Synthetic Faujasite Research Articles

Removal of Diclofenac Sodium Using Synthetic Faujasite from Natural Clay

Removal of Diclofenac Sodium Using Synthetic Faujasite from Natural Clay

Extent of zeolite synthesis via alkaline fusion from tailings dam sediments

Zeolite was synthesized via alkaline fusion from the tailings dam sediments of a sand mine in southern Brazil. The sediments are composed of a mixture of illite, kaolinite, vermiculite, quartz and K-feldspar yielding a silty-loam texture. The extent of zeolite synthesis was tested under varied NaOH:sediment ratio, temperature and fusion time. At the NaOH:sediment ratio of 8:5 and fusion temperature of 600 °C, all minerals were dissolved and converted in faujasite, except a quartz residue of less than 5 wt%. The synthetic faujasite shows intergrown octahedral habit, grain size < 2 µm, specific surface area of 760 m2 g−1 and cation exchange capacity of 4.6 cmol kg−1. Experiments at lower NaOH:sediment ratio produced lower amounts of zeolite from 6:5 to 5:5 and 4:5, faujasite fraction declined from 73 to 50 wt%. At an NaOH:sediment ratio of 3:5, the faujasite fraction dropped to 0.7 wt%, below which no faujasite was formed. By decreasing temperature from 550 to 250 °C, a smooth decrease in faujasite formation was observed, from 64 to 29 wt%. A synthetic analogous of ferrierite appeared in the runs at 300 and 250 °C. Experiments using prolonged heating (up to 12 h) at low temperatures (300, 200 °C) and low NaOH:sediment ratio (3:5) did not enhance zeolite formation. Kaolinite and vermiculite were dissolved in all runs, while residual illite was ubiquitous and residual quartz was present in all experiments.

Mesoporous activated carbon-zeolite composite prepared from waste macadamia nut shell and synthetic faujasite

Abstract Novel activated carbon-zeolite composite adsorbent was prepared from macadamia shell bio-waste and synthetic zeolite X using hydrothermal treatment. Characterisation studies revealed mainly mesoporous structure with 418 m2·g− 1 BET surface area with faujasite clusters on the carbon carrier. Sorption capacity for methylene blue model pollutant increased from 85 to 97 mg·g− 1 with the temperature increase from 25 to 45 °C, and improved with increasing pH. Nonlinear regression analyses found accurate fit to the pseudo-first-order kinetics model and intra-particle diffusion rate controlling mechanism. Excellent fits to the Jovanovic isotherm model indicated monolayer coverage on chiefly homotattic surfaces with variable potential. The thermodynamic analysis confirmed spontaneous and endothermic physisorption process. The spent adsorbent was regenerated with 20% capacity loss over five reuse cycles. Although the adsorbent was developed for ammonia, heavy metal and organic matter removal from water sources, the results also indicate good performance in cationic dye removal from wastewaters.

Hydrothermal Transformation of Natural Zeolite from Ende-NTT and Its Application as Adsorbent of Cationic Dye

A synthetic zeolite was produced from natural zeolite from Ende-Nusa Tenggara Timur (NTT) by hydrothermal method. This study aims to produce synthetic zeolite from Ende natural zeolite to remove cation dye through the adsorption process. Temperature of crystal formation (ageing) was performed at 60 °C for 6 h and hydrothermal process was at 100 °C for 24 h. The natural zeolite produced synthetic NaP1 and synthetic Faujasite. Based on the research results, the synthesis of zeolite by the hydrothermal method can enhance the adsorption capacity and Cation Exchange Capacity (CEC). The adsorption capacity in the natural zeolites of type ZG, ZL and ZC before the hydrothermal process were 17.289, 17.276, and 16.483 mg/g, respectively, and after hydrothermal they increased to 37.398, 37.369 and 37.362 mg/g, respectively. In addition, the CEC increased from 84.154, 81.042, and 77.474 cmol/kg, respectively, to 244.063, 216.354, and 211.432 cmol/kg, respectively. The Langmuir model most closely matched the isothermal adsorption equilibrium process.

Synthesis of Faujasite from Egyptian Clays: Characterizations and Removal of Heavy Metals

Three clay samples with different mineral compositions (kaolinite, smectite-kaoline, and smectite-rich) were used for zeolite synthesis using the method of hydrothermal reactions after fusion with NaOH. The conditions of hydrothermal crystallization (zeolitization) were found to be at temperature of 100°C, and time span between 72 h and 96 h for kaoline and smectite-rich samples, while 48 h for the smectite-kaolinite sample. The results indicate that zeolites began to crystallize from clay samples after 48 h, and crystallization increased with increasing time. The synthetic materials have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR) and thermogravimetric (DTA/TGA) analysis. The results indicate that low silica NaX-faujasite type with well-developed octahedral and cubic crystals was synthesized from the three samples. No big difference in the characterization between the three synthetic materials was detected, but smectite-kaolinite sample as raw material was relatively better in crystallization of synthetic zeolite. Applications of the synthetic materials in the removal of heavy metals proved that the synthetic faujasite has strong effect for removing of Cr3+, Co2+, Ni2+ and Mn2+ from aqueous solution.

A comparison of adsorption equilibrium, kinetics and thermodynamics of aqueous phase clomazone between faujasite X and a natural zeolite from Kenya

In this study, a well-studied synthetic faujasite X (FAU-X) zeolite and a recently discovered natural zeolite material from Kenya (NZ-K) were compared for their efficiency in removal of clomazone, a herbicide and water contaminant, from aqueous solution. The adsorption kinetics, isotherms and thermodynamics parameters were investigated. Equilibrium sorption data were describable by both the Langmuir and Freundlich models. The adsorption kinetics obeyed the pseudo-second-order kinetic law while pore diffusion was not the sole operating rate determining step. The derived thermodynamic parameters, namely DG and DH, indicated the adsorption process was feasible, spontaneous and exothermic for the natural zeolite and non-spontaneous for the synthetic zeolite via a physical and chemical process, respectively. The natural zeolite proved to be a suitable low-cost adsorbent for clomazone removal with removal efficiency above 70 %, five-fold more efficient than faujasite X.

Synthesis of Faujasite and Analcime Using of Rice Husk Ash and Metakaolin

Faujasite and analcime were synthesized by two-step process via hydrothermal method using the rice husk ash and metakaolin as starting materials. In the first step, the raw materials were prepared using the SiO2/Al2O3molar ratio of 4 and pretreatment with NaOH solution under various stirring conditions. The suspension was subjected to hydrothermal treatment at various reacting time and temperature in second step. The mineralogy, morphology, specific surface area and cation exchange capacity of the synthesized products were investigated using X-ray diffraction, Scanning electron microscopy, N2adsorption and desorption isotherm and ammonium acetate method, respectively. Faujasite was obtained using low temperature and short-time synthesis, while the analcime was obtained at high temperature and long-time synthesis. The stirring time did not affect zeolite types but the specific surface area. The cation exchange capacity of the synthetic faujasite and analcime were 263-280 and 280-302 meq/100 g, respectively.

Clavulanic Acid Adsorption Studies in Zeolites

Zeolites are crystalline inorganic solids containing aluminium, silicon and oxygen arranged in a highly regular structure, and they are usually used in separation processes. In this study, zeolites have been shown to act as adsorbents for clavulanic acid. Ion exchange with different compensating cations (Na+, K+, Ca2+, Ba2+, Mg2+, Sr2+) was used to modify the natural zeolite (NZ) and the synthetic faujasite (13X). Kinetic analysis of the adsorption of clavulanic acid indicated that the 13X-Na zeolite was the most appropriate for this purpose. Under equilibrium conditions, the retention by this zeolite was about 17.4% (C*/C0 = 0.826), with the amount of clavulanic acid adsorbed relative to the amount of zeolite employed (q*) being ca. 0.5 mg/g. The 13X-Na zeolite was characterized in terms of its Si/Al ratio (1.5), density (dz = 2.248 g/cm3), superficial area (SBET = 444.860 m2/g), total pore volume (Vpore = 0.308 cm3/g), micropore volume (Vmicro = 0.203 cm3/g) and particle porosity (ep = 0.69). Adsorption...

Szilard-Chalmers and X-ray Absorption Spectroscopy to Locate Copper Cations in Synthetic Faujasite, Zeolite X

ABSTRACTThe sodium in synthetic faujasite, commercial zeolite-X, was exchanged with copper cations at room temperature. A maximum number of 70 out of 86 Na cations were replaced with 35 copper cations (1). The copper exchanged zeolite was divided in six equal parts. Five of them were calcined at 43, 73, 112, 150 and 195 deg C. After calcination the samples were eluted with saturated solution of ammonium chloride to remove copper cations from open sites (super-cages) of the zeolite (Fig 1). The remaining copper cations were in locked sites (sodalite-cages or hexagonal-prisms). Using XAS edge-jump as a measure of quantitative analysis, we found that 9.0, 11.5, 12.7, 13.3 and 20.0 copper cations were locked at calcination temperatures of 43, 73, 112, 150 and 195 deg C respectively. The analysis of the first shell Fourier Transformed radial distribution shows that cations at site I in the hexagonal-prism and site I ‘ and II ’ in the sodalite-cages, adjacent to site I, are distributed at equal proportion, independent of temperature.

Study of the reaction of oxyradicals with antioxidants on synthetic zeolites

The ESR method has been used for the study of the inhibition effect of some antioxidants on polymerization of methyl methacrylate proceeding in the surface of synthetic faujasite of the Na Y type. From equilibrium levels of trapped radicals the inhibitor efficiency has been elucidated as follows: hydroquinone > diphenylamine > 2, 6-di-tert-butyl-4-methylphenol > pyrogallol > N-phenyl-2-naphthylamine > 1-naphthol. Mechanism of hydroperoxides decomposition on zeolite surface has been discussed as well.

Evaluation of Jordanian faujasite tuff by comparison with other natural and synthetic zeolites

The evaluation of the Jordanian faujasite tuff in wastewater treatment is investigated by comparison with synthetic faujasite (13X) and clinoptilolite-rich tuff. The material used (JORD-FAUJ) is concentrated by mineral processing techniques. It has a faujasite content of 57% and phillipsite content of 35%. Thorough characterization of the JORD-FAUJ revealed the high suitability of the product for use in column operation. It either compares closely or gives better thermal stability, attrition resistance, acid resistance, cation exchange capacity (CEC) and water absorption capacity, when compared with products already recommended in column operation. The study has also revealed that the JORD-FAUJ competes efficiently in ammonium removal with the synthetic faujasite 13X and clinoptilolite-rich tuff and gives similar performance. JORD-FAUJ gave a very high performance in removing Pb, Cr, Cu, Zn, and Ni from wastewater, equivalent to 83–100% of that of faujasite 13X and much higher than the clinoptilolite-rich tuff.

Investigation of Microstructure of Zeolite Type Material by &lt;sup&gt;1&lt;/sup&gt;H NMR Spectroscopy and Thermogravimetric Analysis

The application of temperature programmed desorption (TPD) of ammonia as a probe base molecule from synthetic ultrastable faujasite type zeolite is presented. In order to determine the positions and strength of active acid sites in a microstructure of zeolite materials, desorption was monitored by pulse 1 H NMR spectroscopy and thermogravimetric analysis. In performed experiment, the temperature dependence of spin-lattice relaxation time T 1 (namely of two components resolved by spin-grouping technique) was scanned as well as of corresponding relative change in sample mass. The results obtained in this way show considerably higher values of T 1 in certain temperature ranges. and higher values of mass loss in the very same intervals. These results confirm the existence of low temperature peaks (LTP) when slightly bound protons of ammonia leave the samples. These peaks are related to weak and medium active sites, i.e. to silanol groups (SiOH) on external surface of crystal lattice and hydroxyl groups within large, α, super-cages, respectively. High temperature peaks (HTP) were also observed. They originate from La 3+ ions located inside small, β, sodalite cages, acting as strong active centres, from which the tightly bound protons of ammonia are released during desorption.

Zeolites for nuclear waste treatment: Co, Ni and Zn uptake into synthetic faujasite X

Zeolites for nuclear waste treatment: Co, Ni and Zn uptake into synthetic faujasite X

Novel “ship-in-the-bottle” type catalyst: evidence for encapsulation of 12-tungstophosphoric acid in the supercage of synthetic faujasite

A new type of “ship-in-the-bottle” catalyst has been obtained by encapsulation of heteropolyacid H3PW12O40 in the supercage of faujasite. As shown by XRD and IR, the structure of zeolite Y after encapsulation is retained.31P MAS NMR reveals that the signal at −14.4 ppm, assigned to the Keggin unit, is in the case of the encapsulated catalyst much broader than the line observed for a sample containing the heteropolyacid adsorbed on the zeolite. The broadening is due to interaction between phosphorus and aluminium from zeolite. Highly active catalysts are formed by encapsulation, as exemplified here by strongly increased activity and modified selectivity in isomerization and disproportionation ofm-xylene.

Process for producing methyl methacrylate

There is disclosed a process for producing methyl methacrylate through gas-phase catalytic reaction of methyl α-hydroxyisobutyrate as the starting raw material which process comprises feeding methanol in an amount by weight of 0.1 to 3.0 times the amount of the methyl α-hydroxyisobutyrate in a reaction system along therewith and proceeding with the gas-phase catalytic reaction in the presence of a catalyst comprising a synthetic faujasite zeolite having a free alkali content of at most 0.1 milliequivalent/g or a catalyst comprising a molded product which is formed by molding a synthetic faujasite zeolite through the use of a clay whose aqueous solution or suspension has a pH of less than 9. According to the above process, it is made possible to produce methyl methacrylate in high yield over a long period of time by the use of methyl α-hydroxyisobutyrate as the starting raw material.

The fractal dimension in molecular sieves: synthetic faujasite and related solids

Synthetic faujasite (Na-Y) and its variously modified forms have been examined by X-ray diffraction, IR spectroscopy, 29 Si MAS NMR, and sorption of C 1 -C 4 alcohols. A surface fractal dimension, D a , of Na-Y, H,Na-Y, and ultrastable, realuminated, and chemically dealuminated zeolite Y has been calculated from the adsorption isotherms of alcohols. The evolution of the fractal dimension of faujasitic solids is discussed in terms of the parent zeolite treatment

Dealumination of faujasite, mazzite, and offretite with ammonium hexafluorosilicate

Synthetic faujasite, mazzite, and offretite have been dealuminated with ammonium hexafluorosilicate. The products have been characterized by elemental analysis, X-ray diffraction, volumetry, scanning electron microscopy, stepwise thermal desorption of ammonia, solid-state NMR and IR spectroscopy. Their catalytic activity has been evaluated using isooctane cracking as test reaction. The maximum level of dealumination which can be achieved without loss of X-ray crystallinity corresponds to 50% for faujasite and 30% for mazzite and offretite. This result and the fact that the dealumination capability depends on the texture of the crystals suggest that the reaction is diffusion controlled. The comparison of the acidic and catalytic properties of the parent and dealuminated samples shows small differences indicating that the fluorosilicate treatment replaces weakly bound and weakly acidic aluminium atoms.

Effect of hydrothermal dealumination of a synthetic faujasite by IR spectroscopy

Abstract

A high-resolution solid-state nuclear magnetic resonance study of the ordering of silicon and aluminium in synthetic mazzite (zeolite omega)

The 29Si m.a.s.n.m.r. spectrum of synthetic mazzite is the sum of two mutually overlapping families of signals due to the presence of two kinds of crystallographically non-equivalent silicon atoms. Unlike zeolites in which all silicons are equivalent (such as synthetic faujasite), the resultant spectral peaks cannot be directly assigned to various Si(nAl) structural building blocks. We show how considerations based on high-field 27Al and 29Si n.m.r. of the parent and dealuminated mazzite enable us to calculate the populations of Si and Al on each type of site and to assign the spectra fully.

Zeolites treated with silicon tetrachloride vapour. Part 1.—Preparation and characterisation

Crystalline materials with Si/Al ratios ranging from 2.5 to over 100 have been prepared by treating zeolites with silicon tetrachloride vapour at elevated temperatures. Most of the work described involves zeolite Y (synthetic faujasite), but other wide-pore zeolites, such as mordenite, ZSM-5, L, omega (synthetic mazzite) and ferrierite, are also amenable to SiCl4 treatment. We describe the method of preparation of high-silica zeolites and the application of an array of techniques to monitor the degree of crystallinity, unit-cell parameters, the Si/Al ratio and hydrophobicity of the products. Also described are the effects of treatment of wide-pore zeolites with some other inorganic halides.