ZSM-5 Nanoparticles Research Articles

Printable MXene Ink Hybridized with ZSM-5 for Gas Sensing and CO2 Capturing

MXene has garnered significant attention as a two-dimensional material with exceptional physicochemical properties for gas sensing development. This study utilized ZSM-5 nanoparticles loaded with MXene to prepare printable inks, aiming to explore novel applications of MXene in the gas sensing field. The morphology of MXene/ZSM-5 was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), demonstrating the typical layered structure of MXene and particle morphology of composite ZSM-5. X-ray photoelectron spectroscopy (XPS) confirmed no production of TiO2 by providing valence information on elements. Thermogravimetric analysis (TG) revealed excellent thermal stability. To verify functional gas sensing feasibility, various hydrocarbons and common gases underwent adsorption and desorption tests (BET). Results showed that MXene loaded with ZSM-5 exhibited good adsorbability for C4H10, C7H8, SF6, H2O and O2 while having a certain trapping effect on CO2. Through testing and analyzing printing results, it was found that the MXene/ZSM-5 ink overcame dispersion issues present in pure MXene ink.

Synthesis and characterization of enhanced polysulfone-based mixed matrix membranes containing ZSM-5 zeolite for protein and dye removal

In this paper, polysulfone (PSf)-based ultrafiltration (UF) mixed matrix membranes (MMMs) embedded with ZSM-5 zeolite nanoparticles were synthesized via the NIPS method. The membranes were characterized by FESEM, ATR-FTIR, AFM, and tensile analyses, along with contact angle, porosity, and mean pore size measurements. The FESEM images indicated that the addition of hydrophilic ZSM-5 nanoparticles has led to formation of more and larger finger-like macrovoids. Moreover, hydrophilicity and pure water flux (PWF) values were consequently augmented, which was also approved by water contact angle reduction. The maximum PWF was equal to 394.7 L m-2h−1 at 3 bar for the optimum MMM, containing 1 wt% ZSM-5 which is 125.4 % greater than the value for the bare membrane. In addition, filtration of the bovine serum albumin (BSA) protein and aqueous solutions of two organic dyes were carried out. The highest BSA flux value was obtained 217.9 L m-2h−1 for the optimum membrane, where the BSA rejection values were all greater than 98 %. Furthermore, the optimum MMM displayed the highest flux recovery ratio (FRR%) of 60.1 % as well as the dyes rejection values equal to 95.5 % and 74.1 % for reactive black 5 (RB 5) and reactive yellow 160 (RY 160), respectively, representing its great potential to be applied in various wastewater treatment applications.

Preparation and evaluation of biological activity of ZSM-5 nanoparticles loaded with gefitinib for the treatment of non-small cell lung carcinoma

Background: Gefitinib (GEF) is a tyrosine kinase inhibitor that has proven good efficacy against Non-small cell Lung Carcinoma (NSCLC). It has low solubility and dissolution rate and low oral bioavailability. This work aimed to improve efficacy by loading on ZSM-5 silica nanoparticles and testing the prepared delivery system on A-549 lung cancer cells. Methods: ZSM-5 was synthesized in the laboratory and different methods of loading GEF on the nanoparticles were used, then the system was characterized by X-ray diffraction, Fourier Transport Infra-Red (FTIR), and drug release and dissolution. Results and conclusion: GEF-loaded nanoparticles (NPs) showed prolonged release of GEF over 12 hours with an improved biological efficacy expressed by the decrease in IC50 compared to free GEF (P < 0.001) using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Also, there was a significant decrease in migration and colony formation ability of the GEF-loaded NPs on A-549 lung cancer cells. In conclusion, loading GEF onto ZSM-5 NPs resulted in a lower IC50 and improved biological action toward A-549 cells.

Deep Cracking of Bulky Hydrocarbons into Light Products via Tandem Catalysis over Uniform Interconnected ZSM-5@AlSBA-15 Composites.

Deep cracking of bulky hydrocarbons on zeolite-containing catalysts into light products with high activity, desired selectivity, and long-term stability is demanded but challenging. Herein, the efficient deep cracking of 1,3,5-triisopropylbenzene (TIPB) on intimate ZSM-5@AlSBA-15 composites via tandem catalysis is demonstrated. The rapid aerosol-confined assembly enables the synthesis of the composites composed of a continuous AlSBA-15 matrix decorated with isolated ZSM-5 nanoparticles. The two components at various ZSM-5/AlSBA-15 mass ratios are uniformly mixed with chemically bonded pore walls, interconnected pores, and eliminated external surfaces of nanosized ZSM-5. The typical composite with a ZSM-5/AlSBA-15 mass ratio of 0.25 shows superior performance in TIPB cracking with outstanding activity (≈100% conversion) and deep cracking selectivity (mass of propylene + benzene > 60%) maintained for a long time (> 6h) under a high TIPB flux (2mLh-1), far better (several to tens of times higher) than the single-component and physically mixed catalysts and superior to literature results. The high performance is attributed to the cooperative tandem catalytic process, that is, selective and timely pre-cracking of TIPB to isopropylbenzene (IPB) in AlSBA-15 and subsequently timely diffusion and deep cracking of IPB in nanosized ZSM-5.

A versatile electrospinning method to fabricate ZSM-5-decorated MgO nanofibers as a catalyst for methanol to light olefins: Toward remarkable stability and superior performance

In response to the increasing concerns about climate change and the depletion of fossil fuel reserves, the application of zeolite ZSM-5 as a catalyst in the methanol to olefin (MTO) process is considered a promising chemical technique. It holds the potential to produce essential chemical building blocks, such as light olefins, using sustainable raw materials. In this study, electrospun MgO/ZSM-5 nanofibers were synthesized to enhance mass/heat transfer limits during the MTO process and improve catalyst stability. In this synthesis, ZSM-5 nanoparticles with a mean diameter of 600 nm were arranged on magnesium oxide nanofibers with a mean diameter of 200 nm. The catalysts were characterized using various techniques, including XRD, SEM, TEM, EDX-Mapping, NH3-TPD, BET, and TGA. The electrospinning technique prevented nanoparticle accumulation and improved the morphology of the catalyst. In an isothermal fixed-bed reactor, the catalysts were tested at 450 °C, 1 atm, WHSV = 4.5 hr−1, with a methanol-water solution in a 1:1 (v/v) ratio as the feed. The stability of the nanofibers was found to be enhanced compared to ZSM-5 nanoparticles. MgO/ZSM-5-50 nanofibers (50 wt% zeolite), MgO/ZSM-5-80 nanofibers (80 wt% zeolite), and ZSM-5 nanoparticles exhibited methanol conversion rates of 99 %, 88 %, and 76 %, respectively, after 430 min of continuous operation. Furthermore, the amount of coke formed after 10 h for MgO/ZSM-5-50, MgO/ZSM-5-80, and ZSM-5 was 11.83 wt%, 13.63 wt%, and 20.98 wt%, respectively. The reduced coke formation on the electrospun samples compared to ZSM-5 nanoparticles demonstrates improved performance and stability for nanofiber catalysts.

Design and fabrication of the alumina nanofibers decorated with isolated ZSM-5 using electrospinning method: A novel catalyst for methanol conversion to light olefins

ZSM-5 nanoparticles are widely used as the catalyst in the methanol conversion to olefins (MTO) process due to their high surface area and short diffusion path length. However, agglomerate formation is a challenge for this catalyst. To address this issue, in this study, electrospinning was used for the first time to synthesize fibrous catalysts comprised of ZSM-5 nanoparticles embedded in the alumina nanofibers. The catalysts were characterized using XRD, FTIR, SEM, TEM, EDX-map, BET, and NH3-TPD analyses. In the synthesized samples, ZSM-5 nanoparticles with an average particle size of 683 nm are uniformly and homogeneously dispersed over alumina nanofibers with a 300 nm diameter. These composites form core-shell structures and have a reactor porosity of 0.85, which is higher than that of parent ZSM-5. In the MTO process, electrospun catalysts demonstrate superior catalytic activity and a longer lifespan than powder catalysts. 80 wt% ZSM-5- 20 wt% Al2O3 with 47.76 % light olefin selectivity and complete methanol conversion after 321min on stream performed better than 50 wt% ZSM-5-50 wt% Al2O3. Moreover, a lower coke formation of about 3.28 % was achieved for the 80 wt% ZSM-5- 20 wt% Al2O3 sample. The reduced bulk density of the electrospun samples increases the probability of reactant and catalyst contact. Additionally, electrospinning is an effective method for reducing particle aggregation and improving catalytic process efficiency.

Molecular dynamics simulation of urea adsorption on various nanoparticles in a spiral microfluidic system

Microfluidic devices use the physical-chemical features of liquids at a microscale. Microfluidics allow the analysis and employment of fewer volume of specimens and chemicals reducing the cost of applications. A kidney failure will lead to the accumulation of urea toxins in blood and eventually result in patient death. End-stage renal disease (ESRD) occurred when kidneys destructed completely. In this comparative study, a spiral Microfluidic system with an adsorption section is modeled with coated needles. For coated section, various new nanoparticles have been introduced to assess their capability in urea adsorption. Molecular dynamic (MD) technique was applied to assess Urea adsorption capability of nanoparticles. Comparative investigation was accomplished among Boron-Carbon-Nitride Nanolayer (BCNNanolayer), Boron-Carbon-Nitride Nanotube (BCNNanotube), Graphene (GNP), Carbon Nanotube (CNT), Zeolite Y, Zeolite Z, and Zeolite ZSM5 nanoparticles. In this study, 7 different analyses including Gibbs free energy, Solvent accessible surface area (SASA), root mean square deviation (RMSD), radial distribution function (RDF), radius of gyration (Rg), number of hydrogen bonds, and interaction energy have been utilized for testing urea adsorption performance of nanoparticles. Among all mentioned adsorbents, BCNNanotube and BCNNanolayer adsorbed urea molecules better in comparison with other studied adsorbents, especially Zeolite group nanoparticles.

PdZn on ZSM-5 nanoparticles for CO2 hydrogenation to dimethyl ether: comparative in situ analysis with Pd/TiO2 and PdZn/TiO2

PdZn on ZSM-5 nanoparticles for CO2 hydrogenation to dimethyl ether: comparative in situ analysis with Pd/TiO2 and PdZn/TiO2

Dimethyl ether conversion to hydrocarbons on the closely interconnected FER@ZSM-5 nanostructures

A superior catalyst activity and stability for dimethyl ether (DME) conversion to gasoline-range hydrocarbons (DTG) on a novel hierarchically-structured hybridized FER@ZSM-5 were verified in terms of the strong interactions of ZSM-5 on the plate-like FER nanostructures, which were prepared by alcohol additive with two organic structure-directing agent (OSDA). The highly active nanostructured FER@ZSM-5 with a propanol additive showed the closely interconnected and highly dispersed ZSM-5 aggregates on the larger plate-like FER surfaces, which were mainly responsible for the suppressed heavy coke depositions with the help of the closely interconnected ZSM-5 and FER interfaces with abundant acidic sites on 8-membered ring (8-MR) channels. The well-dispersed ZSM-5 nanoparticles on Brønsted acid sites of FER surfaces showed coke-resistant natures for DTG reaction due to the synergy effects of the strong acidic sites of the smaller ZSM-5 particles and larger Brønsted acid sites on the plate-like FER structures. • Superior activity and stability for DTG on the hybrid FER@ZSM-5 composite were verified. • FER@ZSM-5(Propanol) with closely interconnected nanostructures showed higher stability. • Less coke deposition was observed due to closely interconnected ZSM-5 and FER interfaces.

Preparation and Evaluation of SBA-16, ZSM-5 and MCM-41 Mesoporous Silica Nanoparticles as Drug Delivery System for Carvedilol

Carvedilol is a non-selective beta/alpha1 blocker that is broadly used in treatment of arrhythmia, congestive heart failure, hypertension, and myocardial infarction. Enhancing carvedilol low solubility and dissolution rate would help in improving the efficiency of the tablet dosage form. In this study, different types of silica nanoparticle (NPs) (SBA-16, MCM-41 and ZSM-5) were synthesized. Coupling of SBA-16 with 3-Aminopropyl-triethoxysilane (APTES) was performed to improve surface characteristics of SBA-16. Different methods to load carvedilol on these carriers were used with high-performance liquid chromatography (HPLC) as a method of analysis for carvedilol. For the characterization of the loaded NPs Fourier -transform infrared spectroscopy (FT-IR), X ray crystallography (XRD) and Therapeutic goods administration (TGA) were used. MCM-41 loaded with Carvedilol was decided to be formulated as tablet dosage and compared with tablets contain carvedilol without carrier. The results showed that SBA-16, SBA-16 coupled, ZSM-5 and MCM-41 carriers were used successfully to load carvedilol in a good drug load percent of 64.5, 69.3, 82 and 90%, respectively. MCM-41 gave highest loading efficiency of carvedilol using solvent evaporation method and the dissolution of carvedilol from powder was superior to the pure carvedilol where it gave 100% release of the drug at 15 minutes compared to 30% of pure carvedilol. MCM-41 loaded with carvedilol was successfully formulated as tablet dosage form according to the specifications of USP and the release of carvedilol from the prepared tablet was 99% at 15 min compared to the carvedilol released from tablets prepared using carvedilol powder which gave 38% which indicates the efficiency of the carrier in increasing the solubility and dissolution of carvedilol, a class II BCS drugs.

The high efficiency of ZnAl2O4/ZSM-5 in the removal of carbon monoxide contaminants during photocatalytic oxidation process

In this research, ZnAl 2 O 4 nanocomposite was developed using the sol-gel method. Using the inoculation method, it was loaded on a ZSM-5 zeolite with variable molar ratios. The properties of the studied catalysts were determined by XRD, SEM, FT-IR, TEM, and BET methods. The photocatalytic activities of ZnAl 2 O 4 and ZnAl 2 O 4 /ZSM-5 nanocatalysts in the photocatalytic oxidation removal of carbon monoxide (CO) were studied under UV radiation in a discontinuous photocatalytic reactor. A gas chromatograph (GC) was applied for investigating the amount of CO removal in the photoreactor. The results indicated that ZnAl 2 O 4 /ZSM-5 nanoparticles (NPs) eliminate more CO in less time than pure ZnAl 2 O 4 NPs under the same conditions. The results of the kinetics of the photocatalytic oxidation process of CO show that the reaction kinetics to CO is of the first order, and the rate constants for different molar ratios of zeolite to zinc aluminate (0%–20%) range from 99 × 10 −4 to 14 × 10 −2 , respectively. Therefore, spinel/zeolite compounds can be a suitable option for oxidative removal of CO pollutants using the photocatalytic method due to the easy preparation method, low price, and high efficiency of these catalysts. • Using the inoculation method, ZnAl 2 O 4 nanocomposite was loaded on a ZSM-5 zeolite. • The findings reveal that increasing the molar ratio of zeolite to zinc aluminate improves the efficacy of these catalysts. • The reaction kinetics to CO is of the first order. • The zeolites-based spinel compounds can be widely used in the photocatalytic process of pollutants.

Formaldehyde gas sensors based on SnO2/ZSM-5 zeolite composite nanofibers

An additional layer of zeolite on the surface of metal oxides results in an increased selectivity as gas sensors. However, there is insufficient knowledge on how interactions between the zeolite and gas-sensitive materials improve gas sensing properties. To increase the area of the interface between the materials and decrease agglomeration, SnO2/ZSM-5 composite nanofibers were synthesized via an electrospinning technique. “Bone joints,” such as ZSM-5 nanoparticles, were present in the composite nanofibers. Analyses of the gas sensing properties show that the selectivity and sensitivity of the sensors to formaldehyde were improved. Electronic surface states and charge transport properties were measured via X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS), respectively. It was inferred from the XPS results that the adsorbed oxygen on the surface of the composite increased considerably, thus improving the sensitivity of the sensors. The results of the EIS and electrical equivalent circuits indicate that the interface of the two materials plays a significant role. A larger interfacial area between the zeolite and SnO2 can increase electron transfer and enhance the sensitivity and selectivity of the sensors. This study provides a strategy to improve the sensing properties of semiconducting metal oxide gas sensors.

The Synthesis of YNU-5 Zeolite and Its Application to the Catalysis in the Dimethyl Ether-to-Olefin Reaction.

During prior investigations of the synthesis of the novel zeolite YNU-5 (YFI), it was found that a very slight amount of an impurity phase contaminated the desired zeolitic phase. This impurity was very often ZSM-5 (MFI). The phase composition was determined to be sensitive to the water in the synthesis mixture, and it was possible to obtain a pure phase and also to intentionally generate a specific impurity phase. In the present work, trials based on the dimethyl ether-to-olefin (DTO) reaction using a fixed-bed downflow reactor were performed to assess the effect of the purity of YNU-5 on its catalytic performance. Dealuminated pure YNU-5 exhibited rapid deactivation due to coking at time on stream (TOS) values exceeding 5 min. Surprisingly, this deactivation was greatly suppressed when the material contained a trace amount of ZSM-5 consisting of nano-sized particles. The formation of ZSM-5 nanoparticles evidently improved the performance of the catalytic system during the DTO reaction. The product distributions obtained from this reaction using highly dealuminated and very pure YNU-5 resembled those generated by 12-ring rather than 8-ring zeolite catalysts. The high selectivity for desirable C3 and C4 olefins during the DTO reaction over YNU-5 is beneficial.

Enhancing the gas separation properties of mixed matrix membranes via impregnation of sieve phases with metal and nonmetal promoters

In recent years, numerous studies investigated influence of many different sieves on gas separation performance of mixed matrix membranes (MMMs), but few studies have investigated effects of morphology of sieve phases. Herein, we used two transition metal oxides, based on manganese (Mn) and iron (Fe), and also a nonmetal oxide, based on phosphorus (P), as modifier agents in impregnation process of ZSM-5 nanoparticles. These metal/nonmetal oxides are briefly named promoters. Influence of the impregnated ZSM-5 nanoparticles on separation performance of PEBA/ZSM-5 MMMs were investigated, [PEBA: polyether block amide]. Morphological changes made during the impregnation process considerably affected the gas separation properties of the MMMs. ZSM-5 nanoparticles impregnated with Mn, Mn-ZSM5, showed a separation performance beyond that of the parent ZSM-5 nanoparticles. Compared to the parent, Mn-ZSM-5 at the highest loading content, 9 wt%, increased the CO2 permeability by 44%, while CO2/CH4 and CO2/N2 selectivity values respectively enhanced from 22.7 and 48.8 to 33.3 and 52.2. Our results confirmed that impregnation of sieve phases with metal promoters can be considered as a reliable approach to provide a general toolbox for improving the gas separation performance of membranes bearing molecular sieve phases.

Synthesis of supported ZSM-5 nanoparticles

Abstract The influence of the support on the nucleation of ZSM-5 nanoparticles has been studied for three supports: γ-alumina, zirconia and carbon nanotubes (CNT). While zeolite nucleation was suppressed in presence of alumina and strongly delayed in presence of zirconia, it occurred without delay in presence of CNT. These differences are explained by the partial dissolution of the support (for alumina and zirconia supports) that modify the composition of the zeolite nucleation solution. For the CNT/zeolite sample, the obtained composite contains about 60 wt% of zeolite and develops a surface area of 776 m2 g−1.

Three-component mixed matrix membrane containing [Hmim][PF6] ionic liquid and ZSM-5 nanoparticles based on poly (ether-block-amide) for the pervaporation process

Three-component mixed matrix membranes based on poly (ether-block-amide) (PEBA) were prepared by incorporation of ZSM-5 zeolite nanoparticles and [Hmim][PF6] ionic liquid for the separation of ethyl acetate (EAc) from EAc/water mixtures using the pervaporation process. At first, the dual-layer PEBA/polyethersulfone (PES) membranes containing [Hmim][PF6] in the active layer were prepared and employed in the pervaporation process. It was found that the ionic liquid leached out from the membrane during the pervaporation experiments and decreased the membrane selectivity. In order to avoid leaching out of the ionic liquid, triple-layer membranes consisting of a ZSM-5/PEBA as the top layer on a [Hmim][PF6]/PEBA as the intermediate layer and PES as the support layer were developed. The effect of ionic liquid concentration in the intermediate layer on the membrane separation performance was investigated and the results indicated that the membrane containing 2.5%wt. [Hmim][PF6] had the best separation performance in terms of the pervaporation separation index (PSI). Moreover, the ZSM-5 nanoparticles were added to the intermediate layer of the triple-layer membranes to improve the performance of the membranes. It was found that simultaneous loading of the ZSM-5 and [Hmim][PF6] in the PEBA matrix significantly improved the separation performance of the membrane as the PSI of the prepared three-component mixed matrix membrane was 1.5 times the PSI of the neat PEBA membrane.

Temperature-controlled, two-stage synthesis of ZSM-5 zeolite nanoparticles with Al atoms tetrahedrally coordinated in the framework

Herein, we demonstrate a novel strategy of two-stage synthesis for the ZSM-5 nanoparticles that have tetrahedrally coordinated Al atoms in their framework. The particle size is significantly decreased at low temperatures during the synthesis; however, high temperatures are required for the successful incorporation of the Al atoms into the zeolite framework. Because of the rapid heating and cooling of the specially-designed tubular reactor with high thermal conductivity, suppression of the Ostwald ripening and incorporation of Al into the framework are simultaneously accomplished.

The improvement of gas-sensing properties of SnO2/zeolite-assembled composite

SnO2-impregnated zeolite composites were used as gas-sensing materials to improve the sensitivity and selectivity of the metal oxide-based resistive-type gas sensors. Nanocrystalline MFI type zeolite (ZSM-5) was prepared by hydrothermal synthesis. Highly dispersive SnO2 nanoparticles were then successfully assembled on the surface of the ZSM-5 nanoparticles by using the impregnation methods. The SnO2 nanoparticles are nearly spherical with the particle size of ~ 10 nm. An enhanced formaldehyde sensing of as-synthesized SnO2-ZSM-5-based sensor was observed whereas a suppression on the sensor response to other volatile organic vapors (VOCs) such as acetone, ethanol, and methanol was noticed. The possible reasons for this contrary observation were proposed to be related to the amount of the produced water vapor during the sensing reactions assisted by the ZSM-5 nanoparticles. This provides a possible new strategy to improve the selectivity of the gas sensors. The effect of the humidity on the sensor response to formaldehyde was investigated and it was found the higher humidity would decrease the sensor response. A coating layer of the ZSM-5 nanoparticles on top of the SnO2-ZSM-5-sensing film was thus applied to further improve the sensitivity and selectivity of the sensor through the strong adsorption ability to polar gases and the “filtering effect” by the pores of ZSM-5.

Phenol removal by HRP/GOx/ZSM-5 from aqueous solution: Artificial neural network simulation and genetic algorithms optimization

Abstract In this study, horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on mesoporous ZSM-5 nanoparticles by using glutaraldehyde as cross linking agent, and the prepared biocatalyst was characterized using SEM and EDAX mapping analysis. The resulted HRP/GOx/ZSM-5 biocatalyst was used for phenol removal from aqueous solution. In order to prevent the deactivation of HRP in the presence of excess H2O2, required H2O2 was produced by GOx in situ to activate HRP, which led to an increase in removal efficiency of phenol about 30%. Investigations on the removal efficiency of phenol for both immobilized and free enzymes indicated that immobilized enzymes have higher activity and less sensitivity to pH variation compared with free ones. In addition, the effect of parameters such as temperature, pH, HRP/GOx ratio, phenol and glucose concentration on the removal efficiency of phenol was investigated. Finally, an artificial neural network (ANN) was developed to model and express the relationship between removal efficiency of phenol and aforementioned parameters. The optimized values of parameters were determined by optimizing the resulted ANN model using genetic algorithm (GA).

The synthesis of nano-sized ZSM-5 zeolite by dry gel conversion method and investigating the effects of experimental parameters by Taguchi experimental design

ABSTRACTIn this study ZSM-5 Nano particles with high crystallinity were synthesized using a dry gel conversion technique. An L9 orthogonal array of the Taguchi method was applied to investigate the effect of synthesis parameters, such as crystallization time, gel drying temperature, molar composition of template (TPAOH) and water content in the crystallization stage on crystallinity and particle size of the ZSM-5 catalyst. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Beside short crystallization time, the particle sizes were considerably smaller in comparison with those prepared using the hydrothermal method. The results showed that the particle size and crystallinity increased with increasing water content and crystallization time. The effects of gel drying temperature and molar composition of template were found to be more complex, however. Comparing to hydrothermal method, ZSM-5 samples synthesized with the dry gel conversion exhibited higher selectivity to gasoline than other hydrocarbons.