Synthesis Of ZSM-5 Zeolite Research Articles

Synthesis of ZSM-5 catalysts via microwave-assisted heating method for military jet fuel cracking into petroleum gas

Hydrothermal synthesis of ZSM-5 zeolites with different Si/Al ratios was conducted by using a microwave-assisted heating method. Their characteristics, such as morphology, porosity, acidity, and the catalytic performance for the cracking reaction of military jet fuel JP-8, were compared with ZSM-5 zeolites obtained via a conventional heating synthesis method. The microwave-assisted heating method contributed to bigger crystal sizes of the ZSM-5 zeolite as well as broader mesopore size distribution in the zeolite crystal with the same Si/Al ratio. Acidity analysis revealed ZSM-5 zeolites with similar acid properties could be produced with both heating methods. As the different heating methods attributed to different crystal sizes and roughness of the synthesized ZSM-5 zeolite, which are influenced by the fast crystal growth and consumption of silicon and aluminum precursor during the hydrothermal synthesis, different petroleum gas yields, and paraffinic product selectivity were observed from the ZSM-5 zeolite produced via microwave-assisted heating method. • Microwave-assisted heating method for hydrothermal synthesis (MH) of ZSM-5 zeolites were investigated. • MH method exhibited the same acidic properties but bigger and fairer surface of crystal due to fast crystallization. • Catalytic cracking reaction of military jet fuel was firstly explored with the ZSM-5 catalyst synthesized from MH method.

Size Controllable Synthesis of ZSM-5 Zeolite and its Catalytic Performance in the Reaction of Methanol Conversion to Aromatics

Size Controllable Synthesis of ZSM-5 Zeolite and its Catalytic Performance in the Reaction of Methanol Conversion to Aromatics

Sustainable Catalytic Process for Fructose Dehydration using Dicationic Ionic Liquid Assisted ZSM-5 Zeolite

ABSTRACT In this work, a uniquely designed imidazolium-based dicationic ionic liquid (IL) was synthesized as a greener template and applied for the synthesis of ZSM-5 zeolite as a heterogeneous catalyst for the dehydration of fructose to 5-hydroxymethylfurfural (HMF). Characterization results confirmed that due to the presence of dicationic IL as template, effective interactions and structural alterations occurred during the construction of zeolitic framework wherein the vertices of ZSM-5 consisting of Al or Si and O elements were assumed to be bonded between the vertices of dicationic IL-assisted zeolite ZSM-5 catalyst. This resulted in superior structural advantages such as highly crystalline nature and stability as well as variation in mesopores when compared to commercial ZSM-5. Additionally, various reaction variables were investigated wherein synthesized dicationic IL-assisted ZSM-5 zeolite catalyst in the presence of [BMIm][Cl] as solvent demonstrated 95% conversion of fructose and 67.2% yield of HMF at 110°C within 90 min. The altered surface area and porous nature of synthesized ZSM-5 due to the presence of dicationic IL as template was responsible for the enhanced catalytic performance under mild reaction conditions. Most significantly, being a solid catalyst, the newly developed dicationic IL-assisted zeolite ZSM-5 catalyst showed recyclability for four recycles.

Solvent-free, small organic lactam-assisted synthesis of ZSM-5 zeolites

Herein, we report the solvent-free synthesis of ZSM-5 zeolites assisted by the small organic lactam. i.e., N-methyl-2-pyrrolidone (NMP). An array of characterization techniques (XRD, FTIR, and SEM) confirmed the formation of intergrown, highly crystalline ZSM-5 with a size of around 10 μm. To investigate the structure of NMP within the ZSM-5 synthesis, we have performed the 13C liquid NMR spectroscopy measurement, which showed the presence of preserved NMP (cyclic molecule) and a ring-opened NMP molecule. Ultimately, a density functional theory (DFT)-based computational study resulted in the negative formation energies suggested that both molecules could be stabilized within the straight and zig-zag channels of ZSM-5 frameworks. To the best of our knowledge, this is the first time NMP can be utilized as an organic structure-directing agent for crystallizing ZSM-5 zeolites.

Synthesis of ZSM-5 zeolites from biomass power plant ash for removal of ionic dyes from aqueous solution: equilibrium isotherm, kinetic and thermodynamic analysis.

In this work, industrial biomass power plant ash was used to synthesize the ZSM-5 zeolites for the first time with the original intention to turn value-added material into wealth, and then committed to adsorption performance testing. Typical chemical structure and morphology of ZSM-5 zeolite were identified by comprehensive technologies. Uniquely, it was found that there was a low pressure hysteresis loop which was caused by crossed 10-membered rings in the N2 adsorption–desorption isotherm. To investigate the adsorption performance for dyes, the zeolite samples were used to remove cationic (MB) and anionic (CR) dyes from aqueous. The results demonstrated that when it came to adsorbing MB, the isotherm was in line with the Redlich–Peterson model (R2 > 0.99), whereas it was matched up with the Sips model (R2 > 0.99) for adsorbing CR. Kinetic models were assigned to the pseudo-second order equation (R2 ≥ 0.99) along with remarkable intraparticle diffusion. In the end, thermodynamic parameters were ΔG0 < 0, and Ea > 0. Especially, adsorbing MB was ΔS0 > 0, and ΔH0 > 0, whilst adsorbing CR was ΔS0 < 0, and ΔH0 < 0, which indicates that electrostatic interaction plays a significant role in the whole process. All in all, this work might encourage novel attempts to dispose of industrial biomass ash.

Synthesis of ZSM-5 Zeolite from Metakaolin and Rice Husk Ash to CO2 Adsorption

Several mitigation processes involving carbon dioxide injection into adsorbent materials such as zeolites, are currently very popular as research studies. The objective of our present work is to apply the green synthesis method of molecular sieve with rice husk ash and metakaolin in four individual Si/Al ratios (20, 40, 60 and 80). The micrographs obtained with the aid of SEM (sample 80-ZSM-5) revealed a spherical morphology with aggregated particles. Analysis executed with EDS (Energy Dispersive Spectroscopy) confirmed the presence of Si, Al, O, K and Na. X-ray diffraction helped in the identification of crystalline phases related to the structures of zeolites mordenite and ZSM-5 (mostly). The zeolitic materials were tested for CO2 adsorption assays. The results demonstrated a considerable capacity of CO2 adsorption by 6.5 mmol g−1 of adsorbent at the pressure of 9 bar. Therefore, this research establishes zeolites of ZSM-5 type to be promising as adsorbents for CO2 capture.

New insight into the inductive effect of various seeds on the template-free synthesis of ZSM-5 zeolite

This work enables us to obtain an improved understanding of the role of seeds in the template-free synthesis of zeolite.

Optimization and Study of the Response Surface of Properties for the Synthesis of ZSM-5 Zeolites with Hierarchical Pore Structure Obtained by Desilication

Hierarchical ZSM-5 zeolites were prepared by alkali treatment (desilication) at two temperatures, two reaction times, and two NaOH concentrations. A 23 factorial design was used to study the effect of these variables on the crystallinity, microporosity, and mesoporosity of the zeolite due to the desilication treatment. The factorial design analysis showed that the temperature, reaction time and NaOH concentration and the second order interaction between temperature and time have statistically significant effect on the micropore volume. On mesopore volumes (Vmeso) and areas (Smeso), the reaction time and NaOH concentration factors have statistically significant effects. In the case of mesopore volumes, the second order reaction time and NaOH concentration interaction factor are also significant. On the other hand, only the alkali concentration affected, negatively, the relative crystallinity. Two hierarchical ZSM-5 zeolites with the highest relative crystallinity and mesoporosity were selected and further characterized by inductively coupled plasma (ICP) analysis, 29Si nuclear magnetic resonance (NMR), 27Al NMR, Fourier transform infrared (FTIR) spectroscopy in the OH stretch region and pyridine adsorbed FTIR spectroscopy. NMR and FTIR results showed that the alkali treatment selectively removed silica from the zeolite framework, decreasing the SAR (silica-to-alumina ratio) values, while decreasing Brønsted acid site concentrations and increasing Lewis acid sites concentrations.

A Mechanistic Investigation of Sustainable Solvent-Free, Seed-Directed Synthesis of ZSM-5 Zeolites in the Absence of an Organic Structure-Directing Agent.

The solvent-free, seed-directed synthesis using natural precursors has emerged as a sustainable route for the synthesis of zeolite. Albeit the significant progress in the synthesis techniques, the crystallization behaviors of zeolites are somewhat elusive. Herein, we performed a detailed investigation of the crystallization behaviors of ZSM-5 zeolites synthesized through the solvent-free, seed-directed route using rice husk silica as starting materials. The crystallization at 180 °C is completed rapidly in 10 h, with an ultrahigh zeolite yield of at least 95%. Moreover, we evaluated the crystallization kinetics at different temperatures using the nonlinear Avrami equation and found instantaneous nucleation with three-dimensional growth in the studied temperature range, with activation energies for nucleation, transition, and crystal growth of 137, 51, and 51 kJ mol–1, respectively, indicating that nucleation is the rate-determining step. Further investigation of the structural and morphological evolution revealed a preference for secondary nucleation over the seed-growth mechanism. Crystallization proceeds via structural rearrangement within the solid system. We anticipate that our work will provide extensive insights that increase the understanding of zeolite crystallization and expand the highly sustainable production of zeolites.

Synthesis of ZSM-5 zeolites using palygorskite as raw material under solvent-free conditions

Zeolites have extensively been applied in gas adsorption and separation, catalysis, and ion exchange thanks to their numerous interesting features. However, the synthesis of zeolites usually requires solvents, which often lead to water pollution, loss of silicon and aluminium components, and low synthesis efficiency. In this account, ZSM-5 zeolites were synthesized from natural clay palygorskite (PAL) by acid leaching, followed by thermal treatment under solvent-free conditions. The as-obtained ZSM-5 zeolites exhibited high crystallinity and mesoporous structure. The NMR spectra of ZSM-5 zeolites confirmed the presence of aluminium element derived from the acid-treated PAL (APAL) existed in zeolite framework. Thus, PAL was simultaneously employed as silica and aluminium sources for zeolite preparation. The Si/Al molar ratio of ZSM-5 zeolites could be adjusted by adding NaAlO2, but against growth of ZSM-5 zeolites, resulting in formation of analcime. On the other hand, long thermal treatment for 72 h caused the dissolution of ZSM-5 zeolite crystals and formation of analcime. Overall, calcination could enhance the activity of APAL and crystallinity of ZSM-5 zeolites, and solvent-free synthesis of zeolites from clay might efficiently reduce the cost of zeolites.

CATALYTIC PERFORMANCE OF ZSM-5 ZEOLITE IN HEAVY HYDROCARBON CATALYTIC CRACKING: A REVIEW

Low quality heavy oils and residues, which are subsequently obtained by processing heavy crudes, are considered as alternate suitable source for transportation fuels, energy and petrochemicals. ZSM-5 zeolite with high Si/Al ratio and modified with phosphorous and La has showed not only high selectivity to light olefins but also high hydrothermal stability for the steam catalytic cracking of naphtha. Kaolin is promising natural resource as raw material to synthesis of ZSM-5 zeolite. The utilization of acid catalysts with large pore size or hierarchically structured and high hydrothermal stability to resist the severity of the steam catalytic cracking (or thermal and catalytic cracking) operation conditions to maximize the olefin production.

Controlled synthesis of ZSM-5 zeolite with an unusual Al distribution in framework from natural aluminosilicate mineral

Abstract Precisely tuning the location of Al atoms in zeolite framework that plays a critical role in determining the catalytic performance of zeolite based catalysts has attracted considerable attention. In this article, we present an organotemplate-free approach for the controllable synthesis of ZSM-5 zeolite with a high content of Al pairs selectively located at the channel intersections, which is achieved by using a submolten salt (SMS) depolymerized rectorite as both the Al source and heteropical crystalline seeds. The quasi in-situ characterizations tracking the zeolite crystallization process reveal that the depolymerized rectorite with abundant oligomeric aluminosilicate species and Al–O-(Si–O)1,2-Al sequences plays dual roles in the synthesis of ZSM-5 zeolite. These oligomeric aluminosilicate species like 5- and 6-membered ring structures serve as the crystalline seeds to promote the zeolite nucleation; simultaneously, the Al–O-(Si–O)1,2-Al sequences are in-situ transformed into the final zeolite framework leading to the generation of numerous Al pairs selectively located at the channel intersections. Such an unusual Al distribution endows the synthesized ZSM-5 zeolite with excellent catalytic performance in methanol to aromatics (MTA) reaction. Our strategy provides a sustainable and efficient way to design and synthesize high-performance zeolites with special framework Al distributions for catalytic applications.

Synthesis of ZSM-5 zeolite from fly ash and its adsorption of phenol, quinoline and indole in aqueous solution

This work tries to synthesize ZSM-5 zeolite using fly ash (FA) by hydrothermal method and study the adsorption effect of the zeolite on phenol, quinoline and indole in aqueous solution. The zeolites were characterized with x-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray fluorescence (XRF), fourier transformation infrared (FTIR) and N2 adsorption-desorption isotherm. The characterization results showed that HZSM-5 zeolite was successfully synthesized. The higher mass ratio of sodium carbonate to fly ash during melting is beneficial to improve the purity of ZSM-5 zeolite and its removal rate of organic matters. These results have been confirmed by XRD and principal component analysis (PCA). The adsorption process of phenol, quinoline and indole in aqueous can be well described with the double exponential kinetic model. The adsorption capacity of ZSM-5 zeolite for phenol, quinoline and indoles can be up to 24.41 mg g−1, 35.99 mg l−1 and 34.05 mg g−1 respectively, and the removal rates can reach up to 82.80%, 84.86% and 83.20% respectively. The optimal pH value for adsorption ranges from 5 to 7.

Cost-effective and facile one step synthesis of ZSM-5 from silica fume waste with the aid of metakaolin and its NOx removal performance

The disposal of powdery silica fume waste has become an urgent environmental problem, the synthesis of zeolitic materials using silica fume is a commendable remedy to this crisis. In this study, a cost-effective and facile one-step strategy was proposed for the first time for hydrothermal synthesis of ZSM-5 zeolite using silica fume waste with the aid of inexpensive metakaolin in the absence of organic templates. This method allowed the total transformation of silica fume into ZSM-5 which exhibited similar characteristics to those obtained from conventional chemical reagents. The as-synthesized ZSM-5 under the optimized condition was used to prepare Ni, Cu and Zn/ZSM-5 catalysts by means of ion exchange and calcination treatments for NOx removal by NH3-SCR, and they exhibited high NO conversion of 92, 100, and 95%, respectively. This study would be a promising candidate for cost-effective and environment friendly synthesis of zeolite using silica fume waste in large scale.

Facile adjusting the concentration of siliceous seed to obtain ZSM-5 for cycloaddition reaction of styrene oxide and CO2

Cyclic carbonate is an important organic synthesis intermediate in the fine chemistry. The cycloaddition reaction which catalyzed by the nanosized ZSM-5 zeolites can reach a high selectivity of cyclic carbonates. In this study, a facile seed-assisted strategy for synthesis of ZSM-5 zeolites with different sizes was presented. A nano-sized zeolite and another two different sized zeolites with the size range of 4–5 μm were obtained by only changing the seed precursor. The three zeolites all had the MFI structure and a single chemical condition. Moreover, the ZSM-5 zeolites were applied to the cycloaddition of styrene oxide and CO2 in different reaction conditions, and a suitable reaction condition was obtained. In the suitable condition, the catalytic effects of ZSM-5 catalysts were compared, and the final results demonstrated the smallest one had a highest yield, which was 57.6%.

Synthesis of Mn3O4/ZSM-5 zeolite from natural aluminosilicate minerals and its application as heterogeneous catalyst for α-cellulose conversion to levulinic acid

Microporous ZSM-5 was successfully synthesized using Bayat-Klaten natural zeolite and Belitung kaolin as its mineral source through 2 stages of treatment, i.e. pre-treatment of natural zeolite and kaolin followed by synthesis of ZSM-5 zeolite. Bayat-Klaten natural zeolite as source of Si and Al was first treated as follows: activation, purification, fragmentation, and dealumination, whereas Belitung kaolin as the source of Si, to cover Si deficiency in the synthesis, was treated as follows: activation, purification, and Si extraction. Based on Energy Dispersive X-Ray (EDX) analysis, the Si/Al ratio was 24.8 in dealuminated natural zeolite and 98 % of Si after kaolin extraction. ZSM-5 zeolite was synthesized and characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), and Brunauer-Emmett-Teller (BET) analysis. The XRD pattern showed a similarity with typical ZSM-5 zeolites. Impregnation with Mn(II) followed by calcination at 550 °C giving Mn3O4/ZSM-5 (2.2 wt.% of Mn), that then employed as catalyst for α-cellulose conversion to levulinic acid. High Performance Liquid Chromatography (HPLC) analysis in product reaction showed that the conversion reaction for 6 h resulting in the highest yield of levulinic acid (7.2 %). Therefore, it was revealed that the natural mineral-based ZSM-5 has potential to be used as heterogeneous catalyst.

Defining aluminum-zoning during synthesis of ZSM-5 zeolites.

ZSM-5 zeolites attract considerable attention owing to their wide range of applications in catalysis and separation. The crystals that are synthesized with tetrapropylammonium ions (TPA+) as the template show aluminum-zoning, i.e. aluminum being concentrated in the rim part of the crystal. Here, we study the aluminum distribution within individual crystals as a function of synthesis time and find that the degree of aluminum-zoning evolves. Crystals with inhomogeneous aluminum distribution persist since their emergence from the early stages of hydrothermal treatment. The degree of aluminum-zoning in the crystals increases with the synthesis time, accompanied by an increase in the crystal size and subsequently the formation of a well-defined crystal morphology. This indicates a gradual aluminum migration toward the crystal surface during the course of crystallization. Moreover, the addition of high-aluminum-containing species to the existing crystals preferentially takes place at the late stages of synthesis, which contributes to the inhomogeneous aluminum distribution within a crystal. As a result, the finally formed crystals have not only the largest crystal size but also the highest degree of aluminum-zoning. The insight into the origin of aluminum-zoning that our work provides advances our understanding of the relationship between aluminum distribution in zeolites and the synthesis time to design better catalysts.

The influencing factors of hydrothermal synthesis of ZSM-5 zeolite and its adsorption of phenol, quinoline and indole

The factors influencing the hydrothermal synthesis of ZSM-5 have been investigated in detail, such as silicon source, template, pH, reaction temperature, etc The type of template plays a key role. It is difficult to synthesize ZSM-5 without template or using inorganic template under our research conditions. However, the organic template of tetrapropylammonium bromide (TPABr) or n-butylamine (BTA) is beneficial to the synthesis of HZSM-5. The pH range of 10.79–11.14 is favorable for the synthesis of HZSM-5 zeolite. When temperature is greater than or equal to 160 °C, the synthesis of target zeolites is easy. However, if temperature is ≤140 °C, the synthesized product belongs to amorphous solid. Scanning electron microscopy (SEM) shows that the morphology of HZSM-5 crystal is hexagonal columnar. Fourier transform infrared (FTIR) analysis shows the synthesized product has a good ZSM-5 skeleton structure. The synthetic HZSM-5 zeolite has the BET specific surface area of about 387.326 m2 g−1. The adsorption capacities of the synthesized HZSM-5 for phenol, quinoline and indole can reach up to 43.54 mg g−1, 83.10 mg g−1 and 69.51 mg g−1, respectively.

Synthesis of ZSM-5 Zeolite Using Coal Fly Ash as an Additive for the Methanol to Propylene (MTP) Reaction

Using ZSM-5 zeolites as catalysts for the methanol to propylene (MTP) reaction is being widely investigated and has been industrially applied. In this study, pure ZSM-5 zeolite was successfully synthesized by a direct hydrothermal method using the fly ash of coal gasification as an additional raw material. Various analysis methods such as X-ray diffraction, N2 sorption, scanning electron microscopy, and infrared spectroscopy, were employed to characterize the physicochemical properties of parent and modified zeolites. Then, the prepared ZSM-5 catalysts were tested in the MTP reaction. The results showed that pure ZSM-5 could be directly synthesized in the optimized conditions using fly ash as additional silicon and aluminum sources, and those ZSM-5 catalysts turned out to be candidate catalysts for the MTP reaction. Whereas their catalytic lifetimes were not good enough due to the strong acid sites and needed improving.

Emission reduction technique applied in SI engines exhaust by using zsm5 zeolite as catalysts synthesized from coal fly ash

Abstract The present investigation deals with the synthesis of ZSM-5 zeolite from coal fly ash and using it as a catalytic convertor for the reduction of NOx in gasoline powered engine. Copper and cobalt doped zeolite coated in ceramic monolith shows better active for the instantaneous reduction of NOx compared to the conventional catalytic convertor. Experiment was conducted on twin-cylinder petrol engine with eddy current dynamometer and emissions were measured through AVL DI-gas analyzer. The outcome results exposed that in-house made Cu-ZSM5 and Co-ZSM5 is showing 59% compared to the commercial catalytic converter. The best conversion efficiency NOx, CO and HC were observed.