Zeolite Y Research Articles

Equilibrium Behavior of CO2 Adsorption from Biogas onto Zeolites

Biogas is one of the types of renewable energy that has a major gas content of CH4 and CO2. One of the methods for upgrading biogas is adsorption. The principle of adsorption’s work is to deliver biogas into a column with containing adsorbent, so that a CO2 gas is bound to zeolite, causing the CH4 to increase in the result product. The biogas used in research came from a cow feces that was dumped into a 10bar pressure vessel. Adsorbent used zeolite 13X that was activated. The biogas tube has a height 0.3 m and diameter 3 cm. It was made of stainless steel and there was a cartridge heater inside. Biogas was channeled into adsorbent column with pressure variations 0.8, 1.2, 1.6 and 2 bars and temperature variations 30, 50 and 100°C. The flow rate of biogas used 4 L/minute with a 4-minute data retrieval. Data retrieval was continuous, so that the composition of CO2 gas from beginning to end recorded on the Gas analyzer. The research aims to identify the balance of adsorption with variations in pressure and temperature by Langmuir equation which has been developed. The results show if the higher the pressure, then CO2 that was absorbed is inversely proportional to the temperature where the higher the temperature, the less CO2 was adsorbed. This research succeeded in getting the Langmuir constant, maximum amount adsorbed of CO2, and heat of adsorption.

Optically Unobtrusive Zeolite-Based Dry Electrodes for Wearable ECG Monitoring

Novel dry electrodes are increasingly evolving for monitoring electrocardiograms compared to the widely used <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ag/AgCl</i> (wet) electrodes as there is no skin preparation or wet gel needed. Many fabricated dry electrodes are however opaque, and the problem of skin irritation and rashes continue to pose a concern. In this paper, an optically unobtrusive dry electrode based on the iono-electric properties of zeolite is developed and proposed for continuous electrocardiogram (ECG) monitoring. An easily moldable composite of the sodium form of nano-porous zeolite and polydimethylsiloxane (PDMS) is reported for the first time. The electrical and bio-electrical characterizations are evaluated for 24 pairs of electrodes which were fabricated with two filler materials (Zeolite 4A and 13X), two filler concentrations (4 wt% and 12 wt%), three diameters (30 mm, 20 mm, and 10 mm), and differing thicknesses. High input impedance and high conductivity of the electrodes have proven the suitability for biosignal acquisition. ECG signals are acquired using each pair of electrodes. Results related to impedance, conductivity, and SNR measurements over a frequency range up to 10 kHz are presented. Among the 24 pairs, the results indicate that signal-to-noise ratio (SNR) for Zeolite 13X/PDMS- based filler with a concentration of 4 wt% and diameter of 30 mm has the highest SNR of 42.9 dB and conductivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.58 \mu \text{S}$ </tex-math></inline-formula> /mm. These electrodes are optically unobtrusive and easy to fabricate. Hence this process yields promising results for the next generation of wearable cardiovascular heart monitoring systems.

Discrepancy quantification between experimental and simulated data of CO2 adsorption isotherm using hierarchical Bayesian estimation

To quantitatively analyze the inconsistencies commonly observed between experimental and simulated adsorption isotherms, parameter estimation of adsorption isotherm models was conducted by hierarchical Bayesian estimation with parameter uncertainties being quantified as probability distributions. The estimation method was implemented using Markov Chain Monte Carlo (MCMC) to analyze multiple data sets obtained from different sources, including a publicly available database. To describe the discrepancies of experimental and simulated adsorption data, the simulation data was set as the reference to which experimental measurements were compared. We applied the proposed approach to analyze CO2 adsorption isotherms that are measured and simulated on zeolite 13X and MIL-101(Cr). In these case studies, the discrepancy of CO2 adsorption isotherm was successfully quantified between experimental measurements and predictions given by molecular simulations using Grand Canonical Monte Carlo (GCMC), where uncertainties were quantified as probability distributions. Furthermore, experimental data sets that agree well with the GCMC simulation have been identified, providing insights into experimental and measurement methods as well as choosing the right assumptions in the molecular simulation.

Conversion of Harmful Fly Ash Residue to Zeolites: Innovative Processes Focusing on Maximum Activation, Extraction, and Utilization of Aluminosilicate.

Reuse of the solid residue from coal fly ash alumina extraction (FAAE) by acid leaching is problematic. Conversion of this solid residue into aluminum-rich zeolite (13X) and silicon-rich zeolite (ZSM-5) was investigated in this research. The FAAE residue was activated by alkali roasting with Na2CO3 powder (110% mass fraction) at 890 °C for 60 min. Silicon and aluminum were mainly present as two mineral phases, Na2SiO3 and NaAlSiO4, respectively, in the product obtained after roasting. The roasted product was dissolved in water (liquid/solid ratio of 2) after 20 min at 100 °C. The water-leaching liquor was investigated for total conversion to aluminosilicate zeolites without external aluminum or silicon addition. Hydrothermal synthesis of aluminum-rich zeolite 13X was successful after fine tuning of the conditions, although the filtrate had an unusually high SiO2/Al2O3 molar ratio. Production of 13X consumed a large amount of aluminum, which increased the Si/Al ratio to a level suitable for synthesis of ZSM-5. The synthesis of ZSM-5 from the mother liquor of 13X was proved feasible. The FAAE residue was transformed into high-value zeolite products by nearly 100%. Additionally, the tail liquid of this process, mainly containing Na2CO3, was completely recycled. This process could be used to realize high-efficiency and high-value utilization of similar aluminosilicate solid wastes.

Thermodynamics analysis of multi-stage temperature swing adsorption cycle for dilute CO2 capture, enrichment and purification

Direct air capture is a carbon-negative technology that absorbs dilute carbon dioxide from the air directly, which requires a significant amount of energy and the construction of large-scale equipment. The main challenge for direct air carbon dioxide capture is the development of non-fossil energy sources for carbon dioxide compression and purification. In this work, a multi-stage adsorption system based on temperature swing adsorption with adsorption materials that can be driven by thermal energy is designed for direct air capture. The model of adsorption process is built on thermodynamic principles and conservation of mass, and the common tangent plane approach of adsorption is adopted at the end of each step calculation to validate the selected solution. Analysis of the process shows that, the CO2 purity in the storage bed can exceed 90% and the pressure can exceed 14 bar with zeolite 13X at a regeneration temperature of 368 K. Exploration of thermal performance has been investigated regarding specific energy and exergy efficiency of various regeneration temperatures. The influence of mass of adsorbent on the purity and specific energy has also been evaluated. Results show that the specific energy declines from 11.92 MJth/molCO2 to 8.73 MJth/molCO2, and the optimal exergy efficiency increases from 0.205 % to 0.238 % as the regeneration temperature grows from 368 K to 373 K. The values of adsorbent mass in the second and third beds for optimal purity and specific energy are calculated. It means that a thermally-powered carbon separation device can not only meet the requirements of direct air capture but also get the optimal purity of carbon dioxide or specific energy by altering the operation parameters.

Experimental Investigation of Adsorption and CO2/CH4Separation Properties of 13X and JLOX-500 Zeolites during the Purification of Liquefied Natural Gas

Efficient adsorbents are critical to the purification of liquefied natural gas (LNG) by the adsorption method. In this study, the physiochemical properties of JLOX-500 and 13X were examined. JLOX-500 with more Al content had a more compact unit cell, a larger surface area and pore volume, a smaller average pore size, and more microchannels on the surface than 13X. The separation performance of the two adsorbents was evaluated by the adsorption experiment. The CO2 adsorption capacity of JLOX-500 was higher than that of 13X, while the equilibrium and ideal selectivity and separation factor of CO2/CH4 were also larger for JLOX-500. Especially in dynamic adsorption, the CO2 adsorption capacities at 50 ppm of the gas mixture at the outlet were 3.46 and 1.64 mmol/g for JLOX-500 and 13X, respectively. The adsorption heats of CO2 and CH4 on JLOX-500 were 40.50 and 18.77 kJ/mol, whereas these values were 31.49 and 18.50 kJ/mol for 13X, respectively. A better separation performance for JLOX-500 was observed because of fewer binders and a lower Si/Al ratio (1.34). The Toth adsorption isotherm model described best the experimental data. According to the results of this study, JLOX-500 was a more efficient adsorbent used in purification for LNG production at high pressure with low CO2 concentration.

Experimental investigation of dehumidification and regeneration of zeolite coated energy exchanger

Zeolite desiccant particles are well known for their strong affinity to adsorb water vapor molecules; however, they require significant regeneration energy to be created. This paper presents an experimental study of the adsorption and regeneration processes of a monolayer zeolite for indoor dehumidification to the 13X zeolite beads with a 4 × 8 mesh bead size and a pore opening 10 A⁰ were used as this monolayer. An experimental investigation was conducted to determine the effects of the relative humidity, temperature, and air flow rate on the adsorption and regeneration processes. The results show the effectiveness of the monolayer coating method and the relative humidity significantly affects the adsorption process, and that the airflow rate surrounding and through the zeolite beads increases the adsorption and desorption of the water vapor molecules. In the absence of the meniscus radius formation due to the monolayer arrangement prevents external condensation. With an airflow rate of Re = 1773, the full adsorption process at a relative humidity of 99% was obtained within 37 min; meanwhile, the regeneration process proceeded at 100 °C within 66 min. The adsorption time was reduced by 27% and 43% as the Reynold number increases to 2586 and 3325, respectively. Likewise, the effectiveness of the regeneration time is decreased by 0.07% and 14% within the same Reynold number increases. Results obtained from this research can be used to guide the future development of polymer-coated energy exchangers.

Tribological performance of zeolite/sodium dodecylbenzenesulfonate hybrid water-based lubricants

Water-based lubricants are a low-cost and environmentally-friendly alternative to their oil-based counterparts. Developing novel water-based formulations with improved lubricity is the key to broadening their industrial applications. We report herein two new water-based hybrid lubricants that integrate sodium dodecylbenzene sulfonate (SDBS) with 4A and 13X zeolites respectively. Their tribological performance was assessed using a block-on-ring test. The addition of SDBS mitigated stick–slip motion, leading to the reduction of coefficient of friction (COF), but caused chemical erosion of the steel surface. The addition of zeolite into water led to an increase in COF due to the occurrence of three-body abrasion. The combination of SDBS and zeolite brought about unique and superior lubrication performance attributed to the synergetic interactions between them. The application of 4A + SDBS lubricant led to a 10% reduction in COF and a four-fold increase in material removal compared to water. The angular 4A particles augmented material removal in combination with the corrosive effect of SDBS. The use of 13X + SDBS lubricant, on the other hand, resulted in a 60% reduction in COF and a 94% decrease in wear comparing to water. This can be ascribed to the “lubricated micro-bearing” effect as a result of SDBS attachment on the rounded 13X particles.

Semiflow Microwave Heating Reactor with Resonator Moving Mechanism Applied to Zeolite Synthesis.

A semiflow microwave (MW) heating reactor similar to a flow reactor system was developed. Slurry raw materials in the reaction tube were heated continuously and cooled rapidly by moving a thin MW resonator instead of flowing slurry raw materials. From highly viscous mother slurries, Linde-type A (LTA) and faujasite (FAU)-type zeolite nanoparticles of small crystal grains were synthesized quickly. Results show that this heating system can synthesize hydroxy-sodalite (SOD)-type zeolite from coal fly ash particles including those larger than 50 μm. Numerical calculations using the COMSOL Multiphysics program revealed the thermal distribution of liquids of various viscosities using the semiflow MW heating reactor.

Acid Catalysis over Low-Silica Faujasite Zeolites

Low-silica faujasite (FAU) zeolites (with Si/Al ratio of ca. 1.2-1.8) sustain framework integrity and porosity upon moderate ion exchange (0.01 M NH4NO3 solution for 1 h at ambient temperature), which introduces two kinds of protons, distinctive in reactivity and coordination to the zeolite framework, within supercages (HSUP). Moderate ion exchange limited within supercages transpires while maintaining full occupancy of Na+ cations within associated sodalite cages; this in turn helps stabilize the framework of low-silica H-FAU zeolites. Protons located on site II (H3630) and site III (H3650) within supercages on low-silica FAU zeolites can be classified and enumerated by virtue of infrared spectroscopy, providing an opportunity to compare reactivities of these distinct protons for monomolecular protolytic reactions of propane. Protons on site II exhibit prominently higher reactivity for monomolecular propane dehydrogenation and cracking than protons on site III. Low-silica proton-form FAU zeolites (zeolite X) upon moderate ion exchange possess protons on site III that are unavailable on high-silica FAU zeolites (zeolite Y) and limit ion exchange within supercages, providing unprecedented high-temperature structural and chemical stability (>773 K) and enabling their application as solid-acid catalysts.

Towards understanding mesopore formation in zeolite Y crystals using alkaline additives via in situ small-angle X-ray scattering

The formation of micro/mesoporous zeolites by treating zeolite crystals with alkaline hydroxides has received a lot of interest, but fundamental understanding is still lacking. Here, we study the reactivity of a crystalline zeolitic material with various alkaline hydroxides, to close this knowledge gap. The use of ex situ and in situ small-angle X-ray scattering has allowed us to determine the reactivity of faujasite (FAU) type zeolite Y at different pH and Si/Al ratio (SAR), with a variety of different organic ammonium hydroxides. Supplemented with ex situ XRD and BET isotherm measurements, we show that the pH of the starting mixture and SAR of the zeolite significantly influence the stability of the microporous structure and the extent of formation of mesoporous material.

Quantitative Microscale Dynamic Column Breakthrough Apparatus for Measurement of Unary and Binary Adsorption Equilibria on Milligram Quantities of Adsorbents

A microscale dynamic column breakthrough (μDCB) apparatus with the ability to measure unary and binary adsorption equilibria on a milligram-scale quantity of adsorbent is described. The μDCB is a low-cost system that can be constructed through minor modifications of a commercial gas chromatograph and uses a thermal conductivity detector. The small scale of the apparatus allows for the rapid collection of dynamic column breakthrough experiments. The mass balances for adsorption and desorption experiments were derived along with a description of the blank. The microscale dynamic column breakthrough apparatus was tested with 238.9 mg of zeolite 13X and 180.2 mg of activated carbon with single-component N2/He and CH4/He adsorption and desorption measurements. The measured equilibrium data agreed well with volumetrically collected data. These measurements are both accurate and precise. Multicomponent adsorption was also studied on zeolite 13X and activated carbon for CH4/N2 and CO2/CH4 mixtures. This data was compared with ideal adsorbed solution theory, extended dual-site Langmuir calculations, and the literature.

Experimental investigation into cascade thermochemical energy storage system using SrCl2-cement and zeolite-13X materials

Significant improvements can be made to thermochemical energy storage system, through heat transfer and thermodynamics analysis. A cascade thermochemical energy storage system has been theoretically shown to improve thermal and exergy energy efficiencies. In this work, an open, cascade system using zeolite 13X and SrCl2-cement composite material is investigated in a lab-scale reactor and compared to the traditional single material systems. The two materials were chosen based on their respective hydration and dehydration requirements. The volumetric energy density ranged from 108–138 kWh m−3 with dehydration temperatures of 50–130 °C and hydration conditions of 12 °C, 75% RH. The thermal and exergy efficiencies were analysed for each system. It was found that the cascaded system improves power output and temperature lift. Furthermore, the cascade system improved exergy efficiency by 6–38% when compared to a traditional salt-based system. This research demonstrates how a cascade thermochemical energy storage system can be cost-effective whilst still maintaining high energy density, power output and temperature lift over a range of dehydration temperatures.

Experimental investigation into CO2 capture from the cement plant by VPSA technology using zeolite 13X and activated carbon

The article presents the application of the VPSA (Vacuum-Pressure Swing Adsorption) method, relying on solid adsorbents, in post -combustion CO2 capture. Tests to assess the possibility of applying the VPSA method in post-combustion CO2 capture in the cement industry were conducted in a bench-scale installation. Two types of adsorbents, namely zeolite 13X and activated carbon, were used in the tests. The obtained results indicate a potential of the VPSA technology for removing CO2 from the streams of gases coming from cement plants, chiefly owing to the high CO2 concentration, which translates directly into a higher CO2 recovery and a purity possible to be attained in a one-stage VPSA process. The increasing the installation's output by raising the feed gas flow rate reduces the carbon dioxide recovery from the flue gas, however, it allows higher CO2 purities to be attained, and vice versa. The effectiveness of the CO2 capture process is also influenced by the adsorption time. Both for activated carbon and for zeolite 13X, CO2 purity increases with increasing adsorption time.When comparing the CO2 purity results obtained under identical process conditions for activated carbon and zeolite 13X, it can be noticed that higher CO2 purities were obtained for using zeolite 13X.

Role of Zeolite Structural Properties toward Iodine Capture: A Head-to-head Evaluation of Framework Type and Chemical Composition

This study evaluated zeolite-based sorbents for iodine gas [I2(g)] capture. Based on the framework structures and porosities, five zeolites, including two faujasite (FAU), one ZSM-5 (MFI), one mesoMFI, one ZSM-22 (TON), as well as two mesoporous materials, were evaluated for I2(g) capture at room temperature and 150 °C in an iodine-saturated environment. From these preliminary studies, the three best-performing zeolites were ion-exchanged with Ag+ and evaluated for I2(g) capture under similar conditions. Energy-dispersive X-ray spectroscopy data suggest that Ag-FAU frameworks were the materials with the highest capacity for I2(g) in this study, showing ∼3× higher adsorption compared to Ag-mordenite (Ag-MOR) at room temperature, but X-ray diffraction measurements show that the faujasite structure collapsed during the adsorption studies because of dealumination. The Ag-MFI zeolites are decent sorbents in real-life applications, showing both good sorption capacities and higher stability. In-depth analyses and characterizations, including synchrotron X-ray absorption spectroscopy, revealed the influence of structural and chemical properties of zeolites on the performance for iodine adsorption from the gas phase.

Measurements and modeling of CO2 adsorption behaviors on granular zeolite 13X: Impact of temperature and time of calcination on granules properties in granulation process using organic binders

AbstractCO2 adsorption on granulated zeolite 13X by organic binders were studied by volumetric measurements. The goal of research was finding the optimum thermal conditions after shaping by organic binders to enhance the mechanical strength and adsorption capacity of granules. Previously published literature investigated the usage of traditional inorganic binders and the effect of organic binders has never been surveyed. Polyvinyl alcohol and polyethylene glycol were added to zeolite powder as organic binders and the effect of calcination temperature and calcination time on the physicochemical and mechanical properties of granules were studied. The textural/structural and morphological features of synthesized adsorbents were characterized by N2 isotherm, X‐ray diffraction (XRD), Thermogravimetric analysis (TGA), Differential thermal analysis (DTA), Scanning electron microscopy (SEM), and Energy Dispersive X‐ray spectroscopy (EDX). The results showed that using high temperatures and longer periods for the calcination had a favorable effect on their mechanical properties but their effects on the physical properties were negative. Thermodynamic investigations were employed to understand the adsorption behavior. Equilibrium adsorption demonstrated that Langmuir model was the most suitable model for description CO2 adsorption and the maximum adsorption capacity was 4.02 (mmol/g). The thermodynamic analysis indicated that the adsorption process was spontaneous and exothermic in nature. The value of isosteric heat of adsorption was analyzed based on Clausius–Clapeyron equation.

Sustainable and open sorption system for low‐temperature heat storage applications

In the present study, an open sorption thermochemical energy storage (TCES) system was developed and investigated experimentally for low-temperature heat storage applications using zeolites. Desorption and adsorption experiments were carried out sequentially for 15 cycles to study the energy storage and retrieval characteristics. Further, the performance characteristics were analysed to find the system's suitability for intended applications. The charging and discharging processes were carried out respectively at around 95°C and room temperature, for zeolite 13X and zeolite 4A. Zeolite 13X exhibited better average total energy storage density during the desorption and adsorption and they are respectively 129.4 and 57 kWh/m3. The average cumulative energy storage efficiency for zeolite 13X and zeolite 4A are respectively 44.1% and 24%. Similarly, the average exergy efficiency for zeolite 13X and zeolite 4A are respectively 21.5% and 11%. For the tested thermochemical materials (TCMs), the deviations in mass change due to multi-cycle test-run was small and hence suitable for long-term usage without concern about their stability. The present study has demonstrated the technical competence in utilizing the energy sources (eg, solar energy, industrial waste heat) towards low-temperature heat storage applications, viz. building's space heating and water heating.

Rational design of zeolite Y supported oxalate and borohydride ligands functionalized Cu catalysts for CO2 conversion to specialty chemicals

This study investigates the effect of oxalate and borohydride ligands functionalization on the properties and activity of zeolite Y (ZY) supported copper nanoparticles in CO2 hydrogenation to specialty chemicals. The ZY-supported copper oxalate (CuX-ZY) and copper borohydride (CuB-ZY) catalysts exhibited a drastic difference in physicochemical properties compared to a benchmark copper supported on ZY (Cu-ZY) catalyst without any functionalization. The average Cu particle sizes are 7.74, 0.69, and 0.57 nm for Cu-ZY, CuX-ZY, and CuB-ZY, respectively. The smaller the copper oxide particle sizes, the higher the reduction temperatures to the metallic state due to strong-metal-support-interactions. The CO2 conversions (XCO2) at 270 °C are 28.3%, 26.4%, and 14.6%, for CuX-ZY, CuB-ZY, and Cu-ZY which aligns with the trend of basic site-strength, Cu particle sizes, and Cu dispersion of the catalysts. While methanol yield was maximum at 70.5 gproduct gcat−1 ∙ min−1 over CuX-ZY, the dimethyl ether was maximum at 48.9 gproduct gcat−1 ∙ min−1 over CuB-ZY. Furthermore, the oxalate and borohydride functionalization were effective in minimizing CO formation.

Flexible CO2 capture for open-cycle gas turbines via vacuum-pressure swing adsorption: A model-based assessment

As energy systems require flexible and responsive power generators to combat network imbalances, CO2 post-combustion capture (PCC) technologies need to be capable of transient operation. However, currently only amine absorption has been investigated for its efficacy in Flexible-PCC.Within this study we develop and validate a vacuum-pressure swing adsorption (VPSA) process model, capable of processing 33.8 kg/s of exhaust flow from a small-scale open-cycle gas turbine (OCGT). The Flexible response scenario is based on realistic load changes of OCGTs during a 5-h period. To handle the size of flow the system is split into two identical two bed four step VPSA processes, both using Zeolite 13X as the adsorbent material. Included in the Flexible-VPSA operation is the start-up, ramping, and shutdown procedures. Flexible-VPSA showed minute deviations in CO2 purity and recovery rate, and despite the specific energy demand increasing, results show no technical limitations to transient operation. The Flexible VPSA simulations are compared against the benchmark MEA solvent, with both technologies performing similarly when processing highly transient flue gas flowrate. Thus, VPSA is potentially an attractive alternative technology for Flexible-PCC.

Atomic layer deposition precisely modified zeolite 13X: Physicochemical synergistic adsorption of space molecular contaminants

In spaceflight applications, molecular contamination control has become one of the most challenging issues. Porous zeolites are a potent molecular adsorbent with advantages of efficient adsorption at low pressure and/or high temperature, high interaction with adsorbates, and superior durability in extreme environments. Herein, zeolite 13X pellets were selected for adsorption of stearyl alcohol (C18H37OH) as a target molecular contaminant. Considering the excellent hydrophilicity of the zeolite 13X which limits the adsorption of most hydrophobic organic molecules, modification of the zeolite 13X by deposition of TiO2 via atomic layer deposition (ALD) technology was performed. Results show that ALD-grown TiO2 not only improves hydrophobicity but also renders high activity, whilst retains the hierarchical pores of the zeolites. As a result, the as-prepared zeolite 13X@TiO2 exhibits efficient adsorption toward trace stearyl alcohol under low pressure through the synergistic contribution of physisorption and chemisorption. Monte Carlo (MC) simulation, molecular dynamic (MD) and Density Functional Theory (DFT) calculations further discover that pore wall surfaces are primary adsorption sites for the physisorption while ALD-grown TiO2 provides active sites for the chemisorption.