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Zeolite Membrane

Michael Z Hu, Chaiwat Engtrakul, Brian L Bischoff, Mi Lu, Mussie Alemseghed
Surface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc form) were prepared and studied for both vapor-phase separation and liquid pervaporative separations of water-ethanol mixtures. Superhydrophobic nanoceramic membranes demonstrated more selective permeation of ethanol (relative to water) by cross-flow pervaporation of liquid ethanol⁻water mixture (10 wt % ethanol feed at 80 °C). In addition, both superhydrophilic and superhydrophobic membranes were tested for the vapor-phase separations of water⁻ethanol mixtures...
October 12, 2018: Membranes
Sun-Jie Xu, Qian Shen, Gui-E Chen, Zhen-Liang Xu
Organic solvent nanofiltration (OSN) membranes are always troubled by the "trade-off" effect between solvent flux and solute rejection. Hence, a rapid, convenient, and effective way to synthesize novel β-cyclodextrin-enhanced zeolite imidazole framework-8 (β-CD@ZIF-8) nanoparticles was first proposed and the nanoparticles were doped into both selective layer and poly( m -phenylene isophthalamide) support for fabricating thin-film nanocomposite membranes. Transmission/scanning electron microscopy images and X-ray photoelectron spectroscopy results demonstrate the successful synthesis of β-CD@ZIF-8...
September 30, 2018: ACS Omega
Hasan Irvani, Mojtaba Nakhaei Pour, Ali Vahidi, Somayeh Arezoomandan, Hosein Shojaee-Farah Abady
Toluene is a colorless and flammab1le liquid with the same solubilizing capacity as benzene that is in many cases used as an alternative to benzene, because of the uncertainty of being carcinogens. Workers can be exposed to toluene by breathing the chemical. To avoid inhalation and dermal effects caused by exposure to toluene, solutions such as adsorption, thermal oxidation, membrane separation and photocatalytic processes are applied. In this study, removal of toluene vapors with modified natural zeolite and titanium dioxide nanoparticles was discussed...
July 2018: Medical Gas Research
Changlong Zou, Li-Chiang Lin
Molecular dynamics simulations are employed to demonstrate the potential of zeolite nanosheets as pervaporation membranes for ethanol extraction. Our results show that zeolite nanosheets can provide orders of magnitude higher fluxes compared to currently available membranes and achieve outstanding separation factors. The dominant role of membrane surfaces in determining the separation performance is also identified and explored at an atomic level. Developing nanosheet membranes with hydrophobic surfaces and/or with a minimal surface silanol density represents the keys to enable highly selective separation processes...
October 11, 2018: Chemical Communications: Chem Comm
Ravi C Dutta, Suresh K Bhatia
We use atomistic simulations of CH4, H2 and CO2 transport to elucidate the effect of internal interfacial barriers on gas transport within nanoscale zeolite crystals of different morphology; such barriers are shown here to have critical significance for the performance of ultrathin membranes and nanoscale mixed matrix composite membranes for gas separation. These interfacial resistances are seen to be confined to a narrow region within the zeolite, adjacent to the phase boundary, and are distinct from the external fluid phase resistance...
October 11, 2018: Physical Chemistry Chemical Physics: PCCP
Paul J Dauenhauer, Omar A Abdelrahman
Confinement of hydrocarbons in nanoscale pockets and pores provides tunable capability for controlling molecules in catalysts, sorbents, and membranes for reaction and separation applications. While computation of the enthalpic interactions of hydrocarbons in confined spaces has improved, understanding and predicting the entropy of confined molecules remains a challenge. Here we show, using a set of nine aluminosilicate zeolite frameworks with broad variation in pore and cavity structure, that the entropy of adsorption can be predicted as a linear combination of rotational and translational entropy...
September 26, 2018: ACS Central Science
Jorge Escorihuela, Óscar Sahuquillo, Abel García-Bernabé, Enrique Giménez, Vicente Compañ
The preparation and characterization of composite polybenzimidazole (PBI) membranes containing zeolitic imidazolate framework 8 (ZIF-8) and zeolitic imidazolate framework 67 (ZIF-67) is reported. The phosphoric acid doped composite membranes display proton conductivity values that increase with increasing temperatures, maintaining their conductivity under anhydrous conditions. The addition of ZIF to the polymeric matrix enhances proton transport relative to the values observed for PBI and ZIFs alone. For example, the proton conductivity of PBI@ZIF-8 reaches 3...
September 29, 2018: Nanomaterials
Abdelaziz Elgamouz, Najib Tijani
The data presented in this article are generated as part of the research article entitled "from a naturally occurring material (clay mineral) to the production of porous ceramic membranes" (Elgamouz and Tijani, 2018) [1]. This article describe how clays as very abundant versatile materials that have many properties not available in pure materials namely, silica, alumina and zirconia can be used for the preparation of ceramic membranes (Karaborni et al., 1996; Oun et al., 2017; Hollanders et al., 2016; de Oliveira Henriques et al...
August 2018: Data in Brief
Xiaotong Zhang, Ying Yan
Catalytic combustion of isopropanol in the structured fixed-bed reactor was investigated over Co-ZSM-5 zeolite membrane catalysts. Firstly, ZSM-5 zeolite membrane catalysts with different Si/Al ratios were coated onto the surface of stainless steel fibres via secondary growth method and wet lay-up paper-making method. Then, cobalt oxides were loaded onto the zeolite membranes by impregnation method. The performance of catalytic combustion of isopropanol was conducted over the prepared zeolite membrane catalysts, and the experimental results showed that the catalyst with infinite Si/Al ratio has the highest catalytic activity for the combustion with the lowest T 90 of isopropanol (285°C)...
August 2018: Royal Society Open Science
Gokay Avci, Sadiye Velioglu, Seda Keskin
Metal organic frameworks (MOFs) have emerged as great adsorbent and membrane candidates for separation of CO2 /H2 mixtures. The main challenge is the existence of thousands of MOFs, which requires computational screening methods to identify the best materials prior to experimental efforts. In this study, we performed high-throughput computational screening of MOFs to examine their adsorbent and membrane performances for CO2 /H2 separation. Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were used to compute various adsorbent and membrane performance metrics of 3857 MOFs...
October 3, 2018: ACS Applied Materials & Interfaces
Xiaoli Ma, Prashant Kumar, Nitish Mittal, Alexandra Khlyustova, Prodromos Daoutidis, K Andre Mkhoyan, Michael Tsapatsis
Zeolitic imidazolate framework (ZIF) membranes are emerging as a promising energy-efficient separation technology. However, their reliable and scalable manufacturing remains a challenge. We demonstrate the fabrication of ZIF nanocomposite membranes by means of an all-vapor-phase processing method based on atomic layer deposition (ALD) of ZnO in a porous support followed by ligand-vapor treatment. After ALD, the obtained nanocomposite exhibits low flux and is not selective, whereas after ligand-vapor (2-methylimidazole) treatment, it is partially transformed to ZIF and shows stable performance with high mixture separation factor for propylene over propane (an energy-intensive high-volume separation) and high propylene flux...
September 7, 2018: Science
Guangwei He, Deepu J Babu, Kumar Varoon Agrawal
We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol...
August 16, 2018: Journal of Visualized Experiments: JoVE
R Sabarish, G Unnikrishnan
In this work, efficient biodegradable membranes were fabricated using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC) and ZSM-5 zeolite, and their utility for the removal of a cationic dye, methylene blue (MB), was investigated. The physical properties of the membranes were assessed by FTIR, XRD, UTM, SEM, optical microscopy and thermogravimetry. The influence of various parameters viz., zeolite loading, initial dye concentration, temperature and contact time on the dye removal capability of the membranes was investigated...
November 1, 2018: Carbohydrate Polymers
Xiaobin Tang, Xiaoxiang Cheng, Xuewu Zhu, Binghan Xie, Yuanqing Guo, Jinlong Wang, An Ding, Guibai Li, Heng Liang
Ultra-low pressure gravity-driven membrane (GDM) filtration has been proposed as a cost-efficiency alternative for the decentralized drinking water supply in terms of its simple operation and low energy consumptions, whereas its undesirable removals of dissolved organic compounds (DOC) and relatively low flux impede its widespread application. In order to improve its filtration performance, filter media (granular activated carbon (GAC), zeolite and bio-ceramsite) was directly coated on the membrane surface to engineer an integrated GDM system...
November 2018: Chemosphere
Hilal Daglar, Seda Keskin
It has become a significant challenge to select the best metal-organic frameworks (MOFs) for membrane-based gas separations because the number of synthesized MOFs is growing exceptionally fast. In this work, we used high-throughput computational screening to identify the top MOF membranes for flue gas separation. Grand canonical Monte Carlo and molecular dynamics simulations were performed to assess adsorption and diffusion properties of CO2 and N2 in 3806 different MOFs. Using these data, selectivities and permeabilities of MOF membranes were predicted and compared with those of conventional membranes, polymers, and zeolites...
August 2, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Mitali Sen, Kausik Dana, Nandini Das
In this work, sodium aluminosilicate zeolite powder and membranes were synthesized by ultrasonic irradiation at room temperature using montmorillonite clay as precursor material. For comparison, same zeolite powder and membranes were synthesized at 100 °C also. The synthesized zeolites were characterized by X-ray diffraction (XRD), infrared (IR) spectral analysis, and field-emission scanning electron microscopy (FESEM). XRD and IR results showed that phase pure mainly LTA phase was formed after 15 days of aging at room temperature...
November 2018: Ultrasonics Sonochemistry
Mahdi Ahmadi, Saravanan Janakiram, Zhongde Dai, Luca Ansaloni, Liyuan Deng
Application of conventional polymeric membranes in CO₂ separation processes are limited by the existing trade-off between permeability and selectivity represented by the renowned upper bound. Addition of porous nanofillers in polymeric membranes is a promising approach to transcend the upper bound, owing to their superior separation capabilities. Porous nanofillers entice increased attention over nonporous counterparts due to their inherent CO₂ uptake capacities and secondary transport pathways when added to polymer matrices...
July 28, 2018: Membranes
Mohd Ridhwan Adam, Norliyana Mohd Salleh, Mohd Hafiz Dzarfan Othman, Takeshi Matsuura, Mohd Hafizi Ali, Mohd Hafiz Puteh, A F Ismail, Mukhlis A Rahman, Juhana Jaafar
Adsorption is one of the most efficient ways to remove heavy metal from wastewater. In this study, the adsorptive removal of hexavalent chromium, Cr (VI) from aqueous solution was investigated using natural zeolite, clinoptilolite, in the form of hollow fibre ceramic membrane (HFCM). The HFCM sample was prepared using phase inversion-based extrusion technique and followed by sintering process at different sintering temperatures in the range of 900-1050 °C. The fabricated HFCM was characterised using scanning electron microscopy (SEM), contact angle, water permeability, and mechanical strength for all HFCMs sintered at different temperatures...
October 15, 2018: Journal of Environmental Management
Donglong Fu, Joel E Schmidt, Paul Pletcher, Pelin Karakiliç, Xinwei Ye, Carolien M Vis, Pieter C A Bruijnincx, Matthias Filez, Laurens D B Mandemaker, Louis Winnubst, Bert M Weckhuysen
Facile fabrication of well-intergrown, oriented zeolite membranes with tunable chemical properties on commercially proven substrates is crucial to broadening their applications for separation and catalysis. Rationally determined electrostatic adsorption can enable the direct attachment of a b-oriented silicalite-1 monolayer on a commercial porous ceramic substrate. Homoepitaxially oriented, well-intergrown zeolite ZSM-5 membranes with a tunable composition of Si/Al=25-∞ were obtained by secondary growth of the monolayer...
July 24, 2018: Angewandte Chemie
Akshay Modi, Surendra Kumar Verma, Jayesh Bellare
The hydrophobic nature of zeolitic imidazole framework-8 (ZIF-8) nanoparticles restricts their use as additives in hollow fiber membranes (HFMs) for biomedical applications. In this study, hydrophilic ZIF-8 decorated graphene oxide nanosheets (ZGs) were synthesized and used as additives (0-1 wt%) in polyethersulfone (P) HFMs with the aim of improving the biocompatibility and separation performance so as to make the ZGP HFMs suitable for bioartificial liver (BAL) application. Elemental mapping and Fourier transform infrared studies confirmed the efficacious incorporation of ZG nanohybrids in the ZGP HFMs, which resulted in their improved hydrophilicity...
October 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
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