Highly Water-Stable Zirconium Metal-Organic Framework UiO-66 Membranes Supported on Alumina Hollow Fibers for Desalination

In this study, continuous zirconium(IV)-based metal-organic framework (Zr-MOF) membranes were prepared. The pure-phase Zr-MOF (i.e., UiO-66) polycrystalline membranes were fabricated on alumina hollow fibers using an in situ solvothermal synthesis method. Single-gas permeation and ion rejection tests were carried out to confirm membrane integrity and functionality. The membrane exhibited excellent multivalent ion rejection (e.g., 86.3% for Ca2+, 98.0% for Mg2+, and 99.3% for Al3+) on the basis of size exclusion with moderate permeance (0.14 L m-2 h-1 bar-1) and good permeability (0.28 L m-2 h-1 bar-1 μm). Benefiting from the exceptional chemical stability of the UiO-66 material, no degradation of membrane performance was observed for various tests up to 170 h toward a wide range of saline solutions. The high separation performance combined with its outstanding water stability suggests the developed UiO-66 membrane as a promising candidate for water desalination

New investigations on the LGT crystal intended for time and frequency applications

cited By 0International audienceMaterials of the langasite family are of current interest for both Bulk Acoustic Wave and Surface Acoustic Wave devices. In particular, they could be promising solutions to Frequency and Time applications due to their g/product, two to three times higher than for the quartz crystal [1]. We have shown that this encouraging result is strongly linked to the crystal quality [2] and to the post thermal treatment which has been submitted the device. Among the numerous crystals belonging to the LGS family, LGT seems more interesting because of the best combination of quality of growth and material parameters [3, 4]. © 2010 IEEE

Dielectric losses measured in a sodium aluminosilicate glass by using electrical insulating barriers and non-isothermal experimental conditions

Ac conductivity and dielectric losses are measured on a sodium aluminosilicate glass using various experimental conditions. Data obtained using metallic contacts and insulating barriers are compared. The influences of the thermal environment, i.e. iso versus non-isothermal, and of the application of a constant dc electric field, i.e. BIAS, are also investigated. It is thus shown that the use of non-isothermal conditions and insulating barriers is a convenient tool for extracting and hence for analyzing the bulk intrinsic polarization response of the sample. The analysis of this response with a simple model based on distribution of energy barriers gives some insights into the glass structure which turns out to be rather homogeneous. © 2008 Elsevier B.V. All rights reserved

Cation mobility upon adsorption of methanol in NaY faujasite type zeolite: A molecular dynamics study compared to dielectric relaxation experiments

Molecular Dynamics simulations have been carried out to address the question of cation migration upon adsorption of methanol in NaY Faujasite system as a function of the loading. It has been shown that at low and intermediate loadings, SII cations can migrate toward the center of the supercage due strong interaction with the adsorbates, followed by hopping of SI' cations from the sodalite cage into the supercage to fill vacant SII sites. SI cations mainly remain trapped in their initial sites whatever the loading. At higher loading, only limited motion is observed for SII cations due to steric effects induced by the adsorbates within the supercage. These simulated results are in good agreement with those extracted by Complex Impedance Spectroscopy measurements, which provided the evolution of the number of extraframework cations in the different crystallographic sites as a function of the treatment temperature

Effect of water adsorption on ion dynamics in confined geometry: Na+ faujasites and homoionic alkali exchanged montmorillonite

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Role of alkali ions in the radiation sensitivity of the quartz material

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Proton-Conducting Phenolate-Based Zr Metal–Organic Framework: A Joint Experimental–Modeling Investigation

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