Showing papers in "Microporous Materials in 1997"

TL;DR: In this article, a review of non-silica mesostructured materials based on electrostatic interactions (ionic bonding), van der Waals interactions (hydrogen bonding), and direct covalent bonding between organic and inorganic species is presented, discussed and evaluated.

TL;DR: A procedure for the preparation of low-density silica described in a patent filed in 1969 [V. Chiola, J.E. Ritsko, C.T. Vanderpool, US Patent 3 556 725, 1971] leads to the formation of solids having all the properties of MCM-41, the ordered mesoporous silica disclosed in 1991 as discussed by the authors.

TL;DR: The zeolite Raman literature is reviewed in this article, with an emphasis on the structure and synthesis, adsorption, and metal complex formation in zeolites and their properties.

TL;DR: Titanium-containing MCM-41 was prepared from the synthesis gel derived from Ti(OC4H9)4 and several Si sources as mentioned in this paper, which was applicable to the oxidation of bulky alkenes with H2O2 or t-butyl hydroperoxide (TBHP) as an oxidant.

TL;DR: In this paper, the thermal and hydrothermal stability of MCM-41 with a Si/M molar ratio of 40 (M = Al, Ti) was assessed, and the pore structure of Si-MCM-1 and Al-MCm1 collapsed at a calcination temperature of above 800°C.

TL;DR: In this article, the mesoporous materials related to MCM-41 were hydrothermally synthesized and the results reveal the substitution of Si in tetrahedral positions in the pore walls by Al, Ga, and Fe.

TL;DR: In this paper, pure silica MCM-41 materials were synthesized at room temperature at different pH values ranging from 8.5 to 12.5, and the solids were characterized by XRD, 29Si-MAS-NMR spectroscopy and N2 and Ar adsorption measurements.

TL;DR: In this article, Zeolite NaA and KA membranes were obtained by ion exchange from the sodium form and were tested for the removal of water from isopropanol/water mixtures by pervaporation.

TL;DR: In this article, a detailed study on the preparation of highly-ordered MCM-41 molecular sieves based on a new delayed neutralization process is presented, where the authors show that adding a proper amount of alcohols as cosurfactants would improve the XRD patterns of the surfactants with carbon chain lengths less than 14.

TL;DR: In the microwave synthesis of zeolite NaA, the synthesis of an unaged mixture can be improved dramatically by adding aged synthesis mixture to it as discussed by the authors, which suggests that the rearrangement of the synthesis mixture for yield nuclei is the bottleneck in a microwave synthesis.

TL;DR: In this article, a cationic surfactant modified Al-pillared montmorillonite was prepared by reacting a purified bentonite from deposits in Maghnia and Mostaghanem (in the West of Algeria), with a solution of aluminum chlorohydrate alone or with both Al-chlorohydrate and cetyl trimethyl ammonium bromide (CTAB) solutions.

TL;DR: The combination of several physico-chemical techniques such as temperature programmed desorption, microcalorimetry, infrared spectroscopy and photoelectron spectrography, together with structural data (by XRD and NMR), has allowed a detailed study of the acidity of commercial HY faujasites, both non-dealuminated and dealuminated by hydrothermal treatment.

TL;DR: In this article, the effect of steam activation of char prepared from Eucalyptus globulus (EU) and peach stones (PS) on both the porosity development and the amount of oxygen surface groups is presented.

TL;DR: The photocatalytic activities of water splitting by small particles (0.1-2 μm) of K 4 Nb 6 O 17 were studied in this paper, where the milled catalysts were prepared by two kinds of ball-milling methods from powder whose particles were several tens of micrometers in diameter.

TL;DR: In this article, the synthesis of SAPO-34 in the presence of a new templating agent, namely piperidine, was investigated and the effects of the gel composition, the template concentration, the time and temperature of crystallization on the degree of crystallinity and the purity of the crystalline phase were examined.

TL;DR: In this paper, a mesoporous carbon membrane is characterized structurally and tested in terms of high pressure CO 2 permeability at temperatures around the critical and a maximum in the permeance versus relative pressure curve is observed.

TL;DR: In this paper, mesoporous silica precursors were synthesized at room temperature from solutions in the presence of fluoride anions at a pH between 6 and 10 using the cetyltrimethylammonium cation as the surfactant.

TL;DR: In this paper, the preparation of microporous silica gels from particulate as opposed to polymeric suspensions of silica using alkylsilicates as precursors is described.

TL;DR: In this paper, the ion exchange behavior of a sodium and a potassium titanosilicate towards Cs+ and Sr2+ was studied, and the results indicated that these exchangers may act as potential sorbers for groundwater remediation applications.

TL;DR: In this paper, two series of samples were prepared by means of oxidation of a parent activated carbon with either HNO3 or H2O2, and an important effect of the HNO 3 treatment temperature on the textural properties of the resulting samples was found, since below 333 K only the mesoporous region was affected, whereas at 363 K a generation of micropores and a loss of mesopores took place.

TL;DR: In this paper, a new approach has been developed to monitor the synthesis of MCM-41 mesoporous materials based on in situ ATR FTIR measurements, which can be followed using this technique.

TL;DR: The formation of colloidal aggregates which can act as precursors in zeolite crystallization has been studied using small-angle scattering of X-rays (SAXS) as discussed by the authors.

TL;DR: In this paper, the pore diameter for MCM-41 samples from X-ray diffraction and adsorption data was calculated using the α s -plot, allowing for an accurate calculation of the specific surface area of the samples.

TL;DR: In this article, the state of the triethylamine template in AlPO 4 -5 and SAPO-5 and the characteristics of the framework structure of the molecular sieves were studied by means of IR and Raman spectroscopy.

TL;DR: Experimentally determined adsorption isotherms of nitrogen, water and various aromatics and alcohols show that the sorption capacity of MCM-41 is only slightly affected by the aluminum content in the structure.

TL;DR: In this paper, the surface and porosity properties of [Mg-Al-CO3] and [mgAl-Cl] obtained by the coprecipitation method were investigated.

TL;DR: In this article, four different methods of the hydrothermal synthesis of Sn-sil-1 (MFI structure) (Si/Sn > 15) molecular sieves are described.

TL;DR: In this paper, the mechanism of formation of ferrierite (FER) membrane on an alumina support by a vapor-phase transport (VPT) method was studied using XRD, SEM, FE-SEM and EDX.

TL;DR: In this article, Al-MCM-48 with Al incorporated into the walls constructing its mesopores was synthesized by a hydrothermal method and showed a higher activity than MCM-41 in the isopropylation of pyrene.

TL;DR: In this article, the dealuminated zeolites have been characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), acidity measurements with ammonia and Xray photoelectron spectroscopic (XPS), and they have been submitted under similar conditions to known dealumination procedures.