Zeolite Composites Research Articles

Preparation of iron composite filler for PRB technology and its application in the removal of toxic metals(loids) from groundwater

Preparation of iron composite filler for PRB technology and its application in the removal of toxic metals(loids) from groundwater

Catalytic hydroconversion of aryl ethers to polycyclic alkanes over Ni@MCM-41/β composite zeolite: Aromatic α-carbon activation and hydrogen transfer mechanisms

Catalytic hydroconversion of aryl ethers to polycyclic alkanes over Ni@MCM-41/β composite zeolite: Aromatic α-carbon activation and hydrogen transfer mechanisms

Metal-containing zeolite composites with separated phases as catalysts for hydroisomerization of linear hexane

Metal-containing zeolite composites with separated phases as catalysts for hydroisomerization of linear hexane

Controlling Crystal Morphology of Anisotropic Zeolites with Elemental Composition.

The morphology of zeolite crystals strongly affects their textural, catalytic, and mechanical attributes. However, controlling zeolite crystal morphology without using modifiers or structure-directing agents remains a challenging task because of our limited understanding of the relationships between zeolite crystal shape, crystallization mechanism, and composition of the starting synthesis mixture. In this study, we aimed at developing a general method for controlling the morphology of zeolites by assessing the impact of the Si/T molar ratio of the synthesis gel on the growth rate of zeolite crystals in various crystallographic directions and on the final crystal morphology of the UTL germanosilicate with a 2D system of intersecting 14- and 12-ring pores. Our results showed that flat UTL crystals progressively thicken with the Si/Ge molar ratio, demonstrating that Ge concentration controls the relative rate of crystal growth in the perpendicular direction to the pore system. The morphology of other zeolites and zeotypes with an anisotropic structure, including AFI (12R), IFR (12R), MWW (10-10R), and IWW (12-10-8R), can also be predicted based on their Si/T ratio, suggesting a systematic pattern across zeolite structures and in a wide range of zeolite framework elements. Combined, these findings introduce a facile and cost-efficient method for directly controlling crystal morphology of zeolites with anisotropic structures with a high potential for scale-up while providing further insights into the role of elemental composition in zeolite crystal growth.

A Molecular-Sieving Interphase Towards Low-Concentrated Aqueous Sodium-Ion Batteries

HighlightsA molecular-sieving electrode coating towards low-concentrated aqueous sodium-ion batteries is constructed by applying a composite of NaX zeolite and NaOH-neutralized Nafion.Resulting from a molecular sieving effect of zeolite channels and size-shrunken ionic domains in Nafion, the as-prepared coating layer reject hydrated Na+ ions and allow fast dehydrated Na+ permeance.200 cycles of Na2MnFe(CN)6//NaTi2(PO4)3 full cells can be achieved in a practically feasible 2 m aqueous electrolyte.

Sono-assisted adsorption of nitrate by Fe-modified chitosan–zeolite composite material

The negative consequences of nitrate pollution on the environment and human health, that gained substantial attention. The purpose of this work is to formulate and evaluate the potential of the Fe-modified chitosan–zeolite composite (CZFC) as an efficient adsorbent for the removal of nitrate. Physical and chemical characterization techniques such as SEM, XRD, and FTIR were used to analyze the surface and structural properties of the CZFC. The effects of several variables, including the pH, contact time, initial concentration, and adsorbent dosage, were investigated under ultrasonication treatment throughout experiments. When compared to the Freundlich and Temkin models, the Langmuir models had the highest R 2 value (0.99), indicating that they had the best fitting for all the experimental data. The maximum adsorption capacity was found to be 5.18 ± 0.30 mg g−1 with 95.37 ± 2.11% of nitrate removal at pH 3 and 2 g L−1 of adsorbent dose. The pseudo-second-order model exhibited the highest R 2 value (0.99) and proved the chemisorption mechanism for nitrate removal. The thermodynamic properties indicated that the adsorption was spontaneous and exothermic. The regeneration capacity of the CZFC was found to be 80.86 ± 4.17% at pH 10 due to the weakening of electrostatic attraction. According to experimental results, ultrasonication treatment was crucial for increasing nitrate absorption on synthesized CZFC.

Box–Behnken experimental design for optimization of chitosan foam materials reinforced with cellulose and zeolite

AbstractFoam materials produced from biopolymers stand out as a more environmentally friendly insulation material solution. This study presents a comprehensive investigation into the development and optimization of chitosan‐based foam materials using a Box–Behnken design. The foams were engineered using varying proportions of chitosan (0.5–3%), cellulose (0.5–3%), and zeolite (0.5–3%), targeting their application as thermal insulators. The physical and thermal properties of the foams that were produced were affected by the type and ratios of components, with density and thermal conductivity ranging from 0.0853 to 0.1915 g cm−3 and 0.0324 to 0.0921 W mK−1, respectively. Higher chitosan content improved insulation properties and mechanical strength whereas zeolite increments increased density and thermal conductivity. Using statistical analysis through the Box–Behnken design, we optimized the foam formulations, achieving minimum thermal conductivity and maximum compression strength at an averaged density, suggesting a strong potential for environmental sustainability applications. The recommended optimal chitosan:cellulose:zeolite composition ratio of 3:3:0.88 provides a valuable insight for tailored foam material formulation. This study shows the relationships between the composition of a composite material and its resultant properties, optimizing its preparation for industrial applicability in an environmentally conscious way within the context of insulation and construction. This investigation contributes to the field of material science by highlighting the versatility and potential of biopolymers but also aligns with the increasing need for green building materials.

Zirconium-loaded zeolite composites for selective sorption of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) from water: Performance and mechanism

Zirconium-loaded zeolite composites for selective sorption of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) from water: Performance and mechanism

Green Synthesis and Efficient Adsorption: Na-X Zeolite vs. C/Mn/SiO2 Composite for Heavy Metals Removal.

The studies aimed to test the adsorption capacity of two silica-enriched porous materials, synthetic Na-X zeolite and Mn-containing carbon composite, towards Pb(II) and Zn(II) ions in single and mixed systems and in the presence of diclofenac (DCF) and (or) poly(acrylic acid) (PAA). The synthetic zeolite was characterized by a well-developed surface area of 728 m2/g and a pore diameter of 1.73 nm, while the carbon composite exhibited 268 m2/g and 7.37 nm, respectively. Na-X was found to be more efficient than the carbon composite (75-212 mg/g) in adsorbing heavy metal ions in both single and bimetallic systems (322-333 mg/g). In turn, the C/Mn/SiO2 composite was more effective in removing Pb(II) ions from the systems that simultaneously contained DCF or PAA (480 and 476 mg/g, respectively). The Na-X zeolite demonstrated the greatest stability in all the systems studied. The highest stability was observed in the DCF + Pb(II) mixture, in contrast to the carbon composites where the stability was much lower. To evaluate the possibility of regeneration of the solids, HCl proved to be the best desorbent for heavy metal ions (efficiency of 99%). In general, both adsorbents offer promising potential for solving environmental problems.

Nanocrystals Incorporated with Mordenite Zeolite Composites with Enhanced Upconversion Emission for Cu2+ Detection.

In this research, upconversion nanocrystals incorporated with MOR zeolite composites were synthesized using the desilicated MOR zeolite as a host for the in situ growth of NaREF4 (RE = Y, Gd) Yb/Er nanocrystals. The structure and morphology of the composites were studied with XRD, XPS, and TEM measurements, and the spectral studies indicated that the subsequent thermal treatment can effectively improve the upconversion emission intensity of Er3+. By using the NaYF4:Yb/Er@DSi1.0MOR-HT composite that holds the strongest upconversion emission, a probe of UCNC@DSiMOR/BPEI was constructed with the modification of branched poly ethylenimine for the detection of Cu2+. It was indicated that the integrated emission intensity of Er3+ shows a linear dependence with the logarithm value of the Cu2+ concentration ranging from 0.1 to 10 μM. This study offered a feasible method for the construction of UCNC@zeolite composites with enhanced upconversion emission, which may have a potential application as fluorescent probes for the detection of various metal ions by adjusting the doping luminescent center.

Enhanced hydroisomerization of n-heptane over bifunctional catalysts with highly dispersed Pd nanoparticles supported on H-Yβ composite zeolite

Enhanced hydroisomerization of n-heptane over bifunctional catalysts with highly dispersed Pd nanoparticles supported on H-Yβ composite zeolite

Polymer–Zeolite Composites: Synthesis, Characterization and Application

Although the potential of natural minerals for purification of liquid radioactive wastes (LRW) from radionuclides has been widely studied, the use of hybrid polymer composites made of zeolite is still rather scarce. This article reports on the preparation of zeolite-based hybrid polymer composites using the in situ polymerization technique in the body of mineral matrix and its intercalated with copper ferrocyanide (CuFC) forms. This hybrid polymer composites have shown unique and enhanced properties for the removal of micropollutants from wasted water as compared to the individual mineral. The change in conventional properties of two mixed minerals, such as zeolite and bentonite, and their intercalated with CuFC forms were probed using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS) and FT-IR analysis. The totality of analysis showed a coexistence of intercalated and percolated zeolite phases. The hybrid polymer composites exhibited both adsorption and ion-exchange properties in the removal of 134,137Cs+, 57,60Co2+ and 85Sr2+ radionuclides from LRW.

Silver nanoparticles (Ag-NPs) embedded in zeolite framework: A comprehensive study on bromide removal from water, including characterization, antibacterial properties, and adsorption mechanisms

Silver nanoparticles (Ag-NPs) embedded in zeolite framework: A comprehensive study on bromide removal from water, including characterization, antibacterial properties, and adsorption mechanisms

Antimicrobial Properties of Ion-Modified Zeolite Composites: A Study on Biofilm Inhibition and Bacterial Cell Viability

This work investigates the antibacterial efficacy of zeolite composites by using combinations of zinc, manganese, and magnesium ions at concentrations of 1%, 2%, 3%, and 4%. Our assessment of the antibacterial effectiveness was conducted by biofilm inhibition, insitu bacterial colonization, and ion-release tests. The results indicated that the liberation of zinc ions increased from 1.5 parts per million (ppm) at a concentration of 1% to 6.0 ppm at a concentration of 4%. Furthermore, the liberation of manganese ions varied between 2.0 ppm and 6.7 ppm, whereas that of magnesium ions ranged from 1.8 ppm to 5.5 ppm. The biofilm inhibition, as shown by OD570 values, decreased dramatically from 0.85 at 1% to 0.40 at a concentration of 4%. Bacterial viability tests revealed that at a 1% ion concentration, the proportion of damaged cells rose to 60%, while the proportion of viable cells decreased from 70% to 40%. Furthermore, these results indicate that higher ion concentration amplifies the antibacterial activity of the composites, making them very efficient in inhibiting biofilms and deactivating microorganisms. Conclusions of the research suggest that ion-modified zeolite composites might be advantageous for antimicrobial applications in various environments prone to microbial contamination.

Učinkovitost obrade elektrokoagulacije kombinirane s različitim veličinama čestica prirodnog zeolita

In a previous study, the larger size of synthetic zeolite particles was highlighted as better choice for electrocoagulation combined with zeolite (ECZ). This choice resulted in a smaller rise in pH and temperature, a more significant decline in turbidity as well as chemical oxygen demand (COD), and lower electrode wastage, but with greater damage to the electrode surface. The focus of this study was to determine whether natural zeolite of three different particle sizes has the same effect on the ECZ process. The Taguchi method L9 was employed in planning the experiments, with particle sizes of natural zeolite ranging up to 600 μm, three different electrode materials (carbon steel, aluminium alloy, and sacrificial zinc anode), current density in the range of 0.003–0.018 A cm<sup>–2</sup>, and contact time in the range 10–30 min. The Taguchi optimisation results revealed a more significant decrease in COD and turbidity with the smallest particle size of natural zeolite used (90 µm) and with Al electrodes. Evidently, the zeolite particle size, together with the zeolite composition, had a significant influence on the reduction in COD and turbidity. Anode consumption ranged from 0.0172 to 0.6469 g, with minor cathode consumption evident on all electrode materials. Optical microscopy analysis indicated significant corrosion of the anodes, particularly with the largest natural zeolite particle size of 160–600 µm, while minor corrosion damage was also observed on the cathodes.

Influence of feed contamination on the conversion of heavy reformate and toluene over a composite hierarchical zeolite catalyst

The effect of feed contaminants on the conversion of heavy reformate and toluene mixture over a catalyst containing 4 wt% Mo impregnated on a bifunctional hierarchical composite of mordenite and ZSM-5 is reported.

Engineered species-selective ion-exchange in tuneable dual-phase zeolite composites.

Controllable sorption selectivity in zeolites is crucial for their application in catalysis, gas separation and ion-exchange. Whilst existing approaches to achieving sorption selectivity with natural zeolites typically rely on screening for specific geological deposits, here we develop partial interzeolite transformation as a straightforward and highly tuneable method to achieve sorption selectivity via forming dual-phase composites with simultaneous control of both phase-ratio and morphology. The dual-cation (strontium and caesium) exchange properties of a series of granular mordenite/zeolite P composites formed from a parent natural mordenite material are demonstrated in complex, industrially relevant multi-ion environments pertinent to nuclear waste management. The relative uptake of caesium and strontium is controlled via the extent of transformation: composites exhibit significantly increased ion-exchange affinity for strontium compared to both the parent mordenite and physical mixtures of mordenite/zeolite P phases with similar phase ratios. The composite with a 40 : 60 mordenite : zeolite P ratio composite achieves higher uptake rates than the natural clinoptilolite material currently used to decontaminate nuclear waste streams at the Sellafield site, UK. In situ X-ray image-guided diffraction experiments during caesium exchange demonstrate that the mordenite core retains rapid caesium uptake likely responsible for the unique ion-exchange chemistry achievable through the partial inter-zeolite transformation. These results offer a straightforward and controllable route to optimised zeolite functionality and a strategy to engineer composites from low-grade natural sources at low cost and with formulation advantages for industrial deployment.

Oxidative dehydrogenation of propane with the participation of mild oxidants (N2O and СО2) on metal(oxide)-zeolite catalysts

The paper presents the results of the study of textural and acidic characteristics of metal (oxide)-zeolite compositions M-BEA (MTW, MOR, ZSM-5) (М = Ga, Fe, Co, In) and their influence on catalytic properties in the oxidative dehydrogenation of propane to propylene with the participation of CO2 and N2O/ODP-СО2 (N2O). The ODP-N2O process was investigated on indium-, cobalt-, and iron-oxide compositions based on zeolites of structural types BEA, MOR, and ZSM-5 (H-form). The best indices of propylene production were achieved on the sample 10 %Fe2O3/HZSM-5 at the temperature 400 °С: the selectivity of formation and yield of propylene are SС3Н6 = 40 % and YС3Н6 = 21 % at the conversion of С3Н8 – 53 % and N2O – 85 %. In the ODP-СО2 process, among the samples of gallium-containing zeolites of the MTW, BEA, and MOR structure (for the Si/Ga ratio = 15-24), higher indices of selectivity are 70 % and propylene yield – 26 % (at XC3H8 = 37.5 %, 600 °С), were achieved on the Ga5.0MTW catalyst (Si/Ga = 24), which is characterized by a developed mesoporous structure, the largest surface (SBET = 585 m2/g) and the highest concentration of weak, medium and strong acid Lewis sites (according to the FTIR-Py data).

ASSESSMENT OF ZEOLITE USE FOR REMOVAL OF PETROLEUM COMPOUNDS FROM WASTEWATER

ABSTRACT. Zeolites are types of inorganic porous materials that have been widely investigated and applied for their excellent sorption ability for wastewater treatment. Their low cost, safeness, natural abundance and accessibility make them good candidates for a large-scale application. Pollution generated by organic compounds, especially hydrocarbons from oil spills and crude oil refineries emerge as a great concern for aquatic life and the environment. The hydrophobic and highly stable molecules of hydrocarbons determine their persistence toward conventional methods involved in water treatment plants and accidental spills in oceans and seas. This paper presents the works that have been focused on implementation of natural and synthetic zeolites and their modified forms as well as zeolite composites for removal of hydrocarbons from wastewater.

Ionothermal synthesis of ZSM-5/AlPO4-5 composite zeolites and their catalytic performances in the methanol-to-olefin reaction

Ionothermal synthesis of ZSM-5/AlPO4-5 composite zeolites and their catalytic performances in the methanol-to-olefin reaction