Colloidal Silicalite Coating for Improving Ionic Liquid Membrane Loading on Macroporous Ceramic Substrate for Gas Separation

A thin layer of colloidal silicalite was coated on a macroporous alumina substrate to improve the effectiveness in loading and supporting ionic liquid (IL) membrane on macroporous ceramic substrate. The [bmim][BF4] IL and CO2 gas separation were used as the model system in this research. The colloidal silicalite top layer enabled the formation of a pinhole-free IL membrane with significantly reduced load of IL as compared to the bare alumina substrate because the former had a smaller and more uniform inter-particle pore size than the latter. The supported IL membrane was extensively studied for CO2 separation in conditions relevant to coal combustion flue gases. The silicalite-supported IL membrane achieved a CO2/N2 permselectivity of ~24 with CO2 permeance of ~1.0×10-8 mol/m2·s·Pa in dry conditions at 26˚C and reached a CO2/N2 separation factor of ~18 with CO2 permeance of ~1.56×10-8 mol/m2·s·Pa for a feed mixture containing ~11% CO2 and ~9% water vapor at 50oC. This supported IL membrane exhibited excellent stability under a 5-bar transmembrane pressure at 103˚C and chemical resistance to H2O, SO2, and air (O2). Results of this study also indicated that, in order to fully realize the advantages of using the colloidal silicalite support for IL membranes, it is necessary to develop macroporous ceramic supports with optimized pore size distribution so that the IL film can be retained in the micron-thin silicalite layer without penetrating into the base substrate

Zeolite Thin Film-coated Long Period Fiber Grating Sensor for Measuring Trace Chemical

This paper reports the development of a new zeolite thin film-coated long period fiber grating (LPFG) sensor for direct measurement of trace organic vapors. The sensor was fabricated by growing pure silica MFI-type zeolite thin film on the optical fiber grating by in situ hydrothermal crystallization. The sensor measures chemical vapor concentration by monitoring the molecular adsorption-induced shift of LPFG resonant wavelength in near infrared (IR) region. Upon loading analyte molecules, the zeolite\u27s refractive index changes in the close vicinity of the fiber index where the LPFG has a large response to achieve high sensitivity

Synthesis and Characterization of Nanocrystalline (Zr₀.₈₄Y₀.₁₆)O₁.₉₂-(Ce₀.₈₅Sm₀.₁₅)O₁.₉₂₅ Heterophase Thin Films

A new type of nanocrystalline samarium-doped-ceria/yttrium-stabilized-zirconia (SDC/YSZ) heterophase thin film electrolytes was synthesized on MgO and Si substrates by spin coating and thermal treatment of SDC-nanoparticle-incorporated polymeric precursors. In the heterophase films, SDC nanoparticles were uniformly dispersed in a nanocrystalline YSZ matrix. The heterophase structure was stable when fired in air at temperatures up to 850 °C. The nanocrystalline heterophase thin films exhibited electrical conductivities significantly higher than that of the phase-pure YSZ and SDC nanocrystalline thin films at reduced temperatures. The effects of SDC grain size and volume fraction on the electrical conductivity of the heterophase films were also studied

Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor for Detection of Dissolved Organics in Water

A fiber optic intrinsic Fabry-Perot interferometric (IFPI) chemical sensor was developed by fine-polishing a thin layer of polycrystalline nanoporous MFI zeolite synthesized on the cleaved endface of a single mode fiber. The sensor operated by monitoring the optical thickness changes of the zeolite thin film caused by the adsorption of organic molecules into the zeolite channels. The optical thickness of the zeolite thin film was measured by white light interferometry. Using methanol, 2-propanol, and toluene as the model chemicals, it was demonstrated that the zeolite IPFI sensor could detect dissolved organics in water with high sensitivity

Novel modified zeolites for energy-efficient hydrocarbon separations.

We present synthesis, characterization and testing results of our applied research project, which focuses on the effects of surface and skeletal modification of zeolites for significant enhancements in current hydrocarbon (HC) separations. Zeolites are commonly used by the chemical and petroleum industries as catalysts and ion-exchangers. They have high potential for separations owing to their unique pore structures and adsorption properties and their thermal, mechanical and chemical properties. Because of zeolites separation properties, low cost, and robustness in industrial process, they are natural choice for use as industrial adsorbents. This is a multidisciplinary effort to research, design, develop, engineer, and test new and improved materials for the separation of branched vs. linear organic molecules found in commercially important HC streams via adsorption based separations. The focus of this project was the surface and framework modification of the commercially available zeolites, while tuning the adsorption properties and the selectivities of the bulk and membrane separations. In particular, we are interested with our partners at Goodyear Chemical, on how to apply the modified zeolites to feedstock isoprene purification. For the characterization and the property measurements of the new and improved materials powder X-ray diffraction (PXRD), Residual Gas Analyzer-Mass Spectroscopy (RGA-MS), Electron Microscopy (SEM/EDAX), temperature programmed desorption (TPD) and surface area techniques were utilized. In-situ carbonization of MFI zeolite membranes allowed for the maximum separation of isoprene from n-pentane, with a 4.1% enrichment of the binary stream with n-pentane. In four component streams, a modified MFI membrane had high selectivities for n-pentane and 1-3-pentadiene over isoprene but virtually no separation for the 2-methyl-2-butene/isoprene pair

Development of Nano-crystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases

This is a final technical report for the first project year from July 1, 2005 to Jan 31, 2012 for DoE/NETL funded project âDE-FC26-05NT42439: Development of Nanocrystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases.â This report summarizes the technical progresses and achievements towards the development of novel nanocrystalline doped ceramic material-enabled optical fiber sensors for in situ and real time monitoring the gas composition of flue or hot gas streams involved in fossil-fuel based power generation and hydrogen production

Investigations on a Mesoporous Glass Membrane as Ion Separator for a Redox Flow Battery

This article reports extensive studies of a Vycor® porous glass (VPG) membrane as an ion separator for an all-vanadium redox flow battery (VRFB). The VPG membrane had an average pore size of 4 nm and porosity of ~28%. The VPG ion separator exhibited higher proton diffusivity but lower conductivity than the Nafion® 117 membrane because the former is intrinsically nonionic. The VRFB equipped with the VPG ion separator (VPG-VRFB) exhibited much better stability during long-term cyclic operation than the VRFB equipped with the Nafion-117 membrane (Nafion-VRFB) because the ionic Nafion membrane could be contaminated by vanadium ions exchanged into the water channels. This increases its area specific resistance, while the VPG does not have ion exchange capacity and hence has less vanadium ion contamination. The VPG-VRFB was found to outperform the Nafion-VRFB in energy efficiency (EE) during long-term cyclic operation although the former underperformed the latter in the initial period of continued operation. The VPG ion separator also showed markedly better thermal stability and temperature tolerance than the Nafion membrane as indicated by the significantly smaller losses of EE and discharge capacity for the VPG-VRFB than for the Nafion-VRFB after operating at 45 °C. The outstanding temperature tolerance of the VPG ion separator is due primarily to its rigid and non-swelling pore structure and nonionic nature, which are highly resistant to thermal distortion and vanadium ion contamination. The excellent temperature tolerance of the VPG may be useful for applications where temperature control is difficult

Nanocrystalline Cu-doped Zirconia Film-coated Long-period Fiber Grating for CO Monitoring at High Temperature

Dense nanocrystalline copper-doped zirconia (CDZ, Cu:Zr=16:84) thin film was coated on the surface of a 125 µm-diameter long-period fiber grating (LPFG) by a facile synthesis route involving polymeric precursor coating and subsequent thermal treatments. The CDZ film had a uniform thickness of ~100 nm and grain size of 20 to 35 nm after a brief annealing step at 700°C for 1 hour. This CDZ thin film coated LPFG (CDZ-LPFG) was evaluated at a high temperature of 550°C for its change of resonant wavelength (R) in response to the variation of carbon monoxide (CO) concentration in nitrogen (N2). The R was found to shift toward longer wavelength when increasing the CO concentration. The CDZ-LPFG sensor response was found to be reproducible and reversible at low level CO concentrations (\u3c1,000 ppm) but became irreversible when the CO concentration was high (e.g. at 10,000 ppm). The high temperature stability of the CDZ material in CO-containing atmospheres was studied to understand the limit of CO measurement range