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Pesticides effectively manage fungal diseases in fruits and vegetables; however, their toxicity poses significant environmental risks to human beings. Consequently, the chemical industry faces a daunting challenge in controlling or eliminating the presence of pesticides in the natural environment. The present work reports the synthesis of zeolitic materials with distinct structural properties (starting from the layered precursor PREFER and 3D-faujasite) and their use for the removal of the pesticide myclobutanil. The PREFER sample underwent two distinct treatments: external functionalization with CTAB and layers separation (delamination). On the other hand, external functionalization of the faujasite surface with different CTAB contents was performed. The results showed that the potentially delaminated PREFER sample (PREFER-CTAB-90ºC) performed better in removing the pesticide among all the samples due to the higher availability of CTAB on their exposed lamellae. In contrast, the samples with a double-layered arrangement of CTAB chains presented better pesticide removal performance in comparison with the samples with a single CTAB arrangement. DFT calculations were performed to elucidate the interaction mechanism occurring between myclobutanil and CTAB. The obtained results indicate that the adsorption of myclobutanil by two CTAB molecules is more efficient than a single CTAB; the calculated binding energy considering two CTAB molecules in the process was nearly four times larger than for a single CTAB. The theoretical data provided validation for the adsorbent performances, including a detailed discussion of molecular mechanisms (with and without solvent effects). This proof-of-principle study emphasizes the significant potential of CTAB-functionalized zeolite in removing myclobutanil. This represents an important advancement toward better understanding and harnessing the capabilities of this material for effective and efficient pesticide removal. [ABSTRACT FROM AUTHOR]

The synthesis of zeolites from local resources has been an attractive route to address the demand for more economical means in the production of zeolites for commercial applications. In particular, Philippine bentonite -- a local clay material --has been used as a raw ingredient to synthesize zeolites, faujasite-type (FAU), and analcime-type (ANA) via hydrothermal synthesis. The silicon-aluminum ratio (SAR) and crystallization temperature were varied to investigate the conditions in the synthesis of pure FAU and ANA-type zeolites. X-ray diffraction allowed the identification of zeolite phases upon comparison to reference patterns from the International Zeolite Association database. The sample with the highest degree of crystallinity of 98% (ANA-type) was prepared at a temperature of 150 °C and an initial SAR of 1.18. This sample also exhibited the largest particle size of 29.1 µm in diameter. Scanning electron micrographs showed octahedral, spherical, and cross morphologies of the products, with average particle size ranging from 1.24 (± 0.13) to 29.1 (± 1.66) µm. The transformation of Philippine bentonite to different types of zeolites demonstrates the viability of local clays as raw resource material for hydrothermal synthesis of a wide range of zeolite frameworks. [ABSTRACT FROM AUTHOR]

In this research work, we were able to composite Faujasite type zeolite and ZIF-8 metal–organic framework using two different ways to improve the chemical stability of ZIF-8. In these methods, the arrangement of introducing Zn and 2-Methylimidazole as parent material to synthesis of ZIF-8 to zeolite were changed. In addition, the composites were prepared at room temperature under green chemistry conditions. The structure of Fauj/ZIF-8 nanocomposites were confirmed by FT-IR, XRD, SEM, BET, MAP, TGA, NH3-TPD and ICP analysis after synthesis. The Fauj/ZIF-8 nanocomposites with high acidity and micro-meso structure showed good stability. Two prepared composites were used as catalysts in organic reactions including esterification of acetic acid by four different alcohols and aldol condensation of benzaldehyde derivatives 2-X and 4-X. The results of these catalytic applications show that the use of nanocomposites yields is above 90% with good reusability under solvent free condition for esterification and aldol condensation reactions. [ABSTRACT FROM AUTHOR]

Research has focused on biomass as a sustainable energy source, driving biomass valorization to convert carbohydrates. The price of lactose has dropped below the production cost, urging exploration for diverse applications, such as conversion into value-added compounds. Zeolites, especially Y zeolite, enhance hexose conversion when modified with metals. Fe-modified zeolites show promise, with controlled Si/Al ratios impacting acidity and selectivity. The recent challenges remain in active site comprehension, catalyst tunability, and reaction optimization. Therefore, this study explores the selective hydrolysis of lactose, limiting undesired side-product formation catalyzed through a sono-assisted modified zeolite Y with Fe. The obtained series of Fe-modified zeolite Y were evaluated for the hydrolysis of lactose in a screening experiment. The samples with the higher potential were further used to optimize reaction conditions by a response surface methodology (RSM). This revealed that the samples prepared at high pH generated more impurities and that higher temperatures and lactose concentrations favored hydrolysis. Despite their apparent similarities, the selected Fe-modified zeolite Y samples (Fe5Y and FeYII) highlight distinct catalytic behaviors and active sites. Employing UV-Vis spectroscopy, FTIR spectroscopy, and magnetic thermal gravimetric analysis (MTGA), various Fe active sites were detected, including α-Fe(II), FeOx nanoparticles, and iron oxides. These active sites give insight into the mechanisms involved with temperature and time, which play critical roles—evidencing the potential of sono-assisted iron modification of zeolite Y to achieve selective lactose hydrolysis. These findings contribute to understanding metal-zeolite composites as bifunctional catalysts and their application in sustainable processes. Furthermore, this research highlights the complexity of catalytic reactions of modified zeolites and their potential for fine-tuning active sites for various applications, particularly lactose hydrolysis. Such advancements hold the promise of propelling the field of sustainable energy and catalysis towards a more efficient and environmentally friendly future.

A hybrid electrolyte composed of a high-concentration electrolyte made of dimethyl carbonate and lithium bis(fluorosulfonyl)imide and lithium exchanged faujasite-type zeolite exhibits solidification of the electrolyte with high ionic conductivity and excellent contact properties with a lithium metal anode and an olivine-type LiFePO4 cathode. The assembled battery showed excellent cyclability for at least 100 cycles at a charge rate of 1 C at 60 °C with a discharge capacity retention of 98.6 % and high coulombic efficiency.

A study is performed to establish the main factors that allow regulation of the activity and selectivity of the synthesis of solketal from glycerol and acetone, and the acidic and catalytic properties of mordenite zeolites (MOR, SiO2 : Al2O3 = 29.2) and faujasite (FAU, SiO2 : Al2O3 = 14.9; 97 and 810). The reaction is studied in a methanol solution at an acetone : glycerol molar ratio of 2.5 and a temperature of 25–50°C. Using zeolites, the main product is solketal with a selectivity of 88.1–94.7%. It is shown that the main factors determining the conversion of glycerol and the yield of solketal are the accessibility of the reagents to active sites, the number and strength of acid sites, and their resistance to the toxic action of water molecules that form during the reaction. [ABSTRACT FROM AUTHOR]

The present study proposed fabricating an industrially feasible zeolite membrane on an indigenously developed inexpensive tubular ceramic substrate. A type of zeolite framework, Faujasite, was deposited on the substrate using source materials, such as alumina and silica, by hydrothermal treatment. The membrane was characterised by XRD, FESEM, zeta potential, and contact angle analyses. Distinguishable physical and structural characteristics of the zeolite membrane from ceramic substrate substantiated a formation of the composite membrane. Further, the potentiality of the membrane was assessed on the removal of hexavalent chromium from synthetic wastewater at various operating parameters in a crossflow system. The prepared membrane offered a maximum chromium removal of 82% with a flux of 5.05 × 10-5 m³m-2s-1 at the operating conditions of 1,000 ppm concentration, 345 kPa pressure, and 1.11 × 10-6 m³s-1 crossflow rate. The membrane revealed its essential employment by providing a higher flux with better rejection than other membranes applied in chromium removal. [ABSTRACT FROM AUTHOR]

Iron inclusion in the composition of the zeolite crystal structure endows it with new and useful properties. However, direct synthesis involving Fe, frequently creates unfavorable conditions that hinder the crystallization process and generate impurity phases. For this reason, novel methods, which include iron within the zeolitic matrix, are being sought out. This article presents a one-pot synthesis of iron-modified zeolite X. The resulting materials were characterized, and their textural, electrical, and magnetic properties were studied. [ABSTRACT FROM AUTHOR]

Faujasite, a molecular sieve zeolite Y aluminosilicate mineral, has excellent catalytic strength and is employed in various industries. The study therefore, seek to synthesize a faujasite zeolite with a hydrothermal treatment of local clay alumina and rice husk silica using central composite design (CCD) of experiment in response surface methodology (RSM) in a 1000ml 2-neck flat bottom flask on a constant temperature magnetic stirrer at 120oC for 6 hours. SiO2, Al2O3, and NaOH were coded at three levels at various masses and Si/Al mole ratios. A significant model with an F-value of 142.27 and a Predicted R2 of 0.9558 was developed using statistically optimized hydrothermal synthesis. 3.07g NaOH, 10.50g SiO2, and 2.61g Al2O3 were needed to synthesize FAU zeolite with Si/Al mole ratio > 2. At 1095.8cm-1 in IR spectrum, silicone (Si - O - Si) was the most abundant functional group in the zeolite. EDS and XRD revealed a faujasite zeolite-Y with 85.60wt% Si and 17.50wt% Al. Octahedral modified zeolite Y crystals were seen in SEM topography. At low relative pressures (P/P0 < 0.056), BET showed significant N2 absorption, indicating micropores. The zeolite's BET study indicated a specific surface area of 1750.0m2/g and a pore diameter of 1.847nm. Transesterification of high-free fatty acid triglycerides can be catalyzed by microporous faujasite zeolite. [ABSTRACT FROM AUTHOR]

In this study, zeolites prepared by the hydrothermal method from Ecuadorian clay were combined with the precursor clay and with the semiconductor ZnTiO3/TiO2 prepared by the sol-gel method to adsorb and photodegrade cyanide species from aqueous solutions. These compounds were characterized by X-ray powder diffraction, X-ray fluorescence, scanning electron microscopy, energy-dispersive X-rays, point of zero charge, and specific surface area. The adsorption characteristics of the compounds were measured using batch adsorption experiments as a function of pH, initial concentration, temperature, and contact time. The Langmuir isotherm model and the pseudo-second-order model fit the adsorption process better. The equilibrium state in the reaction systems at pH = 7 was reached around 130 and 60 min in the adsorption and photodegradation experiments, respectively. The maximum cyanide adsorption value (73.37 mg g−1) was obtained with the ZC compound (zeolite + clay), and the maximum cyanide photodegradation capacity (90.7%) under UV light was obtained with the TC compound (ZnTiO3/TiO2 + clay). Finally, the reuse of the compounds in five consecutive treatment cycles was determined. The results reflect that the compounds synthesized and adapted to the extruded form could potentially be used for the removal of cyanide from wastewater. [ABSTRACT FROM AUTHOR]

The effect of the hydrothermal synthesis conditions (temperature, duration, mixing), composition, and presynthetic processing of narrow fractions of cenospheres of fly ash, which act as a template and source of Si and Al, on the production of microspherical zeolite materials of the given structural type in the Na2O–H2O–(SiO2–Al2O3)glass of two molar compositions is studied. The synthesis products are characterized by XRD, SEM-EDS, and low-temperature nitrogen adsorption, and their sorption properties in relation to Cs+ and Sr2+ are studied. The factors contributing to the predominant formation of NaX zeolite of the faujasite structural type are revealed. It is established that zeolite products based on cenospheres with a glass phase content of about 95 wt % demonstrate the highest sorption parameters, including the maximum capacity for Cs+ and Sr2+ of up to 250 and 180 mg/g, distribution coefficient of about 104 and 106 mL/g, and degree of extraction of 99.1 and 99.9%, respectively. [ABSTRACT FROM AUTHOR]

The effect of the hydrothermal synthesis conditions (temperature, duration, mixing), composition, and presynthetic processing of narrow fractions of cenospheres of fly ash, which act as a template and source of Si and Al, on the production of microspherical zeolite materials of the given structural type in the Na2O–H2O–(SiO2–Al2O3)glass of two molar compositions is studied. The synthesis products are characterized by XRD, SEM-EDS, and low-temperature nitrogen adsorption, and their sorption properties in relation to Cs+ and Sr2+ are studied. The factors contributing to the predominant formation of NaX zeolite of the faujasite structural type are revealed. It is established that zeolite products based on cenospheres with a glass phase content of about 95 wt % demonstrate the highest sorption parameters, including the maximum capacity for Cs+ and Sr2+ of up to 250 and 180 mg/g, distribution coefficient of about 104 and 106 mL/g, and degree of extraction of 99.1 and 99.9%, respectively. [ABSTRACT FROM AUTHOR]

The direct oxidation of methanol to formaldehyde was crystallographically observed within fully dehydrated, fully Mn2+-exchanged zeolite Y by treating with methanol at 297(1) K, followed by evacuation. The structure of the formaldehyde complex of Mn2+-exchanged zeolite Y was determined by single-crystal synchrotron X-ray diffraction techniques in the space group Fd m at 100(1) K and was refined using all intensities to the final indices R1 = 0.066 and wR2 = 0.192. In this structure, the 37.5 Mn2+ ions are found at four crystallographic sites: I, I', II', and II with the occupancies of 12, 5, 2.5, and 18, respectively. 18 formaldehyde molecules per unit cell were all found opposite 6-rings in supercages, each coordinating to a site II Mn2+ ions. The formaldehyde molecules appear to be formed by oxidation of sorbed methanol molecules within zeolite Y cavities. The bond length of C = O in formaldehyde molecule is 1.399(20) Å. And the distances of Mn(2) to oxygen and carbon atoms of formaldehyde, 2.83(7) and 2.95(8) Å, respectively. These bond lengths are relatively long, indicating that each formaldehyde molecule binds weakly to Mn2+ ion. The distances of carbon and oxygen of formaldehyde to the closest framework oxygens O(2) and O(4) are 3.23 and 3.49 Å, respectively which indicate hydrogen atoms interact with framework oxygens by van der Waals force. [ABSTRACT FROM AUTHOR]

Faujasite, a molecular sieve zeolite Y aluminosilicate mineral, has excellent catalytic strength and is employed in various industries. The study therefore, seek to synthesize a faujasite zeolite with a hydrothermal treatment of local clay alumina and rice husk silica using central composite design (CCD) of experiment in response surface methodology (RSM) in a 1000ml 2-neck flat bottom flask on a constant temperature magnetic stirrer at 120oC for 6 hours. SiO2, Al2O3, and NaOH were coded at three levels at various masses and Si/Al mole ratios. A significant model with an F-value of 142.27 and a Predicted R2 of 0.9558 was developed using statistically optimized hydrothermal synthesis. 3.07g NaOH, 10.50g SiO2, and 2.61g Al2O3 were needed to synthesize FAU zeolite with Si/Al mole ratio > 2. At 1095.8cm-1 in IR spectrum, silicone (Si – O – Si) was the most abundant functional group in the zeolite. EDS and XRD revealed a faujasite zeolite-Y with 85.60wt% Si and 17.50wt% Al. Octahedral modified zeolite Y crystals were seen in SEM topography. At low relative pressures (P/P0 < 0.056), BET showed significant N2 absorption, indicating micropores. The zeolite's BET study indicated a specific surface area of 1750.0m2/g and a pore diameter of 1.847nm. Transesterification of high-free fatty acid triglycerides can be catalyzed by microporous faujasite zeolite.

In the refining industry, Y-type faujasite (FAU) plays an irreplaceable role, being widely used to convert crude oil into more valuable products such as gasoline. However, the demand for fuels and chemicals stimulates the search for alternatives, showing the applications of FAU beyond producing value-added chemicals from petroleum-based derivatives. These alternative applications are further enhanced from active sites that emerge in zeolites when iron is incorporated by a sonochemical treatment. Given that ultrasonic irradiation promotes mass transfer, uniform coverage of active sites is expected to produce more efficient catalysts. Likewise, Fe-zeolites catalyze a wide range of reactions in mild conditions, linked to the research of bio-refinery, biomimicry and environmental remediation. This work explores the potential of a Fe-Y zeolite prepared by a sono-assisted ion exchange method in different applications: biomass conversion (lactose hydrolysis), enzyme mimetic materials (partial oxidation of benzene to phenol) and transformation of renewable energy (photodegradation of nitrobenzene and rhodamine B). The modification of FAU was performed at different sonication times 5, 15, 30 and 120 min and characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), N 2 adsorption-desorption isotherms, magnetic and non-magnetic thermogravimetric analysis (MTGA and TGA), zeta potential (ζ), Fourier-transformed Infrared (ATR-FTIR), and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). Finding that the modification of zeolite Y with Fe species enhances its activity for the tested applications, owing their catalytic activity primarily to α-Fe (II) sites. Presenting the sono-assisted ion exchange method as an alternative for introducing Fe species and enhancing the catalytic activity of zeolites. [Display omitted] • Preparation of a room temperature catalytic iron active site in zeolites by sono-assisted ion exchange. • Sonochemical prepared iron containing faujasite catalyst for the hydrolysis of lactose. • Photoactive iron faujasite catalyst for the degradation of nitrobenzene and rhodamine B under sunlight. • Oxidation of benzene to phenol under mild conditions prepared by a sono-assisted ion exchanged Fe faujasite. [ABSTRACT FROM AUTHOR]

This study investigates the impact of cellulose-derived polymers, anionic carboxymethylcellulose (CMC), and cationic cellulose (CC) on the colloidal and thermal stability of zeolite Na-X materials. By exploring polymer adsorption onto Na-X surfaces and characterising the resultant materials, using FT-IR, XPS, SEM, PSD, CHN, and zeta potential, the research unveils how CMC and CC modify zeolite properties. This investigation elucidates the potential roles of these polymers in colloidal systems with zeolites, revealing their promise for crafting organic-inorganic materials. Additional insight was also provided by careful examination of the thermal stability (TGA-DSC) of the obtained cellulose/zeolite materials. Furthermore, the study distinguishes the different adsorption mechanisms of CMC and CC, with CMC relying on some weak interactions (H-bonding and van der Waals forces), while CC interacts mainly via electrostatic forces. Both CMC and CC can act as stabilizing agents, with CMC being more efficient and using both electrosteric and depletion stabilizations. Importantly, the concentration of CC plays a role in bridging flocculation, highlighting the concentration-dependent nature of the stabilization mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

The faujasite and chabazite zeolites with 100% crystallinity and phase purity of potential practical importance was first obtained based on the mineral raw materials of the Nakhchivan Kyukyuchai deposit where zeolite content varied in the range of 75–80%, by hydrothermal treatment. Hydrothermal synthesis was carried out in the temperature range from 90 to 300°С, the concentration range of the KOH + NaOH thermal solution from 10 to 35% and KCl + NaCl mineralizer of 3–20%, reaction time of 10–100 hours. Areas of existence of chabazite and faujasite with a 100% degree of crystallinity and phase purity were established: KOH + NaOH concentration of 15–20%, KCl + NaCl concentration of 10–15%, temperature at 230°С, processing time of 100 hours, and KOH + NaOH concentration of 20–30%, concentration of KCl + NaCl of 5–10%, temperature at 250°С, processing time of 50 hours, respectively. The formation of these zeolites was confirmed by X-ray phase analysis. The influence of temperature, the concentration of thermal solution and mineralizer, time of synthesis on the crystallization process was studied, and it was shown that a change in the above regions of existence of these zeolites contributes to the production of these zeolites in association with other zeolites and hydrosodalite. [ABSTRACT FROM AUTHOR]

The development of cost‐effective sorbents for direct capture of trace CO2 (<1 %) from the atmosphere is an important and challenging task. Natural or commercial zeolites are promising sorbents, but their performance in adsorption of trace CO2 has been poorly explored to date. A systematic study on capture of trace CO2 by commercial faujasite zeolites reveals that the extra‐framework cations play a key role on their performance. Under dry conditions, Ba−X displays high dynamic uptake of 1.79 and 0.69 mmol g−1 at CO2 concentrations of 10000 and 1000 ppm, respectively, and shows excellent recyclability in the temperature‐swing adsorption processes. K−X exhibits perfect moisture resistance, and >95 % dry CO2 uptake can be preserved under relative humidity of 74 %. In situ solid‐state NMR spectroscopy, synchrotron X‐ray diffraction and neutron diffraction reveal two binding sites for CO2 in these zeolites, namely the basic framework oxygen atoms and the divalent alkaline earth metal ions. This study unlocks the potential of low‐cost natural zeolites for applications in direct air capture. [ABSTRACT FROM AUTHOR]

The discharge of copper ion (Cu(II)) into natural waters can lead to serious environmental and health problems; however, an abundantly porous hierarchical adsorbent, such as faujasite (FAU), can rapidly remove unwanted Cu(II). In this research, a hierarchically structured, abundantly mesoporous faujasite (FAU) was fabricated from industrial-waste lithium-silicon powder (LSP), with the addition of biochar and graphene oxide (GO) via hydrothermal synthesis without high-temperature calcination. The results demonstrated that just a small amount of biochar or GO can significantly improve the mesopore volume (0.14 cm³/g) and the Cu(II) adsorption capacity (115.65 mg/g) of composite FAU. In particular, careful examination of the properties of the composite FAU showed that the biochar and GO had favorably affected the growth of the zeolite crystals, thus promoting the formation of the FAU skeleton structure, ion-exchange sites and Si-OH. The composite FAU exhibited superior adsorption capacities and highly effective Cu(II) selectivity. Thus, the findings of this study provide a novel and cost-effective avenue for the synthesis of composite FAU with high copper-selective removal capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • BaX and BaY most selective adsorbents for glucose/xylose separation. • Ethanol addition enhance the higher sugar adsorption. • Co-solvent presence changes the mixture selectivities. In the frame of lignocellulosic biomass valorization into chemicals or fuels, developing separation methods for streams of carbohydrates by chromatographic separation is necessary. One of the famous separations based on adsorption, is glucose and fructose separation using a SMB technology with ion-exchanged resin. Second generation carbohydrates like glucose and xylose are the main building blocks for various applications including chemicals are fuels, however the fractionation step of these mixtures is needed. In this work, we prepared and characterized X and Y zeolites exchanged by K+, Ca2+, Sr2+ and Ba2+ as potential adsorbents for xylose/glucose separation. We tested their separation performance with adsorption breakthrough experiments. We find that BaX and BaY are the most selective with a selectivity inversion (xylose/glucose selectivity of 1.52 and 0.67 respectively). Addition of ethanol as co-solvent show the higher uptakes of both sugars and changes of selectivities in some adsorbents. [ABSTRACT FROM AUTHOR]

Faujasite is a zeolite that, when in a Y structure, is widely used as a catalyst to produce fuel by fluid catalytic cracking (FCC) and is recently being investigated for applications in sustainable processes. Hence, there is an increased interest in modifying Y zeolites with metals such as Fe to improve and optimize their catalytic properties. Several post-synthesis methods such as chemical vapor deposition, impregnation and ion exchange have been explored for the introduction of Fe. Nevertheless, these currently developed methods can be time-consuming and unable to selectively tune the Fe species. Therefore, this study explores the use of ultrasonic irradiation in a liquid state modification of a Fe-exchanged Y zeolite (FeY) in a buffer solution with different pH values (5 and 9) and oxidation states of Fe ions (ferrous and ferric) for the introduction of Fe species. At the tested ultrasonic modification conditions, the zeolitic structure was preserved with slight Si/Al ratio and pore structure adjustments in correlation with the introduced Fe species (ions, hydroxides and oxides). Setting the sonochemical method as a potential path for the search of reaction conditions for the design and fabrication of Fe-modified zeolitic materials with tuned properties for a wide range of applications. [Display omitted] • Modification of zeolite Y with Fe species can be achieved under ultrasonic irradiation in a buffer solution. • Sono-assisted Fe modification of zeolite Y with potential for tuning the Si/Al ratio, pore structure and Fe species. • Influence of pH and oxidation state of Fe ions on a sonochemically Fe modified zeolite Y. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hybrid exchange method presents Cu+ preferential location on sites III and site V. • Hybrid exchange method prevents the skeleton collapse and saves water resources. • Cu-Y-LS-2 presents 51.3 mL CO per gram of adsorbent under 1 bar and α CO/N2 of 15.1. • Cu-Y-LS-2 exhibits good cyclic stability. This work systematically examines the influence of preparation methods on the active Cu+ anchoring sites over FAU zeolites and their CO storage capacity and selectivity. The involved preparation methods here include individual liquid ion exchange method with CuCl 2 solution, individual solid ion exchange method with CuCl powder and the hybrid exchange method. For the obtained Cu-Y samples, XRD, Ar adsorption/desorption at 87 K, TEM and NMR were used to characterize their skeleton structure, meanwhile, XPS and H 2 -TPR were utilized to identify the Cu+, Cu2+ and CuCl distribution. The CO storage capacity was implemented through CO adsorption–desorption isotherms. The correlation between various Cu species and CO storage capacity was analyzed and DFT calculation was employed to further elucidate the optimal Cu+ location induced by preparation methods. Finally, it is found that the isolated Cu+ is the dominating CO adsorption sites and Cu+ on site III present higher bonding energy with CO molecules. The hybrid preparation method seems the optimal choice for Cu-Y synthesis since the initial liquid ion exchange operation could prevent the framework corrosion from the subsequent solid ion exchange process, which benefits the optimal CO storage capacity and CO/N 2 selectivity. [ABSTRACT FROM AUTHOR]

• A good adhesion between zeolitic powder and polypropylene matrix were detected in composites. • The zeolitic powder increased density and compressive strength of WWP composites. • The durability in UV environmental increased due to powder acting as screen of UV radiation. • Two types of by-products lead to manufacture greener building WWP composites. Polypropylene is a widely used polymer that generates a lot of polypropylene waste. This study presents composite materials with matrix made from polypropylene waste reinforced with zeolitic powder (ZP). This zeolite is a waste from the oil industry. The relationships between the density, compressive strength, microstructure, durability for UV radiation and incorporation of ZP in the polypropylene waste matrix were observed. The durability in UV environmental increased due to powder acting as screen of UV radiation in polypropylene composites. This composite could be used as a civil engineering building material for light structures. [ABSTRACT FROM AUTHOR]

This work aims to develop the microwave-assisted synthesis route for FAU zeolite. The effect of aging and crystallization times, as well as the use of ultrasonication during the synthesis stages, was studied. A highly crystalline, an extended BET surface area (215.45 m 2 /g), and a hierarchical nanostructure of faujasite zeolite were obtained using a combined microwave-assisted synthesis with an ultrasonication treatment (MOFAU). The resulting zeolites were used as supports for Pt and Cu catalysts, using a novel polyol impregnation method was possible to achieve an adequate metal loading and homogeneous dispersion of the metal. X-ray diffraction (XRD), Scattering and Transmission Electronic Microscopy (SEM and TEM), Temperature-Programed Reduction (TPR), Energy Dispersive X-ray spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS) and N 2 physisorption analyses were used to determine the physicochemical properties of the obtained materials. The prepared materials were used in the catalytic transfer hydrogenation (CTH) of gamma-valerolactone (GVL) using formic acid (FA) as H 2 source. The synthesized catalysts presented catalytic activity under the described conditions and 2-MTHF was identified as an interest product observing the highest selectivity with the 3%Pt/MOFAU material. [Display omitted] • Nano-sized hierarchical FAU was achieved using microwave-aided synthesis method. • Polyol method allowed dispersion of Pt and narrow particle size distribution. • Formic acid as proton donor promotes catalytic activity in the hydrogenation of GVL. • The metallic Pt and Cu favored the conversion of GVL to the desired product 2-MTHF. • Pt over zeolite catalysts showed the highest selectivity to 2-MTHF. [ABSTRACT FROM AUTHOR]

This study seeks to investigate the time and the temperature of the formation of the composites faujasite-geopolymer gels in the reaction medium, and also study the compressive strengths and the microstructural properties of the hardened composites after curing at room temperature. Sodium waterglass from rice husk ash, incandescent and fluorescent bulbs known as low-value silica-rich wastes were used as hardeners for the preparation of the composites at room temperature. The X-ray patterns of the composites using sodium waterglass from incandescent and fluorescent bulbs indicate the reflection peaks of faujasite-Na and the broad hump structure belonging to the geopolymer networks. Whereas the one using sodium waterglass from rice husk ash shows only the broad hump structure. The semi-adiabatic results show that geopolymer gels are formed after 18 min at the temperature of the reaction medium of 38 °C in the composites when sodium waterglass from rice husk ash was used as a hardener. Whereas they are formed after 10 min at the temperature of the reaction medium of 34 and 43 °C in the composites using sodium waterglass from incandescent and fluorescent bulbs, respectively. Zeolite type faujasite-Na is formed after 72 and 40 min at the temperature of the system at 76 and 90 °C in the composites using sodium waterglass from incandescent and fluorescent bulbs, respectively. The increase in the temperature of the reaction medium leads to the crystallization of faujasite. The compressive strengths of the hardened composites using sodium waterglass from rice husk ash is higher (47.54 MPa) compared to those from the incandescent bulb (22.42 MPa) and the fluorescent bulb (12.53 MPa). It was found that faujasite-geopolymer composites could be obtained at non-hydrothermal condition using sodium waterglass from incandescent and fluorescent bulbs. It appears that the formation of faujasite in the structure of geopolymer cements decreases the compressive strength of the composites. [ABSTRACT FROM AUTHOR]

Faujasite (FAU) zeolites (with Si/Al ratio of ca. 1.7) undergo mild dealumination at moderate ion exchange conditions (0.01 to 0.6 M of NH4NO3 solutions) resulting in protons circumscribed by sodalite cages becoming accessible for reaction without conspicuous changes to bulk crystallinity. The ratio of protons in sodalite cages (HSOD) to supercages (HSUP) can be systematically manipulated from 0 to ca. 1 by adjusting ammonium concentrations used in ion exchange. The fraction of accessible protons in the sodalite cages is assessed by virtue of infrared spectra for H‐D exchange of deuterated propane based on the band area ratio of OD2620/OD2680 (ODSOD/ODSUP). Protons in sodalite cages (HSOD) show higher rate constants of propane dehydrogenation (kD) and cracking (kC) than protons in supercages (HSUP) plausibly due to confinement effects being more prominent in smaller voids. Rate constants of dehydrogenation and cracking including kD/kC ratios are also augmented as the fraction of accessible protons in the sodalite cages is enhanced. These effects of accessibility and reactivity of protons in sodalite cages hitherto inconspicuous are revealed herein via methods that systematically increase accessibility of cations located in sodalite cages. [ABSTRACT FROM AUTHOR]

Zeolite Y and its ultra‐stabilized hierarchical derivative (USY) are the most widely used zeolite‐based heterogeneous catalysts in oil refining, petrochemisty, and other chemicals manufacturing. After almost 60 years of academic and industrial research, their resilience is unique as no other catalyst displaced them from key processes such as FCC and hydrocracking. The present study highlights the key difference leading to the exceptional catalytic performance of USY versus the parent zeolite Y in a multi‐technique study combining advanced spectroscopies (IR and solid‐state NMR) and molecular modeling. The results highlight a hitherto unreported proton transfer involving inaccessible active sites in sodalite cages that contributes to the exceptional catalytic performance of USY. [ABSTRACT FROM AUTHOR]

The sodium form of Faujasite Y (Na-FAU) zeolite has been synthesized by the hydrothermal method, and it has been exchanged with ammonium sulphate and later with lanthanum (III) chloride solutions to obtain the La-FAU catalyst. The three zeolites Na-FAU, NH4+-FAU and La-FAU have been characterized by microcrystalline X-ray diffraction, X-ray fluorescence, surface area, pore volume and Brönsted acid sites. The La-FAU catalyst has been successfully activated with boron trifluoride etherate, and it has been tested in the alkylation reaction of isobutane with isobutene up to 112 h of time on stream, since the raw La-FAU catalyst showed a rapid deactivation. [ABSTRACT FROM AUTHOR]

In the preparation of self-supporting FAU zeolites as the goal, self-supporting zeolite blocks were prepared by hydrothermal treatment of metakaolin with fly ash or slag. Compressive strength test, XRD, SEM, BET adsorption and a series of methods were used to characterize the effects on the mechanical property, phase composition, microstructure and pore structure characteristics. The results show when hydrothermal treat in 90 °C 2 mol/L NaOH solution for 24 h, adding slag into geopolymer test block on metakaolin base can significantly improve the strength of hydrothermal products. At the same time, in addition to faujasite crystals, type A zeolite is also generated, but it will reduce its pore structure parameters and arise a phenomenon of dry cracking: however, if the metakaolin base is mixed with fly ash, the compressive strength of the test block increases little and the degree of crystallization of the zeolite is not high. [ABSTRACT FROM AUTHOR]

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Ozonation, combined with suitable catalyst represents an interesting option in removing poorly degraded pollutants from stabilized landfill leachate. Therefore, this study aimed to eliminate chemical oxygen demand (COD), color, and ammoniacal nitrogen, and to improve the biodegradability of stabilized landfill leachate using the heterogeneous catalytic ozonation with natural zeolite (Faujasite) in comparison with solo ozone or adsorption treatment. First, Faujasite was characterized and used in batch studies to find the optimum removal, followed by isotherm and kinetic studies to understand the mechanism. Next, ozonation as sole treatment under different operating conditions of pH and reaction time was applied. Subsequently, Faujasite was combined in the same reactor with the ozone in heterogeneous catalytic ozonation to enhance the treatment performance. Removal for ammonia, COD, and color by ozone as sole treatment were 29%, 47%, and 90%, respectively, compared with 63%, 66%, and 60% reductions by Faujasite as adsorbent. Heterogeneous catalytic ozonation with Faujasite shows ∼64% and 93% of the COD and color removal at pH 11. At this pH, Faujasite promoted ozone degradation, whereas 35% of ammonia was removed at pH 5 because of the interaction between direct ozone and pollutants on the Faujasite surface. Leachate biodegradability also improved from 0.016 to 0.1 after the combined treatment. Faujasite augmented in the ozonation improved the removal of pollutants and simultaneously enhanced the biodegradability of the stabilized landfill leachate. [ABSTRACT FROM AUTHOR]

Cs-137 is a radionuclide fission product that poses a significant risk to life, making it crucial to develop effective methods for its separation and sequestration from nuclear waste streams. Zeolitic structures have emerged as promising materials. This work examines the influence of structure, exchange site energetics, and formation enthalpies of nascent and cation-exchanged Faujasite-X, -Y, and -HY zeolites in terms of their Cs-exchange selectivity. Their interplay was quantified with the application of high-temperature calorimetry, adsorption isotherms, X-ray diffraction and density functional theory (DFT) calculations. Greater efficacy of Cs+ exchange was demonstrated for the Na+-substituted Fau-Y (NaY) zeolite than that of the Fau-X (NaX) and Fau-HY (Na-HY) zeolites. This is explained by a higher amount of Na+ in un-exchangeable sites in the case of NaX and a lower stability in NaY that favors the ionic exchange with Cs+. Moreover, Cs+ incorporation in the structure increases the stability of each kind of zeolite. Correspondingly, structure and DFT analyses demonstrated site-exchange thermodynamic favorability as well as the contribution from cage cell, which resulted in an energy landscape far more conducive to Cs+ incorporation for NaY than either NaX or Na-HY. [Display omitted] • Powerful drivers for designing and understanding Cs + Faujasite-based materials. • Computational techniques for a comprehensive zeolitic cation substitution strategy. • Crucial contributing factors correlating stability and Cs-adsorption efficiency. • New insights gaining the importance of considering thermodynamics. [ABSTRACT FROM AUTHOR]

Several parents and Sn-modified microporous and mesoporous catalysts were investigated in Prins cyclization of isoprenol with isovaleraldehyde for the production of the desired cis isomer of pyranol, Florol ® using dimethylcarbonate as a solvent in the temperature range of 30–60 °C. The highest selectivity to pyranols, 70% was obtained over microporous Sn-Y-80 (number denotes SiO 2 /Al 2 O 3 ratio) at 40 °C, while 64% selectivity to pyranols was obtained at 99% conversion over dealuminated H-Y-80 exhibiting mesoporosity and low Brønsted to Lewis acid ratio of 0.16. For microporous catalysts even higher BA/LA ratio and large amounts of Lewis acid sites were beneficial, as was the case for H-Y-30 modified with SnCl 2 , because the reaction occurred mainly on the outer surface of the catalyst. • Parent and Sn-modified microporous and mesoporous catalysts. • Prins cyclization of isoprenol with isovaleraldehyde for cis pyranol. • Highest selectivity to pyranols, 70%, over microporous Sn-Y-80. • Higher Bronsted to Lewis acid sites ratio beneficial. [ABSTRACT FROM AUTHOR]

Risks associated with carbonation are a key limitation to greater replacement levels of ordinary portland cement (OPC) by supplementary cementitious materials (SCMs). The addition of pozzolanic SCMs in OPC alters the hydrate assemblage by forming phases like calcium-(alumina)-silicate-hydrate (C-(A)-S-H). The objective of the present study was to elucidate how such changes in hydrate assemblage influence the chemical mechanisms of carbonation in a realistic OPC system. Here, we show that synthetic zeolite Y (faujasite) is a highly reactive pozzolan in OPC that reduces the calcium content of hydration products via prompt consumption of calcium hydroxide from the evolving phase assemblage prior to CO 2 exposure. Suppression of portlandite at moderate to high zeolite Y content led to a more damaging mechanism of carbonation by disrupting the formation of a passivating carbonate layer. Without this layer, carbonation depth and CO 2 uptake are increased. Binders containing 12–18% zeolite Y by volume consumed all the calcium hydroxide from OPC during hydration and reduced the Ca/(Si+Al) ratio of the amorphous products to near 0.67. In these cases, higher carbonation depths were observed after exposure to ambient air with decalcification of C-(A)-S-H as the main source of CO 2 buffering. Binders with either 0% or 4% zeolite Y contained calcium hydroxide in the hydrated microstructure, had higher Ca/(Si+Al) ratios, and formed a calcite-rich passivation layer that halted deep carbonation. Although the carbonated layer in the samples with 12% and 18% zeolite Y contained 70% and 76% less calcite than the OPC respectively, their higher carbonation depths resulted in total CO 2 uptakes that were 12x greater than the OPC sample. Passivation layer formation in samples with calcium hydroxide explains this finding and was further supported by thermodynamic modeling. High Si/Al zeolite additives to OPC should be balanced with the calcium content for optimal carbonation resistance. [Display omitted] • Portland cement is chemically modified by Synthetic Zeolite Y additions. • Synthetic Zeolite Y reacts promptly as a pozzolan to consume calcium hydroxide. • Calcium hydroxide is required to form a passivating carbonation layer. • The Ca/(Si+Al) ratio of hydrates influences the carbonation mechanisms. • Synthetic Zeolite Y indirectly affected CO 2 uptake in portland cement. [ABSTRACT FROM AUTHOR]

We studied the synthesis variables of the faujasite using natural clinker of the Cotopaxi volcano, and allophane (allofanite) from the province of Santo Domingo de los Tsachilas as raw materials, as well as their physicochemical properties and their influence on the catalytic efficiency for Ecuadorian oil and asphalt. The synthesized materials were subjected to laboratory tests, like thermogravimetric characterization, BET area, FTIR, chemisorption and AFM. Tests of catalytic activity in crude oil and asphalt with different °API and percentage of Sulfur showed ranges of optimal efficiency. These ranges contributed to obtain a logistic regression model with min. 90% accuracy, which was entered into a confusion matrix. This function can be optimized in the intervals of each of the variables of any refinery. It is concluded that the logistic regression model for catalytic efficiency is sensitive to changes in the amount of faujasite and allophane (allofanite) in the catalytic cracking process. In the same way, a fundamental dependence of the surface area (BET) was found, which for the case of allophane is formed in contribution of each of the nanopores whose size is in the order of 3 to 5 nm, while the faujasite has nanopore sizes from 17 to 35 nm.

This study examines a selective removal of Al metal from Al-Beta (BEA), Al-Faujasite (FAU, type Y) and Al-Mordenite (MOR) whose frameworks have high and close Si/Al ratios ≥ 30. Dealumination was performed using acid leaching (nitric acid, 13 M) solution at 100 °C for 20 h. Unlike Al-BEA, Al-FAU and Al-MOR were hardly dealuminated for their ultra-stable structure. Solid-state incorporation (SSI) method was applied to incorporate Lewis acidic Sn metal in dealuminated zeolitic frameworks. Newly formed zeolites have numerous vacant tetrahedral sites with a siliceous-rich framework. These zeolites were characterized by powder XRD, elemental analysis, N2 sorption, DRIFT and 27Al MAS NMR spectroscopies. Meerwein–Ponndorf–Verley (MPV) was selected as a reaction to assess the catalytic performance of prepared zeolites. While SSI-Sn-BEA exhibited superior catalytic activity for the presence of Lewis acid-Sn, FAU and MOR showed less catalytic activity due to their confined structural effects, presence of silanol nest and inadequate Sn incorporation. [ABSTRACT FROM AUTHOR]

Ionic exchange and isomorphic substitution were used for the synthesis and modification of faujasite (zeolite and silicalite Y) catalysts. These two methods were used to synthesize 1 wt% extra-framework and framework gallium modified faujasite zeolites respectively, with a Si/M ratio of 2.6, where M = Al and/or Ga. For the silicalite catalyst, 3.5 wt% of Ga was used to maintain the Si/Ga ratio. A series of BaY, Ga-BaY(IS) and Ga-BaY(Sil) were prepared by isomorphic substitution, where (IS) and (Sil) represent Isomorphic Substitution and Silicalite respectively. Ga-BaY(IE) and BaGa-NaY(IE), were prepared by ionic exchange (IE) using the synthesised BaY and a commercial NaY for the latter. For all the prepared catalysts, barium was kept constant at about 4.2 wt% except for BaGa-NaY(IE), where Ba was 1.4 wt%. For the sodium containing catalysts, Na was 10.3 wt%. Pyridine IR and chemisorption techniques showed that the catalysts prepared had more Lewis acid sites compared to Brønsted acid sites. The Na containing zeolite had the highest total acidity compared to those containing only Ba. Aluminium free silicalite contained the least total acidity, which is consistent with previous studies. Catalytic data at iso-conversion (7 ± 1%) showed that the Ba incorporated by ionic exchange zeolites and the silicalite were more selective to octenes (36 and 33% respectively) and less selective to COx (35 and 33% respectively) compared to the isomorphically substituted Ba catalysts. Selectivity to cracked products was reduced when aluminium, responsible for the strong Brønsted acid sites, was eliminated from the synthesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evidence for C C protonation as prevailing mechanism for alkane cracking. • Identification of a new concerted reaction pathway for propane cracking. • Intrinsic barriers for propane cracking are nearly constant with pore size variation. • CCSD(T) quality potential energy surfaces indispensable for mechanism discrimination. A hybrid QM:QM method (MP2:(PBE+D2) + ΔCCSD(T)) is employed that reaches chemical accuracy (±4 kJ mol−1) for periodic systems. Three mechanisms are considered and evidence is produced that cracking proceeds via protonation of a C C bond at the Brønsted acid site. For H-FER, H-MFI, and H-CHA, the deviations between predictions (uncertainty ± 4 kJ mol−1) and experiment (error ± 5 kJ mol−1) are between −3 and +8 kJ mol−1. The predicted apparent enthalpy barriers for H-FER, H-MFI, H-CHA, and H-FAU at 650 K are 153, 153, 160, and 182 kJ mol−1, respectively. Their variation with the pore size is dominated by the adsorption enthalpies (−55, −47, −40, and −29 kJ mol−1, respectively), whereas the intrinsic enthalpy barriers vary within a narrow range of 10 kJ mol−1 only. Routine PBE+D2 calculations show large errors, −16 to −20 and −40 to −60 kJ mol−1 for adsorption enthalpies and enthalpy barriers, respectively. [ABSTRACT FROM AUTHOR]

• Faujasite zeolites are active in the esterification of 5-hydroxymethylfurfural (5-HMF) to 5-acetoxymethylfurfural (AcMF). • The Si/Al ratio influences the textural and acid properties and also modify the catalytic performance in the reaction. • The maximum 5-HMF conversion of 87.28% was achieved using the zeolite with Si/Al = 5. We present this study on FAU-type zeolites were prepared varying the Si/Al ratio (4, 5 and 6) and crystallization time (4, 6 and 8 h) to produce a highly pure and homogeneous material with enhanced surface area values. Bimetallic Pd-Ru and Pt-Ru (0.5 wt.% of each metal) were impregnated onto the zeolites matrix by the incipient wetness impregnation method. The materials were characterized by X-ray diffraction (XRD), nitrogen physisorption, Fourier Transform Infrared spectroscopy (FT-IR), Scattering Electronic Microscopy (SEM), Scattering and Transmission Microscopy (STEM), temperature-programmed desorption (TPD), temperature-programmed desorption (TPR) and Inductively Couples Plasma- Mass Spectrometer (ICP-MS). Results indicated that using lower Si/Al ratios favored the catalytic activity. Also, the longest crystallization time had a positive effect on surface area, homogeneous particle size distribution and crystallinity. The catalytic performance in the esterification of 5-hydroxymethylfurfural (5-HMF) to produce 5-acetoxymethylfurfural (AcMF) was investigated. The maximum 5-HMF conversion of 87.28 % was achieved using pure zeolite with relation Si/Al = 5, and 8 h of crystallization. Pd-Ru supported onto same zeolite showed a conversion of 84.22 %. The highest selectivity towards AcMF of 71.29 % with pure zeolite Si/Al = 5 and 8 h of crystallization was achieved, followed by Pd-Ru/FAU with Si/Al = 5 and 8 h of crystallization, achieving 60.42 %. Finally, results shown that the interaction between the properties of zeolitic support and the metallic species, specifically Pd, had a positive effect in the catalytic process the pristine zeolite showed improved catalytic characteristics related to its acid strength. [ABSTRACT FROM AUTHOR]

The aim of this research is to illustrate the feasibility of transforming a byproduct of coal combustion process (fly ash) into a highly crystalline zeolite with enhanced ion exchange capacity and molecular sieving ability that can be used in various phase separation applications. The main crystalline phases present were: α‐quartz, Mullite, Hematite, Magnetite and Lime. The hydrothermal synthesis process resulted in the formation of a Na‐A in low alkalinity, and Na‐X (Na88Al88Si104O384 (H2O)172.1) in higher alkalinity – classified as FAU (Faujasite). Physisorption analysis using BET method revealed the presence of micropores. Cation exchange capacity increased, as high as 374 meq/g, by increasing the crystallization time. Highly ordered pore structure, enhanced specific surface area and the presence of a negative charge in the framework of Na‐X zeolite (FAU) make it a strong adsorbent and an effective molecular sieve with high shape/size selectivity for various applications, including petroleum refinery catalytic cracking units. [ABSTRACT FROM AUTHOR]

Faujasite zeolite was synthesized on the basis of the native zeolite of Nakhchivan, and its physicochemical properties were studied. The zeolitic tuffs of Nakhchivan (Kyukyuchaiskoe field) served as the native sample. It was determined that faujasite exists under a wide range of conditions; the optimal conditions of its hydrothermal synthesis were found to be temperature 100 – 200°C, thermal solution concentration 10 – 15% Ca(OH)2, and process time 50 h. [ABSTRACT FROM AUTHOR]