Papers by Keyword: Mordenite

Abstract: Mordenite is well-known as a commercial catalyst in oil refineries. Conventionally, mordenite is produced through hydrothermal method under static condition for long period of time. In this investigation, the effect of intermittent agitating of the solution during the hydrothermal process on the mordenite properties and ammonium sorption was studied. The synthesized mordenite samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). The XRD pattern of the intermittent agitated sample showed broader peaks with similar intensity peaks as compared to the non-intermittent agitated sample. According to the SEM images, the average particle size of the intermittent agitated sample was 1.8 μm, while the non-intermittent agitated sample was larger with 13 μm. Both of samples show similar morphology as ellipsoid like. The sample of mordenite from the intermittent agitated sample showed a lower bulk density and high particle dispersion in water. The ammonium adsorption on the mordenite samples were tested by using various volume of ammonium solution. The ammonium adsorption capacity of the intermittent agitated sample slightly higher than the non-intermittent agitated mordenite. This simple intermittent agitated action which favored smaller particle size of mordenite could be beneficially applied for other applications dealing with bulky molecules due to the lower mass transfer limitation.

Abstract: Acid treatment of mordenite was conducted using acetic acid to increase the Si/Al ratio. The acid treatment of mordenite by acetic acid was performed using sonication. The various time of treatments was used to investigate the effect of sonication in acid treatment of mordenite. Mordenite and all samples after treatment were characterized by ICP, FT-IR, XRD, and ammonia adsorption to measure their acidity. The Si/Al ratio of mordenite was increased from 11.33 to 17.31, 19.47, and 20.58 respectively for 3, 6, and 9 h of sonication. This result was supported by the T‒O bond vibration of samples which shift to higher wavenumber. The increase of the Si/Al ratio was followed by the decrease of acidity. The XRD test result revealed partial loss of mordenite framework after acid treatment. The results indicated that the sonication method can be used for acid treatment of mordenite.

Abstract: The world's energy production is generated mainly from fossil fuels, so it is important to develop fuels from renewable sources. Growing caution with the environmental impact imposes restrictions on emissions from the combustion of fossil fuels. With increasing human population and expanding economies in both developing and developed countries, there is an increase in energy consumption and production. The need arises to supply this high energy production with a renewable and reliable source fuel [1]. These facts have stimulated research by alternative sources for the development of renewable fuels. One of the most promising fuels is biodiesel, an alternative to petroleum diesel from high-quality renewable sources, which allows the replacement of fossil diesel oil without modifications to the vehicle's engine [2, 3]. In recent years, methyl esters of fatty acids derived from vegetable oil have gained considerable attention as alternative fuel [4, 5].

Abstract: Morphology of silver nanoparticle coated on ZSM-5, mordenite, and Y-Type zeolite by Stöber’s and Tollen’s methods was characterized. The silver element was confirmed by SEM, EDX spectrum and XRD. Nanoparticle size of the silver fabricated on the surface of all three types of zeolite by Stöber’s method appeared in 1.8-7.9 times smaller than the Tollen’s methods depending on the Si/Al ratio of the zeolite. The ZSM-5, containing the highest Si/Al ratio and the largest crystal size, provided the best adhesion to the silver nanoparticles. Analysis of the SEM image showed a well distribution of silver nanoparticles on all types of zeolites, but only for the Stöber’s coating technique. A 4.54% coverage area of the silver nanoparticles on the Y-Type zeolite was enough for transformation the crystalline structure of zeolite surface to amorphous as consequent of the broad peak XRD spectrum. Since the zeolite surface was not fully obscured by silver nanoparticles as confirmed by FTIR, its absorption property of zeolite was also preserved. The Raman signal enhancement was evident when zeolite was coated with silver nanoparticle.

Abstract: The mordenite zeolite is one of the most important industrially zeolites, used as a solid catalyst for various reactions hydrocracking, hydroisomerization, alkylation, reforming, alkane oxidation, Fischer-Tropsch reaction. The aim of this study was to hydrothermal synthesis mordenite zeolite in its sodium form under hydrothermal conditions, in organic-free synthesis. The form HMOR of the zeolite mordenite was obtained by an ion exchange. For the preparation of the catalysts precursor salts were used: ammonium heptamolybdate, nickel nitrate, cobalt nitrate dispersed from the impregnation by incipient wetness impregnation, such impregnated supports were calcined at 550 °C/4h to obtain the catalyst. The zeolite synthesized in the sodium form NaMOR in its ammonium form NH₄MOR in form acid HMOR and their catalysts MoO₃/HMOR, NiO/HMOR and Co₂O₃/HMOR were characterized by X-ray diffraction (XRD) and Fluorescence Spectroscopy of by Energy X-ray dispersive (FRX-ED). From the results it was possible to observe the formation of zeolite phase mordenite in its sodium and acid form and the effective impregnation and formation of the proposed catalysts.

Abstract: The grafted materials of silaned-graphene oxide-mordenite (s-GO-MOR) were synthesized by grafting graphene oxide (GO) sheets to acid-treated mordenite and followed by functionalization with silane. GO sheets were prepared according to the modified Hummers method. 3-mercaptopropyltriethoxysilane (MPTES) was used as a silane coupling agent. The products were characterized by a Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. The results confirmed the success of s-GO-MOR and showed excellent thermal stability.

Abstract: The removal and recuperation of copper from the residual liquors of galvanic industry by ion exchange have been studied using the natural clinoptilolite and mordenite zeolites from different deposits of Russia and Georgia.

Abstract: This paper presents the application of Design of Experiments (DOE) to an alkaline treatment in mordenite zeolite, in order to identify the optimum settings of the variables (temperature and concentration of NaOH) that promote greater desilication. Samples of commercial mordenite with Si / Al ratio = 9 have been treated with aqueuos NaOH solution of various concentration (0,1;0,5;1,0) and temperature (30,50,70°C). Statistical analysis was carried out based on a 2² factorial design with center point replicates. Seven experiments were executed and the data of Si/Al ratio obtained. The resulting samples were characterized by x-ray difraction (XRD) and energy dispersive x-ray (EDX), to identify the structures and crystalline phases, and to determine the percentages of silicon and aluminum, respectively. In all samples, a decrease in the Si / Al ratio was observed, keeping the crystalline structure. The treatment was most effective, especially, at high temperature and NaOH concentration (experiment 4). DOE was shown to be a powerful techinique for the study of the variables, allowing determining which variables and value ranges have more influence on response, enabling optimization.

Abstract: This work is devoted to the study of copper ion positions in zeolite matrices. Copper cations were exchanged in mordenite and zeolite X from aqueous solutions of different copper salts varying their concentrations. Electronic state of copper in ion-exchanged samples exchanged and dried at different temperatures was evaluated by XPS spectroscopy. Depending on conditions of exchange treatment copper was found to be distributed between two different accessible sites in zeolites. These copper ions are stabilized as isolated species with well-defined oxygen coordination polyhedra.

Abstract: Three different zeolites (erionite, mordenite and natural clinoptilolite) were used to study influence of zeolite topology on the state of copper during ion-exchange and following reduction in hydrogen flow. This comparative study clearly demonstrates the influence of used zeolite matrices on the process of implantation of copper nanospecies. Starting from the ion-exchange, the alterations in the state of Cu²⁺ ions start to be evident due to variations of the intensity of charge transfer band. Copper ions start to reduce at specific temperatures depending on the type of zeolite matrix. Copper plasma resonance band change its shape and position for different zeolites. In the case of Cu-CLI samples this band change both the shape and position for different temperature of reduction. These observations permit to suggest that the mechanism of copper ion reduction and agglomeration to form copper nanoparticles noticeably depend on the type of zeolite matrix. This mechanism is more complex for the Cu CLI than for the Cu-MOR and Cu-ERI systems. Copper nanoparticles formed at low temperatures in the case of Cu-CLI samples undergo changes while temperature of reduction grow.