Zeolite Y Research Articles

Characterization of ion-exchanged zeolites with lithium for Pressure Swing Adsorption (PSA) applications

The method used for the Ion Exchange process to determine the characteristics of the zeolite is refluxing the zeolite using a 4 M LiCl solution for 36 hours at a temperature of 72℃ and calcined at a temperature of 400℃ for 10 hours. XRF characterization results showed natural zeolite Lampung had moderate Si/Al levels with 8.97 and 8.79 for those given lithium, while zeolite 13X had low Si/Al levels with 4.31 and 3.77 for those given lithium. The XRD results show that Lampung's natural zeolite is clinoptilolite and 13X zeolite is NaX. The results of the adsorption test using the PSA tool, namely for natural zeolite Lampung, the highest oxygen value was 21.3% and that was given lithium at 21.2% for the single bed and double bed types. For zeolite 13X, the highest oxygen value was 22% and that given lithium was 24% for the single bed type, and for the double bed type the highest oxygen value was 21.8% and those given lithium were 24.9%.

Assessment of the Catalytic Performances of Nanocomposites Materials Based on 13X Zeolite, Calcium Oxide and Metal Zinc Particles in the Residual Biomass Pyrolysis Process.

Nanocomposites based on 13X zeolite (13XZ), calcium oxide (CaO) and metal zinc particles (Zn) were prepared. The resulting nanocomposites were characterized by different techniques. Then, a comparative study on catalytic and noncatalytic pyrolysis of biomass waste was performed to establish the influence of nanocomposites used as catalysts on the yields and characteristics of liquid and solid products. Residual rapeseed biomass (RRB) was employed for pyrolysis experiments and a fixed bed reactor was used. By introducing CaO and metal zinc particles into 13X zeolite mass, the surface area (SBET) of nanocomposites was reduced, and this decrease is due to the introduction of nano-calcium carbonate and nano-zinc particles, which occupied an important space into zeolite structure. By adding CaO to 13XZ, the pore structure was changed and there was a decrease in the micropores volume. The analysis of the pore area distribution showed a hierarchical pore structure for nanocomposites. The elements composition showed that the main elements contained in nanocomposites are Si, Al, Ca and Zn, confirming the preservation of the zeolite structure. Using these nanocomposites as catalysts in pyrolysis process, the residual biomass could be valorized, producing bio-oil and biochar for the management and sustainability of this low-value waste.

Solid Fe Resources Separated from Rolling Oil Sludge for CO Oxidation.

The efficient recycling of valuable resources from rolling oil sludge (ROS) to gain new uses remains a formidable challenge. In this study, we reported the recycling of solid Fe resources from ROS by a catalytic hydrogenation technique and its catalytic performance for CO oxidation. The solid Fe resources, after calcination in air (Fe2O3-H), exhibited comparable activity to those prepared by the calcinations of ferric nitrate (Fe2O3-C), suggesting that the solid resources have excellent recycling value when used as raw materials for CO oxidation catalyst preparation. Further studies to improve the catalytic performance by supporting the materials on high surface area 13X zeolite and by pretreating the materials with CO atmosphere, showed that the CO pretreatment greatly improved the CO oxidation activity and the best activity was achieved on the 20 wt.%Fe2O3-H/13X sample with complete CO conversion at 250 °C. CO pretreatment could produce more oxygen vacancies, facilitating O2 activation, and thus accelerate the CO oxidation reaction rate. The excellent reducibility and sufficient O2 adsorption amount were also favorable for its performance. The recycling of solid Fe resources from ROS is quite promising for CO oxidation applications.

Possibilities of Using Zeolites Synthesized from Fly Ash in Adsorption Chillers

Adsorption chillers produce cold energy, using heat instead of electricity, thus reducing electrical energy consumption. A major industrial waste, fly ash, can be converted to zeolite and used in adsorption chillers as an adsorbent. In this research, three different types of zeolites were synthesised from fly ash via a hydrothermal reaction in an alkaline solution (NaOH). The obtained samples (Na-A zeolites) were modified with K2CO3 to increase the water adsorption capacity of these samples. Phase and morphology analyses shows that desired zeolites formed properly but other crystalline phases also exist along with nonporous amorphous phases. The determined specific surface areas for Na-A zeolite (12 h) and Na-A zeolite (24 h) are 45 m2/g and 185 m2/g respectively, while the specific surface area for synthesized 13X zeolite is almost negligible. Water-isotherm for each of these samples was measured. Considering the application of adsorption chillers, average adsorption capacity was very low, 1.73% and 1.27%, respectively, for the two most probable operating conditions for synthesized 13X zeolite, whereas no water was available for the evaporation from Na-A zeolite (12 h) and Na-A zeolite (24 h). This analysis implies that among the synthesized materials only 13X zeolite has a potential as an adsorber in sorption chillers.

Thermal stabilization of extraframework Cs+ in zeolite 13X

Given the reversible nature of ion exchange, Cs+-exchanged zeolite 13X was thermally treated to safely retain extraframework Cs+. By thermal gravimetric-differential scanning calorimeter (TG-DSC) analysis, both endothermic and exothermic peaks, indicative of phase transitions, gradually shifted to higher temperatures at the higher surface loading of Cs+ (i.e., [Cs+]0/[NaX]0), indicating that extraframework Cs+ stabilized the zeolite framework. By thermal treatment at ≤ 800 °C, X-ray diffraction (XRD) showed that the samples with [Cs+]0/[NaX]0 = 0.5 and 5 mmol/g maintained the faujasite framework. Nonetheless, as indicated by Cs LIII-edge X-ray absorption spectroscopy (XAS) analysis, the Cs-Si(Al) interaction at ∼4.37 Å became stronger relative to the Cs-O interaction at ∼2.98 Å with the increasing treatment temperature, indicating that thermally induced dehydration caused extraframework Cs+ to migrate from spacious sites to confined (less exchangeable) sites. Thus, the redistribution of extraframework Cs+ among exchange sites was responsible for the lower leaching with the increasing treatment temperature. On the other hand, by thermal treatment at ≥ 900 °C, bulk-phase analyses such as XRD, scanning electron microscopy, and surface area measurement showed that the zeolite framework completely broke down to form non-porous phases. The XAS analysis further indicated that Cs+ was mainly incorporated into amorphous phases at 900 °C and pollucite at ≥ 1,000 °C. This was consistent with the markedly low Cs+ leaching for the ≥ 900 °C-treated samples. Since pollucite can provide the greatest retainability of Cs+, the thermal treatment leading to its formation is recommended before storing Cs+-exchanged zeolite 13X at nuclear waste repositories.

Superhydrophobic Surface-modified zeolite to regulate the migration of nonadsorbed liquid water in an Open-loop adsorption heat pump

Superhydrophobic surface-modified zeolite 13X has been utilized to regulate nonadsorbed liquid water in an open-loop adsorption heat pump system for steam generation. The zeolite is modified by vinyltrimethoxysilane to achieve a superhydrophobic surface effect. The measured static water contact angles of the modified zeolite reached 152°. Thermogravimetric analysis results show good thermal stability at temperatures less than 400 °C. The measured adsorption capacity and adsorption heat slightly decrease for the modified zeolite. During the regeneration process dry air at 140 °C drives wet zeolite to remove adsorbed and free water. Then generation process proceeds for steam generation at a maximum of 220 °C from water at 72 °C. The mass and temperature of the steam generated from the modified zeolite bed increase compared with those of unmodified zeolite 13X. This is because of the apparent decrease in the total amount of free water, which allows the released adsorption heat to be transferred to passing water quickly for steam generation. Energy consumption during regeneration simultaneously reduces. System indicators such as the coefficient of performance for heating (COPh), specific heating power (SHP), gross temperature lift (GTL) and exergy efficiency (ηe) increase with increasing hydrophobicity of zeolite particles. The surface hydrophobicity decreases the affinity of zeolite for useless free water which cannot contribute to increasing the overall adsorption heat.

Metal-organic framework derived ZnO/porous carbon − 13X zeolite composite modified with chitosan and silver nanoparticles as versatile antibacterial agent

• ZnO-porous carbon has been successfully synthesized by the carbonization of Zn-MOF. • ZnO-Metal-Organic Framework derived Carbon (Zn-MOFC) has good antibacterial activity. • The antibacterial activity of ZnO-MOFC increased with the addition of chitosan/AgNP. • Variation of AgNP loading affects the antibacterial activity. In this work, metal-organic framework consists of zinc, and terephthalic acid (H 2 BDC) as linkers (Zn-MOF) was utilized as a starting material to prepare a composite for antibacterial agents. First, the as-synthesized Zn-MOF was carbonized, leaving porous ZnO-metal-organic framework derived carbon (ZnO-MOFC), then composited with zeolite 13X to enhance its polarity. Second, the ZnO-MOFC/13X composite was decorated with chitosan/Ag nanoparticles (ZnO-MOFC/13X/Chi/AgNP) to promote its antibacterial activity. The characterizations using XRD, FTIR, SEM, TGA and BET N 2 sorption analysis provide the physicochemical properties of each component and their interaction in the composite. Based on TGA, Zn-MOF has changed into ZnO-MOFC at 600 °C, while the BET reveals that ZnO-MOFC is nanoporous (ø = 2.668 nm), and 13X is microporous (ø = 2.317 nm) materials with large surface areas. The morphology of ZnO-MOFC depicts layerd structure with reguler pore and 13X morphology shows octahedral cuboid structure. The chitosan assisted the dispersion of AgNP on the surface of the composite. The antibacterial properties were tested using the agar diffusion method on S. aureus and E. coli bacteria. The results show that the ZnO-MOFC/13X/Chi/AgNP composite has high antibacterial activity based on the average diameter of the inhibition zone of 14.5 mm and 11.5 mm on both S. aureus and E. coli bacteria, respectively. The results are comparable to erythromycin and vancomycin as antibiotics for E. coli and S. aureus giving the inhibition zone of 11.06 mm and 11.93 mm, respectively.

Kinetics and Activation Complex Thermodynamic Study of the Acidity Removal of Oleic Acid via Esterification Reaction on Commercial 13X Zeolite

The study involved the removal of acidity from free fatty acid via the esterification reaction of oleic acid with ethanol. The reaction was done in a batch reactor using commercial 13X zeolite as a catalyst. The effects of temperatures (40 to 70 °C) and reaction time (up to 120 minutes) were studied using 6:1 mole ratio of pure ethanol to oleic acid and 5 wt. % of the catalyst. The results showed that acid removed increased with increasing temperature and reaction time. Also, the acidity removal rises sharply during the first reaction period and then changes slightly afterward. The highest acidity removal value was 67 % recorded at 110 minutes and 70 °C. An apparent homogeneous reversible reaction kinetic model has been proposed and solved with the experimentally obtained kinetics data to evaluate reaction rate constants versus temperature, pre-exponential factors, and activation energy values for the forward and the backward esterification reactions. The activation energies were 34.863 kJ/mol for the forward reaction and 29.731 kJ/mol for the backward reaction. The thermodynamics of the activation step of the forward and reverse reactions was studied based on the hypothesis of forming a complex material that decomposes into a product. The activation steps were studied using Eyring bimolecular collision theory approach, and both ΔH* and ΔS* were determined for forward and backward esterification reactions. The enthalpies of activation were 32.141 kJ/mol and 27.080 kJ/mol for the forward reaction and the backward reaction, and the entropies of activation were - 193.7 and -212.7 J/mol. K for the forward reaction and the backward reaction, respectively.

Sequential separation of cobalt and lithium by sorption: Sorbent set selection

The sorption of cobalt and lithium was studied using low-cost natural (dolomite, diatomite, barite), commercial (13X zeolites and clinoptilolite) and synthesized (mesoporous carbon and NaY zeolite) sorbents. The pH of the medium was a key factor in the sorption process which can be modified due to the active chemical groups on the surface of the sorbents. Therefore, the doses of each sorbent were selected to avoid cobalt precipitation, working at pH below 8. Sorption with monometallic solution was carried out to select the best set of sorbents for subsequent selective separation. Only mesoporous activated carbon and dolomite allow to achieve significant cobalt removal, 85% and 65% respectively, with negligible lithium removal. 13X zeolite (high surface area and low Si/Al molar ratio) removed both metals without selectivity. Therefore, dolomite and mesoporous activated carbon were selected for the selective separation of cobalt, as they allow to achieve an adsorbed Co2+/Li+ weight ratio of 16 and 4, respectively. 13X was selected to remove lithium once cobalt was removed from the solution. The best separation was carried out by a two-sequential sorption stage, using dolomite in a first stage to separate cobalt and 13X zeolite in a second stage to remove lithium, reaching an almost complete removal of both metals. The pH control for working with high doses of dolomite was achieved by means of a solid phase pH buffer (solid buffer) composed by a mixture of the dolomite itself and non-activated mesoporous carbon (without sorption capacity) in a 1:4 weight ratio. This solid buffer allowed the pH of the medium to be controlled to around 6.5.

Experimental study on particulate matter removal using packed-bed dielectric barrier discharge plasma reactor

In this study, a packed-bed dielectric barrier discharge (DBD) reactor was developed for particulate matter (PM) removal. The effects of operating conditions such as the packing materials, applied power, and discharging gap were systematically investigated. The results revealed that Zeolite 13X exhibited the highest PM removal efficiency based on its high electrostatic adsorption capacity. A narrow discharge gap (2.4 mm) and increased power density resulted in an enhancement of the PM removal efficiency in the system. Further, these operating conditions increased the electric field strength, which was proportional to the current density in the system. The energy yield decreased with an increase in the specific energy input into the packed-bed DBD reactor. Among the tested operating parameters, maintaining a narrow discharging gap was determined to be the most important for achieving high energy efficiency and PM removal in the system. Moreover, an air cleaning procedure was applied for the regeneration of the packing materials, resulting in a high recovery rate of over 80%.

Anion-pillared porous materials with suitable pore size for the efficient discrimination of cyclohexene from cyclohexane

The separation of medium and high carbon number linear and cyclic olefins and alkanes is a great challenge in the petrochemical industry, due to the closer molecular structure and physical properties with increased carbon chains. The adsorptive separation offers an alternative to conventional energy-intensive distillations, but its separation efficiency is limited by the low adsorption capacity and high energy penalty for regeneration. Herein, we employed anion-pillared porous materials (SIFSIX-1-Cu, SIFSIX-2-Cu-I, and ZU-61) that addressed the separation challenge of cyclohexene and cyclohexane. ZU-61 with suitable pore size and high-density anions exhibits excellent cyclohexene uptake capacity (6.11 mmol·g−1), 3 times the common zeolite 13X (2.11 mmol·g−1) as well as the high separation selectivity. Combined with single-crystal diffraction experiment and simulation studies, the results demonstrate the dominant role of anions in discriminating different kinds of H atoms (CH and CH), which enables the efficient discrimination towards cyclohexene from cyclohexane. Moreover, benefiting from the moderate strength enabled by the anions, the cyclohexene saturated ZU-61 could be easily regenerated under 80 °C, the value is lower than that of zeolite 13X (200 °C). This work demonstrates the superiority of anions in recognizing the olefins and paraffins with medium and high carbon number and offers guidance to the related challenging separations.

Degradation of desiccants in temperature swing adsorption processes: The temperature dependent degradation of zeolites 4A, 13X and silica gels

Many raw and treated natural gas streams are dehydrated using temperature swing adsorption with molecular sieves. These systems are designed to operate for years at a time, with adsorbent materials subjected to thousands of cycles. Despite all the efforts in adsorption research, there is very little open literature on the degradation of these materials over prolonged cycling. In this work, we investigated the degradation rates of zeolite 4A, zeolite 13X and three different pore size silica gels using a rapid cycling thermal swing adsorption apparatus. Zeolite 13X was found to lose 31 %, 51 % and 68 % of its adsorption capacity after 5,000 temperature swing adsorption cycles at regeneration temperatures of T = 150, 200 and 250 ℃, respectively. It is noted that all tested materials had a higher capacity loss at a higher regeneration temperature. At a regeneration temperature of T = 250 ℃ zeolite 4A, 22 Å pore size silica, 30 Å pore size silica and 60 Å pore size silica were observed to lose 6 %, 52 %, 33 % and 19 % adsorption capacity, respectively, after 5,000 temperature swing adsorption cycles. Interestingly, all five materials showed lower degradation rates when water was included in the regenerating gas stream, indicating that a wet gas regeneration can mitigate the degradation of the desiccants.

Heteroatom Manipulation of Zeolite Crystallization: Stabilizing Zn-FAU against Interzeolite Transformation.

The preparation of metastable zeolites is often restricted to a limited range of synthesis conditions, which is exemplified in commercial syntheses lacking organics to stabilize the crystal structure. In the absence of an organic structure-directing agent, interzeolite transformation is a common phenomenon that can lead to undesirable products or impurities. Many studies have investigated the substitution of Si and Al in zeolite frameworks with alternative elements (heteroatoms) as a means of tailoring the properties of zeolites; however, relatively few studies have systematically explored the impact of heteroatoms on interzeolite transformations and their concomitant effects on zeolite crystallization. In this study, we examine methods to prepare isostructures of faujasite (FAU), which is one of the most commercially relevant zeolites and also a thermodynamically metastable structure. A survey of multivalent elements revealed that zinc is capable of stabilizing FAU at high temperatures and inhibiting its frequent transformation to zeolite gismondine (GIS). Using combined experimental and computational studies, we show that zinc alters the chemical nature of growth mixtures by sequestering silicates. Zinc heteroatoms incorporate in the FAU framework with a loading-dependent coordination. Our collective findings provide an improved understanding of driving forces for the FAU-to-GIS interzeolite transformation where we observe that heteroatoms (e.g., zinc) can stabilize zeolite FAU over a broad range of synthesis conditions. Given the growing interest in heteroatom-substituted zeolites, this approach to preparing zinc-containing FAU may prove applicable to a broader range of zeolite structures.

Investigation of open-type 1 kW-scale thermochemical heat storage system with zeolite 13X for power-to-heat applications

Investigation of open-type 1 kW-scale thermochemical heat storage system with zeolite 13X for power-to-heat applications

Investigation of adsorption properties of modified DD kaolins to microporous material type 13X zeolite in treatment of textile industry effluent: experiments and theoretical approach

Investigation of adsorption properties of modified DD kaolins to microporous material type 13X zeolite in treatment of textile industry effluent: experiments and theoretical approach

Adsorption equilibria and kinetics of ethane and ethylene on zeolite 13X pellets

To establish a design basis of the cyclic adsorption process for ethylene purification, the adsorption equilibria and kinetics of ethane and ethylene on zeolite 13X pellets were measured by a volumetric method at 303–343 K under pressure up to 600 kPa. The Sips model showed better prediction of ethane in the full pressure range, but the dual-site Langmuir (DSL) model was more accurate for ethylene in the pressure range of <250 kPa. The strong cation-π interaction between ethylene and Na+ in zeolite 13X led to higher adsorption capacity and affinity than those of ethane. It resulted in a greater isosteric heat of adsorption (Qst) of ethylene at a low loading amount, while Qst variance in ethane was almost linearly increased with a dominant lateral interaction. At 303 K, the adsorption amount and affinity of ethylene at <5 kPa were slightly greater than those of propane but lower than those of propylene. However, the adsorption isotherms of ethane/ethylene became higher than those of propane/propylene above a certain pressure. The experimental uptake curves of ethane and ethylene were well predicted by a non-isothermal sorption model, considering the adsorption thermal effects. The difference in the apparent reciprocal diffusional time constant (Dapp/R2) between ethane and ethylene was mainly attributed to the thermal effects by the heat of adsorption. The comparison of Dapp/R2 values between zeolite 13X pellet and powder indicated that macropore diffusional resistance also contributed to the adsorption kinetics.

Efficient Bayesian Optimization of Industrial-Scale Pressure-Vacuum Swing Adsorption Processes for CO2 Capture

The design of adsorption systems for separation of CO2/N2 in carbon capture applications is notoriously challenging because it requires constrained multiobjective optimization to determine appropriate combinations of a moderately large number of system operating parameters. The status quo in the literature is to use the nondominated sorting genetic algorithm II (NSGA-II) to solve the design problem. This approach requires 1000s of time-consuming process simulations to find the Pareto front of the problem, meaning it can take days of computational time to obtain a solution. As an alternative approach, we have employed a Bayesian optimization algorithm, the Thompson sampling efficient multiobjective optimization (TSEMO). For constrained productivity/energy usage optimization, we find that the TSEMO algorithm is able to find an essentially identical solution to the design problem as that found using NSGA-II, while requiring 14 times less computational time. We have used the TSEMO algorithm to design a postcombustion carbon capture system for a 1000 MW coal fired power plant using two adsorbent materials, zeolite 13X and ZIF-36-FRL. Although ZIF-36-FRL showed promising process-scale performance in previous studies, we find that the industrial-scale performance is inferior to the benchmark zeolite 13X, requiring a 21% greater cost per tonne of CO2 captured. Finally, we have also tested the performance of the Bayesian design framework when coupled with a data-driven machine learning process modeling framework. In this instance, we find that the incumbent NSGA-II offers better computational performance than the Bayesian approach by a factor of 3.

Finite Element Modeling of Atmospheric Water Extraction by Way of Highly Porous Adsorbents: A Roadmap for Solver Construction with Model Factor Sensitivity Screening.

A finite element model (FEM) is developed for use in determining adsorption system performance. The model is intended to guide novel adsorbent structure fabrication and atmospheric water harvesting device design. We survey a variety of governing equation factor inputs and relationships which describe the interaction between zeolite 13X and water vapor. Mitigation strategies are discussed for detecting the breakdown of continuum modeling at the microscale wherein Knudsen effects and other anomalous behaviors emerge. Characterization of model factor inputs and the techniques for their sourcing is described with consideration to the construction of a high throughput multiscale shape optimized computational schema. Four objectives guided the development of this model. Our first objective was to understand the implementation of adsorption system equations and the assumptions that could prevent reliable predictability. The second objective was to assemble, reduce, and analyze model constants and approximations that express FEM coefficient calculations as physical forces and thermodynamic properties which could be derived from other computational methods. Third, we analyzed factor sensitivity of model inputs by way of a 2k factorial screening to determine which inputs are driving the physics of water harvesting adsorption systems. The fourth objective was to design the FEM solver for integration into a multiscale high throughput topologically optimized schema. The main finding of the solver factor screening indicates that total micropore volume has the highest value characteristics in relation to water uptake.

Natural zeolites as host matrices for the development of low-cost and stable thermochemical energy storage materials

Advanced thermal energy storage technologies based on physical adsorption and chemical reactions of thermochemical materials (TCMs) are capable of storing large shares of renewable energy with high energy density. Further research and development is required to improve the performance and reduce the cost of these materials. A promising approach to developing low-cost TCM is to use natural zeolite adsorbents as host matrices in the development of salt-loaded composite TCM. In this study, the thermal properties of various species of low-cost zeolites from natural deposits across Canada were investigated. Two high purity crystal (HPC) zeolites from the Trans Canada (TC-HPC) and Juniper Creek (J-HPC) deposits in British Columbia were determined to have the highest water uptake capacity (0.145 g/g and 0.113 g/g, respectively) and enthalpy of adsorption (408 J/g and 304 J/g, respectively). Despite having approximately half of the water uptake capacity and adsorption enthalpy of the commercially available synthetic zeolite 13X, the cost of thermal energy storage ($CAD/kWhth) of the natural zeolites was determined to be 72–79% lower than that of the synthetic zeolite. Repeated adsorption and desorption experiments demonstrated the hydrothermal stability of the HPC zeolites over multiple charge and discharge cycles. Overall, the experimental results and cost analysis indicate that Canadian HPC zeolites are promising alternatives to synthetic zeolites in the pursuit of low-cost and stable TCM.

Numerical Investigation of the Adsorption Process of Zeolite/Water in a Thermochemical Reactor for Seasonal Heat Storage

Zeolite 13X molecular sieve with high sorption capacity and significant sorption rate has been considered a promising candidate for seasonal heat storage. In this study, a code is developed to simulate the adsorption process between zeolite and water in all ranges of partial pressures, temperatures, and sorbate loadings. The results from the proposed code were compared with experiments and good agreement was observed. After validation, the developed model was used to study the effective parameters involved in the adsorption process of binder-free Zeolite 13X. A parametric study considering various temperatures and water content in the inflow air was conducted and the influence of different factors on the outlet temperature and adsorption enthalpy has been studied. This parametric study gives a good insight into the measures which can be taken for achieving the desired released energy or having the outlet temperature in the preferred range. The simulations have been conducted in a variety of temperature ranges provided during the desorption process, the humidity amount, and the mass flow rate of the incoming air. The relative influence of each parameter in the specified ranges is presented. The results have demonstrated the direct relationship of the partial pressure of water vapor and the desorption temperature with the adsorbed water amount and adsorption enthalpy while changing the mass flow rate mostly influences the discharging time.