSIL)sol-gel chemistryBond formationHeterogeneous catalysisCatalysisCatalysis
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Are high-temperature fractionations in the solar nebula preserved in highly siderophile element systematics of the Earth's mantle?

2004

The relative abundances of the highly siderophile elements (HSE) Os, Ir, Ru, Pt, Rh, and Pd in relatively pristine lherzolites differ from solar abundance ratios and are several orders of magnitude higher than predicted for equilibrium distribution between metal/silicate (core-mantle). The samples are characterized by a mean Ca/Al ratio of 1.18 ± 0.09 σM and a mean Ca/Si ratio of 0.10 ± 0.01 σM, overlapping with a mean Ca/Al of 1.069 ±  0.044 σM and a mean Ca/Si of 0.081 ± 0.023 σM found in chondrites (Wasson and Kallemeyn 1988). Interestingly, the CI-normalized abundance pattern shows decreasing solar system normalized abundances with increasing condensation temperatures. The abundance of …

Solar SystemGeochemistryAnalytical chemistryengineering.materialSilicatechemistry.chemical_compoundGeophysicschemistrySpace and Planetary ScienceAbundance (ecology)ChondriteEnstatiteengineeringFormation and evolution of the Solar SystemGeologyEarth (classical element)Refractory (planetary science)Meteoritics & Planetary Science
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Enhancing extraction performance of organophosphorus flame retardants in water samples using titanium hierarchical porous silica materials as sorbent…

2021

Abstract A sorbent for the extraction of organophosphorus flame retardants has been proposed, based on UVM-7 (University of Valencia Materials) mesoporous silica doped with titanium. Designed cartridges have been applied to the extraction and preconcentration of flame retardants in water samples, followed by gas chromatography coupled to a mass spectrometry detector. Firstly, UVM-7 materials with different contents of titanium were synthesized and characterized by several techniques, thus confirming the proper mesoporous architecture. The potential of these materials was assessed in comparison with their morphological properties, resulting Ti50-UVM-7 the best solid phase. Several extraction…

Sorbent010402 general chemistry01 natural sciencesBiochemistryAnalytical Chemistrychemistry.chemical_compoundOrganophosphorus CompoundsLimit of DetectionSolid phase extractionSolid Phase MicroextractionFlame RetardantsDetection limitTitaniumChromatographyChemistry010401 analytical chemistryOrganic ChemistryExtraction (chemistry)WaterGeneral MedicineMesoporous silicaSilicon DioxideOrganophosphates0104 chemical sciencesGas chromatographyAdsorptionMesoporous materialPorosityTriphenyl phosphateJournal of chromatography. A
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CCDC 265898: Experimental Crystal Structure Determination

2006

Related Article: Zhenyu Shi, Jun Peng, C.J.Gomez-Garcia, S.Benmansour, Xiaojun Gu|2006|J.Solid State Chem.|179|253|doi:10.1016/j.jssc.2005.09.051

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters(mu~10~-Silicato)-octakis(mu~3~-oxo)-octadecakis(mu~2~-oxo)-bis(110-phenanthroline)-dodecaoxo-di-copper(i)-tetra-molybdenum(v)-octa-molybdenum(vi)-di-vanadium(iv) bis(bis(110-phenanthroline)-copper(i))Experimental 3D Coordinates
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CCDC 116337: Experimental Crystal Structure Determination

2000

Related Article: J.A.Aguilar, T.Clifford, A.Danby, J.M.Llinares, S.Mason, E.Garcia-Espana, K.Bowman-James|2001|Supramol.Chem.|13|405|doi:10.1080/10610270108029457

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters4814182327-Hexa-ammonio-111-diaza-61625(13)-tribenzenabicyclo(9.9.9)nonacosaphane fluoride bis(hydrogen difluoride) sesquikis(hexafluorosilicate) heptahydrate clathrateExperimental 3D Coordinates
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CCDC 1851193: Experimental Crystal Structure Determination

2019

Related Article: Yan Hou, Haijun Pang, Carlos J. Gómez-García, Huiyuan Ma, Xinming Wang, Lichao Tan|2019|Inorg.Chem.|58|16028|doi:10.1021/acs.inorgchem.9b02516

Space GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinatescatena-[hexakis(mu-124-triazolyl)-deca-silver(i) (mu-silicato)-tetracosakis(mu-oxo)-dodeca-oxo-dodeca-tungsten]
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CCDC 665727: Experimental Crystal Structure Determination

2009

Related Article: E.Coronado, C.Gimenez-Saiz, C.J.Gomez-Garcia, F.M.Romero|2008|Solid State Sciences|10|1794|doi:10.1016/j.solidstatesciences.2008.01.031

Space GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinatestetrakis((4455-Tetramethyl-2-(1-methylpyridinium-4-yl)-3-oxido-45-dihydro-1H-imidazol-1-yl)oxidanyl radical) (mu~12~-silicato)-tetracosakis(mu~2~-oxo)-dodeca-oxo-dodeca-tungsten dimethylformamide solvate
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CCDC 619251: Experimental Crystal Structure Determination

2007

Related Article: L.Lisnard, P.Mialane, A.Dolbecq, J.Marrot, J.M.Clemente-Juan, E.Coronado, B.Keita, P.de Oliveira, L.Nadjo, F.Secheresse|2007|Chem.-Eur.J.|13|3525|doi:10.1002/chem.200601252

Space GroupCrystallographyCrystal SystemCrystal StructureCell ParametersPenta-potassium tri-sodium (mu~12~-silicato)-tris(mu~3~-hydroxo)-tris(mu~2~-acetato)-henicosakis(mu~2~-oxo)-nonaoxo-tetra-cobalt(ii)-nona-tungsten octadecahydrateExperimental 3D Coordinates
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CCDC 1004974: Experimental Crystal Structure Determination

2014

Related Article: Alexander N. Chernyshev, Dmitry Morozov, Jarkko Mutanen, Vadim Yu Kukushkin, Gerrit Groenhof, Matti Haukka|2014|J.Mater.Chem.C|2|8285|doi:10.1039/C4TC01165A

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parametersbis(2-(pyridin-1-ylamino)pyridinium) hexafluorosilicate dihydrateExperimental 3D Coordinates
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