Different Types Of Zeolites Research Articles

Adsorption of water on zeolites of different types

We have investigated the interaction of water with Na+-ion exchanged zeolites of different structures (LTA, FAU, ERI, MOR and MFI) by means of temperature-programmed desorption (TPD). The non-isothermal desorption of water shows, depending on the zeolite type, differently structured desorption profiles. In every case the profiles have, however, two main ranges. Using a regularization method, desorption energy distribution functions have been calculated. The desorption energy distributions between 42–60 kJ mol−1, which can be attributed to a non-specific interaction of water, show two clearly distinguished energy ranges. The water desorption behaviour of this range correlates with the electronegativity of the zeolites and the average charge of the lattice oxygen atoms calculated by means of the electronegativity equalization method (EEM). The part of the desorption energy distributions in the range of 60–90 kJ mol−1, reflecting interactions of water with Na+ cations, shows two more or less pronounced maxima. In agreement with vibrational spectroscopic studies in the far infrared region, it may be concluded that all samples under study possess at least two different cation sites.

The use of zeolites as amendments in radiocaesium- and radiostrontium-contaminated soils: A soil-chemical approach. Part IV: A potted soil experiment to verify laboratory-based predictions

A potted soil experiment was performed to test the effect of the addition of different types of zeolites on the 137Cs or 85Sr uptake by spinach grown on a sandy podzol soil. In all cases, a significant reduction of the 137Cs or 85Sr soil-to-plant transfer was observed. The observed effects were compared with predictions based on a quantitative evaluation of the different factors that govern the solid/liquid partitioning of radiocaesium and radiostrontium both in the soil and in the zeolites. Predictions agree rather well with experimental observations, but analysis of the soil solution indicates that the net effect cannot solely be attributed to the decrease of 137Cs or 85Sr solution concentrations upon zeolite addition.

Determination of water in zeolites by a neutron reflection method

Water content in zeolites has been determined by an improved neutron reflection method using a Pu-Be neutron source of 106 n·s−1 intensity and a BF3 counter. It was found that the water content of different types of zeolites collected in Hungary varies between 9 and 12 wt.%. The standard deviation of the determination does not exceed 0.5 wt.%. The matrix effect on the sensitivity and accuracy was also studied. An approximate relation is given between the count rate and the neutron physical parameters of the samples.

Preparation and preliminary testing of MnO 2 prepared on different types of zeolites as support Part I

In order to reproducibly prepare MnO 2 samples for use in mild oxidation of organic substances, three different types of zeolites have been applied as supports for ‘active MnO 2’. After ion-exchanging the Y-FAU, MOR and 4A zeolites with MnSO 4 solutions, MnO 2 was formed by oxidation with KMnO 4. Part of the sample was exchanged again with KCl to eliminate residual Mn 2+ cations and H + ions from the cationic positions. Allyl alcohol oxidation to acrolein was performed as a test reaction. Preliminary results show that the Y-type zeolite is the most suitable support, that no acrylic acid is formed, and that the double bond is preserved.

Selective liquid-phase bromination of toluene catalysed by zeolites

The liquid-phase bromination of toluene catalysed by zeolites has been investigated. Different types of zeolites as well as several cation-exchanged Y-type zeolites have been used. The initial rates are increased in comparison to the uncatalysed or Lewis acid-catalysed reaction. With some zeolites, the para/ortho isomer ratio could be increased.

Synthesis of polymethylbenzenes by methanol conversion on different types of zeolite

1. 1. The conversion of methanol ( P 0·1 MPa, t 360°C, volumetric flowrate 0·3 hr −1) H- and La-formsof TsVM, mordenite, and dealuminized mordenite zeolites has been studied. 2. 2. It has been established that the introduction of lanthanum into a mordenite-type zeolite by means of ion exchange leads to an increase in its selectivity in relation to the formation of penta- and hexamethylbenzenes.

Einsatz von deuterierten Molekülen zur Bestimmung von Selbstdiffusionskoeffizienten bei der Zweikomponentenadsorption in Zeolithen unter Anwendung der NMR-Meßtechnik

The nmr pulsed field gradient technique is an efficient tool for measuring molecular self-diffusion in sorplion systems. Applying alternatively perdeutcrated substances, in this way for the first lime the self-diffusion coefficients of the individual components at mullicomponent adsorption could be measured. Examples of self-diffusion results for mixtures of water, ammonia and liydrocarbons adsorbed on different types of zeolites are given.

Sorption, separation, and conversion of hydrogen nuclear spin isomers on zeolites, alumina, and silicagel

Sorption of ortho- and para-hydrogen as well as -deuterium on silica, alumina, and different types of zeolites is investigated by low-temperature gas chromatography. Adsorption isotherms and thermodynamic properties are determined from their elution profiles (first statistical moment ), temperature, and coverage dependence. Separation factors on alumina over a wide temperature range are evaluated and compared to calculated values. On zeolites a slight conversion is observed. The conversion rates due to different mechanisms are presented and discussed.

Catalytic cracking of heavy oil over catalysts containing different types of zeolite Y in active and inactive matrices

The effects of addition of alumina to the matrices of cracking catalysts containing different types of zeolite Y, on their cracking performance, were investigated using a micro activity test and two different feed oils. For the heavier feed oil, the alumina addition resulted in a higher conversion at the same catalyst to oil ratio independent of the type of zeolite. This higher conversion was accompanied by a greater selectivity for coke and a lower selectivity for gasoline. For the lighter feed oil the effect of alumina addition on the total conversion was much less pronounced while the effects on the selectivity were similar to those observed using the heavier feed. The performance of the catalysts in a commercial fluid catalytic cracking unit is discussed in view of their coke forming tendencies and the heat balance of the cracker.

Reactions of alcohols with hydrogen sulphide over zeolites: II. Activity of faujasite-type and ZSM-5 zeolites in the reaction of C 2 and C 3 alcohols with H 2S

The reactions of ethanol and propanol with H 2 S were studied over different types of zeolites at 523 and 623 K. The most active of all investigated zeolites is Na-X at 623 K. The first step of the hydrosulphurization of C 2 and C 3 alcohols is the dehydration of alcohols toward olefins, which react with chemisorbed H 2 S, giving thiols and other organic sulphur compounds. The role of sodium cations as active sites is stressed. The dehydration of alcohols increases in the presence of H 2 S.

Malignant mesothelioma induced by asbestos and zeolite in the mouse peritoneal cavity

The carcinogenicity of asbestos (amosite and chrysotile) and zeolite (fibrous erionite, mordenite, and synthetic zeolite 4A) were studied in the peritoneum of 586 BALB C male mice after a single intraperitoneal or intraabdominal wall injection. As controls, 182 mice treated with and without saline solution were used. Both asbestos types and fibrous erionite frequently produced malignant peritoneal tumors after long latency; tumors developed in 93 of 394 animals (23.6%) treated with asbestos or fibrous erionite 7 months or more after administration. All of the induced peritoneal tumors were intimately associated with marked peritoneal fibrosis, in which asbestos or erionite fibers were regularly detected. Histopathologically, 83 (73 fibrous, 9 biphasic, and 1 epithelial) of 93 were consistent with malignant mesotheliomas. Other tumors consisted of 6 plasmacytomas, 1 histiocytoma, 1 liposarcoma, 1 osteosarcoma, and 1 adenocarcinoma of the pancreas. Two of the cases of mesotheliomas were associated with plasmacytoma. In many instances, the primary site of the mesotheliomas seemed to be multiple, the favorite sites being the omentum, mesentery, serosae of the gastrointestinal and genital organs, the diaphragm, the capsule of the liver and spleen, and the abdominal wall peritoneum. In these cases, asbestos or erionite-tissue burden followed by fibrosis was frequently observed. In addition to the 93 peritoneal tumors, 3 extraperitoneal tumors (1 fibrosarcoma and 2 rhabdomyosarcomas) were induced by amosite which was probably accidentally injected into the extraperitoneal connective issue and the striated muscle tissue of the abdominal wall, respectively. These three tumors were also intimately associated with focal fibrosis in which amosite fibers were detected. Among the three different types of zeolite, only fibrous erionite showed striking carcinogenicity and marked fibrogenicity. The erionite-induced mesotheliomas were similar to those induced by asbestos in exhibiting long latency, in gross appearance, in histology, and in close association with fibrosis. Long-term persistence of asbestos or fibrous erionite around progenitor cells of the induced tumors and the consequent fibrosis seemed to be an important precondition of the malignant transformation of the progenitor cells.

Chromatographic separation of low-boiling inorganic and hydrocarbon gas mixtures on zeolites

The possibility of using different types of zeolites of both synthetic and natural origin for the chromatographic separation of low-boiling inorganic and C 1-C 4 hydrocarbon gas mixtures is shown. A large effect of the zeolite structure and its cation modification on the character of the separation of individual model mixtures was found, in particular, on the elution sequence of separate components of the mixtures. It was established that the use of surface layer sorbents (zeolites coated on the solid support) allows a better separation of hydrocarbon gas mixtures and at lower column temperatures than on ordinary volumetric zeolite chromatographic columns.

ChemInform Abstract: ADSORPTION OF 1‐TETRADECENE/DODECANE MIXTURES ON DIFFERENT TYPES OF ZEOLITES

Chemischer InformationsdienstVolume 14, Issue 49 Article ChemInform Abstract: ADSORPTION OF 1-TETRADECENE/DODECANE MIXTURES ON DIFFERENT TYPES OF ZEOLITES M. JARONIEC, M. JARONIECSearch for more papers by this authorA. W. MARCZEWSKI, A. W. MARCZEWSKISearch for more papers by this authorW. D. EINICKE, W. D. EINICKESearch for more papers by this authorH. HERDEN, H. HERDENSearch for more papers by this authorR. + SCHOELLNER, R. + SCHOELLNERSearch for more papers by this author M. JARONIEC, M. JARONIECSearch for more papers by this authorA. W. MARCZEWSKI, A. W. MARCZEWSKISearch for more papers by this authorW. D. EINICKE, W. D. EINICKESearch for more papers by this authorH. HERDEN, H. HERDENSearch for more papers by this authorR. + SCHOELLNER, R. + SCHOELLNERSearch for more papers by this author First published: December 6, 1983 https://doi.org/10.1002/chin.198349073Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume14, Issue49December 6, 1983 RelatedInformation

Adsorption of 1-tetradecene/dodecane mixtures on different types of zeolites

The influence of heterogeneity parameters on the shape of excess adsorption isotherms has been discussed. These isotherms have been calculated according to the equations corresponding to different energy distributions. Next, the isotherm equations have been applied to examine the experimental excess isotherms for 1-tetradecene/dodecane mixture adsorption on different types ofX-zeolites at 293 K, 313 K and 333 K. The zeolite samples have been prepared from NaX-zeolite by exchanging the sodium ions for ions of alkalines and calcium group. Analysis of the above adsorption data by means of different isotherm equations showed that the parameters of aDubinin-Radushkevich-type equation change correctly with temperature and the contents of alkalines in the zeolite samples.

Uses of i.r. spectroscopy in identifying ZSM zeolite structure

The study of i.r. lattice vibrational bands (400–1200cm–1) for different types of zeolites with different particle sizes indicates, when synthesising a ZSM-type zeolite, that (i) the presence of a band at ca. 550 cm–1 in addition to the one at 450 cm–1 shows that ZSM-type zeolite, crystallites may have been formed, even if X-ray diffraction shows nothing, and (ii) the absence of the 550cm–1 band unambiguously shows that such a zeolite has not been formed.

Studies on the Mechanism and Kinetics of Propylene Oligomerization and Hydrooligomerization on Zeolites

Abstract The propylene conversion process has been studied in the presence of synthetic zeolites of different types and metal ions. The NiX zeolite is selective for the oligomerization of propylene. On the zeolites of different other metal ions, the hydro-oligomerization process took place. It has been found that the obtained 3-methylpentenes are primary products of the propylene oligomerization. A scheme mechanism has been proposed assuming an intermediate of a cyclobutane derivative. The mechanism explains the formation of all the obtained products of propylene conversion on the synthetic zeolites.

Study of the selectivity of different types of zeolites towards some non-ferrous metals

The selective properties of zeolites of types A, X and Y towards some non-ferrous metals (copper, nickel, zinc and cobalt) have been investigated. The values of the isotherms of sorption-exchange capacity of the zeolites have been defined, and thermodynamic equilibrium constants are calculated.