Zeolite Y Research Articles

Sequestration and Thermal Stabilization of Cesium Ions by Zeolite 13x: In a Mechanistic Perspective

Sequestration and Thermal Stabilization of Cesium Ions by Zeolite 13x: In a Mechanistic Perspective

Evaluation of Behavior of 13X Zeolite Modified with Transition Metals for Catalytic Applications

This work was intended to develop catalysts based on 13X zeolite modified with transition metals for catalytic applications. In this regard, 13X zeolite was modified by loading of transition metals such as Fe, Co, Cu and various types of catalysts such as Fe-, Co-, Cu-, Fe-Co-, Fe-Cu-, and Co-Cu/13X zeolite were obtained. To prepare these catalysts, the wet impregnation method and metallic precursors were used. The catalysts were characterized by SEM, XRD, BET, and ammonia adsorption. Then the catalytic performance was investigated during upgrading of rapeseed residual biomass pyrolysis vapors using this catalysts and a fixed-bed reactor in two stages. Experimental results showed that the addition of transition metals improved the catalytic selectivity towards aromatic hydrocarbons and Fe-Cu/13X zeolite catalyst was the best and had a high deoxygenation activity (from 62.45% to 20.56%), produced maximum monoaromatic hydrocarbons (of 27.45%), the oxygen content in bio-oil was reduced from 34.98 wt% to 16.06 wt%, the calorific value increased and thus the bio-oil quality was improved.

Removal of Chromium (VI) and Lead (II) from Aqueous Solution Using Domestic Rice Husk Ash- (RHA-) Based Zeolite Faujasite

Rice husk ash (RHA), is a widely available biobased source for high purity silica. In this work, zeolite Faujasite (FAU) is synthesized using extracted silica from RHA (collected from a local region of Bangladesh). The synthesized zeolite FAU was used as an adsorbent for Cr(VI) and Pb (II) batch-wise adsorptive removal from respective aqueous solution. The synthesized zeolite FAU was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen-sorption, and Fourier transfer infrared (FT-IR) spectroscopy. Metal ion adsorption studies were performed by varying metal concentration (20–100 mg/L for Cr(VI) and 900–133 mg/L for Pb(II)), sorbent dosage (2–10 g/L for chromium and 0.5–1.5 g/L for lead), and contact time (10–120 min for both metal ions). The maximum adsorption capacity of RHA-based zeolite FAU was found to be 3.56 mg/g and 342.16 mg/g for Cr(VI) and Pb(II), respectively. Since the sorption data was found to match with Langmuir isotherm, a monolayer adsorption was occurred. The regeneration of the RHA-based zeolite FAU by NaCl solution showed the potential of repeated as well as continuous operation.

A shortcut to high-quality gmelinite through steam-assisted interzeolite transformation

Mechanochemical activation and steam-assisted interzeolite transformation offer a simple, fast and cost-efficient synthesis route to gmelinite (GME) zeolite. The use of faujasite (FAU) as the parent zeolite precursor facilitates the reaction and results in high yields of high-quality GME in less than 20 h under optimized conditions. The accessible porosity and amounts of stacking-faults were determined by N2 physisorption and XRD analysis, respectively. The results show that the quality of the prepared materials easily competes with GME zeolites synthesized by conventional hydrothermal synthesis, which encourages further research in this area. By changing the reaction parameters, the approach may also be used for the production of several other types of zeolites, including MOR, MFI and ANA.

Degradation of Desiccants in Temperature Swing Adsorption Processes: The Temperature Dependent Degradation of Zeolites 4a, 13x and Silica Gels

Degradation of Desiccants in Temperature Swing Adsorption Processes: The Temperature Dependent Degradation of Zeolites 4a, 13x and Silica Gels

Adsorption Equilibria and Kinetics of Ethane and Ethylene on Zeolite 13x Pellets

Adsorption Equilibria and Kinetics of Ethane and Ethylene on Zeolite 13x Pellets

Comparative Study on the Catalytic Performance of a 13X Zeolite and its Dealuminated Derivative for Biodiesel Production

Natural kaolin clay was used to successfully prepare 13X zeolite catalysts, which were modified by dealumination with citric acid. Acid leaching eliminates impurities and aluminum, and improves the Si/Al ratio of the zeolite framework. The X-ray diffraction (XRD) patterns of both the original and modified 13X zeolites were the same, indicating that the crystalline frameworks were not destroyed during the dealumination process. X-ray fluorescence data of the dealuminated 13X zeolite showed an improved Si/Al ratio. Also, Atomic Force Microscopy (AFM) was used for the characterization of the catalysts. The catalytic performance of the original and modified catalysts was tested in the esterification reaction of oleic acid in a batch reactor. A higher conversion of oleic acid was obtained using the modified 13X zeolite. The resulting experimental data from the esterification reactions were fitted to the heterogeneous Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model to determine the rates of reaction. The results of the reaction kinetics showed an increase in the rate of reaction velocity and a distinct decrease in the activation energy when using the modified zeolite, indicating that employing the modified catalyst will give a higher conversion over a shorter time through a reaction with less sensitivity to temperature. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Enhanced Reactivity of Accessible Protons in Sodalite Cages of Faujasite Zeolite.

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 NH4 NO3 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.

Changes in Porous Parameters of the Ion Exchanged X Zeolite and Their Effect on CO2 Adsorption.

Zeolite 13X (NaX) was modified through ion-exchange with alkali and alkaline earth metal cations. The degree of ion exchange was thoroughly characterized with ICP, EDS and XRF methods. The new method of EDS data evaluation for zeolites was presented. It delivers the same reliable results as more complicated, expensive, time consuming and hazardous ICP approach. The highest adsorption capacities at 273 K and 0.95 bar were achieved for materials containing the alkali metals in the following order K < Na < Li, respectively, 4.54, 5.55 and 5.94 mmol/g. It was found that it is associated with the porous parameters of the ion-exchanged samples. The Li0.61Na0.39X form of zeolite exhibited the highest specific surface area of 624 m2/g and micropore volume of 0.35 cm3/g compared to sodium form 569 m2/g and 0.30 cm3/g, respectively. The increase of CO2 uptake is not related with deterioration of CO2 selectivity. At room temperature, the CO2 vs. N2 selectivity remains at a very high stable level prior and after ion exchange in co-adsorption process (XCO2 during adsorption 0.15; XCO2 during desorption 0.95) within measurement uncertainty. Additionally, the Li0.61Na0.39X sample was proven to be stable in the aging adsorption-desorption tests (200 sorption-desorption cycles; circa 11 days of continuous process) exhibiting the CO2 uptake decrease of about 6%. The exchange with alkaline earth metals (Mg, Ca) led to a significant decrease of SSA and micropore volume which correlated with lower CO2 adsorption capacities. Interestingly, the divalent cations cause formation of mesopores, due to the relaxation of lattice strains.

A Review on the Challenges of Using Zeolite 13X as Heat Storage Systems for the Residential Sector

In recent years, several attempts have been made to promote renewable energy in the residential sector to help reducing its CO2 emissions. Among existing approaches utilizing substances capable of directly storing and transporting thermal energy has recently become a point of interest. Zeolite 13X with exceptional capacity to safely store thermal energy for long periods and release heat due to its unique molecular structure is known to be one of the best options serving this purpose. However, the application of this ceramic as a heat storage material in the residential sector is associated with significant challenges dictated by the limitations of the sector, such as space restrictions and affordability. The current review attempts to explore the extent of these challenges, mainly related to design and efficiency from different perspectives. The main aim here is to provide a clear vision for a better understanding of the state of the art of this technology and to help to identify possible solutions fostering the adaptation of this technology to the residential sector.

Microchannel zeolite 13X adsorbent with high CO2 separation performance

• Microchanneled zeolite monoliths for removal of CO 2 through phase separation. • CO 2 dynamic uptake of 3.4 mmol g −1 was obtained for 13X monoliths. • The monoliths present markedly low pressure drop under fast flow rate. • Mass transfer resistance in monolith significantly lower than those for beads. • Ultra high mechanical strength and thermal conductivity for zeolite adsorbent. Uniform 13X films with thicknesses of 3 and 11 µm were grown on supports in the form of steel monoliths with a cell density of 1600 cpsi and microchannels width of 0.5 mm. Sharp breakthrough fronts and a dynamic uptake of 3.4 mmol CO 2 g −1 zeolite were observed in the forwarding step of breakthrough experiments for a feed of 10% CO 2 in N 2 with a high flow rate at 293 K and 1 bar. Numerical modeling showed that the adsorption process was very fast and that the transport of CO 2 in the thin zeolite layer was the rate-limiting step, the mass transfer resistance for the 11 µm film is 2.2 times lower than zeolite 13X pellets and 100 times lower than zeolite 4A beads. Axial dispersion, pressure drop, and gas film resistance were shown to be negligible. The steel monolith support provides good mechanical strength and excellent thermal conductivity for the 13X films. The combination of properties makes this adsorbent a good performer when compared with other types of structured zeolite adsorbents in reported literatures. This microchannel adsorbent is a promising alternative to traditional adsorbents in processes of fast CO 2 separation with short cycle times.

Feasibility Study of Vacuum Pressure Swing Adsorption for CO2 Capture From an SMR Hydrogen Plant: Comparison Between Synthesis Gas Capture and Tail Gas Capture

In this paper, a feasibility study was carried out to evaluate cyclic adsorption processes for capturing CO2 from either shifted synthesis gas or H2 PSA tail gas of an industrial-scale SMR-based hydrogen plant. It is expected that hydrogen is to be widely used in place of natural gas in various industrial sectors where electrification would be rather challenging. A SMR-based hydrogen plant is currently dominant in the market, as it can produce hydrogen at scale in the most economical way. Its CO2 emission must be curtailed significantly by its integration with CCUS. Two Vacuum Pressure Swing Adsorption (VPSA) systems including a rinse step were designed to capture CO2 from an industrial-scale SMR-based hydrogen plant: one for the shifted synthesis gas and the other for the H2 PSA tail gas. Given the shapes of adsorption isotherms, zeolite 13X and activated carbon were selected for tail gas and syngas capture options, respectively. A simple Equilibrium Theory model developed for the limiting case of complete regeneration was taken to analyse the VPSA systems in this feasibility study. The process performances were compared to each other with respect to product recovery, bed productivity and power consumption. It was found that CO2 could be captured more cost-effectively from the syngas than the tail gas, unless the desorption pressure was too low. The energy consumption of the VPSA was comparable to those of the conventional MDEA processes.

Adsorption separation of liquid-phase C5-C6 alkynes and olefins using FAU zeolite adsorbents

Isoprene is of great importance as a valuable monomer for most chemical industries owing to the increasing demand for synthetic rubber. To obtain polymer-grade olefins, the removal of alkyne compounds from isoprene is mandatory and challenging. Adsorption separation using zeolites is one of the most promising alternatives for alkyne/olefin separation. Herein, a combination of batch, fixed bed column experiments and configurational-bias grand canonical Monte Carlo (CB-GCMC) simulations was applied to study alkyne’s selective adsorption from binary liquid-phase isoprene/1-pentyne mixtures in faujasite (FAU) zeolites. The adsorption separation performance, including the adsorption capacity and selectivity, was obtained based on the liquid-phase measurement method developed in this study. FAU zeolites exhibited 218 mg/g alkyne adsorption capacity and relatively high adsorption selectivity at low alkyne concentrations. Liquid adsorption separation of linear alkyne/olefin mixtures, covering 1-pentyne/1-pentene (C5) and 1-hexyne/1-hexene (C6), in FAU zeolites, was performed further to investigate the separation performance for alkynes and olefins. The binary isotherms for the 1-pentyne/isoprene system and extended studied olefin/alkyne systems were reproduced well by CB-GCMC simulations. The visualized average occupation profiles of adsorbate molecules in FAU zeolites showed that alkyne and olefin molecules were mainly distributed near the 4-rings and 6-rings. The concentrated areas were arranged perpendicular to each other.

Enhanced thermal conductivity and adsorption rate of zeolite 13X adsorbent by compression-induced molding method for sorption thermal battery

Sorption thermal battery is an effective thermal energy storage technology for solar energy utilization and waste heat recovery. However, the low thermal conductivity and packing density of loose particle adsorbents are the common drawbacks for realizing high energy-density and power-density sorption thermal battery. Herein, we propose a compression-induced molding method for preparing high-performance modular adsorbents with high thermal conductivity and packing density by compacting loose particle adsorbents with tunable packing densities and thicknesses. The experimental results showed that the thermal conductivity and packing density of modular adsorbents can be enhanced by 3 times and 2 times, respectively, when compared to that of particle adsorbents. The water adsorption rate can be also improved by this method at an optimized compression pressure of 10 MPa and thickness of 2 mm. Furthermore, we constructed a sorption thermal battery by employing the modular adsorbents to realizing high-efficient thermal charging/discharging processes. The experimental results demonstrate the maximum volumetric power density is as high as 145 kW/m3 and the maximum volumetric energy density up to 75 kWh/m3, which are 1.61 times and 1.27 times higher than those of pristine particle adsorbent, respectively. Therefore, it is verified that the sorption thermal battery with modular adsorbent is more powerful and compact than using conventional particle adsorbent.

Micelle Formation inside Zeolites: A Critical Step in Zeolite Surfactant-Templating Observed by Raman Microspectroscopy.

Micelle formation inside faujasite (FAU) zeolite, a critical step in the introduction of mesoporosity in zeolites by surfactant templating, has been confirmed by both 13C NMR and Raman spectroscopy. Here we provide unambiguous evidence of the incorporation of surfactant molecules inside zeolites during the first step of the surfactant-templating process followed by their self-assembly into micelles after hydrothermal treatment. The homogeneous presence of these micelles throughout zeolite crystals has been directly observed by Raman microspectroscopy, confirming the uniform incorporation of mesoporosity in zeolites by surfactant templating.

A novel synergistic method on potential green and high value-added utilization of blast furnace slag

In order to utilize blast furnace slag resource at low cost, pollution-free, refinement and high value-added, a novel technical route was proposed to collaboratively produce zeolite and hydrotalcite-like compound. In this study, the changing property of slag in the treatment process was investigated and the thermodynamic and kinetic analyses of the leaching reaction were conducted to prove its feasibility. The silica gel and residue liquid were separated effectively from the slag. Then, 13X zeolite and hydrotalcite-like compound were successfully synthesized from water quenching blast furnace slag using hydrochloric acid treatment followed by hydrothermal method and co-precipitation method. The successful formation of 13X zeolite and hydrotalcite-like compound were obtained effectively with good surface morphology and crystal structure. Mass balance of the blast furnace slag utilization process was established. Meanwhile, these two samples exhibited good behavior of CO2 adsorption capacity and enjoyed a promising market prospect. The maximum adsorption capacities of 13X zeolite and hydrotalcite-like compound were 116.48 mg g−1 at 313 K and 149.63 mg g−1 at 873 K, respectively. Finally, the preliminary economic evaluation of the integrated system was conducted, and the economic benefit of 1 kg slag was about 1.281 $.

Efficient Method to Catch Adsorption Behavior: Understanding the Effect of Sodium Ions on Benzene/Thiophene Adsorption in Na‐FAU

AbstractIn this paper, grand canonical Monte Carlo simulations are applied to study the adsorption performance of thiophene and benzene. Pure adsorption and binary adsorption are performed in all silica faujasite (FAU) and Na‐FAU zeolite combined with density distributions and radial distribution functions (RDF). A new method to describe the adsorption mechanism in FAU has been proposed. One adsorbate is fixed in the center of 12 ring (12C) or the center of supercage (CSC) as the reference point. Then, RDFs represent the probability to find other adsorbates in a shell at the distance r of the reference point. Thus, the adsorption sites appeared are obtained as several ring shape areas. The intersection points, especially with high occurrence possibilities, is regarded as the main adsorption sites, showing good agreement with density distribution. Comparing RDFs of sorbate‐12C and the location of Na ions, the curve of thiophene‐12C and the curve of Na‐12C overlap can be found, which means thiophene prefers to adsorb around Na ions. On this point, the reason why the separation property of Na‐FAU zeolites is better than that of all silica FAU zeolites can be clearly explained.

A systematic analysis of the dynamics of microwave- and conventionally-assisted swing adsorption on zeolite 13X and an activated carbon under post-combustion carbon capture conditions

This work presents a detailed parametric experimental work on the feasibility of microwave regeneration of two commercial adsorbents in a dynamic carbon capture swing adsorption system. A synthetic flue gas (15% v/v CO2 in N2) dry or with 15% relative humidity was selected, along with Norit R2020CO2 activated carbon and zeolite 13X. A purpose-modified experimental apparatus was used to compare microwave-assisted and conventional thermal swing regeneration. The impact of operating parameters on the dynamic process performance was measured for microwave and conventional heating. Parameters considered were type of adsorbent, flue gas composition, quantity of adsorbent (and bed size), and time of full regeneration, on CO2 capture capacity, recovery, purity and desorption kinetics. Results showed that microwave-assisted regeneration presents advantages over its conventional equivalent, as CO2 purity, recovery, and productivity were found to be higher under the former for the two adsorbents studied. For the time needed to achieve 50, 80, 90, and 99% regeneration, the benefits of microwave regeneration over conductive regeneration increased with an increase in sample size. Under the wet gas feed, Norit R2020CO2 and zeolite 13X showed an appreciably higher working capacity with microwave regeneration than with conventional regeneration (39.68 and 24.23% higher, respectively). Under the dry gas feed, the two adsorbents also maintained a higher working capacity with microwave heating as opposed to conductive heating (9.36 and 20.39% higher, respectively). The larger working capacity observed with microwave-assisted regeneration is attributed to the better regeneration.

Syngas production by bi-reforming of methane on a bimetallic Ni-ZnO doped zeolite 13X

Ennoblement of carbon dioxide, particularly the one produced by anaerobic digestion or by biomass combustion, is a motivation to develop novel or improving already existing processes. In this context, an interesting idea is to use carbon dioxide combined together with methane and water. Therefore, bi-reforming of methane (BRM) for syngas production appears to be a good choice. In this work, BRM was studied over a Ni-catalyst supported on a ZnO-doped zeolite 13X in the temperature range 300 to 900 °C. This material was deeply characterized by different techniques. The pure zeolite 13X shows relative good sorption capacity for CO2 at low temperatures (<100 °C). The ZnO phase introduced on zeolite 13X did not show a significant improvement for BRM, while 13X zeolite material impregnated with Ni and ZnO showed promising activities, achieving CO2 conversions in the range of 50–60% at a maximum operating temperature of 800 °C and atmospheric pressure. The results obtained suggest that ZnO acts as an oxygen supplier when methane is activated by surface nickel, thus destabilizing the feed in the following order: methane, water and carbon dioxide. The influence of the operating conditions in the reactants conversion and products distribution was also analyzed, and it can be concluded that the molar ratios of hydrogen-to-carbon monoxide are close to two at high temperatures.

CO2 Separation from Flue Gases by Adsorption

This paper deals with gas separation by adsorption processes. The key objective is to investigate the adsorption suitability for Post-combustion Carbon Dioxide (CO2) Capture (PCC). Adsorption is a promising technology suitable for a high volume of diluted gas processing. Unlike commercialised amine-based absorption processes, adsorption seems to require less energy for sorbent regeneration and extends the sorbent lifetime. Two common industrial methods utilizing a difference in adsorption equilibrium of the gas components were investigated: 1) Pressure Swing Adsorption (PSA) including Vacuum Swing Adsorption (VSA), 2) Temperature Swing Adsorption (TSA). A comparison of their energy consumption, suitability for industrial use with consideration of Carbon Capture and Storage standards is evaluated. A complex mathematical model for the adsorption step of the fixed bed adsorber was proposed and solved by the structural programming. Three adsorbent materials: Mg-MOF-74, UTSA-16, and Zeolite 13X were evaluated based on their CO2 adsorption capacity, selectivity, and market availability. Zeolite 13X was further explored. As a benchmark case, a medium-sized natural gas cogeneration unit was used to study the potential of VSA unit. The lower limit of CO2 capture efficiency in simulations was 75 %. The results presented in this paper suggest that adsorption can be a feasible CO2 capture solution for a low-carbon emission power generation technologies. Optimal parameters for the adsorption step and column configuration are proposed.